JP3424372B2 - Noise reduction device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise reduction device for satisfactorily removing noise components contained in a video signal without damaging the original video signal.

[0002]

2. Description of the Related Art As a noise reduction device, a cyclic type, which utilizes the fact that a video signal has a high autocorrelation in the time direction, but a noise component has almost no autocorrelation,
There is a non-recursive noise reducer, or a noise reducer using a coring circuit that clips a high-frequency minute component and improves S / N.

As a typical non-recursive type and cyclic type S / N improving device, for example, "Blow-out, digital signal processing of image, Nikkan Kogyo Shimbun, p115-118" is shown. Figure
36 is a block diagram of this conventional one-frame cyclic noise reduction device, in which 500 is an input terminal for inputting a video signal, 501 is an adder, and 502 is an output for outputting a video signal with reduced noise. Terminal, 503 is a non-linear limiter, 504 is a frame memory that delays the input video signal by one screen, 5
Reference numeral 05 is a subtractor for finding the difference between the input signal and the output of the frame memory 504. FIG. 37 shows an example of the characteristic of the nonlinear limiter 503 in FIG.

In the conventional cyclic noise reduction apparatus configured as described above, first, the difference between the video signal input to the input terminal 500 and the video signal one frame before output from the frame memory 504 is subtracted. It is calculated by the device 505. If the input signal is a completely static image, the output of the subtractor 505 is noise that has no temporal correlation, and this signal is multiplied by an appropriate gain of 1 or less and added by the adder 501 with the original input signal. By doing so, a video signal with reduced noise can be obtained from the output terminal 502.

On the other hand, when the input signal is a moving image, the subtractor 50
The output of 5 contains a motion component in addition to noise, and motion blur will occur if the adder 501 adds it to the input signal as it is. Therefore, the non-linear limiter 503 outputs a signal based on the input only when the output of the subtractor 505 is within a range of ± 2a as shown in the characteristic shown in FIG. The output of the nonlinear limiter 503 thus obtained and the signal input to the input terminal 500 are added by an adder.
By adding at 501, a signal subjected to noise reduction adapted to the motion of the image is obtained from the output terminal 502. At the same time, the output of the adder 501 is input to the frame memory 504 and 1
The difference from the input signal of the next frame after being delayed by the frame is obtained by the subtractor 505, and the S / N of the input video signal is improved by repeating the above processing.

That is, when the difference signal between one frame is small, it is regarded as noise and noise reduction is performed, and when it is large, it is regarded as motion and noise reduction is not performed to prevent multi-line blurring of a moving portion. In FIG. 37, a
As the value of is increased, the range in which noise reduction is applied increases, so the S / N improvement amount increases, but motion blur also increases.

FIG. 38 is a block diagram of a noise reduction device using a conventional coring circuit. The noise reduction device using the coring circuit shown in Fig. 38 is a noise reducer in the same field without processing in the time direction.
This is an example.

In FIG. 38, 510 is an input terminal for inputting a video signal, 511 is an adder, 512 is an output terminal for outputting a noise-reduced video signal, 513 is a low-pass filter, 514 is a subtractor, and 515 is non-linear. It is a limiter. FIG. 37 shows an example of the characteristic of the non-linear limiter 515 in FIG.

In the noise reduction device using the conventional coring circuit configured as described above, first, the input terminal 51 is used.
The low-pass filter 513 extracts low-frequency components from the video signal input to 0. The subtractor 514 calculates the difference between the output of the low-pass filter 513 and the video signal input from the input terminal 510. The output of the subtractor 514 is a high frequency component and a high frequency noise component of the input video signal. Next, the non-linear limiter 515 outputs a signal based on the input only when the output of the subtractor 514 is within ± 2a as shown in the characteristic shown in FIG. The output of the nonlinear limiter 515 thus obtained and the input terminal 510
By adding the signals input to the adder 511,
A noise-reduced signal is obtained from output terminal 512.

That is, when the output of the subtractor 514 is small, it is regarded as noise and noise reduction is performed, and when it is large, it is regarded as the original signal component and noise reduction is not performed, thereby blurring the high-frequency component of the original video signal. It is preventing. In FIG. 37, as the value of a is increased, the range in which noise reduction is applied increases, and thus the S / N improvement amount increases, but the original high frequency component of the video signal also increases in blur.

[0011]

However, in the configuration of the noise reducing apparatus utilizing the correlation in the time direction as described above, since it is determined whether the signal is a motion signal or noise based on the level of the differential signal between frames, the amplitude In a video signal including a small motion, the motion is determined to be noise, and a slight motion image blur occurs. Further, in the configuration of the noise reduction device using the coring circuit as described above, since it is determined whether the high-frequency component or the noise is determined by the level of the high-frequency component, it is high in the video signal including the high-frequency component of small amplitude. The range component is determined to be noise, and the minute component of the original video signal is blurred.

Further, in a video system provided with a non-linear operation means for suppressing a low level signal of the video signal, it is more difficult to separate the signal and noise in the low level area than in the high level area. Particularly in a natural image such as a landscape, a fine signal component is often included in a region having a low luminance level and a light color, and it is a problem to improve the S / N by minimizing the blur. there were.

That is, in the configuration of the conventional noise reduction device,
Blurring of the video signal has occurred because the discrimination between the signal and the noise in the low signal level region was insufficient. In order to suppress these blurs, it is necessary to reduce the S / N improvement amount by reducing the value of a in the characteristic of the nonlinear limiter shown in FIG. There was a problem that the N improvement effect was reduced.

In view of the above point, the present invention has an object to provide a noise reducing apparatus which suppresses blurring due to movement of an area having a low signal level and blurring of a high frequency component in an area having a low signal level and improves S / N. To do.

[0015]

[Means for Solving the Problems] To achieve the above object
According to the present invention, a noise reducer capable of inputting a video signal and varying an S / N improvement amount with respect to the input video signal, and an absolute luminance signal level and a color difference signal input by inputting the video signal. and S / N improving amount control signal generation means to output for each pixel a signal corresponding to at least one of the values levels, low outputs those inputs the luminance signal of the video signal of a level lower than a predetermined value Level signal detecting means, high-frequency component detecting means for detecting the high-frequency component of the video signal by inputting the video signal, and output of the low-level signal detecting means and high-frequency component detecting means for input signals Logic means for outputting a signal only when a high level component is detected at a low level, a counter for counting the number of outputs of the logic means in a predetermined video section with the output of the logic means as an input, A threshold value means for receiving the output of the counter and comparing it with a predetermined value to output a magnitude relationship, and the output of the S / N improvement amount control signal generating means is the luminance signal level and the absolute value level of the color difference signal. When it is low, a control signal for reducing the S / N improvement amount of the noise reducing means is output, and the output of the S / N improvement amount control signal generating means outputs a large S / N improvement amount by the output of the threshold value means. The noise reduction device is characterized by controlling so that

In order to achieve the above object, the present invention is provided with a noise reducing means capable of inputting a video signal and varying an S / N improvement amount with respect to the input video signal, and inputting the video signal. and S / N improving amount control signal generation means to output a signal corresponding to at least one for each pixel of the absolute value level of the luminance signal level and color-difference signals, the predetermined value inputted luminance signal of the video signal Low-level signal detection means for outputting a low-level signal, a first counter for counting the number of pixels determined to be low-level in a predetermined video section with the output of the low-level signal detection means as input, and the video signal Is input to the high-frequency component detecting means for detecting the high-frequency component of the video signal, and the outputs of the low-level signal detecting means and the high-frequency component detecting means are input, and the input signal is low level and high-frequency. A logic means for outputting a signal only when a component is detected, a second counter which receives the output of the logic means as an input and counts the number of outputs of the logic means in a predetermined video section, and an output of the first counter And the second
The S / N improvement amount is provided with division means for inputting the output of the counter to obtain the ratio of the two, and threshold means for inputting the output of the division means and outputting a magnitude relation by comparing with a predetermined value. The output of the control signal generating means outputs a control signal for reducing the S / N improvement amount of the noise reducing means when the luminance signal level and the absolute value level of the color difference signals are low, and the S value is output by the threshold value means. The output of the / N improvement amount control signal generating means is a noise reduction device characterized by controlling so that the S / N improvement amount becomes large.

In order to achieve the above object, the present invention has a noise reducing means for inputting a video signal and varying an S / N improvement amount with respect to the input video signal, and for inputting the video signal. and S / N improving amount control signal generation means to output a signal corresponding to at least one for each pixel of the absolute value level of the luminance signal level and color-difference signals, the predetermined value inputted luminance signal of the video signal Low-level signal detecting means for outputting a low-level signal, motion detecting means for detecting a motion in at least one field period, low-level signal detecting means and an output of the motion detecting means as input and a low-level input signal And a logic means for outputting a signal only in the case of movement, a counter for counting the number of outputs of the logic means in a predetermined video section with the output of the logic means as an input, and the counter. A threshold value means for receiving the output of the counter as an input and comparing it with a predetermined value to output a magnitude relation, and the output of the S / N improvement amount control signal generating means has a luminance signal level and an absolute value level of the color difference signal When it is low, a control signal for reducing the S / N improvement amount of the noise reducing unit is output, and the output of the S / N improvement amount control signal generating unit outputs a large S / N improvement amount by the output of the threshold value unit. The noise reduction device is characterized by controlling so that

In order to achieve the above object, the present invention has a noise reducing means for inputting a video signal and varying an S / N improvement amount with respect to the input video signal, and inputting the video signal for input. and S / N improving amount control signal generation means to output a signal corresponding to at least one for each pixel of the absolute value level of the luminance signal level and color-difference signals, the predetermined value inputted luminance signal of the video signal Low-level signal detecting means for outputting a low-level signal, a first counter for counting the number of pixels determined to be low-level in a predetermined video section with the output of the low-level signal detecting means as an input, and at least one field Motion detection means for detecting movement during a period, the low-level signal detection means and the outputs of the motion detection means are input, and a signal is output only when the input signal is at a low level and is in motion. Inputting the output of the logic means, a second counter that receives the output of the logic means and counts the number of outputs of the logic means in a predetermined video section, and the output of the first counter and the output of the second counter The output of the S / N improvement amount control signal generating means includes a dividing means for obtaining the ratio of the both and a threshold means for receiving the output of the dividing means as an input and comparing it with a predetermined value to output a magnitude relationship. Outputs a control signal for reducing the S / N improvement amount of the noise reducing means when the luminance signal level and the absolute value level of the color difference signal are low, and outputs the S / N improvement amount control signal by the output of the threshold value means. An output of the generation means is a noise reduction device characterized by controlling so that the S / N improvement amount becomes large.

In order to achieve the above-mentioned object, the present invention has a noise reducing means for inputting a video signal and varying the S / N improvement amount with respect to the input video signal, and for inputting the video signal. and S / N improving amount control signal generation means to output a signal corresponding to at least one for each pixel of the absolute value level of the luminance signal level and color-difference signals, the predetermined value inputted luminance signal of the video signal Low level signal detecting means for outputting a low level signal, motion detecting means for detecting a motion in at least one field period, and high frequency component detecting means for receiving the video signal and detecting a high frequency component of the video signal And the output of the low-level signal detecting means, the output of the motion detecting means, and the output of the high-frequency component detecting means are input, and a signal is output only when the input signal is at a low level and the high-frequency component is moving. Logic means, a counter that receives the output of the logic means as an input and counts the number of outputs of the logic means in a predetermined video section, and a threshold value that outputs the counter and outputs a magnitude relationship by comparing with a predetermined value. Means for outputting the control signal for decreasing the S / N improvement amount of the noise reducing means when the luminance signal level and the absolute value level of the color difference signal are low. However, the noise reduction device is characterized in that the output of the S / N improvement amount control signal generation unit is controlled by the output of the threshold value unit so that the S / N improvement amount becomes large.

In order to achieve the above object, the present invention is provided with a noise reducing means for inputting a video signal and varying an S / N improvement amount with respect to the input video signal, and for inputting the video signal. and S / N improving amount control signal generation means to output a signal corresponding to at least one for each pixel of the absolute value level of the luminance signal level and color-difference signals, the predetermined value inputted luminance signal of the video signal Low-level signal detection means for outputting a low-level signal, a first counter for counting the number of pixels determined to be low-level in a predetermined video section with the output of the low-level signal detection means as an input, and at least one field Motion detection means for detecting movement during a period, high frequency component detection means for detecting the high frequency component of the video signal by inputting the video signal, the low level signal detection means, and Logic means for inputting the output of the detection means and the output of the high frequency component detection means and outputting a signal only when the input signal is at a low level and the movement of the high frequency component, and the output of the logic means A second counter for counting the number of outputs of the logic means in the video section, a division means for inputting the output of the first counter and the output of the second counter, and an output of the division means And a threshold value means for outputting a magnitude relation by comparing with a predetermined value when the luminance signal level and the absolute value level of the color difference signal are low. A control signal for reducing the S / N improvement amount of the noise reducing means is output, and the output of the S / N improvement amount control signal generating means is increased by the output of the threshold value means. Control A noise reduction device characterized by the above.

[0021]

According to the present invention, when the number of pixels of the high frequency component having a low signal level does not exceed the threshold value in a predetermined video section, blurring of the high frequency component is less likely to occur. And a color difference signal having an absolute value level that does not control the S / N improvement amount of the noise reducer according to at least one of the absolute values of the color difference signals. Then, S / N is improved on the entire screen.

