JP2531096B2 - Motion detection circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion adaptive Y / C for separating a luminance signal (hereinafter referred to as Y signal) and a chrominance signal (hereinafter referred to as C signal) from a composite video signal in accordance with the motion of an image.
The present invention relates to a motion detection circuit in a separation circuit, and more particularly to a motion detection circuit that detects a change in hue.

[0002]

2. Description of the Related Art A block diagram of an example of a conventional motion adaptive Y / C separation circuit is shown in FIG. In the figure, an input terminal 1 is supplied with an NTSC composite video signal (hereinafter referred to as V signal) sampled at a clock which is four times the color subcarrier frequency (FSC). The V signal input from the terminal 1 is input to the intra-field Y / C separation circuit 2, the inter-framer Y / C separation circuit 3, the Y signal motion detection circuit 7, and the C signal motion detection circuit 8. Further, the output of the Y signal motion detection circuit 7 (my) and the output of the C signal motion detection circuit 8 (mc) are input to the synthesis circuit 9. The Y signal motion detecting circuit 7, the C signal motion detecting circuit 8 and the synthesizing circuit 9 constitute a motion detecting circuit 10.

Further, the Y signal mixing circuit 4 detects a motion of the Y signal (y1) separated by the intra-field Y / C separation circuit 2 and the Y signal (yf) separated by the inter-frame Y / C separation circuit 3. The output (m) of the circuit 10 is input, and the C signal mixing circuit 5 separates the C signal separated by the intra-field Y / C separation circuit 2.
The signal (c1), the C signal (cf) separated by the inter-frame Y / C separation circuit 3, and the output (m) of the motion detection circuit 10 are input. The output of the Y signal mixing circuit 4 is output from the terminal 6a as a Y signal output of Y / C separation, and the output of the C signal mixing circuit 5 is output from the terminal 6b as a C signal output of Y / C separation.

The Y signal motion detection circuit 7 is constructed, for example, as shown in FIG. 8, and uses the Y comb filter 11 to extract the Y signal from the V signal input from the terminal 1b, and the 1-frame delay circuit 1 and the subtractor. 13 is used to obtain the one-frame difference of the Y signal, the absolute value circuit 14 obtains the absolute value, and the non-linear conversion circuit 15 converts the absolute value into a signal (my) indicating the amount of movement of the Y signal. The signal is output from the terminal 16 (this nonlinear circuit has, for example, the characteristic shown in FIG. 2).

The Y comb filter 11 is constructed as shown in FIG. 9, for example, and a 1-line delay circuit 17 and an adder 18 constitute a vertical filter, and a low pass filter (hereinafter referred to as LPF) 19 constitutes a horizontal filter. Then, the Y signal is separated.

The C signal motion detection circuit 8 is constructed, for example, as shown in FIG. 10 (see Japanese Patent Application Laid-Open No. 1-162089. However, since the 1-frame delay circuit and the C comb filter are linear processing, the processing is performed. The order is reversed). Here, using the C comb filter 21, the terminal 1
The C signal is extracted from the V signal input from d, the 1-frame difference of the absolute value of the C signal is obtained using the 1-frame delay circuit 22, the absolute value circuits 23 and 24, and the subtracter 25, and the absolute value circuit 26 Then, the absolute value is obtained, and the absolute value is converted into a signal (mc) indicating the amount of movement of the C signal by the non-linear conversion circuit 27 and output from the terminal 28.

The C-comb filter 21 is constructed, for example, as shown in FIG. 11, and a 1-line delay circuit 31 and a subtractor 32 constitute a vertical filter, and a band pass filter (hereinafter referred to as BPF).
33) forms a horizontal filter to separate the C signal. Further, the synthesizing circuit 9 uses, for example, the Y signal motion amount (m
y) and the C signal movement amount (mc), the larger value is selected and output.

