JPH0430826A - Electronic endoscope - Google Patents

Abstract

PURPOSE:To enable reconstruction of a still picture without color deviation constantly by a method wherein one field or one frame of surface sequence image signals is inputted and stored at a speified cycle and the memory contents are updated each time judgment gives a still picture based on signals before and after the signals inputted and the updating is forbidden when a.freeze command is putted. CONSTITUTION:An object illuminated by lights R. G and B is picked up with a camera lens 22 of an endoscope and an image signal thereof is outputted by the photoelectric conversion with a CCD sensor 24 to be sent to an A/D converter 28 and a freeze control circuit 60. RGB image signal is converted into a digital signal per pixel and a RBG video signal converted in a simultaneous manner is reconstructed as color image. The free control circuit 60 judges whether an image is a still picture or an animation picture based on a G signal for each 6 field period and the memory contents of field memories 42, 44 and 46 are updated to the newest RGB image signal, each time judgment gives a still picture. When a freeze command signal is inputted, the field memories are latched. Thus, the memory contents will not be updated during a set freeze period thereby producing a still picture without color deviation as a monitor image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic endoscope device, and particularly to a medical electronic endoscope device that captures images in a frame-sequential manner.

[Conventional technology 2] The field sequential method, which sequentially obtains color images corresponding to each color of illumination light from one CCD two-dimensional sensor, is effective when the number of CCD two-dimensional sensors cannot be increased, and in recent years medical electronic endoscope devices have been used. It is being applied to

Such an electronic endoscope device simultaneously converts the sequential image signals of each color obtained by sequentially capturing images corresponding to the illumination light through red, green, and blue field memories, and displays the image as a color image on a color TV. It is configured so that it can be played back. In addition, when a freeze command is applied to freeze the monitor image, the stored images in the field memory, green, and blue are latched, allowing the still image to be monitored. Once the command is added, the still image can be made into a hard copy.

By the way, in the field sequential method, each color channel has one color image.
This occurs with a frame-by-frame delay, and this is converted into a simultaneous system and reproduced as a color image. Therefore, in conventional electronic endoscope devices, when the monitor image is frozen by the freeze command, the subject and the endoscope are Movement between the tips could cause color shift in a stationary monitor image.

Conventionally, in order to prevent color shift in static monitor images, when a freeze command is input, it is determined whether the image currently being captured is a still image or a video, and only when it is determined that the image is a still image, red, green, An electronic endoscope device has been proposed which latches the image stored in the blue field memory and obtains a still image without color shift (Japanese Patent Laid-Open No. 2-41131, Japanese Patent Laid-Open No. 2-41132, JP-A-2-55030).

[Problem to be solved by the invention]

However, in the conventional electronic endoscope device described above, if the image currently being captured is determined to be a moving image when a freeze command is input, the image stored in the field memory for each color is not latched, and a still image is immediately taken. In this case, a time lag occurs between when a freeze command is output and when a still image without color shift is actually obtained.

The present invention was made in view of these circumstances, and it is possible to always reproduce a still image without color shift even in the frame sequential imaging method by using a freeze command, and it is also possible to reproduce a still image without color shift even in the frame-sequential imaging method. It is an object of the present invention to provide an electronic endoscope device that can be immediately stopped without causing any discomfort.

[Means to solve problems]

In order to achieve the above-mentioned object, the present invention has an electronic internal system that sequentially captures images of each color side using a frame-sequential method, converts the obtained frame-sequential image signals into a simultaneous system, and reproduces them as a color image. In a viewing device, 1 field or 1
A storage means for storing frame sequential image signals for each color and outputting them simultaneously; and a storage means for inputting one field or one frame of frame sequential image signals at a predetermined period, and manually inputting one field or one frame of one field or one frame before and after inputting them at a predetermined period. a determining means for determining whether the sequential image is a still image or a moving image at predetermined intervals based on the sequential image signal; and each time the determining means determines that the image is a still image, the storage contents of the storage means are updated to the latest frame sequential image signal. and control means for inhibiting updating of the storage contents of the storage means when a freeze command is input.

[Effect]

According to the present invention, a sampling check is performed at predetermined intervals to determine whether the image currently being photographed is a still image or a moving image, and each time it is determined that the image is a still image, frame-sequential image signals are stored for each color and output simultaneously. 2. The storage contents of the storage means are updated to the latest frame-sequential image signals. As a result, the latest frame sequential image signal without color shift is always stored in the storage means.