According to the present invention, when the ratio of the high frequency component in the low signal level area does not exceed the threshold value, the high frequency component is less likely to be blurred. Since the control for suppressing the S / N improvement amount of the noise reducer according to at least one of the absolute value levels of the signal is not performed, the proportion of high frequency components in the low signal level area is small. On the screen, S / N improvement is applied to the entire screen.

According to the present invention, when the number of pixels of the motion component having a low signal level does not exceed the threshold value in the predetermined video section, the motion amount is small and the motion blur is less likely to occur. An image in which the number of pixels of the motion component having a low signal level is small is configured by not performing the control for suppressing the S / N improvement amount of the noise reducer according to at least one of the level and the absolute value level of the color difference signal. Then, S / N is improved on the entire screen.

According to the present invention, when the ratio of the motion component in the low level area does not exceed the threshold value, the motion amount is small and blurring due to the motion is less likely to occur. A screen having a small proportion of motion components in a region where the signal level is low is configured by not performing control for suppressing the S / N improvement amount of the noise reducer according to at least one of the absolute value levels of the signal. Then, S / N is improved on the entire screen.

According to the present invention, due to the above-mentioned configuration, when the number of pixels of high frequency component movement having a low signal level does not exceed the threshold value in a predetermined video section, there is little movement, but blurring due to the movement may occur. Since the amount of the noise reduction is small, the control for suppressing the S / N improvement amount of the noise reducer according to at least one of the luminance signal level and the absolute value level of the color difference signal is not performed, so that a high frequency component with a low signal level is obtained. For images with a small number of pixels in motion,
S / N improvement is applied to the entire screen.

According to the present invention, according to the above-mentioned configuration, when the ratio of the high-frequency component motion component in the low signal level region does not exceed the threshold value, the motion is small, but the motion blur is less likely to occur. Therefore, in a region where the signal level is low, the control is not performed to suppress the S / N improvement amount of the noise reducer according to at least one of the luminance signal level and the absolute value level of the color difference signal. On a screen in which the proportion of high-frequency component movement is low, S / N improvement is applied to the entire screen.

[0027]

Figure 1 DETAILED DESCRIPTION OF THE INVENTION (Embodiment 1) shows a block diagram of a noise reduction apparatus in the first embodiment. In FIG. 1, 1 is an input terminal for inputting a video signal, 5 is an S / N improvement amount control signal generation circuit, 6 is a subtractor, 7 is a non-linear limiter, 8 is an adder, and 9 is a frame of video. 1 is a frame memory, 10 is an output terminal for outputting a noise-reduced signal, and 11 is a cyclic noise reduce circuit whose S / N improvement amount is variable. The configuration of the S / N improvement amount control signal generation circuit 5 in FIG. 1 is shown in FIG. Figure
In 2, reference numeral 31 is an input terminal, 4 is an absolute value circuit for obtaining an absolute value of a color difference signal (RY, BY signal) of the input signal,
34 is the minimum value circuit that outputs the smaller of the absolute values of the two types of color difference signals that are input as the C signal, and 35 is the luminance signal (Y signal) of the input signals that is input 1, a Y signal threshold circuit that outputs 0 when it is smaller, 36 is a C signal threshold circuit that outputs 1 when the input C signal is greater than a preset threshold value, and outputs 0 when it is smaller, 37 is a Y signal threshold circuit 35
And an output of the C signal threshold circuit 36 as inputs, and a YC level control circuit for generating a signal for controlling the nonlinear limiter 7, and 38 is an output terminal of the S / N improvement amount control signal generation circuit 5. The operation of the noise reduction device of this embodiment configured as described above will be described below.

First, the operation of the noise reduce circuit 11 will be described. The subtracter 6 obtains the difference between the video signal input to the input terminal 1 and the video signal one frame before output from the frame memory 9. The non-linear limiter 7 applies an appropriate gain of 1 or less to the difference signal between the frames output from the subtractor 6, and the original input signal is added by the adder 8 The level difference is reduced.
The output of the adder 8 is the output of the noise reducing circuit, and at the same time, the output of the adder 8 is input to the frame memory 9 and the above process is repeated for the next frame. If the input signal is a completely static image, the output of the subtractor 6 is noise that has no temporal correlation, so a video signal with reduced noise can be obtained from the output terminal 10, but the input signal is a moving image. In the case of, since the output of the subtractor 6 includes a motion component in addition to noise, motion blur occurs. Therefore, the motion blur is reduced by setting the characteristics of the non-linear limiter 7 as shown in FIG. That is, when the difference signal between 1 frames is small, it is regarded as noise and noise reduction is applied,
If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 5.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the operation of the S / N improvement amount control signal generation circuit 5 for controlling the non-linear limiter 7 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 31 of the improvement amount control signal generation circuit 5, the Y signal is input to the Y threshold circuit 35. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then by the minimum value circuit 34, and the minimum value of them is input to the C threshold circuit 36. Y threshold circuit
35 and the C threshold circuit 36 output 1 if the input signal is larger than a preset threshold value, and output 0 if it is smaller. The signals binarized by the Y threshold circuit 35 and the C threshold circuit 36 are input to the YC level circuit 37. The YC level circuit 37 outputs a signal for controlling the non-linear limiter 7 based on the characteristics shown in FIG.

[0030] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 5, the S / N improvement amount in the region where the luminance signal level is low and the saturation level of the color signal is low is smaller than that in the region where the luminance signal level is high and the saturation level of the color signal is high. By doing so, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to the noise reducer is suppressed. N improvement can be performed. That is, the S / N improving effect can be obtained in the bright region while suppressing the blurring of the low level signal.

(Second Embodiment) FIG. 5 is a block diagram of a noise reduction device according to a second embodiment . In FIG. 5, 1 is an input terminal for inputting a video signal, 5 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, and 41 is a non-cyclic noise reduce circuit whose S / N improvement amount is variable. S / in Figure 5
The configuration of the N improvement amount control signal generation circuit 5 is shown in FIG. In FIG. 2, 31 is an input terminal, 4 is a color difference signal (R
-Y, BY signal) absolute value circuit for obtaining the absolute value of the signal, 34 is the absolute value of the two types of color difference signals input, and the smaller one is C
A minimum value circuit for outputting as a signal, 35 is a Y signal threshold circuit for inputting a luminance signal (Y signal) in the input signal and outputting 1 when it is larger than a preset threshold value, and 0 when it is smaller than the preset threshold value, 36 Is a C signal threshold circuit that outputs 1 if the input C signal is larger than a preset threshold value, and outputs 0 if it is smaller. 37 is the output of the Y signal threshold circuit 35 and the C signal threshold. The YC level control circuit 38 receives the output of the value circuit 36 and generates a signal for controlling the non-linear limiter 44, and 38 is an output terminal of the S / N improvement amount control signal generation circuit 5. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The operation of the noise reduce circuit 41 will be described. Video signal input to input terminal 1 and frame memory 4
The subtractor 43 obtains the difference from the video signal delayed by one frame by 2. The non-linear limiter 44 applies an appropriate gain of 1 or less to the difference signal between the frames output from the subtractor 43, and the original input signal is added by the adder 45 to obtain the signal between the frames. The level difference is reduced. The output of the adder 45 becomes the output of the noise reduce circuit. If the input signal is a completely static image, the output of the subtractor 43 is noise that has no temporal correlation, so a video signal with reduced noise can be obtained from the output terminal 10, but the input signal is a moving image. In this case, the output of the subtractor 43 includes a motion component in addition to noise, so that motion blur occurs. Therefore,
Motion blur is reduced by setting the characteristics of the nonlinear limiter 44 as shown in FIG. That is, when the difference signal between 1 frames is small, it is regarded as noise and noise reduction is performed, and when it is large, it is regarded as motion and noise reduction is not performed, so that multi-line blurring of a moving part is prevented. Furthermore, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 5. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the operation of the S / N improvement amount control signal generation circuit 5 for controlling the non-linear limiter 44 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 31 of the improvement amount control signal generation circuit 5, the Y signal is input to the Y threshold circuit 35. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then by the minimum value circuit 34, and the minimum value of them is input to the C threshold circuit 36. Y threshold circuit
35 and the C threshold circuit 36 output 1 if the input signal is larger than a preset threshold value, and output 0 if it is smaller. The signals binarized by the Y threshold circuit 35 and the C threshold circuit 36 are input to the YC level circuit 37. The YC level circuit 37 outputs a signal for controlling the non-linear limiter 44 based on the characteristic shown in FIG.

[0034] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 5, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low compared to the area where the luminance signal level is high and the saturation degree of the color signal is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. It is possible to perform an appropriate S / N improvement. That is, the S / N improving effect can be obtained in the bright region while suppressing the blurring of the low level signal.

(Third Embodiment) FIG. 6 is a block diagram of a noise reduction apparatus according to the third embodiment . In FIG. 6, 1 is an input terminal for inputting a video signal, 5 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 53 is a subtractor, 54 is a non-linear limiter, and 55 is an addition. , 52 is a low-pass filter that passes the low-frequency component of the input signal, 10 is an output terminal that outputs a signal with reduced noise, and 51 is a noise reduce circuit that uses a coring circuit with a variable S / N improvement amount. is there.
FIG. 6 shows the configuration of the S / N improvement amount control signal generation circuit 5 in FIG.
Shown in 2. In FIG. 2, 31 is an input terminal, 4 is an absolute value circuit for obtaining the absolute value of color difference signals (RY, BY signals) of the input signals, and 34 is the smaller of the absolute values of the two types of input color difference signals. Is a minimum value circuit that outputs as a C signal, and 35 is a Y signal threshold circuit that inputs a luminance signal (Y signal) of the input signals and outputs 1 when it is larger than a preset threshold value, and outputs 0 when it is smaller. , 36 is a C signal threshold circuit that outputs 1 when the input C signal is larger than a preset threshold value, and outputs 0 when it is smaller, 37 is the output of the Y signal threshold circuit 35 and the C signal The YC level control circuit 38 receives the output of the threshold circuit 36 as an input and generates a signal for controlling the nonlinear limiter 54, and 38 is an output terminal of the S / N improvement amount control signal generation circuit 5. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The operation of the noise reduce circuit 51 will be described. The subtracter 53 calculates the difference between the video signal input to the input terminal 1 and the output of the low pass filter 52. This signal is a high frequency component of the input video signal. The high frequency component signal of the input video signal output from the subtractor 53 is multiplied by an appropriate gain of 1 or less by the non-linear limiter 54 and added to the original input signal by the adder 55 to obtain the high frequency component. Is obtained, and the output of the adder 55 becomes the output of the noise reduce circuit. In the noise reducing circuit according to this configuration, it is possible to reduce the noise of the high frequency component which is easily noticeable, but at the same time, the high frequency component of the signal component is also reduced. As a result, blurring of high frequency components of the signal occurs. Therefore, the characteristic of the nonlinear limiter 54 is set as shown in FIG. 4 to reduce the blur of the high frequency component. That is, when the high frequency component is small, it is considered as noise and noise reduction is performed. When the high frequency component is large, it is considered as the high frequency component of the image and noise reduction is not performed to prevent blurring of the high frequency component. Further, the non-linear limiter 54 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 5. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the range of the output of the nonlinear limiter 54 becomes narrower, so that the S / N improvement amount becomes smaller and the blur of the high frequency component also becomes smaller.

Next, the operation of the S / N improvement amount control signal generating circuit 5 for controlling the non-linear limiter 54 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 31 of the improvement amount control signal generation circuit 5, the Y signal is input to the Y threshold circuit 35. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then by the minimum value circuit 34, and the minimum value of them is input to the C threshold circuit 36. Y threshold circuit
35 and the C threshold circuit 36 output 1 if the input signal is larger than a preset threshold value, and output 0 if it is smaller. The signals binarized by the Y threshold circuit 35 and the C threshold circuit 36 are input to the YC level circuit 37. The YC level circuit 37 outputs a signal for controlling the non-linear limiter 54 based on the characteristics shown in FIG.

[0038] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 5, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low compared to the area where the luminance signal level is high and the saturation degree of the color signal is high.
By reducing the improvement amount, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and the blur of high frequency components due to the noise reducer is suppressed, and the luminance signal level is large and the color saturation is high. Moderate S /
N improvement can be performed. That is, the S / N improving effect can be obtained in the bright region while suppressing the blurring of the low level signal.