The determination result by the motion detection circuit 10 having the above-described configuration is expressed in the form of a motion coefficient k (0≤k≤1). For example, when it is determined that the still image is a perfect still image, k =
0, and when it is determined that the moving image is complete, k = 1.

The inter-frame Y / C separation circuit 3 is configured, for example, as shown in FIG. 12, and the yf signal is extracted by the 1-frame delay circuit 41 and the adder 42 and output from the terminal 44a to output the 1-frame delay circuit 41. Cf by subtractor 43
The signal is extracted and output from the terminal 44b.

Further, the in-field Y / C separation circuit 2 is
For example, the one-line delay circuit 45 configured as shown in FIG.
And the adder 46 extract the yl signal and output it from the terminal 48a, and the 1-line delay circuit 45 and the subtractor 47 c
The l signal is extracted and output from the terminal 48b.

Since the Y comb filter 11 and the C comb filter 21 are linear processing, the processing is performed by one frame delay circuit 1.
It may be changed after 2, 22. In that case, the 1-frame delay circuits 41, 12, 22 can be shared by one 1-frame delay circuit.

Y signal mixing circuit 4 and C signal mixing circuit 5
Then, according to the motion coefficient k, Y = k · yl + (1-k) · yf C = k · cl + (1-k) · cf, that is, in the field Y / C When the output of the separation circuit 2 is increased, and when it is determined to be a still image, the inter-frame Y / C separation circuit 3 is mixed so that the output of the output is increased.

Here, as shown in FIG. 14A, the Y signal is flat, the hue one frame before is θ1, and the hue of the current frame is θ.
Let us consider the case where a signal such that θ1 + θ2 = 180 degrees is input when the value is 2. Here, the V signal input from the terminal 1 can correspond to the line n, the output of the 1-line delay circuit 45 to the line n-1, and the outputs of the 1-frame delay circuits 41 and 22 to the line n '. Now, the C signal of the n line is Cn (iT) = A.sin (2πf _SC iT + θ2) where A: C signal amplitude f _SC : sub-carrier frequency of color T: sampling period = 1/4 f _SC i = 0, 1, 2. , if indicated and ...., 'each line of the signal Cn-1 (iT) = - a · sin (2πf SC iT + θ2) Cn' n-1, n expressed as (iT) = a · sin ( 2πf SC iT + θ1) (Here, π = 180 degrees).

At this time, the subtracter 2 of the C signal motion detection circuit 8
5 outputs are | Cn (iT) | − | Cn ′ (iT) | = | A · sin (2πf _SC iT + θ2) | − | A · sin [2πf _SC iT + (π−θ2)] | = 0 (where θ1 + θ2 = π) and it is determined to be a still image.

However, the inter-frame Y / C separation circuit 3
14B, erroneous Y / C separation is performed as shown in FIG. 14B, and the C signal enters the Y signal output, which should be originally flat, and appears as dot interference.

The C signal motion detection circuit 8 shown in FIG. 10 has the characteristics shown in FIG. 15 for the hues θ1 and θ2 of the V signal. In FIG. 15, 1) θ1-θ2
= (180 degrees) (C) is the original amount of change in the NTSC signal and may be determined to be stationary. 2) When θ1 = θ2 (D) is the same as the still image of the Y signal. As described above, the C signal motion detection circuit using the 1-frame delay circuit is a limit point where motion cannot be detected. Also 3) θ1 + θ
When 2 = 180, 360, and 540 degrees (E), it can be said that it is determined to be stationary due to erroneous detection.

Although the motion adaptive Y / C separation circuit has been described above, the motion detection circuit is also used in a motion adaptive scanning line interpolating device for converting interlaced scanning into progressive scanning, and similarly, a motion erroneous motion is detected. The problem of detection occurs.

[0018]

In the conventional motion detection circuit described above, a still image is generated for a V signal in which the entire frame hue θ1 and the current frame hue θ2 are θ1 + θ2 = 180,360,540 degrees. Y /
There is a problem in that C separation is incomplete and dot interference occurs.

