JPH04263832A - Electronic endoscope device - Google Patents

Abstract

PURPOSE:To select the data which is optimum for storing it as recording from the data and to edit it after an inspection by an endoscope by writing successively image data which does not generate color slurring as a still image while an object to be photographed is being photographed in a still picture memory, based on a signal from a motion detecting circuit, and recording it in an external storage device each time. CONSTITUTION:Image signals of each color of R, G and B obtained by driving face-sequentially an image pickup means is inputted to a freeze control circuit 33 provided with a motion detector 40, and stored in a still picture memory circuit 30 therefrom. Whenever the storage contents of this still picture memory circuit 30 are rewritten, this image data is stored in an external storage device 51. Also, when a freeze operation is executed, rewriting of the still picture memory circuit is inhibited, based on a signal from a freeze control means 46, and also, a monitor device 50 is switched from an animated picture display state to a still picture display state.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an electronic endoscope used for medical, industrial, etc. purposes, and in particular, when a solid-state image sensor is driven in a frame sequential manner to capture a clear image of a subject. The present invention relates to an electronic endoscope device that is capable of acquiring frozen images.

0002

[Prior Art] As is well known, electronic endoscopes are equipped with a solid-state imaging device such as a CCD at the tip of an insertion section inserted into a body cavity, etc., and in order to reduce the diameter of the insertion section. As the solid-state image sensor, a solid-state image sensor made of a single plate is used, and from the viewpoint of improving resolution, etc., this solid-state image sensor is driven in a frame sequential manner, for example, R (red), G (green), and B.
By sequentially acquiring image data of three colors (blue) and combining these three color images, a simultaneous video signal is generated and a color image of the subject is displayed on a monitor device. Furthermore, it is now possible to display this subject image not only in a moving image state but also in a still image state, and to create a hard copy of the subject image. A freeze control mechanism is provided to obtain such a still image, that is, a frozen image.

[0003] In order to obtain a complete color image of the subject, a plurality of image data that differ over time (in the case of a field image, three image data of each color of R, G, and B, and a frame image) are required. In some cases, it is necessary to synthesize six image data of each color of R, G, and B in odd and even fields, so the relative movement between the subject and the solid-state image sensor installed in the insertion section is required. This does not pose a particularly big problem when displayed as a moving image, but when displayed as a still image, color shift occurs in the image, resulting in poor resolution and difficulty in viewing. Therefore, when acquiring a still image, in order to capture a frozen image in a clear state without color shift, the movement of the subject is detected based on images continuously acquired from a solid-state image sensor. Even if the freeze control is performed, the image is not frozen immediately, but the image is frozen only when the motion detection circuit detects that the subject is stationary. Specifically, A
At the stage before /D conversion, this image signal is taken into a motion detection circuit, and the presence or absence of motion is detected by comparing the image data of the previous and following fields, and it is determined whether the subject is stationary or not. Even if there is, if it is such that color shift does not occur, updating of data in the image memory circuit is prohibited, and the image in this state is displayed on the monitor device.

0004

[Problem to be Solved by the Invention] As mentioned above, when controlling the image freeze operation, if the subject is moving, wait until the subject stops, and then freeze the image when the subject becomes still. However, depending on the condition of the subject, a considerable amount of time may elapse between the freeze operation and the actual display of the frozen image. There is a drawback that the state image cannot be displayed in a timely manner.

[0005] Therefore, the present inventor provided a still image memory means in parallel with the image memory means, and even when the image is not frozen, the still image memory means is loaded every time an image without color shift is obtained as a frozen image. A device was developed in which data regarding the latest still image recorded in the still image memory means is written sequentially, and when a freeze operation is performed, the data regarding the latest still image recorded in this still image memory means is immediately output.
A patent application was filed as No.-139044. The use of the device of this prior invention has extremely excellent advantages such as good responsiveness to freezing operations and the ability to display the frozen image closest to the region and condition currently being observed. However, there is still room for improvement in this prior invention.

By the way, when performing an examination or diagnosis using an endoscope, it is necessary to record the examination. For this purpose, a video tape recorder (VTR) is connected to the processor, and the video state is recorded on the VTR. It goes without saying that it is possible to record video images, but it is also now possible to connect a hard copy device to create hard copies of still images. Here, when observing an image of a subject recorded in an endoscopy, it may be preferable to display it in a still image state rather than in a moving image state in order to perform a detailed inspection. The recording of this still image data is
Data is read from the still image memory circuit only when a freeze operation is performed. However, the image obtained when the freeze operation was performed is not necessarily the optimal image for inspection and diagnosis, and images from before or after the freeze operation are required. In some cases, if the freeze operation is not performed during the operation, no frozen image can be obtained at all.