(Embodiment 4) FIG. 7 is a block diagram of a noise reduction apparatus according to Embodiment 4 . In FIG. 7, 1 is an input terminal for inputting a video signal, 61 is a high-pass filter for outputting the high frequency component of the input signal, and 62 is an S / N improvement amount control signal for outputting a non-linear signal to the input signal. Generation circuit, 6 is a subtractor, 7 is a non-linear limiter, 8 is an adder, 9 is a frame memory that stores one frame of video, 10 is an output terminal that outputs a noise-reduced signal, and 11 is S / N improvement. It is a cyclic noise reduce circuit whose amount is variable. S in FIG.
FIG. 8 is a block diagram showing the configuration of the / N improvement amount control signal generation circuit 62. In FIG. 8, 63 is a video signal input terminal,
66 is an input terminal for inputting the output signal of the high pass filter 61, 4 is an absolute value circuit for obtaining the absolute value of the color difference signals (RY, BY signals) of the input signal, and 67 is the two types of color difference input A minimum value circuit that outputs the smaller one of the absolute values of the signals as the C signal, 68 is a luminance signal (Y signal) of the input signals, and outputs 1 when it is larger than a preset threshold value, and outputs 0 when it is smaller Y signal threshold circuit,
69 is a C signal threshold circuit that outputs 1 when the input C signal is larger than a preset threshold value, and outputs 0 when it is smaller. 70 is a preset absolute value of the input high frequency component. 0 if greater than threshold, 1 if less
, 71 is a high frequency component threshold circuit, 71 is a YC level control which receives the output of the Y signal threshold circuit 68 and the output of the C signal threshold circuit 69 and generates a signal for controlling the non-linear limiter 7. A circuit, 72 is a logical sum circuit for taking the logical sum of the output of the YC level control circuit 71 and the high frequency component threshold circuit 70, and 73 is S /
The output terminal of the N improvement amount control signal generation circuit 62. Also,
The characteristics of the nonlinear limiter 7 in FIG. 7 are shown in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. In addition, the implementation already described
The same numbers are given to the same forms as the above.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 62. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the operation of the S / N improvement amount control signal generation circuit 62 for controlling the non-linear limiter 7 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 63 of the improvement amount control signal generation circuit 62, the Y signal is input to the Y threshold circuit 68. Of the video signals, the R-Y and B-Y signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 67 is used to obtain the minimum value of the two, which is input to the C threshold circuit 69. Y threshold circuit
68 and the C threshold circuit 69 output 1 when the input signal is larger than a preset threshold value, and output 0 when the input signal is smaller than the preset threshold value. The high frequency component obtained by the high pass filter 61 is input to the input terminal 66 and the high frequency component threshold circuit 70
Is binarized by a preset threshold value. In this embodiment , 0 when the input signal is in the high frequency range.
Is output, and 1 is output for low frequencies. Y threshold circuit 68, C
The signal binarized by the threshold circuit 69 is the YC level circuit 71.
The YC level circuit 71 outputs a signal based on the characteristics shown in FIG. The output of the YC level circuit 71 and the output of the high frequency component threshold circuit 70 are input to the logical sum circuit 72, and the output signal shown in FIG. 9 is used as the output signal of the S / N improvement amount control signal generation circuit 62. Output from output terminal 73.

[0042] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 62, the S / N improvement amount is smaller in the region where the luminance signal level is low and the saturation level of the color signal is lower than that in the region where the luminance signal level is high and the color signal saturation is high. By doing so, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to the noise reducer is suppressed. In addition to being able to improve N, S / N can be improved because even if the signal level is low, blurring of the video signal due to noise reduction is unlikely to occur if it is a low frequency component. That is, the S / N improvement effect can be obtained in a bright region or a region of low-frequency component signals while suppressing blurring of low-level high-frequency signals.

(Fifth Embodiment) FIG. 10 is a block diagram of a noise reduction apparatus according to the fifth embodiment . In FIG. 10, 1 is an input terminal for inputting a video signal, 61 is a high-pass filter for outputting the high frequency component of the input signal, and 62 is an S / N improvement amount control signal for outputting a non-linear signal to the input signal. Generation circuit, 43 is a subtractor, 44 is a non-linear limiter, 45 is an adder, 42 is a frame memory that stores one frame of video, 10 is an output terminal that outputs a noise-reduced signal, 41 is S / N improvement It is a non-recursive noise reduce circuit whose amount is variable. FIG. 8 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 62 in FIG. In FIG. 8, 63 is a video signal input terminal, 66 is an input terminal for inputting the output signal of the high-pass filter 61, and 4 is a color difference signal (RY, BY) of the input signals.
Absolute value circuit for calculating the absolute value of (signal), 67 is input 2
The minimum value circuit that outputs the smaller of the absolute values of the color difference signals of the type as the C signal, 68 is 1 when the luminance signal (Y signal) of the input signals is input and is larger than a preset threshold value, and 0 when it is smaller. Y signal threshold circuit for outputting
69 is a C signal threshold circuit that outputs 1 when the input C signal is larger than a preset threshold value, and outputs 0 when it is smaller. 70 is a preset absolute value of the input high frequency component. 0 if greater than threshold, 1 if less
, 71 is a high frequency component threshold circuit, and 71 is a YC level control which receives the output of the Y signal threshold circuit 68 and the output of the C signal threshold circuit 69 and generates a signal for controlling the non-linear limiter 44. A circuit, 72 is a logical sum circuit for taking the logical sum of the output of the YC level control circuit 71 and the high frequency component threshold circuit 70, and 73 is an S /
The output terminal of the N improvement amount control signal generation circuit 62. Also,
The characteristic of the nonlinear limiter 44 in FIG. 10 is shown in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 62. Figure
As shown in 4, the output range of the nonlinear limiter 44 becomes narrower as the value of the S / N improvement amount control signal becomes smaller.
The / N improvement amount becomes small and the motion blur becomes small.

Next, the operation of the S / N improvement amount control signal generation circuit 62 for controlling the non-linear limiter 44 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 63 of the improvement amount control signal generation circuit 62, the Y signal is input to the Y threshold circuit 68. Of the video signals, the R-Y and B-Y signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 67 is used to obtain the minimum value of the two, which is input to the C threshold circuit 69. Y threshold circuit
68 and the C threshold circuit 69 output 1 when the input signal is larger than a preset threshold value, and output 0 when the input signal is smaller than the preset threshold value. The high frequency component obtained by the high pass filter 61 is input to the input terminal 66 and the high frequency component threshold circuit 70
Is binarized by a preset threshold value. In this embodiment , 0 when the input signal is in the high frequency range.
Is output, and 1 is output for low frequencies. Y threshold circuit 68, C
The signal binarized by the threshold circuit 69 is the YC level circuit 71.
The YC level circuit 71 outputs a signal based on the characteristics shown in FIG. The output of the YC level circuit 71 and the output of the high frequency component threshold circuit 70 are input to the logical sum circuit 72, and the output signal shown in FIG. 9 is used as the output signal of the S / N improvement amount control signal generation circuit 62. Output from output terminal 73.

[0046] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 62, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the saturation degree of the color signal is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform an appropriate S / N improvement, it is possible to perform an S / N improvement because even if the signal level is low, blurring of the video signal due to noise reduction is unlikely to occur if it is a low frequency component. . That is, the S / N improvement effect can be obtained in a bright region or a region of low-frequency component signals while suppressing blurring of low-level high-frequency signals.

(Sixth Embodiment) FIG. 11 is a block diagram of a noise reduction apparatus according to the sixth embodiment . In FIG. 11, 1 is an input terminal for inputting a video signal, 62 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 53 is a subtractor, 54
Is a non-linear limiter, 55 is an adder, 52 is a low-pass filter that passes low-frequency components of the input signal, 10 is an output terminal that outputs a noise-reduced signal, and 51 is a coring circuit with variable S / N improvement. Is a noise reduce circuit using. FIG. 8 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 62 in FIG. In FIG. 8, 63 is a video signal input terminal, 66 is an input terminal for inputting the output of the subtractor 53 as a high frequency component, and 4 is a color difference signal (R
-Y, BY signal) absolute value circuit for calculating the absolute value of 67, 67 is the absolute value of the two types of color difference signals input
A minimum value circuit for outputting as a signal, 68 is a Y signal threshold circuit for inputting a luminance signal (Y signal) of the input signals and outputting 1 if it is larger than a preset threshold value, and 0 if it is smaller. Is a C signal threshold circuit that outputs 1 if the input C signal is larger than a preset threshold value, and outputs 0 if it is smaller. 70 is a threshold value for the absolute value of the input high frequency component to be preset. 0 if greater than the value
If it is smaller, a high-frequency component threshold circuit that outputs 1; 71 is the output of the Y signal threshold circuit 68; and C signal threshold circuit 69.
YC level control circuit for generating a signal for controlling the non-linear limiter 54 by using the output of the
The output of 71 and the logical sum circuit for obtaining the logical sum of the high frequency component threshold circuit 70, and 73 is the output terminal of the S / N improvement amount control signal generation circuit 62. Further, FIG. 4 shows the characteristic of the nonlinear limiter 54 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 51 is a noise reducer using the coring circuit described in the third embodiment . When the high frequency component is small, it is regarded as noise and noise reduction is performed. It is considered that there is no noise reduction to prevent blurring of high frequency components. Furthermore, in the nonlinear limiter 54, S / N
The S / N improvement amount can be changed by the output signal of the improvement amount control signal generation circuit 62. As shown in Figure 4, S / N
Nonlinear limiter as the value of the improvement control signal decreases
Since the output range of 54 is narrowed, the amount of S / N improvement is small and the blurring of high frequency components is also small. Further, in the present embodiment , the output of the subtractor 53 is supplied to the S / N improvement amount control signal generation circuit 62 as a high frequency component.

Next, the operation of the S / N improvement amount control signal generation circuit 62 for controlling the non-linear limiter 54 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 63 of the improvement amount control signal generation circuit 62, the Y signal is input to the Y threshold circuit 68. Of the video signals, the R-Y and B-Y signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 67 is used to obtain the minimum value of the two, which is input to the C threshold circuit 69. Y threshold circuit
68 and the C threshold circuit 69 output 1 when the input signal is larger than a preset threshold value, and output 0 when the input signal is smaller than the preset threshold value. The high frequency component output from the subtracter 53 is input to the input terminal 66 and binarized by the high frequency component threshold circuit 70 according to a preset threshold value. In the present embodiment , 0 is input when the input signal is in the high frequency range, and 1 when it is in the low frequency range.
Is output. 2 in Y threshold circuit 68 and C threshold circuit 69
The binarized signal is input to the YC level circuit 71, and the YC level circuit 71 outputs a signal based on the characteristics shown in FIG. Output of YC level circuit 71 and high frequency component threshold circuit 70
9 is input to the logical sum circuit 72, and the output signal shown in FIG. 9 is output from the output terminal 73 as the output signal of the S / N improvement amount control signal generation circuit 62.

[0050] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 62, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the saturation degree of the color signal is high.
By reducing the improvement amount, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and the blur of high frequency components due to the noise reducer is suppressed, and the luminance signal level is large and the color saturation is high. Moderate S /
In addition to being able to improve N, S / N can be improved because even if the signal level is low, blurring of the video signal due to noise reduction is unlikely to occur if it is a low frequency component. That is, in a bright region or a low-frequency component signal region, S is suppressed while suppressing blurring of a low-level high-frequency signal.
/ N improvement effect is obtained.

(Embodiment 7) FIG. 12 is a block diagram of a noise reduction apparatus according to Embodiment 7 . In FIG. 12, 1 is an input terminal for inputting a video signal, 82 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 80 is an input terminal for inputting motion information, and 81 is a motion. A motion information decoding circuit that decodes an information signal and outputs 0 when indicating a motion vector, 6 is a subtractor, 7 is a non-linear limiter, 8 is an adder, and 9 is 1
A frame memory that stores images for frames, 10 is an output terminal that outputs a signal with reduced noise, and 11 is a cyclic noise reduce circuit in which the S / N improvement amount is variable. Figure
FIG. 13 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 82 in 12. In FIG. 13, reference numeral 83 is a video signal input terminal, 86 is an input terminal for inputting the output signal of the motion information decoding circuit 81, and 4 is a color difference signal (R
-Y, BY signal) absolute value circuit for obtaining the absolute value of the signal, 87 is the absolute value of the two types of color difference signals input, and the smaller one is C
A minimum value circuit for outputting as a signal, 88 is a Y signal threshold circuit for inputting a luminance signal (Y signal) of the input signals and outputting 1 if it is larger than a preset threshold value, and 0 if it is smaller than this threshold value, 89 Is a C signal threshold circuit that outputs 1 if the input C signal is larger than a preset threshold value, and outputs 0 if it is smaller. 90 is the output of the Y signal threshold circuit 88 and the C signal threshold. A YC level control circuit which receives the output of the value circuit 89 and generates a signal for controlling the non-linear limiter 7, and a logical AND of the output of the YC level control circuit 90 and an input terminal 86 to which a motion information signal is inputted. An AND circuit 92 is an output terminal of the S / N improvement amount control signal generation circuit 82. Further, FIG. 4 shows the characteristic of the nonlinear limiter 7 in FIG.
The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 82. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the operation of the S / N improvement amount control signal generation circuit 82 which controls the nonlinear limiter 7 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 83 of the improvement amount control signal generation circuit 82, the Y signal is input to the Y threshold circuit 88. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 87 is used to obtain the minimum value of the two, which is input to the C threshold circuit 89. Y threshold circuit
The 88 and C threshold circuit 89 output 1 if the input signal is larger than a preset threshold value, and output 0 if it is smaller than the preset threshold value. The signal binarized by the Y threshold circuit 88 and the C threshold circuit 89 is input to the YC level circuit 90, and the YC level circuit 90 outputs a signal based on the characteristics shown in FIG. The motion information signal input to the input terminal 86 is a signal that becomes 0 only when the motion information signal decoding circuit 81 indicates a motion vector. The output of the YC level circuit 90 and the motion information signal input to the input terminal 86 are input to the AND circuit 91 so that the output signal shown in FIG. 14 is used as the output signal of the S / N improvement amount control signal generation circuit 82. Output from output terminal 92.

[0054] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 82, the S / N improvement amount in the region where the luminance signal level is low and the color signal saturation is low is smaller than that in the region where the luminance signal level is high and the color signal saturation is high. By doing so, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to the noise reducer is suppressed. In addition to being able to improve N, when the control signal indicates a motion vector, the S / N ratio is maintained regardless of the signal level.
Since the improvement amount is reduced, motion blur can be effectively suppressed.

