JPH0734792B2 - Electronic endoscopic device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus, and more particularly to a medical electronic endoscope apparatus for imaging in a frame sequential method.

[Conventional technology]

The field sequential method of sequentially obtaining color images corresponding to illumination light of each color from one CCD two-dimensional sensor is effective when the number of CCD two-dimensional sensors cannot be increased, and is being applied to medical electronic endoscope devices in recent years. .

Such an electronic endoscope apparatus simultaneously converts the frame-sequential image signals for each color obtained by sequentially capturing in accordance with the illumination light through the red, green, and blue field memories, and color TV as a color image. It is configured to be playable. When a freeze command to freeze the monitor image is added, the stored images in the red, green, and blue field memories are latched,
A still image can be monitored, and when it is connected to a hard copy device and a recording command is applied, the still image can be hard copied.

By the way, in the frame sequential method, the color image of each color channel is 1
Frames are delayed one by one, and they are simultaneously converted and reproduced as a color image. Therefore, when the conventional electronic endoscope device freezes the monitor image according to the freeze command, the subject and the endoscope are stopped. Color shift may occur in a still monitor image due to the movement between the tips.

Therefore, conventionally, in order to prevent color misregistration of a still monitor image, when a freeze command is input, it is determined whether the image currently being shot is a still image or a moving image. , An electronic endoscope apparatus has been proposed in which a stored image in a blue field memory is latched to obtain a static image without color shift (Japanese Patent Laid-Open No. 2-41131, Japanese Patent Laid-Open No. 2-4).
1132, JP-A-2-55030).

[Problems to be Solved by the Invention]

However, in the above-mentioned conventional electronic endoscope apparatus, when the freeze command is input and the image currently being photographed is determined to be a moving image, the stored image in the field memory for each color is not latched and a still image is immediately displayed. In some cases, it may not be possible to obtain a still image. In this case, there is a time lag between the output of the freeze command and the actual acquisition of a still image without color shift.

The present invention has been made in view of the above circumstances, and it is possible to always reproduce a still image with no color shift even with a frame sequential imaging method by a freeze command, and to shift the time shift when a desired scene is to be stopped. An object of the present invention is to provide an electronic endoscopic device that can be immediately stopped without feeling it.

[Means for solving the problem]

In order to achieve the above object, the present invention sequentially captures images of respective colors by a frame sequential method, and converts the field sequential image signals obtained by this imaging into a simultaneous method through a first storage means for storing each color. Then, in the electronic endoscope apparatus adapted to reproduce as a color image, the second storage means for storing the field sequential image signal of one field or one frame for each color and outputting them at the same time, and the first storage. Switching means for switching and outputting either one of the output of the means and the output of the storage means, and the field sequential image signal of one field or one frame is input at a predetermined cycle, and one field before or after the input A discriminating unit that discriminates a still image or a moving image at predetermined intervals based on a frame-sequential image signal of one frame, and the stored content of the second storage unit is updated every time the discriminating unit discriminates a still image. Face order And a control means for prohibiting the update of the stored contents of the storage means and for switching the switching means to the output side of the second storage means while updating the image signal and inputting a freeze command. I am trying.

[Action]

According to the present invention, a sampling check is performed at a predetermined cycle whether the image currently being captured is a still image or a moving image, and each time it is determined that the image is a still image, a frame sequential image signal is stored for each color and these are simultaneously output. (2) The storage contents of the storage means are updated to the latest frame sequential image signal. As a result, the latest frame-sequential image signal having no color shift is always stored in the storage means.

Then, when the freeze command is input, the updating of the contents stored in the storage means is immediately prohibited, so that the latest still image signal having no color shift can be obtained from the storage means.

Further, by switching the output of the first storage means and the output of the second storage means by the switching means, it is possible to appropriately switch and display the moving image and the still image on one monitor.