An object of the present invention is to solve such problems and provide a motion detection circuit which prevents erroneous detection of a still image of a V signal.

[0020]

The motion detecting circuit according to the present invention has a structure in which a color signal of a composite video signal is input and an image of the image is detected.
A one-frame delay circuit that gives a delay of one frame, and a first hue that receives the output of the one-frame delay circuit and the color signal and adds the inputs to detect a first hue region that is a motion region. A detection circuit, a second hue detection circuit for inputting the output of the one-frame delay circuit and the color signal, detecting the signs of these inputs, and detecting a second hue region which is a static region; A first absolute value circuit for inputting the output of the delay circuit and outputting its absolute value, a second absolute value circuit for inputting the color signal and outputting its absolute value, and these first and second absolute values A subtractor that inputs the output of the circuit and outputs the difference between them, a third absolute value circuit that inputs the output of the subtractor and outputs the absolute value thereof, an output of the third absolute value circuit and the Input the outputs of the first and second hue detection circuits, and And having a motion amount control circuit for detecting a region to be a specific still region from Luo each output logically.

[0021]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the V signal is input from the terminal 1d and processed up to the absolute value circuit 26 in the same manner as in the conventional C signal motion detection circuit of FIG. Further, the output of the 1-frame delay circuit 22 and the output of the C comb filter 21 are input to the adder 54, and the sum thereof is the absolute value circuit 55 and the nonlinear conversion circuit 56.
It is converted to a signal mc2 representing the first hue through and and output.

The non-linear conversion circuit 56 has a characteristic as shown in FIG. 2, for example, and has a constant output (K1) up to a constant input value (L1) and zero output when the input reaches a predetermined value (L2). I am trying to become.

The adder 54, the absolute value circuit 55, and the non-linear conversion circuit 56 constitute a first hue detection circuit 51.

The code detection circuit 61 detects the code of the output of the one-frame delay circuit 22, and the code detection circuit 62 detects C.
The output of the comb filter 21 is output, the exclusive OR circuit (hereinafter referred to as EXOR) 63 determines whether the code detectors 61 and 62 are in agreement, and the delay circuits 64 and 65 and the inverters 66 and 6 are used.
9, 70 and AND circuit (hereinafter referred to as AND) 67, 71
Then, the signal is converted into a signal mc3 representing the second hue through an OR circuit (hereinafter referred to as OR) 68 and a coefficient unit 72 and output.

The sign detection circuits 61 and 62 output "0" when the input signal is positive or 0, and output "1" when the input signal is negative. The EXOR 63 outputs "0" when the codes match and outputs "1" when the codes do not match. Code detection circuits 61 and 62, EXOR 63 and delay circuit 64,
65, inverters 66, 69 and 70, AND 67, 71 and O
The R68 and the coefficient unit 72 form a second hue detection circuit 52.

The output of the first hue detecting circuit 51 and the output of the second hue detecting circuit 52 are input to the subtractor 57, and the output of the absolute value circuit 26 and the output of the subtractor 57 are input to the adder 58. . Further, the subtractor 57 and the adder 58 constitute a motion amount control circuit 53, and the output of the adder 58 is passed through the non-linear conversion circuit 27 to obtain a signal (m
It is output from the terminal 28 as c).

When the output of the absolute value circuit 26 is mc1, the characteristics of the output mc1 are almost the same as those shown in FIG. 15, and (1) θ1-θ2 = 180, 360, 540 degrees is determined to be stationary. To be done.

On the other hand, in the first hue detection circuit 51, as shown in FIG.
As shown in (a), when θ1−θ2 = ± 180 degrees, the adder 54
Output becomes small and mc2 = k1.