(Embodiment 8) FIG. 15 is a block diagram of a noise reduction apparatus in Embodiment 8 . In FIG. 15, 1 is an input terminal for inputting a video signal, 82 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 80 is an input terminal for inputting motion information, and 81 is a motion. A motion information decoding circuit that decodes an information signal and outputs 0 when indicating a motion vector, 43 is a subtractor, 44 is a non-linear limiter, 45 is an adder, 42
Is a frame memory that stores one frame of video, 10 is an output terminal that outputs a signal with reduced noise, and 41 is a non-cyclic noise reduce circuit in which the S / N improvement amount is variable. FIG. 13 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 82 in FIG. In FIG. 13, reference numeral 83 is a video signal input terminal, 86 is an input terminal for inputting an output signal of the motion information decoding circuit 81, and 4 is an absolute value of color difference signals (RY, BY signals) of the input signals. Absolute value circuit, 87 is a minimum value circuit that outputs the smaller of the absolute values of the two types of color difference signals that are input as the C signal, and 88 is a threshold value that is preset by inputting the luminance signal (Y signal) of the input signals Y signal threshold circuit that outputs 1 if it is larger, 0 if it is smaller, 89 is 1 if the input C signal is larger than a preset threshold value, 0 if it is smaller
A C signal threshold circuit 90 for outputting a YC level control circuit 90 which receives the output of the Y signal threshold circuit 88 and the output of the C signal threshold circuit 89 as input and generates a signal for controlling the nonlinear limiter 44. , 91 is a logical product circuit for taking the logical product of the output of the YC level control circuit 90 and the input terminal 86 to which the motion information signal is inputted, and 92 is the output terminal of the S / N improvement amount control signal generation circuit 82. Further, FIG. 4 shows the characteristic of the nonlinear limiter 44 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the non-linear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 82. Figure
As shown in 4, the output range of the nonlinear limiter 44 becomes narrower as the value of the S / N improvement amount control signal becomes smaller.
The / N improvement amount becomes small and the motion blur becomes small.

Next, the operation of the S / N improvement amount control signal generating circuit 82 which controls the nonlinear limiter 44 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S / N
Of the video signals input to the input terminal 83 of the improvement amount control signal generation circuit 82, the Y signal is input to the Y threshold circuit 88. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 87 is used to obtain the minimum value of the two, which is input to the C threshold circuit 89. Y threshold circuit
The 88 and C threshold circuit 89 output 1 if the input signal is larger than a preset threshold value, and output 0 if it is smaller than the preset threshold value. The signal binarized by the Y threshold circuit 88 and the C threshold circuit 89 is input to the YC level circuit 90, and the YC level circuit 90 outputs a signal based on the characteristics shown in FIG. The motion information signal input to the input terminal 86 is a signal that becomes 0 only when the motion information signal decoding circuit 81 indicates a motion vector. The output of the YC level circuit 90 and the motion information signal input to the input terminal 86 are input to the AND circuit 91 so that the output signal shown in FIG. 14 is used as the output signal of the S / N improvement amount control signal generation circuit 82. Output from output terminal 92.

[0058] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 82, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low compared to the area where the luminance signal level is high and the saturation degree of the color signal is high.
By reducing the improvement amount, the S / N improvement amount is reduced in regions where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in regions where the luminance signal level is high and color saturation is high. In addition to being able to perform an appropriate S / N improvement, when the control signal indicates a motion vector, S / N is irrespective of the signal level.
Since the N improvement amount is reduced, motion blur can be effectively suppressed.

(Ninth Embodiment) FIG. 16 is a block diagram of a noise reduction device according to a ninth embodiment . In FIG. 16, 1 is an input terminal for inputting a video signal, 102 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 100 is an input terminal for inputting motion information, 101 is a motion A motion information decoding circuit that decodes an information signal and outputs 1 in the case of complete stationary or quasi-static, 6 is a subtractor, 7 is a non-linear limiter, 8 is an adder, 9 is a frame memory that stores one frame of video, 10 Is an output terminal for outputting a signal with reduced noise, and 11 is a cyclic noise reduce circuit whose S / N improvement amount is variable. S / N improvement amount control signal generation circuit in FIG.
A block diagram showing the configuration of 102 is shown in FIG. In FIG. 17, 103 is a video signal input terminal, 106 is an input terminal for inputting the output signal of the motion information decoding circuit 101, and 4 is an absolute value of color difference signals (RY, BY signals) of the input signals. An absolute value circuit 107 is a minimum value circuit which outputs the smaller absolute value of the two types of input color difference signals as a C signal, 108
Is 1 when the luminance signal (Y signal) is input from the input signals and is greater than a preset threshold value, and 0 when it is less than
Y signal threshold circuit for outputting, 109 is 1 when the input C signal is larger than a preset threshold value,
C signal threshold circuit which outputs 0 when it is small, 110 is Y
The output of the signal threshold circuit 108 and the C signal threshold circuit 109
YC level control circuit for generating a signal for controlling the non-linear limiter 7 with 111 output as an input, and 111 is an OR circuit for taking the logical sum of the output of the YC level control circuit 110 and the input terminal 106 to which the motion information signal is input. , 112 are output terminals of the S / N improvement amount control signal generation circuit 102. Further, FIG. 4 shows the characteristic of the nonlinear limiter 7 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 102. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the operation of the S / N improvement amount control signal generation circuit 102 for controlling the non-linear limiter 7 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S /
Of the video signals input to the input terminal 103 of the N improvement amount control signal generation circuit 102, the Y signal is input to the Y threshold circuit 108. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 107 is used to obtain the minimum value of the two, which are input to the C threshold circuit 109. Each of the Y threshold circuit 108 and the C threshold circuit 109 outputs 1 if the input signal is larger than a preset threshold value, and outputs 0 if it is smaller than the preset threshold value. The signal binarized by the Y threshold circuit 108 and the C threshold circuit 109 is input to the YC level circuit 110, and the YC level circuit 110 outputs a signal based on the characteristics shown in FIG. Further, the motion information signal input to the input terminal 106 is a signal which becomes 1 by the motion information signal decoding circuit 101 only when it is completely stationary or quasi stationary. The output of the YC level circuit 110 and the motion information signal input to the input terminal 106 are input to the logical sum circuit 111, and the output signal shown in FIG. 18 is used as the output signal of the S / N improvement amount control signal generation circuit 102. Output from the output terminal 112.

[0062] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 102, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform an appropriate S / N improvement, motion blur is less likely to occur when the control signal is completely stationary or quasi-stationary, so S / N can be improved on the entire screen by cutting off adaptive control based on the signal level. Can be achieved.

(Embodiment 10) FIG. 19 is a block diagram of a noise reduction device according to Embodiment 10 . In FIG. 19, 1 is an input terminal for inputting a video signal, 102 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 100 is an input terminal for inputting motion information, 101 is a motion A motion information decoding circuit that decodes the information signal and outputs 1 in the case of complete stationary or quasi-static, 43 is a subtractor, 44 is a non-linear limiter, 45
Is an adder, 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal,
Reference numeral 41 is a non-cyclic noise reduce circuit in which the S / N improvement amount is variable. FIG. 17 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 102 in FIG. Figure 1
In FIG. 7, 103 is an input terminal for a video signal, 106 is an input terminal for inputting an output signal of the motion information decoding circuit 101, and 4 is an absolute value for obtaining an absolute value of a color difference signal (RY, BY signal) of the input signal. A value circuit, 107 is a minimum value circuit that outputs the smaller one of the absolute values of the two types of color difference signals that are input as the C signal, and 108 is a luminance signal (Y signal) of the input signals that is input and the threshold value is preset A Y signal threshold circuit that outputs 1 when it is large and 0 when it is small. 109 is a C signal threshold that outputs 1 when the input C signal is larger than a preset threshold value, and outputs 0 when it is smaller. Value circuit,
110 is a YC level control circuit that receives the output of the Y signal threshold circuit 108 and the output of the C signal threshold circuit 109 and generates a signal for controlling the nonlinear limiter 44. 111 is an output of the YC level control circuit 110. And 112 is an output terminal of the S / N improvement amount control signal generation circuit 102. Further, FIG. 4 shows the characteristic of the nonlinear limiter 44 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. In addition, the
The same number is given to the same form .

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 102.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the operation of the S / N improvement amount control signal generation circuit 102 for controlling the non-linear limiter 44 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S /
Of the video signals input to the input terminal 103 of the N improvement amount control signal generation circuit 102, the Y signal is input to the Y threshold circuit 108. Of the video signals, the RY and BY signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 107 is used to obtain the minimum value of the two, which are input to the C threshold circuit 109. Each of the Y threshold circuit 108 and the C threshold circuit 109 outputs 1 if the input signal is larger than a preset threshold value, and outputs 0 if it is smaller than the preset threshold value. The signal binarized by the Y threshold circuit 108 and the C threshold circuit 109 is input to the YC level circuit 110, and the YC level circuit 110 outputs a signal based on the characteristics shown in FIG. Further, the motion information signal input to the input terminal 106 is a signal which becomes 1 by the motion information signal decoding circuit 101 only when it is completely stationary or quasi stationary. The output of the YC level circuit 110 and the motion information signal input to the input terminal 106 are input to the logical sum circuit 111, and the output signal shown in FIG. 18 is used as the output signal of the S / N improvement amount control signal generation circuit 102. Output from the output terminal 112.

[0066] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 102, compared to a region where the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, in a region where the level is low and it is difficult to distinguish between signal and noise, the S / N improvement amount is reduced to suppress the motion blur due to the noise reducer, and the luminance signal level is increased to a high color saturation region. In addition to being able to perform appropriate S / N improvement, motion blur is unlikely to occur when the control signal is completely stationary or quasi-static, so improving S / N on the entire screen by cutting off adaptive control based on the signal level. Can be achieved.

(Embodiment 11) FIG. 20 is a block diagram of a noise reduction device according to an eleventh embodiment . In FIG. 20, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 6 is a subtractor, 7 is a non-linear limiter, and 8 is addition. 9 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 11 is a cyclic noise reduce circuit with variable S / N improvement, and 131 is input The low-level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal to be input is smaller than a certain level, 132 finds the high frequency component of the Y signal of the input video signal and determines the absolute value of the high frequency component. A high-frequency component detection circuit that outputs a signal only when the level is higher than a certain level, and 113 is a case where the output of the low-level detection circuit 131 and the output of the high-frequency component detection circuit 132 are input and the input signal is a low-level high-frequency component. AND circuit that outputs only signal,
115 is a counter that counts the number of outputs of the AND circuit 113 per field, 117 is a threshold value that outputs 0 when the output of the counter 115 exceeds the threshold value and 1 when it does not exceed the threshold value as a YC level control fixed signal Circuit. S in Fig. 20
FIG. 21 is a block diagram showing the configuration of the / N improvement amount control signal generation circuit 118. In FIG. 21, reference numeral 120 is a video signal input terminal, 123 is an input terminal for inputting a YC level control fixed signal which is an output of the threshold circuit 117, and 4 is a color difference signal (RY, BY signal among the input signals). ) Is an absolute value circuit for obtaining the absolute value of), 124 is a minimum value circuit that outputs the smaller of the absolute values of the two types of input color difference signals as the C signal, and 125 is the input of the luminance signal (Y signal) of the input signals. A Y signal threshold circuit that outputs 1 if it is larger than a preset threshold value and 0 if it is smaller. 126 is 1 if the input C signal is larger than a preset threshold value, and 0 if it is smaller. A Y signal level control circuit for outputting a signal for controlling the non-linear limiter 7 by inputting the output of the Y signal threshold circuit 125 and the output of the C signal threshold circuit 126. , 128 are YC input to the input terminal 123 OR circuit for ORing the output signal of the bell control fixed signal and the YC level circuit 127, 129 is an output terminal of the S / N improving amount control signal generation circuit 118. Further, FIG. 4 shows the characteristic of the nonlinear limiter 7 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The counter 115 counts the number of pixels in one field of low level signals among the signals detected by the high frequency component detection circuit 132. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the number of low-frequency high-frequency component pixels in one field is large, and 1 is output when the number is low.

Next, the operation of the S / N improvement amount control signal generation circuit 118 which controls the nonlinear limiter 7 to generate a control signal for changing the S / N improvement amount will be described with reference to the drawings. S /
Of the video signals input to the input terminal 120 of the N improvement amount control signal generation circuit 118, the Y signal is input to the Y threshold circuit 125. Of the video signals, the R-Y and B-Y signals are first obtained by the absolute value circuit 4 and then the minimum value circuit 124 is used to obtain the minimum value of both signals. Each of the Y threshold circuit 125 and the C threshold circuit 126 outputs 1 if the input signal is larger than a preset threshold value, and outputs 0 if it is smaller. The signal binarized by the Y threshold circuit 125 and the C threshold circuit 126 is input to the YC level circuit 127, and the YC level circuit 127 outputs a signal based on the characteristics shown in FIG. Further, the YC level control fixed signal input to the input terminal 123 and the output of the YC level circuit 127 are input to the logical sum circuit 128, so that the output signal shown in FIG. 22 is output to the S / N improvement amount control signal generation circuit 118. The output signal is output from the output terminal 129.

[0071] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform appropriate S / N improvement, if the number of low-level high-frequency components in one field is small, motion blur due to noise reduction is unlikely to occur, so adaptive control according to the signal level should be cut off. S / N on the whole screen by
Can be improved.