When a freeze command is input, updating of the storage contents of the storage means is immediately prohibited, thereby obtaining the latest still image signal without color shift from the storage means.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electronic endoscope apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of an electronic endoscope device according to the present invention. This electronic endoscope device sequentially captures desired color images in a frame-sequential manner, converts the frame-sequential image signals obtained by the second imaging into a simultaneous system, and reproduces the color image. The light from the condensing lens 1
2. The object 18 is illuminated from the end of the endoscope via the color filter disk 14 and the light guide 16. That is, the color filter disk 14 has a red filter, a green filter, and a blue filter, each having a central angle of 120 degrees, and the motor 2
0 at a predetermined rotation speed (for example, 20 rps). Thereby, the light from the illumination lamp 10 is transmitted through the rotating color filter disk 14.
Red (R), green (G), blue (
B) is applied to the subject 18 via the light guide 16.

The imaging lens 22 provided at the tip of the endoscope has R, G,
image the subject 18 illuminated by each illumination light of B;
This is imaged on the light receiving part of the CCD sensor 24, and the CCD sensor 24 photoelectrically converts the incident light into an RG image corresponding to each illumination light.
The B image signal is outputted via the amplifier 26 to the A/D converter 28 and freeze control circuit 60, respectively.

The A/D converter 28 converts the input RGB image signals (analog signals) into digital signals pixel by pixel, and converts these digital signals into two sets of R and G signals respectively.

The data is output to field memory 32.34.36 and field memory 42.44.46 of B.

The field memories 32, 34, 36 are controlled by a field selection pulse generation circuit 38.

That is, the field sorting pulse generation circuit 38 inputs signals synchronized with each of the R, G, and B illumination lights from the color filter position detector 30, and converts the RGB image signal corresponding to each illumination light into that color. A write signal is sequentially outputted to each field memory 32, 34, 36 to update the stored contents of the feed memory so as to store it in the corresponding field memory. The RGB image signals stored in these field memories 32, 34, 36 are simultaneously read out and outputted from video output terminals 57, 58, 59 via changeover switches 48 and D/A converters 52, 54, 56, respectively. be done.

The RGB video signals simultaneously converted as described above are added to a color TV and reproduced as a color image.

On the other hand, the field memories 42, 44, and 46 are controlled by a field selection pulse generation circuit 38 and a freeze control circuit 60.

As mentioned above, the freeze control circuit 60 is sequentially supplied with RGB image signals, and also receives a freeze command signal for freezing the monitor image and a G image signal from the field selection pulse generation circuit 38 for a six-field period ( 0,1
It is possible to input a G-EN pulse for inputting every second). This freeze control circuit 60 determines whether a captured image is a still image or a moving image at each cycle (every 0, 1 second) based on the G image signal inputted every 6 field periods, and every time it is determined that it is a still image. field memory 42.44.4
6 is updated to the latest RGB image signal, and when a freeze command signal is input manually, each field memory 42, 44, and 46 is immediately latched. As a result, each field memory 42, 44, 46 does not update its stored contents for a preset freeze period (several seconds), outputs RGB image signals of the same screen, and displays a static monitor image with no color shift. It becomes a picture.

Next, the freeze control circuit 60 will be explained in detail with reference to FIGS. 2 and 3.

FIG. 2 is a block diagram showing one embodiment of the freeze control circuit 60. The freeze control circuit 60 includes a contour signal generation circuit 61, a comparison circuit 62, a memory 63, a counter 64, a discrimination circuit 65, an AND circuit 66, and a NAND circuit 6.
It consists of 7.

The contour signal generation circuit 61 receives an RGB plane sequential image signal (FIG. 3(B)) from an input terminal B. This image signal is an RlG, B image signal manually generated in a frame sequential manner, and has a waveform synchronized with the period of the -ψT pulse (FIG. 3(A)). In FIG. 3(A), 0 indicates an odd field and E indicates an even field.

The contour signal generation circuit 61 detects the contour portion of the image indicated by the large-power image signal (the position where the contrast suddenly changes) and outputs the contour signal to the comparison circuit 64 and the memory 63.

The memory 63 temporarily stores the contour signal and outputs it to the comparator circuit 62 after a certain period of time (0.1 seconds).
The G-EN pulse (FIG. 3(E)) applied via the G-EN pulse (FIG. 3(E)) enables operation only during the output period of the even field G image signal (FIG. 3(C)), and the contour signal applied from the contour signal generating circuit 61. is written, and the written contour signal is read out 0.1 seconds later.