〔Example〕

Hereinafter, preferred embodiments of an electronic endoscope apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of the electronic endoscope apparatus according to the present invention. This electronic endoscope apparatus is for sequentially capturing desired color images in a frame-sequential method, converting the field-sequential image signals obtained by this imaging into a simultaneous system, and reproducing them as a color image. The light of the condenser lens 12,
The subject 18 is illuminated from the tip of the endoscope through the color filter disc 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 °, and is rotated by a motor 20 at a predetermined rotation speed (for example, 20 rps). As a result, the light from the illumination lamp 10 passes through the rotating color filter disc 14 and the illumination light of each color of red (R), green (G), and blue (B) is sequentially changed at a cycle of 1/60 seconds. Then, it is added to the subject 18 via the light guide 16.

The imaging lens 22 provided at the distal end of the endoscope has R, G, B
The subject 18 illuminated by each illumination light is imaged, and this is imaged on the light receiving portion of the CCD sensor 24. The CCD sensor 24 photoelectrically converts the incident light and an RGB image signal corresponding to each illumination light is amplified by the amplifier 26. To the A / D converter 28 and the freeze control circuit 60, respectively.

The A / D converter 28 converts an input RGB image signal (analog signal) into a digital signal pixel by pixel, and the digital signal is converted into two sets of R, G, B field memories 32, 34, respectively.
36 and the field memories 42, 44 and 46.

The field memories 32, 34 and 36 are controlled by the field selection pulse generation circuit 38. That is, the field selection pulse generation circuit 38 receives a signal synchronized with each of the R, G, and B illumination lights from the color filter position detector 30,
To store the RGB image signal corresponding to each illumination light in the field memory corresponding to that color, each field memory
Write signals are sequentially output to 32, 34, and 36 to update the contents stored in the feed memory. These field memories 3
The RGB image signals stored in 2, 34 and 36 are simultaneously read out and output from the video output terminals 57, 58 and 59 via the changeover switch 48 and the D / A converters 52, 54 and 56, respectively.

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

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

As described above, the freeze control circuit 60 is sequentially applied with the RGB image signals, and the freeze command signal for keeping the monitor image stationary and the G image signal from the field selection pulse generation circuit 38 for 6 field periods (0.1 seconds). ) G-EN pulse for each input can be input. The freeze control circuit 60 determines whether the captured image is a still image or a moving image for each cycle (every 0.1 seconds) based on the G image signal input every 6 field periods, and for each determination as a still image, a field memory is provided. The contents of 42, 44, 46 are stored in the latest RG
When the B image signal is updated and the freeze command signal is input, the field memories 42, 44 and 46 are immediately latched. As a result, each field memory 42, 44,
The stored contents of 46 are not updated during the preset freeze period (several seconds), the RGB image signals of the same screen are output, and the monitor image becomes a still image without color shift.

Next, the freeze control circuit 60 is shown in FIGS.
Detailed description will be made with reference to the drawings.

FIG. 2 is a block diagram showing an 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 determination circuit 65, an AND circuit 66, and a NAND circuit 67.

The contour signal generation circuit 61 receives an RGB frame sequential image signal (FIG. 3 (B)) from the input terminal B. This image signal is an R, G, B image signal that is input in the frame-sequential method, and has a waveform synchronized with the period of the pulse (Fig. 3A). In FIG. 3A, O indicates an odd field and E indicates an even field.

The contour signal generation circuit 61 detects a contour portion (a position where the contrast suddenly changes) of the image indicated by the input image signal 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 comparison circuit 62 after a lapse of a fixed time (0.1 seconds). The G-EN pulse applied from the field selection pulse generation circuit 38 via the input terminal E. (Fig. 3 (E)) enables operation only during the output period of the even field G image signal (Fig. 3 (C)). The contour signal added from the contour signal generating circuit 61 is written, and the writing is performed 0.1 seconds later. The contour signal is read.