(Embodiment 12) FIG. 23 is a block diagram of a noise reduction apparatus according to Embodiment 12 . In FIG. 23, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition. Device, 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 41 is a non-cyclic noise reduce circuit with variable S / N improvement, and 131 is an input A low level detection circuit that outputs a signal only when the pixel of the Y signal of the input video signal is smaller than a certain level, 132 is a high frequency component of the high frequency component of the Y signal of the input video signal. Is a high level component detection circuit that outputs a signal only when is above a certain level, and 113 is an input signal with the output of the low level detection circuit 131 and the output of the high frequency component detection circuit 132 being the low level and high frequency component. AND circuit that outputs a signal only when 115 is a counter that counts the number of outputs of the AND circuit 113 per field, 117 is a threshold value that outputs 0 when the output of the counter 115 exceeds the threshold value and 1 when it does not exceed the threshold value as a YC level control fixed signal Circuit. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Further, FIG. 4 shows the characteristic of the nonlinear limiter 44 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The counter 115 counts the number of pixels in one field of low level signals among the signals detected by the high frequency component detection circuit 132. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the number of low-frequency high-frequency component pixels in one field is large, and 1 is output when the number is low.

As described in the eleventh embodiment, the S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 44 to generate the control signal for changing the S / N improvement amount, as shown in FIG.
The output signal shown in 2 is used as the S / N improvement amount control signal generation circuit 118.
Output from the output terminal 129.

[0076] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 118, compared to a region in which the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, in a region where the level is low and it is difficult to distinguish between signal and noise, the S / N improvement amount is reduced to suppress the motion blur due to the noise reducer, and the luminance signal level is increased to a high color saturation region. In addition to being able to perform appropriate S / N improvement, if the number of low-level high-frequency component pixels in one field is small, motion blur due to noise reduction is unlikely to occur, so adaptive control by signal level is cut off. S /
N can be improved.

(Embodiment 13) FIG. 24 shows a block diagram of a noise reduction apparatus in Embodiment 13 . In FIG. 24, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 53 is a subtractor, 54 is a non-linear limiter, and 55 is an addition. Device, 52 is a low-pass filter that passes the low-frequency component of the input signal, 10 is an output terminal that outputs a signal with reduced noise, 51 is a noise reduce circuit that uses a coring circuit with a variable S / N improvement amount, Reference numeral 131 is a low level detection circuit that outputs a signal only when the pixels of the Y signal of the input video signal are smaller than a certain level, and 132 is a high frequency component of the high frequency component of the Y signal of the input video signal. The high frequency component detection circuit that outputs a signal only when the absolute value of is higher than a certain level, 113 is the input of the output of the low level detection circuit 131 and the output of the high frequency component detection circuit 132, Signal only if it is a component AND circuit which, 115 counts the number of outputs of the AND circuit 113 per 1 field counter, 117 is 0 when the output of counter 115 exceeds the threshold value, if not exceeded
A threshold circuit that outputs 1 as a YC level control fixed signal. S / N improvement amount control signal generation circuit in FIG. 24
A block diagram showing the configuration of 118 is shown in FIG. Since FIG. 21 is exactly the same as that already described, the description is omitted. Further, FIG. 4 shows the characteristic of the nonlinear limiter 54 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 51 is a noise reducer using the coring circuit described in the third embodiment . When the high frequency component is small, it is regarded as noise and noise reduction is performed. It is considered that there is no noise reduction to prevent blurring of high frequency components. Furthermore, in the nonlinear limiter 54, S / N
The S / N improvement amount can be changed by the output signal of the improvement amount control signal generation circuit 118. As shown in Figure 4, S /
As the value of the N improvement amount control signal becomes smaller, the output range of the non-linear limiter 54 becomes narrower, so that the S / N improvement amount becomes smaller and the blur of the high frequency component also becomes smaller.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The counter 115 counts the number of pixels in one field of low level signals among the signals detected by the high frequency component detection circuit 132. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the number of low-frequency high-frequency component pixels in one field is large, and 1 is output when the number is low.

As described in the eleventh embodiment, the S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 54 to generate the control signal for changing the S / N improvement amount, as shown in FIG.
The output signal shown in 2 is used as the S / N improvement amount control signal generation circuit 118.
Output from the output terminal 129.

[0081] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 118, compared to a region in which the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and blurring of high frequency components due to the noise reducer is suppressed. Moderate S for high areas
/ N can be improved, and if the number of low-level high-frequency components in one field is small, blurring of high-frequency components is less likely to occur, so adaptive control by the signal level is cut off to display the entire screen. S / N can be improved.

(Embodiment 14) FIG. 25 is a block diagram of a noise reduction device according to Embodiment 14 . In FIG. 25, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 6 is a subtractor, 7 is a non-linear limiter, and 8 is addition. , 9 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 11 is a cyclic noise reduce circuit with variable S / N improvement, and 131 is input. The low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal to be input is smaller than a certain level, 132 finds the high frequency component of the Y signal of the input video signal and determines the absolute value of the high frequency component. A high frequency component detection circuit that outputs a signal only when the level is higher than a certain level, and 113 is a case where the output of the low level detection circuit 131 and the output of the high frequency component detection circuit 132 are input and the input signal is a low level and high frequency component. AND circuit that outputs only signal,
114 is a first counter that counts the number of outputs of the low-level signal detection circuit 131 per field, 115 is a second counter that counts the number of outputs of the AND circuit 113 per field, and 116 is a second counter The output of 115 the first counter 11
A divider for obtaining a quotient divided by the output of 4 is a threshold circuit 117 for outputting 0 when the output of the divider 116 exceeds the threshold value and 1 when it does not exceed the threshold value as a YC level control fixed signal.
FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Fig. 25
The characteristics of the non-linear limiter 7 are shown in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. In addition, the
The same number is given to the same form .

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the second counter 115 counts the number of pixels in one field of the low level signals detected by the high frequency component detection circuit 132.
Count with. Divide the ratio of the outputs of these counters by 11
The threshold value circuit 117 obtains the threshold value and compares it with a preset threshold value to output a binary signal as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of high frequency components in the low level region in one field is high, and 1 is output when the ratio is low.

As described in the eleventh embodiment, the S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 7 to generate the control signal for changing the S / N improvement amount, as shown in FIG.
The output signal shown in 2 is used as the S / N improvement amount control signal generation circuit 118.
Output from the output terminal 129.

[0086] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform an appropriate S / N improvement, the adaptive control by the signal level is cut off only when the proportion of high frequency components in the low level region is small, so that the high frequency components in the low level region are deteriorated. It is possible to improve the S / N on the entire screen while preventing the above. For example, even if the number of pixels in the high-frequency component having a low level is small on the entire screen, if the ratio in the low-level region is large, the S / N improvement amount in that region can be suppressed to a low level, so blurring of the high-frequency component can be suppressed. To be

(Fifteenth Embodiment) FIG. 26 shows a block diagram of a noise reduction apparatus in the fifteenth embodiment . In FIG. 26, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition. Device, 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 41 is a non-cyclic noise reduce circuit with variable S / N improvement, and 131 is an input A low level detection circuit that outputs a signal only when the pixel of the Y signal of the input video signal is smaller than a certain level, 132 is a high frequency component of the high frequency component of the Y signal of the input video signal. Is a high level component detection circuit that outputs a signal only when is above a certain level, and 113 is an input signal with the output of the low level detection circuit 131 and the output of the high frequency component detection circuit 132 being the low level and high frequency component. AND circuit that outputs a signal only when 114 is a low-level signal detection circuit per field
A first counter that counts the number of outputs of 131, a second counter that counts the number of outputs of the AND circuit 113 per field, and a reference numeral 116 that outputs the output of the second counter 115 to the output of the first counter 114 A divider that calculates the quotient divided by, 117 is a divider 11
If the output of 6 exceeds the threshold value, 0; if not, set 1 to Y
It is a threshold circuit that outputs as a C level control fixed signal. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Also, FIG.
The characteristic of the nonlinear limiter 44 in is shown in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. In addition, the
The same number is given to the same form .

The noise reduce circuit 41 is a non-cyclic noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as motion and no noise reduction is applied to prevent multi-line blurring in the motion part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the second counter 115 counts the number of pixels in one field of the low level signals detected by the high frequency component detection circuit 132.
Count with. Divide the ratio of the outputs of these counters by 11
The threshold value circuit 117 obtains the threshold value and compares it with a preset threshold value to output a binary signal as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of high frequency components in the low level region in one field is high, and 1 is output when the ratio is low.

As described in the eleventh embodiment, the S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 44 to generate the control signal for changing the S / N improvement amount, as shown in FIG.
The output signal shown in FIG.
Output from the output terminal 129.

[0091] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 118, compared to a region in which the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, in a region where the level is low and it is difficult to distinguish between signal and noise, the S / N improvement amount is reduced to suppress the motion blur due to the noise reducer, and the luminance signal level is increased to a high color saturation region. In addition to being able to perform an appropriate S / N improvement, since the adaptive control by the signal level is blocked only when the ratio of the high frequency component in the low level region is small, the high frequency component in the low level region A sufficient S / N improvement can be achieved on the entire screen while preventing deterioration. For example, even if the number of pixels in the high-frequency component having a low level is small on the entire screen, if the ratio in the low-level region is large, the S / N improvement amount in that region can be suppressed to a low level, so blurring of the high-frequency component can be suppressed. To be

(Embodiment 16) FIG. 27 shows a block diagram of a noise reduction apparatus in Embodiment 16 . In FIG. 27, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 53 is a subtractor, 54 is a non-linear limiter, and 55 is an addition. Device, 52 is a low-pass filter that passes the low-frequency component of the input signal, 10 is an output terminal that outputs a signal with reduced noise, 51 is a noise reduce circuit that uses a coring circuit whose S / N improvement amount is variable, Reference numeral 131 denotes a low level detection circuit that outputs a signal only when the Y signal pixel of the input video signal is smaller than a certain level, and 132 denotes a high frequency component of the Y signal of the input video signal to obtain a high frequency component. The high-frequency component detection circuit that outputs a signal only when the absolute value of is above a certain level, 113 is the input of the output of the low-level detection circuit 131 and the output of the high-frequency component detection circuit 132, Signal only if it is a component AND circuit 114, a first counter 114 for counting the number of outputs of the low-level signal detection circuit 131 per field, 115 a second counter for counting the number of outputs of the AND circuit 113 per field, 116 Is the second counter 115
Is a divider that obtains the quotient of the output of the first counter 114 divided by the output of the first counter 114, and 117 is the case where the output of the divider 116 exceeds a threshold value
This is a threshold circuit which outputs 0 as a YC level control fixed signal and 0 when it does not exceed. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description is omitted. Further, FIG. 4 shows the characteristic of the nonlinear limiter 54 in FIG. In the produced noise reduction apparatus according <br/> of this embodiment as described above, the operation thereof will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 51 is a noise reducer using the coring circuit described in the third embodiment . When the high frequency component is small, it is regarded as noise and noise reduction is performed. It is considered that there is no noise reduction to prevent blurring of high frequency components. Furthermore, in the nonlinear limiter 54, S / N
The S / N improvement amount can be changed by the output signal of the improvement amount control signal generation circuit 118. As shown in Figure 4, S /
As the value of the N improvement amount control signal becomes smaller, the output range of the non-linear limiter 54 becomes narrower, so that the S / N improvement amount becomes smaller and the blur of the high frequency component also becomes smaller.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the second counter 115 counts the number of pixels in one field of the low level signals detected by the high frequency component detection circuit 132.
Count with. Divide the ratio of the outputs of these counters by 11
The threshold value circuit 117 obtains the threshold value and compares it with a preset threshold value to output a binary signal as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of high frequency components in the low level region in one field is high, and 1 is output when the ratio is low.

As described in the eleventh embodiment, the S / N improvement amount control signal generation circuit 118 for controlling the nonlinear limiter 54 to generate the control signal for changing the S / N improvement amount is shown in FIG.
The output signal shown in FIG.
Output from the output terminal 129.

[0096] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 118, compared to a region in which the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, the S / N improvement amount is reduced in a region where the level is low and it is difficult to distinguish between signal and noise, and blurring of high frequency components due to the noise reducer is suppressed. Moderate S for high areas
/ N can be improved, and adaptive control by the signal level is cut off only when the proportion of high frequency components in the low level region is small, so that deterioration of high frequency components in the low level region is prevented. , S / N can be sufficiently improved on the entire screen. For example, even if the number of pixels in the high-frequency component of low level is small on the entire screen, if the proportion in the low-level area is large,
Since the S / N improvement amount in that region is suppressed to a low level, blurring of high frequency components can be suppressed.

(Embodiment 17) FIG. 28 shows a block diagram of a noise reduction apparatus in Embodiment 17. In FIG. In FIG. 28, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 6 is a subtractor, 7 is a non-linear limiter, and 8 is addition. 9 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 11 is a cyclic noise reduce circuit with variable S / N improvement, and 131 is input. A low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal is smaller than a certain level. 130 receives the output of the subtracter 6 which is a difference signal between 1 frames of the input signal as an input. A motion detection circuit that outputs a signal only when the difference signal of the signal is a certain level or more, and 113 is a signal only when the output of the low level detection circuit 131 and the output of the motion detection circuit 130 are input and the input signal is a motion at a low level. AND circuit that outputs 115 is a counter that counts the number of outputs of the AND circuit 113 per field, 117 is a threshold value that outputs 0 when the output of the counter 115 exceeds the threshold value, and 1 when it does not exceed the threshold value as a YC level control fixed signal Circuit. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Further, FIG. 4 shows the characteristic of the nonlinear limiter 7 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as motion and noise reduction is not applied to prevent multi-line blurring in the motion part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. A counter 115 counts the number of pixels in one field of low level signals detected by the motion detection circuit 130. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the number of pixels with low level motion in one field is large, and 1 is output when the number is small.