The present invention has been made in view of the above-mentioned points, and provides an electronic endoscope device that can sequentially record still images without color shift without performing a freeze operation. The purpose is to

[0008]

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention provides an illumination means for sequentially illuminating a subject with light of different wavelengths, and a means for sequentially illuminating a subject with light of different wavelengths under this sequential illumination. An imaging means for photographing an image of a subject, a video signal processing means for processing image signals of each color from the imaging means, and a field memory circuit for storing image data of each color processed by the video signal processing means. , a still image memory circuit provided in parallel with the field memory circuit and selectively capturing image data from the video signal processing means; a motion detection means for determining whether or not there is movement in the subject; still image control means for controlling write and read operations of the still image memory circuit based on signals from the still image memory circuit; The invention comprises an image freezing means for displaying the latest still image on a monitor device, and an external storage device for capturing still image data each time it is sequentially updated in the still image memory circuit and storing this image data. This is a characteristic feature.

[0009]

[Operation] While a subject is being photographed, image data that does not cause color shift as a still image is sequentially written into the still image memory circuit based on the signal from the motion detecting means. The data written in the still image memory circuit in this way is recorded in the external storage device each time. Therefore, by later reading and editing the data stored in this external storage device, an image optimal for recording can be obtained from a large number of still images. Furthermore, all of the image data stored in this external storage device is a clear, high-quality image with no color shift.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, in FIG. 1, 1 represents an endoscope, 10 represents a light source device, and 20 represents a processor. Endoscope 1
has an insertion section 1a that is inserted into a patient's body cavity, etc.,
An illumination light irradiation section 2 and an observation section 3 are provided at the distal end of the insertion section 1a. The emission end 4a of the light guide 4 faces the illumination light irradiation section 2, and an objective lens 5 is attached to the observation section 3, and a CCD 6 is provided as an imaging means at the imaging position of the objective lens 5. ing.

The other end of the light guide 4 is guided into the light source device 10. The light source device 10 is provided with a light source lamp 11, and an aperture 1 is connected between the light source lamp 11 and the incident end 4b of the light guide 4 from the light source lamp 11 side.
2. Condenser lens 13 and rotating color filter 14
are arranged in sequence. The rotating color filter 14 is R(
R filter area 14R that selectively transmits wavelength light (red)
, a G filter region 14G that selectively transmits G (green) wavelength light, and a B filter region 14G that selectively transmits B (blue) wavelength light.
Filter areas 14B are provided with a light blocking area in between. Therefore, when this rotating color filter 14 is rotated, R, G,
Illumination B is sequentially irradiated from the light guide 4 toward the subject.

Signal charges are accumulated in the CCD 6 during each of the R, G, and B illumination periods, and during the light-blocking period, the signal charges accumulated in the CCD 6 are read out, transmitted to the processor 20, and processed. The signal is processed. That is, the signal from the CCD 6 is first sent to the video signal processing circuit 21.
The signal is then transmitted to the signal processor and subjected to well-known signal processing such as signal clamping, blanking processing, and gamma correction. After the signal is processed in this way, it is converted into a digital signal by the A/D converter 22, and the field image signal of each color is sent to each R, G, and B memory 2 constituting the field memory circuit 23.
3R, 23G, and 23B, respectively. In a state where the field image signals of each color of R, G, and B are stored in the field memory circuit 23 in this way, for example, when the R field image signal is taken into the field memory circuit 23, the image data of the memory 23R is is updated, and at the same time, the field memory circuit 23
The two-color field image signals of G and B stored in the R field are read out together with the R field real-time signal, and converted into analog signals by the D/A converters 24R, 24G, and 24B to produce a simultaneous image. It will be output as a signal. This field memory circuit 23
In order to control the rewriting and updating of each memory 23R, 23G, 23B in the rotary color filter 14, a sensor 25 is provided to detect which of the filter areas 14R, 14G, 14B faces the illumination optical path. The R, G, and B enable signals (R-EN, G-EN, and B-EN signals) generated from this sensor 25 are input to the memory control circuit 26, and the VD ( Writing and reading of data to and from the memories 23R, 23G, and 23B are controlled based on control signals consisting of a vertical synchronization signal (vertical synchronization signal), HD (horizontal synchronization signal), and R-EN, G-EN, and B-EN. Then, the output signal from this field memory circuit 23 is sent to a signal output circuit 27 equipped with a color encoder, etc.
, B are mixed to generate a video signal such as NTSC, which is displayed on the monitor device 50.