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

To the other input of the discrimination circuit 65, the G-EN pulse (FIG. 3 (E)) from the input terminal E and the line G from the counter 64 are input.
EN pulse (Fig. 3 (G)) is added. Here, the counter 64 inputs the G-EN pulse and the ▲ ▼ pulse, and becomes the H level in synchronization with the rising of the G-EN pulse (Fig. 3 (E)) as shown in Fig. 3. After that, when the three pulses (Fig. 3 (A)) are counted, the EN pulse (Fig. 3 (G)) falling to the L level is output.

The discriminating circuit 65 outputs a discriminating pulse indicating whether the captured image is a still image or a moving image. Therefore, as shown in FIG. 3 (F), this discriminating pulse is H in synchronization with the comparison signal (first pulse signal). When the discrimination pulse is at the H level, it falls to the L level, and when it is at the L level, it rises to the H level in synchronization with the fall of the G-EN pulse.
Furthermore, when the discrimination pulse is at H level, it is a pulse signal which is synchronized with the fall of the EN pulse.

That is, the discrimination circuit 65 outputs a discrimination pulse which rises in synchronization with the fall of the G-EN pulse when it is determined to be a still image and falls after the lapse of three field periods. Signal to output a discrimination pulse that rises in synchronization with the falling edge of the G-EN pulse.

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

A freeze command signal (FIG. 3 (I)) which becomes L level at the time of a freeze command can be input from the input terminal I to the other input of the NAND circuit 67.
When the output of the AND circuit 66 becomes H level and the freeze command signal is not output (when it is H level signal),
L level rewrite command pulse (Fig. 3 (J))
Enable terminals for field memories 42, 44, 46 via
Output to EN.

On the other hand, to the terminals R / W of the field memories 42, 44 and 46, write signals of RGB image signals from the NAND circuits 43, 45 and 47 are added. Here, the NAND circuit 43, 45
Field selection pulses RR / W, GR / W, BR / W for selecting RGB image signals for each color are added to 47 and 47, and a freeze command signal is added to the other inputs, respectively, and the NAND circuit 43 , 45 and 47 sequentially output the write signal (L level signal) of the RGB image signal to the terminals R / W of the field memories 42, 44 and 46 when the freeze command signal is not output (when it is an H level signal).

The field memories 42, 44 and 46 can be rewritten only when the rewrite command pulse is applied from the freeze control circuit 60 to the enable terminal EN, and the NAND circuit 4 is connected to the R / W terminal.
By the write signal sequentially applied from 3, 45 and 47,
Write the frame sequential RGB image signal for each color. That is, the contents stored in the field memories 42, 44 and 46 are the image signals of B _-1 to B ₃ during t ₁ of the rewriting command pulse of FIG. 3 (J) and the contents of R ₀ to R ₄ during t ₂ . The image signal is rewritten from G ₀ to G ₄ during t ₃ . And the field memories 42, 4
The RGB image signals stored in 4 and 46 are simultaneously read and output to the R, G, and B output terminals K, L, and M (Fig. 3, (K), (L), and (M)). . During writing of the image signal in 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 surface and the freeze command is not output (when the freeze command signal is an H level signal), as described above, and therefore the field memories 42 and 44. In and 46, the image signals of the latest still image before the freeze command is input are stored. On the other hand, when the freeze command is input, the rewrite command pulse is not output and the field memory 4
Updating the stored contents of 2, 44, and 46 is prohibited, and as a result, a still image without color shift can be obtained.

Now, the RGB image signals read out simultaneously from the field memories 42, 44 and 46 are outputted to the changeover switch 48 as shown in FIG. 1 and also output from the video output terminals via the D / A converters 72, 74 and 76. Output from 77, 78, 79.

The change-over switch 48 switches and outputs one of the outputs of the field memories 42, 44, 46 and the field memories 32, 34, 36 depending on whether or not the freeze command signal is input. Therefore, color the video output terminals 57, 58, 59.
By connecting to a TV, you can play back movies or still images.

On the other hand, by connecting the video output terminals 77, 78, 79 to the color TV, when the freeze command is not input,
When the freeze command is input while the latest still image without color shift during image capturing is sequentially updated, and the freeze command is input, the latest still image without color shift stored at the time of input of the freeze command can be played back. .