The S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 7 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0102] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform an appropriate S / N improvement, motion blur due to noise reduction is unlikely to occur when the number of low-level motion pixels in one field is small, so the adaptive control based on the signal level is cut off to display the screen. S / N can be improved as a whole.

(Embodiment 18) FIG. 29 shows a block diagram of a noise reduction apparatus in Embodiment 18. In FIG. In FIG. 29, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition. Device, 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 41 is a non-cyclic noise reduce circuit with variable S / N improvement, and 131 is an input A low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal to be output is smaller than a certain level, and 130 receives as an input the output of a subtractor 43 which is a difference signal between 1 frames of the input signal and receives 1 frame. A motion detection circuit that outputs a signal only when the difference signal between them is a certain level or more, and 113 is only when the output of the low level detection circuit 131 and the output of the motion detection circuit 130 are inputs and the input signal is a motion at a low level Logic that outputs a signal Circuit, AND circuit per field 115
A counter for counting the number of outputs of 113, 117 for a counter 115
Is 0 if the output exceeds the threshold value, 1 if it does not exceed YC
This is a threshold circuit that outputs as a level control fixed signal. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Also,
The characteristic of the nonlinear limiter 44 in FIG. 29 is shown in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 41 is a non-cyclic type noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as motion and no noise reduction is applied to prevent multi-line blurring in the motion part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. A counter 115 counts the number of pixels in one field of low level signals detected by the motion detection circuit 130. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is set when the number of low-level motion pixels in one field is large,
If the number is small, 1 is output. S / N that controls the non-linear limiter 44 to generate a control signal that changes the S / N improvement amount
The improvement amount control signal generation circuit 118 is the same as the eleventh embodiment.
22. When the YC level control fixed signal is 1, as shown in FIG. 22, the output of the S / N improvement amount control signal generation circuit 118 is fixed.

[0105] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 118, compared to a region in which the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, in a region where the level is low and it is difficult to distinguish between signal and noise, the S / N improvement amount is reduced to suppress the motion blur due to the noise reducer, and the luminance signal level is increased to a high color saturation region. In addition to being able to perform an appropriate S / N improvement, if the number of low-level motion pixels in one field is small, motion blur due to noise reduction is unlikely to occur, so by cutting off the adaptive control according to the signal level. S / N can be improved on the entire screen.

(Embodiment 19) FIG. 30 shows a block diagram of a noise reduction apparatus in Embodiment 19. In FIG. In FIG. 30, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 6 is a subtractor, 7 is a non-linear limiter, and 8 is addition. 9 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 11 is a cyclic noise reduce circuit with variable S / N improvement, and 131 is input. A low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal is smaller than a certain level. 130 receives the output of the subtracter 6 which is a difference signal between 1 frames of the input signal as an input. A motion detection circuit that outputs a signal only when the difference signal of the signal is a certain level or more, and 113 is a signal only when the output of the low level detection circuit 131 and the output of the motion detection circuit 130 are input and the input signal is a motion at a low level. AND circuit that outputs 114 counts the number of output of the low-level signal detecting circuit 131 per one field first counter, 115 is a second counting the number of outputs of the AND circuit 113 per one field
, 116 is a divider that divides the output of the second counter 115 by the output of the first counter 114, and 117 is a divider
This is a threshold circuit that outputs 0 when the output of 116 exceeds the threshold and 1 when it does not exceed the threshold as a YC level control fixed signal. S / N improvement amount control signal generation circuit 118 in FIG.
FIG. 21 is a block diagram showing the configuration of the above. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Further, FIG. 4 shows the characteristic of the nonlinear limiter 7 in FIG.
The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the second counter 115 counts the number of pixels in one field of low level signals detected by the motion detection circuit 130. The output ratios of these counters are obtained by a divider 116 and compared with a preset threshold value by a threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of movement of a low level area in one field is large, and 1 is output when the ratio is small.

The S / N improvement amount control signal generation circuit 118 for controlling the nonlinear limiter 7 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0110] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform an appropriate S / N improvement, adaptive control by the signal level is cut off only when the ratio of motion components in the low level region is small, so deterioration of high frequency components in the low level region is prevented. It is possible to achieve sufficient S / N improvement on the entire screen while preventing it. For example, even if the number of pixels of the low-level motion component is small on the entire screen, if the ratio in the low-level area is large, the S / N improvement amount of the area can be suppressed to a low level, so that the blur of the motion component can be suppressed.

(Embodiment 20) FIG. 31 is a block diagram of a noise reduction device according to Embodiment 20 . In FIG. 31, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition. Device, 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 41 is a non-cyclic noise reduce circuit with variable S / N improvement, and 131 is an input A low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal to be output is smaller than a certain level, and 130 receives as an input the output of a subtractor 43 which is a difference signal between 1 frames of the input signal and receives 1 frame. A motion detection circuit that outputs a signal only when the difference signal between them is a certain level or more, and 113 is only when the output of the low level detection circuit 131 and the output of the motion detection circuit 130 are inputs and the input signal is a motion at a low level Logic that outputs a signal Circuit, 114 a first counter for counting the number of output of the low-level signal detecting circuit 131 per one field, 11
5 is a second counter for counting the number of outputs of the AND circuit 113 per field, 116 is a divider for obtaining a quotient obtained by dividing the output of the second counter 115 by the output of the first counter 114, 11
Reference numeral 7 is a threshold circuit which outputs 0 as a YC level control fixed signal when the output of the divider 116 exceeds the threshold and 1 when it does not exceed the threshold. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Figure 2
The description of 1 is omitted because it is completely the same as that already described. In addition, the characteristics of the nonlinear limiter 44 in FIG.
Shown in 4. The operation of the noise reduction device of this embodiment configured as described above will be described below. In addition,
The same parts as those in the above- described embodiment are designated by the same reference numerals.

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the second counter 115 counts the number of pixels in one field of low level signals detected by the motion detection circuit 130. The output ratios of these counters are obtained by a divider 116 and compared with a preset threshold value by a threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of movement of a low level area in one field is large, and 1 is output when the ratio is small.

The S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 44 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0115] Also in this embodiment as described above,
Due to the characteristics of the S / N improvement amount control signal generation circuit 118, compared to a region in which the luminance signal level is high and the saturation of the color signal is high,
S / of the area where the luminance signal level is low and the saturation of the color signal is low
By reducing the N improvement amount, in a region where the level is low and it is difficult to distinguish between signal and noise, the S / N improvement amount is reduced to suppress the motion blur due to the noise reducer, and the luminance signal level is increased to a high color saturation region. In addition to being able to perform an appropriate S / N improvement, the adaptive control by the signal level is cut off only when the ratio of the motion component in the low level region is small, so that the high frequency component in the low level region is deteriorated. It is possible to improve the S / N on the entire screen while preventing the above. For example, even if the number of pixels of the low-level motion component is small on the entire screen, if the ratio in the low-level area is large, the S / N improvement amount of the area can be suppressed to a low level, so that the blur of the motion component can be suppressed.

(Embodiment 21) FIG. 32 shows a block diagram of a noise reduction apparatus in Embodiment 21 . In FIG. 32, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 6 is a subtractor, 7 is a non-linear limiter, and 8 is addition. 9 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 11 is a cyclic noise reduce circuit with variable S / N improvement, and 131 is input. The low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal to be input is smaller than a certain level, 132 finds the high frequency component of the Y signal of the input video signal and determines the absolute value of the high frequency component. A high-frequency component detection circuit that outputs a signal only when the level is a certain level or more, 130 is an input of the output of the subtracter 6 which is a difference signal between the one frame of the input signal, and the difference signal between the one frame is more than a certain level. Motion detection times to output signal only when , 113 is a logical product that inputs the output of the low level detection circuit 131, the output of the high frequency component detection circuit 132 and the output of the motion detection circuit 130 and outputs a signal only when the input signal is a low level and high frequency component motion A circuit, 115 is a counter for counting the number of outputs of the AND circuit 113 per field, 117 is 0 when the counter 115 exceeds the threshold value, and 1 when it does not exceed the threshold value.
This is a threshold circuit that outputs as a level control fixed signal. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is exactly the same as that already described, the description thereof will be omitted. Also,
The characteristic of the nonlinear limiter 7 in FIG. 32 is shown in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. In addition, the implementation already described
The same numbers are given to the same forms as the above.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The AND circuit 113 outputs only when the input signal is a low-level and high-frequency component movement, and the counter counts the number of pixels in one field. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the number of high-frequency component low-level components in one field is large, and 1 is output when the number is small.

The S / N improvement amount control signal generation circuit 118 for controlling the nonlinear limiter 7 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0120] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform appropriate S / N improvement, if the number of pixels of low-level high-frequency component movement is small in one field, motion blur due to noise reduction is unlikely to occur, so adaptive control by signal level is cut off. By doing so, S / N can be improved on the entire screen. As a result, for example, even if the movement is at a low level, if the high-frequency component is not included so much, Y
Since the suppression of the S / N improvement amount by the C level is prohibited, the improvement amount becomes large as compared with the case where the S / N improvement amount control signal generation circuit 118 is controlled only by the low level movement.

(Embodiment 22) FIG. 33 is a block diagram of a noise reduction device according to Embodiment 22 . In FIG. 33, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition. , 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 41 is a non-cyclic noise reduce circuit whose S / N improvement amount is variable, and 131 is an input A low level detection circuit that outputs a signal only when the pixel of the Y signal of the input video signal is smaller than a certain level, 132 represents the high frequency component of the Y signal of the input video signal, and the absolute value of the high frequency component Is a high-frequency component detection circuit that outputs a signal only when is above a certain level, 130 is an input of the output of the subtractor 43 which is a difference signal between one frame of the input signal, and the difference signal between one frame is above a certain level Motion to output signal only when The output circuit 113 receives the output of the low level detection circuit 131, the output of the high frequency component detection circuit 132 and the output of the motion detection circuit 130 as an input and outputs a signal only when the input signal is a low level and high frequency component motion. AND circuit 115, a counter that counts the number of outputs of the AND circuit 113 per field, 117 outputs 0 when the output of the counter 115 exceeds the threshold value, 1 when it does not exceed the threshold value as a YC level control fixed signal It is a threshold circuit that does. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Figure 21
Is completely the same as that already described, and the description thereof will be omitted. In addition, the characteristics of the nonlinear limiter 44 in FIG. 33 are shown in FIG.
Shown in. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The AND circuit 113 outputs only when the input signal is a low-level and high-frequency component movement, and the counter counts the number of pixels in one field. The output of the counter is compared with a threshold value set in advance by the threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the number of high-frequency component low-level components in one field is large, and 1 is output when the number is small.

The S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 44 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0125] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in areas where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducer is suppressed, and in areas where the luminance signal level is large and color saturation is high. In addition to being able to perform appropriate S / N improvement, if the number of pixels of low-level high-frequency component movement is small in one field, motion blur due to noise reduction is unlikely to occur, so adaptive control by signal level is cut off. By doing so, S / N can be improved on the entire screen. As a result, for example, even if the movement is at a low level, if the high-frequency component is not included so much, Y
Since the suppression of the S / N improvement amount by the C level is prohibited, the improvement amount becomes large as compared with the case where the S / N improvement amount control signal generation circuit 118 is controlled only by the low level movement.

(Embodiment 23) FIG. 34 is a block diagram of a noise reduction apparatus according to Embodiment 23 . In FIG. 34, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 6 is a subtractor, 7 is a non-linear limiter, and 8 is addition. 9 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 11 is a cyclic noise reduce circuit with variable S / N improvement, and 131 is input. The low level detection circuit that outputs a signal only when the pixel of the Y signal of the video signal to be input is smaller than a certain level, 132 finds the high frequency component of the Y signal of the input video signal and determines the absolute value of the high frequency component. A high-frequency component detection circuit that outputs a signal only when the level is higher than a certain level, and 130 receives the output of the subtractor 6 which is the difference signal between the 1-frame of the input signal as an input, and the difference signal between the 1-frame is higher than the constant level. Motion detection times to output signal only when , 113 is a logical product that inputs the output of the low level detection circuit 131, the output of the high frequency component detection circuit 132 and the output of the motion detection circuit 130 and outputs a signal only when the input signal is a low level and high frequency component motion A circuit, 114 is a first counter that counts the number of outputs of the low-level signal detection circuit 131 per field, 115 is a second counter that counts the number of outputs of the AND circuit 113 per field, and 116 is a second counter Of the counter 115 is divided by the output of the first counter 114 to obtain a quotient, and 117 is 0 when the output of the divider 116 exceeds a threshold value.
This is a threshold circuit that outputs 1 as a YC level control fixed signal when it does not exceed. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is the same as that already described, the description is omitted. Further, FIG. 4 shows the characteristic of the nonlinear limiter 7 in FIG. The operation of the noise reduction device of this embodiment configured as described above will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 11 is a cyclic noise reducer using the differential signal between 1 frames described in the first embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. If it is large, it is regarded as movement and noise reduction is not applied to prevent multi-line blurring in the moving part. Further, the nonlinear limiter 7 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118. As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 7 becomes narrower, so the S / N ratio becomes smaller.
The improvement amount is small and the motion blur is also small.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the AND circuit 113 outputs only when the input signal is a low-level and high-frequency component movement, and the counter 2 counts the number of pixels in one field. The output ratios of these counters are obtained by a divider 116 and compared with a preset threshold value by a threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of motion of the high frequency component in the low level region in one field is high, and 1 is output when the ratio is low.