Next, the circuit configuration for creating a frozen image includes a still image memory circuit 30 provided in parallel with the field memory circuit 23, and this still image memory circuit 30 is similar to the field memory circuit 23. to R memory 3
0R, a G memory 30G, and a B memory 30B, and image signals converted into digital signals are taken into each of these memories 30R, 30G, and 30B by an A/D converter 22. However, unlike the field memory circuit 23, the still image memory circuit 30 is configured not to capture all output signals from the CCD 6, but to selectively capture image signals with no movement. And each of these memories 30R, 30
The output signals of G and 30B are outputted via noise reducers 31R, 31G and 31B for reducing noise. The still image signals from the memories 30R, 30G, and 30B of the still image memory circuit 30 are outputted by the switching means 28 so as to be switchable with the moving image signals from the field memory circuit 23, and the signal output circuit 2
7 to the monitor device 50, and can be displayed selectively with the moving image. Further, from the still image memory circuit 30, noise reducers 31R and 31G
, 31B are routed separately from the route output via the field memory circuit 23 described above.
It is converted into a digital signal by the D/A converters 32R, 32G, and 32B, and output to the signal output circuit 27, and as described later, an external storage device such as a VTR, magnetic disk, optical disk, etc., connected to this signal output circuit 27. 51.

Here, as described above, the still image memory circuit 30 is configured to selectively capture only still images with no color shift, and for this purpose, the video signal processing circuit 21
An output signal from the still image memory circuit 30 is transmitted to the still image memory circuit 30 via a freeze control circuit 33. This freeze control circuit 33 detects the movement of the subject from the signal transmitted from the CCD 6, and only when it is determined that there is no movement, takes in the signal from the A/D converter 22 and rewrites the stored information. It is now possible to do this. Although motion detection can be performed for each R, G, and B color image, for example, the G image signal,
In particular, it is preferable to perform motion detection only on G image signals of even fields from the viewpoint of motion detection accuracy and simplification of processing. Therefore, as a result of motion detection based on this G image signal, if it is determined that there is no motion, in the case of a field image, the sampling time of the following three image data of G, B, and R ( In the case of a frame image, due to the interlaced relationship, it is possible to write to and read from the still image memory circuit 30 for the sampling time of six image data of each color of R, G, and B in odd and even fields. The F-EN signal corresponds to each R, G, and B enable signal (R-
EN, G-EN, B-EN signals) to the still image memory circuit 30, and writing and reading operations of still image data to each memory 30R, 30G, and 30B are executed within the period of the pulse width of this enable signal. be done.

The circuit configuration of the freeze control circuit 33 will now be explained based on FIG. In the following description, a configuration is shown in which freeze control is performed based on an even field G image signal, but the present invention is not limited to this, and freeze control can be performed based on any field image signal. You can, and in the case of a framed image,
The same operation as in the case of field images is performed except that six fields of data are taken in.

In the same figure, 40 indicates a motion detector, and every time an even field G image signal is input to this motion detector 40, this signal and the previous even field G image signal are input to the motion detector 40. (That is, the signal from six fields ago) and the contour, etc., it is possible to detect whether the subject is stationary or moving. This motion detection signal is an even field G
-EN signal is input to the flip-flop circuit 41. In addition, this flip-flop circuit 41 has a VD pulse, R-EN, G-EN, B-EN.
After the C-EN signal generated from the signal, that is, the G-EN signal of an even field, the signal that is at H (high) level for 3 fields and is at L (low) level for the next 3 fields is used as a reset signal. It is now entered. Therefore, the G input to this flip-flop circuit 41
- If there is no movement based on the EN signal and the motion detection signal, a rewrite signal is input to the still image memory circuit 30,
Based on this rewriting signal, rewriting of the stored contents of the still image memory circuit 30 is started. The rewriting period of the still image memory circuit 30 continues only while the C-EN signal maintains the H state, and when the C-EN pulse becomes L, the rewriting period of the still image memory circuit 30 continues. ends. Therefore, this C-EN pulse defines the period during which the memory can be rewritten, and thereby the flip-flop circuit 41 outputs the rewritable signal F-EN signal of the still image memory circuit 30. Therefore, this F-EN signal is generated immediately after the even field G-EN signal changes from H level to L level, and has a time interval of 3 fields from time t1 to t3. All R, G, B memories 30R, 30
The data in G and 30B will be rewritten with certainty.