By the way, as shown by the dotted line in FIG.
When a freeze command is input during the H level output of 66, a rewrite command pulse having a length of 3 fields as shown in FIG. 3 (J) cannot be obtained.

As a countermeasure against this, for example, as shown in FIG. 4, a differentiation circuit 68 and a one-shot circuit 69 are provided in the stage subsequent to the NAND circuit 67 of the freeze control circuit 60, and the differentiation circuit 68 causes the output of the NAND circuit 67 to fall. It suffices to take the differentiation and apply the differentiation signal to the one-shot circuit 69 as a trigger signal so that the one-shot circuit 69 outputs a rewrite command pulse having a length of three fields.

FIG. 5 is a principal block diagram showing another embodiment of the electronic endoscope apparatus according to the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 5, the freeze control circuit 80 is configured almost the same as the freeze control circuit 60 of FIG. 1, but it outputs a rewrite command pulse having a length of one field when it is determined to be a still image. Is different. Also, the field memories 92, 94 and 96 are respectively the field memories 32, 34 and
It is configured to input 36 outputs.

Then, when a rewrite command pulse is applied from the freeze control circuit 80 to each of the field memories 92, 94 and 96, the RGB image signals stored in each of the field memories 92, 94 and 96 are then stored in the field memories 32, 34. And 36 are simultaneously rewritten to the 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 it is possible to rewrite the RGB image signal closer to the time when it is determined as a still image (closer by two fields). .

Although the same color images are compared with each other among the color images sequentially input in the present embodiment, different color images may be compared with each other. Further, the means for discriminating between the moving image and the still image is not limited to the present embodiment, but based on the coincidence or non-coincidence of two color images such as a method of discriminating based on the cross-correlation between the preceding color image and the subsequent color image. Any method may be used as long as it can be determined by the above method.

〔The invention's effect〕

As described above, according to the electronic endoscope apparatus of the present invention, a still image or a moving image is discriminated based on whether or not a temporally preceding image and a subsequent image captured by the frame sequential method match or do not match. Then, every time it is determined to be a still image, the contents stored in the freeze-only memory are updated to the latest frame-sequential image signal,
Since the update of the above stored contents is prohibited immediately when the freeze command is input, it is possible to always play back a still image with no color shift due to the freeze command, and without feeling the time lag when the freeze command is input. Can be immediately quiescent.

Further, since the output of the normal memory for converting the frame sequential image signal to the simultaneous system and the output of the freeze dedicated memory are appropriately switched, the moving image or the still image is displayed on one monitor as necessary. Can be made.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the electronic endoscope apparatus according to the present invention, FIG. 2 is a block diagram including details of the freeze control circuit of FIG. 1, and FIGS. 3 (A) to 3 (M). Is a signal waveform diagram of each part used to explain FIG. 2, and FIG.
FIG. 5 is a block diagram showing an improved example of the freeze control circuit shown in FIG. 2, and FIG. 5 is a main part block diagram showing an embodiment of the present invention. 32, 34, 36, 42, 44, 46, 92, 94, 96 ... Field memory, 38 ... Field selection pulse generation circuit, 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)

[Claims] 1. An image for each color is sequentially captured by a frame sequential method,
In the electronic endoscope apparatus in which the field-sequential image signals obtained by this imaging are simultaneously converted through the first storage means for storing each color and reproduced as a color image, the field of one field or one frame Second storage means for sequentially storing image signals for each color and outputting them simultaneously, and switching means for switching and outputting either one of the output of the first storage means and the output of the second storage means. , 1-field or 1-frame frame-sequential image signal is input at a predetermined cycle, and a still image or a moving image is discriminated at predetermined intervals based on the input 1-field or 1-frame frame-sequential image signal And a discriminating means, each time the discriminating means discriminates a still image, the stored content of the second storing means is updated to the latest frame-sequential image signal, and when a freeze command is inputted, the storing means And a control means for prohibiting the update of the stored contents of the storage means and switching the switching means to the output side of the second storage means.