Further, in the second hue detection circuit 52, as shown in FIG.
As shown in (b), θ1 and θ2 are (0 ° <θ1 <90 °
Or 180 ° <θ1 <270 ° and 90 ° <θ2 <1
80 ° or 270 ° <θ2 <360 °), or (9
0 ° <θ1 <180 ° or 270 ° <θ1 <360 °
And 0 ° <θ2 <90 ° or 180 ° <θ2 <270
°), the output of the EXOR 65 is such that "0" and "1" alternately appear, and the delay circuits 64 and 65 and the inverter 6 are turned on.
6 and AND67, the output of EXOR63 is "1, 0,
It is detected that the EXOR 63 output is “0, 0” by the delay circuits 64 and 65, the inverters 69 and 70, and the AND 71.
Then, the OR 68 mixes these two detection results. That is, the output of OR68 is EX
The output of OR63 is "1,0,1" or "0,1,0"
Is output and "1" is output. Then, the coefficient unit 72 outputs mc3 = k1.

These first and second hue detection circuits 5
The characteristics of 1,52 are as shown in FIG. Motion control circuit 5
3, first, consider the operation when mc2 = 0. At this time, since mc3 is added to mc1 by the adder 58, the shaded area B shown in FIG. 4 is newly determined to be moving, and thus the area C shown in FIG. 15 can be determined to be moving. However, it should be judged that it is still still.
There is also an adverse effect that the area A, which is a straight line of A, is partially determined to be moving. Therefore, the subtracter 57 performs mc3-mc2 to prevent the area A in FIG. 4 from being determined to be motion.

Therefore, as shown in the characteristic diagram of FIG. 5, the C signal motion detection circuit 8 is in the case of θ1 = θ2 (D) and θ1-θ2 =
In the case of ± 180 degrees, (C) can be determined to be still.

FIG. 6 shows a block diagram of the second embodiment of the present invention. In the figure, the V signal is input from the terminal 1 and the processing up to the absolute value circuit 26 is the same as that of the conventional C signal motion detection circuit shown in FIG. The processing from the terminal 1a to the absolute value circuit 55 is the same as in the first embodiment.

In this embodiment, the output of the absolute value circuit 55 is used as the input of the comparator 81, and the comparison with the reference level L3 is performed. The adder 54, the absolute value circuit 55 and the comparator 81 constitute a first hue detection circuit 51a. Also, the terminal 81a
The processing from to OR68 is also the same as the embodiment of FIG.

Sign detection circuits 61, 62, EXOR 63, delay circuits 64, 65, inverters 66, 69, 70 and AND
The second hue detection circuit 52 is composed of 67 and 71 and the OR 68. The output of the first hue detection circuit 512 and the output of the second hue detection circuit 52 are mixed through an inverter 82 and an AND 83 and used as a control input of a switch 84. The switch 84 receives mc1 and the reference level k1. When the control input is "0", mc1 is selected, and when it is "1", k1 is selected.

The inverter 82, the AND 83 and the switch 84 constitute a movement amount control circuit 53a. Switch 84
Is output from the terminal 28 as a signal mc indicating the amount of movement of the C signal through the non-linear conversion circuit 27.

In the first hue detection circuit 51a, C in FIG.
Similar to the signal motion detection circuit, θ1 and θ2 are (0 ° <θ1 <
90 ° or 180 ° <θ1 <270 ° and 90 ° <θ
2 <180 ° or 270 ° <θ2 <360 °), or (90 ° <θ1 <180 ° or 270 ° <θ1 <3
60 ° and 0 ° <θ2 <90 ° or 180 ° <θ2 <
270 °), mc3 = “1”.

In the motion amount control circuit 53a, mc3 =
When “1” and mc2 = “0”, the switch 84 selects the reference level k1 and it is determined that the movement is made. Therefore, this C
The characteristics of the signal motion detection circuit are also as shown in FIG.

[0038]

As described above, in the motion detection circuit according to the present invention, the previous frame hue θ1 and the current frame hue θ
There is an effect that even a V signal in which 2 and θ become θ1 + θ2 = 180, 360, 540 degrees can be detected as a moving image.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a characteristic diagram of the nonlinear conversion circuit of FIG.