However, if this F-EN signal is present, the still image memory circuit 30 is not always rewritten, but when freeze control is performed, even if the F-EN signal is output, the still image memory circuit 30 is not necessarily rewritten. The content stored in the image memory circuit 30 is not rewritten. For this purpose, the output side of the flip-flop circuit 41 has a NAN
A D circuit 42 is connected, and this NAND circuit 42 is switched between H level and L level based on the F-EN signal from the flip-flop circuit 41 and a signal from a freeze operation means (not shown). (In this case, the signal from the freeze selection means 43 is inputted, which is at H level when no freeze selection is made, and switches to L level when freeze selection is made.)
Even if the F-EN signal is output from the flip-flop circuit 41, the still image memory circuit 30 is not rewritten. That is, only when the F-EN signal is output from the flip-flop circuit 41 when the freeze selection means 43 is in the H level state, the memory content rewriting signal is applied to the still image memory circuit 30. There is. Here, the freeze selection signal from the freeze selection means 43 is switched in conjunction with the VD signal, and is selected from R, G,
Even if a freeze operation is performed during each enable period of B,
The freeze selection means 43 is set to H until the VD signal is output.
It is designed so that it does not switch from level to L level. Furthermore, while the still image memory circuit 30 is being rewritten, if this rewriting starts, it will be prioritized, and even if a freeze operation is performed during that time, a command to prohibit rewriting will not be issued. ing.

As described above, when a still image is acquired without a freeze operation being performed, the memory contents of the still image memory circuit 30 are rewritten each time. Still image data is output from the still image memory circuit 30. This output is noise reducer 3
The signals are sent to the signal output circuit 27 via 1R, 31G, and 31B, converted into simultaneous signals, and sequentially taken into the external storage device 51 and stored in the external storage device 51.

The present embodiment is constructed as described above, and its operation will now be described with reference to FIG. 3. The endoscope 1 is inserted into a predetermined observation site such as inside the body, and an image of the subject is captured by the CCD 6 provided at its tip, synchronized with the VD pulse shown in (a) in FIG. The signal from the CCD 6 of the lever is read out, and this signal is transmitted to the processor 20, and the video signal processing circuit 2
By processing in step 1, R shown in FIG. 3(b),
G and B image signals are acquired. The R, G, and B color image signals obtained in this manner are numbered sequentially starting from 1 in chronological order. The image signal acquired in this way is A/D
It is converted into a digital signal via the converter 22 and stored in the field memory circuit 23. For example, when the R real-time signal is transmitted, the G memories 23G and B
The stored signals in the memory 23B are read out and these three color image signals are sent to the D/A converters 24R, 24G, 24, respectively.
These signals are mixed by the signal output circuit 27 and transmitted as a simultaneous signal to the monitor device 50, where a color image of the subject is displayed.

At the same time, the signal from the signal processing circuit 21 is taken into the motion detector 40, and motion is detected by executing processing such as contour extraction. Here, in order to perform motion detection, if the previous data, that is, the G signal of an even field, is used for motion detection, the G signal of the previous even field that is actually compared in this motion detection is 6 fields earlier. Therefore, the signals before and after these six fields are compared. Then, from this motion detector 40, (
As shown in c), a pulse is output when there is movement in the subject, and no pulse is output when there is no movement. In this figure, it is shown that there is movement in the image signals of G1, G5, and G7, and there is no movement in the image signals of G3, G9, and G11.

The above-mentioned motion detection signal and the G-EN of the even field shown in FIG. 3(d) are transmitted from the memory control circuit 26.
When the image is a still image, the output signal of the flip-flop circuit 41 becomes H level. Further, this flip-flop circuit 41 has a C-
Since the EN signal is input, the fall of this C-EN signal becomes a reset signal and returns to the L level. As a result, the F-EN signal, which is a rewritable signal for the still image memory circuit 30, as shown in FIG. 3(e) is output. However, when this F-EN signal is output, the memory contents of the still image memory circuit 30 are not always rewritten, but the freeze selection means 43 is referred to and the image freeze operation is performed by this freeze selection means 43. When this is being performed, rewriting of the still image memory circuit 30 is prohibited to prevent the frozen image displayed on the monitor device 50 from changing. That is, the F-EN signal mentioned above is input to the NAND circuit 42 together with the signal from the freeze selection means 43, and the output signal from the freeze selection means 43 (FIG. 3(g)) is at H level, that is, the freeze operation is performed. Only when it is not, the storage contents of the still image memory circuit 30 are rewritten, and when it is at L level, rewriting of the still image memory circuit 30 is prohibited. Therefore, the actual rewriting of the still image memory circuit 30 is executed during the period indicated by the arrow in FIG. However, even if a freeze start signal is output from the freeze selection means 43 while the still image memory circuit 30 is being rewritten, as shown in FIG. starts at C-, as shown by the dotted line.
Even after the EN signal changes to L level and the rewriting is completed, and even if the freeze end signal is output, the still image memory circuit 30 detects the motion after the C-EN signal rises. Rewriting is performed only when a detection signal indicating that the device 40 is in a stationary state is output. Therefore, in this (i), F-EN
Even if the freeze end signal is output while the signal is being output from the flip-flop circuit 41, rewriting of the signal does not immediately start in the still image memory circuit 30.