The S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 7 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0130] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in regions where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducers is suppressed, and in regions where the luminance signal level is high and color saturation is high. In addition to being able to perform an appropriate S / N improvement, the adaptive control by the signal level is cut off only when the ratio of the movement of the high frequency component in the low level region is small, so that the high frequency component of the low level region is blocked. It is possible to achieve sufficient S / N improvement on the entire screen while preventing deterioration of As a result, for example, even if the movement is of a low level, if the high-frequency component is not included so much, the S of the YC level is used.
Since the / N improvement amount suppression is prohibited, the improvement amount becomes larger than that in the case where the S / N improvement amount control signal generation circuit 118 is controlled only by the low-level movement. Further, even if the number of pixels of the low-level high-frequency motion component is small on the entire screen, if the ratio in the low-level area is large, the S / N improvement amount of the area can be suppressed to a low level, so the high-frequency motion can be suppressed. Blurring of ingredients is suppressed.

(Embodiment 24) FIG. 35 is a block diagram of a noise reduction device according to Embodiment 24 . In FIG. 35, 1 is an input terminal for inputting a video signal, 118 is an S / N improvement amount control signal generation circuit for outputting a non-linear signal to the input signal, 43 is a subtractor, 44 is a non-linear limiter, and 45 is an addition. , 42 is a frame memory for storing one frame of video, 10 is an output terminal for outputting a noise-reduced signal, 41 is a non-cyclic noise reduce circuit whose S / N improvement amount is variable, and 131 is an input A low level detection circuit which outputs a signal only when the pixel of the Y signal of the input video signal is smaller than a certain level, 132 represents the high frequency component of the Y signal of the input video signal, and the absolute value of the high frequency component Is a high-frequency component detection circuit that outputs a signal only when is above a certain level, 130 is an input of the output of the subtractor 43 which is a difference signal between one frame of the input signal, and the difference signal between one frame is above a certain level Motion to output signal only when The output circuit 113 receives the output of the low level detection circuit 131, the output of the high frequency component detection circuit 132 and the output of the motion detection circuit 130 as an input and outputs a signal only when the input signal is a low level and high frequency component motion. AND circuit 114 is a first AND circuit for counting the number of outputs of the low-level signal detection circuit 131 per field.
Counter, 115 is an AND circuit 113 per field
A second counter that counts the number of outputs of the second counter, 116 is a divider that calculates the quotient of the output of the second counter 115 divided by the output of the first counter 114, and 117 is the output of the divider 116 that exceeds the threshold value. It is a threshold circuit that outputs 0 when it is exceeded and 1 when it is not exceeded as a YC level control fixed signal. FIG. 21 is a block diagram showing the configuration of the S / N improvement amount control signal generation circuit 118 in FIG. Since FIG. 21 is the same as that already described, the description is omitted. In addition, the nonlinear limiter 44 in FIG.
Figure 4 shows the characteristics. This implementation configured as above
The operation of the noise reduction device of this form will be described below. Incidentally, the same as the previously described embodiments describing the same numbers.

The noise reduce circuit 41 is a non-recursive noise reducer using the differential signal between 1 frames described in the second embodiment. When the differential signal between 1 frames is small, it is regarded as noise and noise reduction is performed. , If it is large, it is regarded as movement and no noise reduction is applied to prevent multi-line blurring in the movement part. Further, the nonlinear limiter 44 can change the S / N improvement amount by the output signal of the S / N improvement amount control signal generation circuit 118.
As shown in FIG. 4, as the value of the S / N improvement amount control signal becomes smaller, the output range of the nonlinear limiter 44 becomes narrower, so that the S / N improvement amount becomes smaller and the motion blur becomes less.

Next, the generation of the YC level control fixed signal for controlling the output of the S / N improvement amount control signal generation circuit will be described. The number of pixels in one field of the signal detected by the low-level signal detection circuit 131 is counted by the first counter 114. At the same time, the AND circuit 113 outputs only when the input signal is a low-level and high-frequency component movement, and the counter 2 counts the number of pixels in one field. The output ratios of these counters are obtained by a divider 116 and compared with a preset threshold value by a threshold circuit 117, and a binarized signal is output as a YC level control fixed signal. In the present embodiment , 0 is output when the ratio of motion of the high frequency component in the low level region in one field is high, and 1 is output when the ratio is low.

The S / N improvement amount control signal generation circuit 118 for controlling the non-linear limiter 44 to generate the control signal for changing the S / N improvement amount is exactly the same as that described in the eleventh embodiment . As shown in 22, when the YC level control fixed signal is 1, the S / N improvement amount control signal generation circuit 118
The output of is fixed.

[0135] As described above, according to this embodiment, S
Due to the characteristics of the / N improvement amount control signal generation circuit 118, the S / N ratio of the area where the luminance signal level is low and the saturation degree of the color signal is low is higher than that of the area where the luminance signal level is high and the color signal saturation is high.
By reducing the improvement amount, the S / N improvement amount is reduced in regions where the level is low and it is difficult to distinguish between signal and noise, and motion blur due to noise reducers is suppressed, and in regions where the luminance signal level is high and color saturation is high. In addition to being able to perform an appropriate S / N improvement, the adaptive control by the signal level is cut off only when the ratio of the movement of the high frequency component in the low level region is small, so that the high frequency component of the low level region is blocked. It is possible to achieve sufficient S / N improvement on the entire screen while preventing deterioration of As a result, for example, even if the movement is of a low level, if the high-frequency component is not included so much, the S of the YC level is used.
Since the / N improvement amount suppression is prohibited, the improvement amount becomes larger than that in the case where the S / N improvement amount control signal generation circuit 118 is controlled only by the low-level movement. Further, even if the number of pixels of the low-level high-frequency motion component is small on the entire screen, if the ratio in the low-level area is large, the S / N improvement amount of the area can be suppressed to a low level, so the high-frequency motion can be suppressed. Blurring of ingredients is suppressed.

In all the embodiments , the characteristics of the YC level circuit are such that the Y signal and the C signal are both output as shown in FIG. 3, but only the Y signal or the C signal is output. It may be a characteristic that outputs a signal based on. The input video signal may be a signal such as a MUSE in which a luminance signal and a color difference signal are time-multiplexed, and the color difference signal is line-sequential. In that case, a decoding circuit for matching the timing of the color difference signal with the luminance signal is used. By providing the same effect. Also, the input signal is MUSE
Needless to say, in the case of a signal in which sub-samples make one round in four fields as described above, the cyclic and non-cyclic noise reducers use two-frame differences. The configuration of the noise reducer, (form the Y signal of the embodiment) signal applying noise Reduce, S / N improving amount control method are not limited to those described in the above embodiment,
Other configurations may be used as long as the S / N improvement amount can be controlled from the outside. The characteristic of the nonlinear limiter shown in FIG. 4 is not limited to this, and may include the improvement amount 0 as long as the S / N improvement amount can be changed. Further, Y threshold circuits 35, 68, 88, 108, 125, C threshold circuits 36, 69, 89, 109, 126, high frequency component threshold circuit 70,
Motion information decoding circuits 81, 101, high frequency component detection circuit 132,
Motion detection circuit 130, output of threshold circuit 117, number of bits,
In addition, the output characteristics and the number of bits of the YC level circuits 37, 71, 90, 110, 127 are not limited to those shown in the present embodiment , and a signal for changing the S / N improvement amount of the noise reduce circuit is used. Others may be used as long as they are generated. Furthermore, the part that is performing the binarization process may be multivalued. Further, the low-pass filter 52, the high-pass filter 61, and the high-frequency component detection circuit 132 may be configured to obtain any of two-dimensional frequency components in the horizontal direction, the vertical direction, and the horizontal and vertical directions. In addition, the motion detection and the high-frequency component motion detection methods in Embodiments 17 to 24 are the same as the embodiment.
The present invention is not limited to the configuration described in the above, and similar effects can be obtained even if it is obtained by frequency separation such as Hadamard transform. Further, in the sixth embodiment , the high frequency component is subtracted by the subtractor 53.
However, it is also possible to newly provide a high-pass filter and obtain a high-frequency component from the input signal. In Embodiments 21 to 24 , the motion signal and the high frequency component signal are separately detected to obtain the motion of the high frequency component. However, another configuration may be used as long as the motion of the high frequency component can be detected. For example, a high frequency component detection circuit may be provided at the output of the motion detection circuit to detect the movement of the high frequency component. In addition , in Embodiments 11 to 24, it is assumed that the input video is an interlaced signal and the counter 11
Although 4,115 is configured to count the number of pixels on a field-by-field basis, the input signal is not limited to the interlaced signal, and the video section for counting the number of pixels may be any area, or any number of fields or frames. Embodiment 11
24 to 24 , the S / N improvement amount control signal generation circuit 118
The output of is controlled by the threshold circuit 117 on a field-by-field basis, but the S / N improvement amount control signal generation circuit 11
With respect to the pixel having a high signal level, that is, in the bright area according to 8, processing for increasing the improvement amount may be added.

[0137]

As described above, according to the present invention, when the number of pixels of the high frequency component having a low signal level does not exceed the threshold value on the entire screen, blurring of the high frequency component is less likely to occur. The number of pixels of high frequency components having a low signal level is configured by not performing control to suppress the S / N improvement amount of the noise reducer according to at least one of the luminance signal level and the absolute value level of the color difference signal. In the case of an image with a small number of images, the S / N is improved on the entire screen, and the practical effect is great.

According to the present invention, when the ratio of the high frequency component in the low signal level area does not exceed the threshold value, the high frequency component is less likely to be blurred. By adopting a configuration in which the control for suppressing the S / N improvement amount of the noise reducing means in accordance with at least one of the absolute value levels is not performed, a screen with a small proportion of high frequency components in a low signal level area is displayed. , S / N improvement is applied to the entire screen, and even if the number of pixels of low level high frequency components is small on the entire screen, if the ratio in the low level area is large, the S / N improvement amount in that area Is suppressed to a low level, so that blurring of high frequency components is suppressed, and its practical effect is great.

According to the present invention, when the number of pixels of the motion component having a low signal level does not exceed the threshold value on the entire screen, there is little motion and blurring due to the motion is less likely to occur. By controlling the noise reduction means to suppress the S / N improvement amount according to at least one of the absolute value levels of the S / N is improved, and its practical effect is great.

According to the present invention, when the ratio of the motion component in the area where the signal level is low does not exceed the threshold value, there is little motion and blurring due to motion is less likely to occur. Noise reduction means S / N according to at least one of the absolute value levels of
By making a configuration that does not control the amount of improvement,
On a screen with a low proportion of motion components in a low signal level area, S / N is improved on the entire screen, and even if the number of pixels with low motion components is small in the entire screen, If the ratio of is large, the amount of S / N improvement in that region can be suppressed to a low level, so blurring of motion components can be suppressed,
Its practical effect is great.

According to the present invention, when the number of pixels in the high frequency component motion having a low signal level does not exceed the threshold value on the entire screen, the motion is small, but the motion blur is less likely to occur. Pixels of high-frequency components having a low signal level are configured by not performing control to suppress the S / N improvement amount of the noise reducer according to at least one of the signal level and the absolute value level of the color difference signal. In the case of a small number of images, S / N improvement is applied to the entire screen. For example, even if the movement is at a low level, if the high frequency component is not included too much, the suppression of the S / N improvement amount by the YC level is prohibited. Compared with the case where the S / N improvement amount control signal generating circuit is controlled only by the low-level movement, the improvement amount becomes large and the practical effect thereof is great.

According to the present invention, when the ratio of the edge component of the motion of the high frequency component in the low signal level area does not exceed the threshold value, the motion is small but the motion blur is less likely to occur. Therefore, in a region where the signal level is low, the control is not performed to suppress the S / N improvement amount of the noise reducer according to at least one of the luminance signal level and the absolute value level of the color difference signal. On a screen where the proportion of high-frequency component movement is small, S / N improvement is applied to the entire screen. For example, if there is not much high-frequency component even for low-level movement, the S / N improvement amount according to the YC level. Since the suppression is prohibited, the improvement amount becomes large as compared with the case where the S / N improvement amount control signal generation circuit is controlled only by the low level movement. Further, even if the number of pixels of the low-level high-frequency motion component is small on the entire screen, if the ratio in the low-level area is large, the S / N improvement amount of the area can be suppressed to a low level, so the high-frequency motion can be suppressed. Blurring of ingredients is suppressed,
Its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a noise reduction device according to a first embodiment of the present invention .

FIG. 2 is a configuration diagram of an S / N improvement amount control signal generation circuit 5.

FIG. 3 is a diagram showing a relationship between inputs and outputs of a YC level circuit in all the embodiments of the present invention .

FIG. 4 is an input / output characteristic diagram of a non-linear limiter in all the embodiments of the present invention .