3A and 3B are waveform diagrams and code diagrams for explaining the operation of FIG.

4 is a characteristic diagram of an example of the hue detection circuit of FIG.

5 is a characteristic diagram of the C signal motion detection circuit of FIG.

FIG. 6 is a block diagram of a second embodiment of the present invention.

FIG. 7 is a block diagram of an example of a conventional motion adaptive Y / C separation circuit.

8 is a block diagram of an example of the Y signal motion detection circuit of FIG.

9 is a block diagram of an example of the Y comb filter of FIG.

10 is a block diagram of an example of the C signal motion detection circuit of FIG. 7.

11 is a block diagram of an example of the C comb filter of FIG.

12 is a block diagram of an example of the inter-frame Y / C separation circuit of FIG.

13 is a block diagram of an example of the intra-field Y / C separation circuit of FIG. 7.

14A and 14B are schematic diagrams and waveform diagrams illustrating the operation of FIG.

15 is a characteristic diagram of an example of the C signal motion detection circuit of FIG.

[Explanation of symbols]

 1, 1a to 1f, 6a, 6b Terminal 2 In-field Y / C separation circuit 3 Inter-frame Y / C separation circuit 4 Y signal mixing circuit 5 C signal mixing circuit 7 Y signal motion detection circuit 8 C signal motion detection circuit 9 Synthesis Circuit 10 Motion detection circuit 11 Y comb filter 12, 22, 41 1 Frame delay circuit 13, 25, 32, 43, 57 Subtractor 14, 23, 24, 26, 47, 55 Absolute value circuit 15, 27, 56 Non-linear conversion Circuit 17, 31, 45 1 line delay circuit 18, 42, 46, 54, 58 Adder 19 LPF 21 C comb filter 33 BPF 51, 51a First hue detection circuit 52, 52a Second hue detection circuit 53, 53a Motion amount control circuit 61,62 Code detection circuit 63 EXOR 64,65 Delay circuit 66,69,70,82 Inverter 67,71,83 A D 68 OR 72 coefficient unit 81 comparator 84 switches

Claims (3)

(57) [Claims] 1. A one-frame delay circuit for inputting a color signal of a composite video signal to delay one frame of an image, and an input of the output of the one-frame delay circuit and the color signal. And a first hue detection circuit for detecting a first hue area which is a moving area, and the output of the 1-frame delay circuit and the color signal are input to detect a sign of these inputs to determine a still area. A second hue detection circuit for detecting the second hue area, a first absolute value circuit for inputting the output of the 1-frame delay circuit and outputting the absolute value thereof, and an absolute value for the color signal. A second absolute value circuit, a subtractor that inputs the outputs of these first and second absolute value circuits and outputs the difference between them, and an output of this subtractor that outputs the absolute value The third absolute value circuit and the output of this third absolute value circuit And a motion amount control circuit for inputting the respective outputs of the first and second hue detecting circuits and logically detecting a specific still region from these respective outputs. . 2. A first hue detection circuit receives an output of a one-frame delay circuit and a color signal and adds them, and an adder for inputting the output of the adder and outputting an absolute value thereof .
Fourth absolute value circuit, the fourth motion detection circuit according to claim 1, further comprising a non-linear conversion circuit for receiving an output of the absolute value circuit. 3. A second code detecting circuit for inputting a 1-frame delay circuit output and detecting the code thereof, and a second code detecting circuit for inputting a color signal and detecting the code thereof. A match detection circuit that inputs the outputs of the first and second code detection circuits and detects a match between them, and a first delay circuit that inputs the output of the match detection circuit and provides a predetermined delay, A second delay circuit that inputs the output of the first delay circuit and gives a predetermined delay, an output of the coincidence detection circuit, and outputs of the first and second delay circuits are input to form a predetermined pattern. A determination circuit for determining that there is,
The motion detection circuit according to claim 1, further comprising a coefficient unit which receives an output of the determination circuit and gives a predetermined coefficient.