The comparison circuit 62 compares the contour signal applied from the contour signal generation circuit 61 with the contour signal of the even field G image signal added from the memory and delayed by 0.1 seconds. Then, as shown in FIG. 3 (G), a comparison signal (a pulse signal that becomes H level when there is a mismatch (D>) in FIG. 3) indicating whether the two human input signals match or do not match is outputted to the discrimination circuit 65 via line D. do.

Other inputs of the discrimination circuit 65 include input terminals E to G-EN.
pulse (Fig. 3(E)) and line G from the counter 64.
An EN pulse (FIG. 3(G)) is applied via the EN pulse (FIG. 3(G)). Here, the counter 6 inputs the G-EN pulse and the VD pulse, and as shown in FIG. 3, it becomes H level in synchronization with the rise of the G-EN pulse (FIG. 3 (E)). After counting three VD pulses (JR3 (A)), it outputs an EN pulse (Figure 3 (G)) that falls to the L level.

Since the discrimination circuit 65 outputs a discrimination pulse indicating whether the captured image is a still image or a moving image, this discrimination pulse is as shown in FIG. 3(F).
As shown in , it goes to H level in synchronization with the comparison signal (first pulse signal), and goes down to L level when the discrimination pulse is at H level in synchronization with the falling edge of the G-EN pulse, and goes to L level. It is a pulse signal that rises to the H level when the discrimination pulse is at the H level, and further falls in synchronization with the fall of the EN pulse when the discrimination pulse is at the H level.

That is, when the determination circuit 65 determines that it is a still image, the G-EN
It outputs a discrimination pulse that rises in synchronization with the falling edge of the pulse and falls after 3 field periods, and when it is determined that it is a moving image, it rises in synchronization with the comparison signal (first pulse signal) and falls in synchronization with the falling edge of the G-EN pulse. Outputs a discrimination pulse that falls in synchronization with the falling edge.

The discrimination pulse output from the above discrimination circuit is the AND circuit 6.
Added to 6. An EN pulse is applied from the counter 64 to the other input of the AND circuit 66.
6 takes the AND condition of the two manual pulses and applies the AND output (FIG. 3 (H)) to the NAND circuit 67 via line H.

Other inputs of the NAND circuit 67 include a freeze command signal (Fig. 3 (■
)) can be input, and when the output of the AND circuit 66 is at H level and the freeze command signal is not output (when it is an H level signal),
Line J
t to the enable terminal EN of the field memory 42.44.46 via the terminal R/W of the field memory 42.44.46.
Write signals of RGB image signals are applied from NAND circuits 43, 45, and 47 to . here,
The NAND circuits 43, 45 and 47 each have a field selection pulse R-R for sorting RGB image signals for each color.
/W, G-R/WSB-R/W are applied, and freeze command signals are applied to the other inputs, respectively. When the freeze command signal is not output, the NAND circuits 43, 45 and 47 signal), write signals (L level signals) of RGB image signals are sequentially sent to the field memory 4.
2. Output to terminals R/W of 44 and 46.

The field memories 42, 44 and 46 can be rewritten only when a rewrite command pulse is applied from the freeze control circuit 60 to the enable terminal EN, and write signals are sequentially applied from the NAND circuits 43, 45 and 47 to the R/W terminal. Accordingly, the field sequential RGB image signals are written for each color, that is, the stored contents of the field memories 42, 44 and 46 are changed from B to B image signals between t1 and t2 of the rewrite command pulse in FIG. 3(J). Between Ro and R4
G between 17 and 17 for the image signal. The image signal is rewritten from G to G. And field memory 42.44
．． The RGB image signals stored in 46 are simultaneously read out and output to R, G, and B output terminals K, L, and M (Fig. 3 (K), (L), and (M)). Note that while an image signal is being written into the field memory, the image signal being written is simultaneously read out.

By the way, the rewrite command pulse is output when the captured image is determined to be a still image and the freeze command is not output (when the freeze command signal is an H level signal), so the rewrite command pulse is output from the field memory 42.44. and 46, the image signal of the latest still image before the input of the freeze command is stored. On the other hand, when the freeze command is input, the rewrite command pulse is no longer output, and updating of the stored contents of the field memories 42, 44 and 46 is prohibited.
As a result, a still image without color shift can be obtained.