FIG. 5 is a block diagram of a noise reduction device according to a second embodiment of the present invention .

FIG. 6 is a block diagram of a noise reduction device according to a third embodiment of the present invention .

FIG. 7 is a block diagram of a noise reduction device according to a fourth embodiment of the present invention .

FIG. 8 is a configuration diagram of an S / N improvement amount control signal generation circuit 62.

FIG. 9 is a diagram showing an output of an S / N improvement amount control signal generation circuit 62.

FIG. 10 is a block diagram of a noise reduction device according to a fifth embodiment of the present invention .

FIG. 11 is a block diagram of a noise reduction device according to a sixth embodiment of the present invention .

FIG. 12 is a block diagram of a noise reduction device according to a seventh embodiment of the present invention .

FIG. 13 is a configuration diagram of an S / N improvement amount control signal generation circuit 82.

FIG. 14 is a diagram showing an output of an S / N improvement amount control signal generation circuit 82.

FIG. 15 is a block diagram of a noise reduction device according to an eighth embodiment of the present invention .

FIG. 16 is a block diagram of a noise reduction device according to a ninth embodiment of the present invention .

FIG. 17 is a configuration diagram of an S / N improvement amount control signal generation circuit 102.

FIG. 18 is a diagram showing an output of the S / N improvement amount control signal generation circuit 102.

FIG. 19 is a block diagram of a noise reduction device according to a tenth embodiment of the present invention .

FIG. 20 is a block diagram of a noise reduction device according to an eleventh embodiment of the present invention .

FIG. 21 is a configuration diagram of an S / N improvement amount control signal generation circuit 118.

FIG. 22 is a diagram showing the output of the S / N improvement amount control signal generation circuit 118.

FIG. 23 is a block diagram of a noise reduction device according to a twelfth embodiment of the present invention .

FIG. 24 is a block diagram of a noise reduction device according to a thirteenth embodiment of the present invention .

FIG. 25 is a block diagram of a noise reduction device according to a fourteenth embodiment of the present invention .

FIG. 26 is a block diagram of a noise reduction device according to a fifteenth embodiment of the present invention .

FIG. 27 is a block diagram of a noise reduction device according to a sixteenth embodiment of the present invention .

FIG. 28 is a block diagram of a noise reduction device according to a seventeenth embodiment of the present invention .

FIG. 29 is a block diagram of a noise reduction device according to an eighteenth embodiment of the present invention .

FIG. 30 is a block diagram of a noise reduction device according to a nineteenth embodiment of the present invention .

FIG. 31 is a block diagram of a noise reduction device according to a twentieth embodiment of the present invention .

FIG. 32 is a block diagram of a noise reduction device according to a twenty-first embodiment of the present invention .

FIG. 33 is a block diagram of a noise reduction device according to a twenty-second embodiment of the present invention .

FIG. 34 is a block diagram of a noise reduction device according to a twenty- third embodiment of the present invention .

FIG. 35 is a block diagram of a noise reduction device according to a twenty-fourth embodiment of the present invention .

FIG. 36 is a block diagram of a conventional noise reduction device.

FIG. 37 is an input / output characteristic diagram of a non-linear limiter in a conventional noise reduction device.

FIG. 38 is a block diagram of another conventional noise reduction device.

[Explanation of symbols]

1 Y signal input terminal 4 Absolute value circuit 5,62,82,102,118 S / N improvement amount control signal generation circuit 7,44,54,503 Nonlinear limiter 9,42,504 frame memory 34,67,87,107,124 Minimum value circuit 35,68,88,108,125 Y threshold circuit 36,69,89,109,126 C threshold circuit 37,71,90,110,127 YC level circuit 70 High frequency component threshold circuit 81,101 Motion information signal decoding circuit 91 AND circuit 72,111,128 OR circuit 113 AND circuit 114,115 counter 116 divider 117 Threshold circuit

Front page continued (72) Inventor Atsushi Ishizu 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-300409 (JP, A) JP-A-4-176269 (JP , A) JP-A-5-304622 (JP, A) JP-A-4-273669 (JP, A) JP-A-5-115069 (JP, A) JP-A-6-141288 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 5/14-5/217

Claims (18)

(57) [Claims] 1. A video signal is input, and the input video signal is input.
On the other hand, noise reduction means that can change the S / N improvement amount
And input the video signal to the signal level of the video signal.
S / N improvement amount control signal generation that outputs a corresponding signal for each pixel
And a low level signal detecting means for inputting the luminance signal of the video signal and outputting a signal having a level lower than a predetermined value,
High-frequency component detecting means for inputting the video signal and detecting a high-frequency component of the video signal; logic means for inputting the outputs of the low-level signal detecting means and the high-frequency component detecting means;
A counter for counting the number of outputs of the logic means in a predetermined video section using the output of the logic means as an input, and a threshold value means for receiving the output of the counter and comparing the value with a predetermined value to output a magnitude relationship. The threshold value means
Force controls the output of the S / N improvement amount control signal generating means.
Of the S / N improvement amount control signal generating means.
The S / N improvement amount of the noise reducing means is determined by the output.
A noise reduction device characterized by controlling . 2. The logic means outputs a signal only when the input signal of the logic means is at a low level and a high frequency component is detected, and the output of the S / N improvement amount control signal generating means. Is the counter of the counter in the threshold means
Output noise reduction apparatus according to claim 1, wherein the S / N improving amount is controlled to increase to indicate smaller result than a predetermined value. 3. A video signal is input, and the input video signal is input.
On the other hand, noise reduction means that can change the S / N improvement amount
And input the video signal to the signal level of the video signal.
S / N improvement amount control signal generation that outputs a corresponding signal for each pixel
And a low level signal detecting means for inputting the luminance signal of the video signal and outputting a signal having a level lower than a predetermined value,
A first counter that counts the number of pixels that have been determined to be at a low level in a predetermined video section using the output of the low level signal detection means as an input, and a high counter that receives the video signal and detects a high frequency component of the video signal. Band component detecting means, logic means for receiving the outputs of the low level signal detecting means and the high band component detecting means, and the number of outputs of the logic means in a predetermined video section with the output of the logic means as input. A second counter for counting, an output of the first counter and the second counter
The output of the counter and the input to the dividing means for determining the ratio of the two inputs the output of said dividing means comprises a threshold means for outputting a comparison to the magnitude relationship between the predetermined value, the
The S / N improvement amount control signal is generated by the output of the threshold value means.
The output of the generating means is controlled and this S / N improvement amount system
The noise reducing means is based on the output of the control signal generating means.
A noise reduction device characterized by controlling the S / N improvement amount of 4. The logic means outputs a signal only when an input signal of the logic means is at a low level and a high frequency component is detected, and the output of the S / N improvement amount control signal generating means. Is the dividing means in the threshold means
4. The noise reduction device according to claim 3 , wherein the S / N improvement amount is controlled to be large when the output of the above-mentioned shows a result smaller than a predetermined value . Wherein said S / N improving amount control signal generation means, according to claim 1 or 3, wherein the outputting a signal corresponding to at least one of the luminance signal or the chrominance signal of the video signal Noise reduction device. 6. The S / N improvement amount control signal generating means outputs a control signal for reducing the S / N improvement amount of the noise reducing means when the luminance signal level and the absolute value level of the color difference signals are low. The noise reduction device according to claim 1 or 3 , characterized in that. 7. A video signal is input, and the input video signal is input.
On the other hand, noise reduction means that can change the S / N improvement amount
And input the video signal to the signal level of the video signal.
S / N improvement amount control signal generation that outputs a corresponding signal for each pixel
And a low level signal detecting means for inputting the luminance signal of the video signal and outputting a signal having a level lower than a predetermined value,
Motion detection means for detecting motion in at least one field period, logic means for receiving the output of the low-level signal detection means and the motion detection means, and output for the logic means as an input in a predetermined video section It comprises a counter for counting the number of outputs of the logic means, and threshold means for inputting the output of the counter and comparing it with a predetermined value to output a magnitude relation. The S / N is provided by the output of the threshold means.
While controlling the output of the improvement amount control signal generating means,
The output of the S / N improvement amount control signal generation means
Characterized by controlling the S / N improvement amount of the reduce means
Noise reduction device to. 8. The logic means outputs a signal only when the input signal of the logic means is at a low level and is moving, and the output of the S / N improvement amount control signal generating means is the threshold value. In the means , the output of the counter is above a predetermined value.
The noise reduction device according to claim 7 , wherein the noise reduction device is controlled so as to increase the S / N improvement amount when the result is smaller than the above. 9. A video signal is input, and the input video signal is input.
On the other hand, noise reduction means that can change the S / N improvement amount
And input the video signal to the signal level of the video signal.
S / N improvement amount control signal generation that outputs a corresponding signal for each pixel
And a low level signal detecting means for inputting the luminance signal of the video signal and outputting a signal having a level lower than a predetermined value,
A first counter that counts the number of pixels determined to be at a low level in a predetermined video section using the output of the low-level signal detection means as an input, a motion detection means that detects motion in at least one field period, and the low counter A logic means which receives the output of the level signal detecting means and the motion detecting means; a second counter which receives the output of the logic means and counts the number of outputs of the logic means in a predetermined video section; and the first counter. the output of the counter and receiving the output of said second counter and dividing means for determining the ratio of the two, and a threshold means for outputting a comparison to the magnitude relationship to a predetermined value and an output of said dividing means The output of the threshold means
Control the output of the S / N improvement amount control signal generating means.
And the output of this S / N improvement amount control signal generating means.
To control the S / N improvement amount of the noise reducing means by
A noise reduction device characterized by: 10. The logic means outputs a signal only when the input signal of the logic means is at a low level and is moving, and the output of the S / N improvement amount control signal generating means is the threshold value. In the means , the output of the dividing means is predetermined
The noise reduction device according to claim 9 , wherein the noise reduction device is controlled so that the S / N improvement amount is increased when the result is smaller than the value . 11. The S / N improvement amount control signal generating means comprises:
10. The noise reduction device according to claim 7, wherein a signal corresponding to at least one of a luminance signal and a color difference signal in the video signal is output. 12. The S / N improvement amount control signal generating means comprises:
Claim and outputs a control signal to reduce the S / N improving amount of said noise Reduce means when the luminance signal level and the absolute value level of the color difference signal low 7 or 9
The described noise reduction device. 13. A video signal is input and the input video signal is input.
Noise reducer that can change S / N improvement amount against
And the signal level of the video signal input to the stage
S / N improvement amount control signal for outputting a signal corresponding to each pixel
Generating means, low level signal detecting means for inputting a luminance signal of the video signal and outputting a signal having a level lower than a predetermined value, motion detecting means for detecting motion in at least one field period, and inputting the video signal And high-frequency component detecting means for detecting high-frequency components of the video signal, logic means for receiving the outputs of the low-level signal detecting means, the motion detecting means and the high-frequency component detecting means, and the logic. A counter for counting the number of outputs of the logic means in a predetermined video section using the output of the means as an input; and a threshold value means for receiving the output of the counter and comparing with a predetermined value to output a magnitude relationship , By the output of the threshold means,
Controlling the output of the S / N improvement amount control signal generating means
The output of the S / N improvement amount control signal generating means
Controlling the S / N improvement amount of the noise reducing means
Noise reduction device characterized by. 14. The logic means outputs a signal only when the input signal of the logic means is at a low level and is a movement of a high frequency component, and the output of the S / N improvement amount control signal generation means is The output of the counter in the threshold means
The S / N improvement amount is controlled to be large when the force shows a result smaller than a predetermined value.
13. The noise reduction device according to 13 . 15. A video signal is input, and the input video signal
Noise reducer that can change S / N improvement amount against
And the signal level of the video signal input to the stage
S / N improvement amount control signal for outputting a signal corresponding to each pixel
Generating means, low-level signal detecting means for inputting a luminance signal of the video signal and outputting a signal having a level lower than a predetermined value, and output of the low-level signal detecting means as inputs to determine low level in a predetermined video section A first counter that counts the number of the generated pixels, a motion detection unit that detects a motion in at least one field period, and a high frequency component detection unit that receives the video signal and detects a high frequency component of the video signal. A logic means having inputs of the output of the low level signal detecting means, the output of the motion detecting means and an output of the high frequency component detecting means, and an output of the logic means in a predetermined video section with the output of the logic means as an input. A second counter for counting the number, a division means for inputting the output of the first counter and the output of the second counter, and a ratio of the two, and an output of the division means And provided with a threshold value means for outputting the magnitude relationship is compared with a predetermined value, said threshold means
The output of the S / N improvement amount control signal generating means is output.
Controlling and S / N improvement amount control signal generating means
S / N improvement amount of the noise reducing means by the output of
A noise reduction device characterized by controlling. 16. The logic means outputs a signal only when the input signal of the logic means is at a low level and is a movement of a high frequency component, and the output of the S / N improvement amount control signal generating means is In the threshold value means of the division means
The noise reduction device according to claim 15 , wherein the S / N improvement amount is controlled to be large when the output shows a result smaller than a predetermined value . 17. The S / N improvement amount control signal generating means comprises:
The noise reduction device according to claim 13 or 15, wherein a signal corresponding to at least one of a luminance signal and a color difference signal of the video signals is output. 18. The S / N improvement amount control signal generating means,
Luminance signal level, claim 13 or, characterized in that the absolute value level of the color difference signal and outputs a control signal to reduce the S / N improving amount of said noise Reduce means is lower
15. The noise reduction device according to 15 .