Therefore, a moving image is always displayed on the monitor device 50, and when a freeze operation is performed, the switching means 28 switches and the still image memory circuit 3
0 is read out, and a clear image whose noise has been reduced by the noise reducers 31R, 31G, 31B is sent from the switching means 29 to the D/A converters 24R, 24G. 24B into a digital signal and transmitted to the monitor device 50, where a still image is displayed. At this time, since the still image memory circuit 30 is maintained in a state in which updating of its stored contents is prohibited, inconveniences such as changes in the image displayed on the monitor device 50 do not occur.

As described above, the still image memory circuit 30 stores whether there is any movement between the subject and the insertion section of the endoscope 1, or even if there is movement, when the image is displayed as a still image. The stored contents are updated by sequentially capturing images with no color shift in the still image memory circuit 30. Each time information is rewritten in the still image memory circuit 30, the stored contents are updated to the still image memory circuit 30. is output from the signal output circuit 2 via the noise reducers 31R, 31G, and 31B.
7 and stored in an external storage device 51 connected to this signal output circuit 27. Therefore, the external storage device 51 can store extremely high-quality images without color shift and which have been subjected to noise reduction processing by the noise reducers 31R, 31G, and 31B, without performing any special operations to obtain frozen images. be able to obtain it. Therefore, after an examination, diagnosis, etc. are completed, by reproducing the image from this external storage device 51, the most suitable image can be selected from a large number of images to be kept as a record.

[0024]

As explained above, the present invention provides a still image memory circuit that selectively takes in image data from a video signal processing means in parallel with a field memory circuit, and stores contents in this still image memory circuit. Since the configuration is configured so that information about the still image is recorded in the external storage device every time there is an update of the still image, there is no need to perform a special freeze operation.
It is possible to record a large number of still images with no color shift, and by replaying and editing the contents of this external storage device, it is possible to obtain the most suitable image to keep as a record. become.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of an electronic endoscope device showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of the memory control circuit of FIG. 1;

FIG. 3 is a signal waveform diagram of each part in the electronic endoscope device.

[Explanation of symbols]

1 Endoscope 6 CCD 20 Processor 21 Signal processing circuit 23 Field memory circuit 23R, 23G, 23B Memory 26 Memory control circuit 27 Signal output circuit 30 Still image memory circuit 30R, 30G, 30B Memory 31, 31R, 31G, 31B Noise reducer 3
3 Freeze control circuit 40 Motion detector 41 Flip-flop circuit 42 NAND circuit 43 Freeze selection means 50 Monitor device 51 External storage device

Claims (3)

[Claims] Claim 1: illumination means for sequentially illuminating a subject with light of different wavelengths; imaging means for capturing images of the subject using light of wavelengths of each color under the sequential illumination; A video signal processing means for processing an image signal; a field memory circuit for storing image data of each color processed by the video signal processing means; A still image memory circuit that selectively captures image data, a motion detection means that detects whether or not there is movement in the subject image, and writing and reading operations for the still image memory circuit based on signals from the motion detection means. still image control means for controlling the still image; image freezing means for prohibiting updating of data in the still image memory circuit and displaying the latest still image stored in the still image memory circuit on a monitor device; An electronic endoscope apparatus comprising: an external storage device that captures still image data each time it is updated in an image memory circuit and stores the image data. 2. The image signal acquired by the imaging means is a field image signal of each color of R, G, and B,
2. The electronic computer according to claim 1, wherein when the motion detection means detects a still state, the still image control means inputs a data update command for three fields to the still image memory circuit. Viewing device. 3. The image signals acquired by the imaging means are odd and even frame image signals that are interlaced for R, G, and B color image signals, respectively, and the motion detection means detects a stationary state. 2. The electronic endoscope apparatus according to claim 1, wherein when the still image control means inputs a data update command for at least three fields to the still image memory circuit.