Now, field notes! The RGB image signals simultaneously read out from 42, 44 and 46 are output to the changeover switch 48 as shown in FIG. 1, and are also sent to the video output terminals 77, 78, .
79.

The changeover switch 48 selectively outputs either the output of the field memory 42.44.46 or the output of the field memory 32.34.36 depending on whether or not a freeze command signal is input. Therefore, the video output terminal 57
．． By connecting 58 and 59 to a color TV, moving images or still images can be played back.

On the other hand, by connecting the video output terminals 77, 78, and 79 to a color TV, when the freeze command is not manually issued, the latest still image being captured without color shift is played back while being updated sequentially, and the freeze command is issued. When done manually,
The latest still image with no color shift stored at the time of input of the freeze command can be reproduced.

By the way, as shown by the dotted line in Fig. 3 (I), when the freeze command is input in the middle of the H level output of the AND circuit 66, the length of 3 fields as shown in Fig. 3 (J) is It becomes impossible to obtain the rewriting command pulse.

As a countermeasure against this, for example, as shown in FIG. What is necessary is to take the differentiation, apply the differential signal as a trigger signal to the single yacht circuit 69, and output a rewrite command pulse having a length of three fields from the single yacht circuit 69.

FIG. 5 is a block diagram of main parts showing another embodiment of the electronic endoscope device according to the present invention. Note that the same parts as those in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 5, a freeze control circuit 80 has almost the same configuration as the freeze control circuit 60 in FIG. They differ in that they do so. Also, field notes! J92.94 and 96 are configured to input the outputs of field memories 32.34 and 36, respectively.

Then, when a rewrite command pulse is applied from the freeze control circuit 80 to each field memo 1J92.94 and 96, the RGB image signals stored in each field memory 92.94 and 96 are changed to the field memory 3.
2.34 and 36 are simultaneously rewritten into RGB image signals.

According to the above configuration, the time required for rewriting is shorter than in the case of the embodiment shown in FIG. 1, and the RGB image signal can be rewritten to an RGB image signal that is closer to the time when it is determined to be a still image (closer by two fields). I can do it.

Incidentally, in this embodiment, out of color images input sequentially, images of the same color are compared with each other, but images of different colors may be compared with each other. Further, the means for determining whether it is a moving image or a still image is not limited to this embodiment, and may be based on the coincidence or mismatch between two color images, such as a method of determining based on a cross-correlation between a preceding color image and a subsequent color image. Any method 1) may be used as long as it can be determined based on the

〔Effect of the invention〕

As explained above, according to the electronic endoscope device according to the present invention, it is determined whether a still image or a moving image is present based on the coincidence or mismatch between a temporally preceding image and a subsequent image captured in a frame sequential manner. The contents of the freeze-only memory are updated to the latest frame-sequential image signal each time it is determined that the image is a still image.
As soon as a freeze command is input, updating of the memory contents is prohibited, so the freeze command can always reproduce a still image with no color shift, and the time lag can be detected at the same time as the freeze command is input. It can be stopped immediately without stopping.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the electronic endoscope device according to the present invention, FIG. 2 is a block diagram including details of the freeze control circuit shown in FIG. 1, and FIGS. ) are signal waveform diagrams of each part used to explain Fig. 2, and Fig. 4
This figure is a block diagram showing an improved example of the freeze control circuit shown in FIG. 2, and FIG. 5 is a block diagram of main parts showing an embodiment of the present invention. 32.34.36.42.44.46.92.94.9
6... Field memory, 38... Pulse generation circuit for field selection, 48... Changeover switch, 60
．． 80...Freeze control circuit, 61...Contour signal generation circuit, 62...Comparison circuit, 63...Memory, 64...Counter, 65...Discrimination circuit,
66...AND circuit, 67...NAND circuit.

Claims (1)

[Scope of Claims] An electronic endoscope device that sequentially captures images of each color in a frame-sequential manner, converts the field-sequential image signals obtained by this imaging into a simultaneous system, and reproduces it as a color image, A storage means for storing one field or one frame of a field sequential image signal for each color and outputting them simultaneously; a determining means for determining whether the image is a still image or a moving image at predetermined intervals based on a frame-sequential image signal of one frame; and each time the determining means determines that the image is a still image, the storage contents of the storage means are stored in the latest frame-sequential image signal. An electronic endoscope comprising: control means for updating to an image signal and prohibiting updating of the storage contents of the storage means when a freeze command is input.