JP3527859B2 - Electronic endoscope device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus, and more particularly to an electronic endoscope apparatus capable of selectively and easily utilizing an all-pixel reading method for reading all pixels in addition to a conventional pixel-mixing reading method. Regarding the configuration of.

[0002]

2. Description of the Related Art In a solid-state image pickup device used in an electronic endoscope apparatus, for example, a CCD (Charge Coupled Device), an image signal (video signal) is generated by reading charges accumulated in a pixel unit by a photoelectric conversion element. You can get it. In such a CCD used in a simultaneous electronic endoscope apparatus, Mg (magenta), Cy (cyan), G (green)
A color filter of Ye (yellow) is arranged to form a color image.

According to the conventional color-difference line-sequential mixed read (pixel mixed read) system, the accumulated charges of pixels on the upper and lower horizontal lines are added and mixed and read, whereby the video of the odd field and the even field is read. Signals are sequentially formed at a timing of 1/60 seconds, for example. Thereafter, the odd field signal and the even field signal are interlaced-scanned to form one frame image, and this image is displayed as a moving image on the monitor. Further, in such an electronic endoscope apparatus, a freeze switch is arranged in the operation section, and when the freeze switch is pressed, a still image at that time is formed and displayed.

[0004]

However, in the above-described pixel mixture read-out method, 1/1 is formed between the odd field image and the even field image for forming one frame image (between two exposures). If there is a time lag of 60 seconds and there is blurring of the endoscope itself, movement of the observed object, etc. during this time, there is a problem that the image quality (resolution, color misregistration, etc.) is degraded.

In addition, the electronic endoscope apparatus often employs an electronic shutter function for changing the signal accumulation time. According to this, if the accumulation time is shortened in a bright place at a short distance, the image quality is improved. Can be planned. However, since there is a time lag of 1/60 seconds as described above, there is also a disadvantage that the effect of shortening the accumulation time cannot be fully enjoyed in still images and the like.

The present invention has been made in view of the above problems, and an object thereof is to propose an all-pixel reading method capable of obtaining a high-quality image instead of the conventional pixel-mixing reading method. An object of the present invention is to provide an electronic endoscope apparatus that can select one of these methods according to the situation of the user.

[0007]

In order to achieve the above object, the electronic endoscope apparatus according to the invention of claim 1 is a pixel mixture read-out method in which a pixel signal is mixed and read from an image sensor between upper and lower horizontal lines. Or a circuit part of an all-pixel readout system that reads out all pixel signals from the image pickup device while utilizing a predetermined light-shielding period, is mounted as standard, and the other can be selectively mounted. , A control circuit that determines whether or not there is a circuit section that can be selectively mounted, and controls the execution of the operation of the method of the circuit section when the presence of this circuit section is detected. It is characterized by being prepared. The invention according to claim 2 is characterized in that a display indicating which one of the pixel mixed read-out method and the all-pixel read-out method is in operation is provided on the monitor screen.

According to the above construction, for example, the pixel mixed read-out type circuit board is mounted as a standard, and the other all-pixel read-out type circuit board can be attached by a connector or the like. Then, when the control circuit determines the mounting state of the all-pixels reading method circuit board and the presence of the circuit board is not detected, a pixel mixing signal of two horizontal lines is output from the solid-state image sensor by the pixel mixing reading method similar to the conventional one. Is read out, and a moving image and a still image are formed based on this.

On the other hand, when the presence of the all-pixel readout system circuit board is detected, the signals of all the pixels are read out from the solid-state image pickup device by the system. That is, for example, 1/60
For the charge accumulated by the exposure (exposure time is arbitrary) within the period of every second (vertical synchronization period), for example, an odd line signal is read during the next light-shielding period (shielded by the light-shielding means), and the next period is read. The signals of all the pixels obtained by one exposure are extracted by reading the signals of the even lines in the (exposure period).

Then, for example, the above-mentioned signals of the odd line and the even line are later mixed with each other in the upper and lower lines, and finally made into a mixed signal similar to the conventional one to become signals of an odd field and an even field. A video is formed from. On the other hand, although a still image is also displayed based on the freeze signal, in this all-pixel reading method, a still image is formed based on the image data obtained by one exposure, and this still image is the above-mentioned pixel. The image quality is higher than that of the mixed read method.

According to the second aspect of the present invention, for example, "H" is displayed on the monitor screen during the operation of the all-pixel reading method, and "L" is displayed during the operation of the pixel-mixing reading method. Can be easily confirmed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a circuit configuration of an electronic endoscope apparatus which is a first example of the embodiment, and FIG. 2 shows a configuration of a color filter of a solid-state image pickup device, a pixel mixture read-out system, and Both processes of the all pixel reading method are shown. The electronic endoscope apparatus of FIG. 1 is provided with a CCD 11 provided with a color filter at the tip of an electronic scope, and the color filter of this CCD 11 is, for example, pixel by pixel as shown in FIG. Mg (magenta) and Cy (cyan) filters are arranged on even-numbered lines, and G (green) and Ye (yellow) filters are alternately arranged on odd-numbered lines. Then, in the color image processing, a color image signal is formed by performing a mixing operation on the signals obtained through these color filters.

A CCD drive circuit 12 for driving the CCD 11 is connected to the CCD 11. The drive circuit 12 is controlled by a microcomputer 14 to drive both the pixel mixed read system and the all pixel read system. To do. For example, in the case of the all-pixel reading method, the CCD can be exposed with one exposure.
The CCD driving circuit 12 supplies two types of pulses (P1, P2) with different time intervals for reading out the accumulated data for all pixels accumulated in 11 by dividing them into an odd line and an even line. The odd line signal and the even line signal are sequentially read separately. On the other hand, in the pixel mixed read method, one type of read pulse is applied to each line. It should be noted that the microcomputer 14 performs overall control of the apparatus and switching control for performing image processing by both of the above methods.

On the other hand, the CCD 11 is provided with an A / D converter 15 for converting an analog signal into a digital signal, and at the subsequent stage of the A / D converter 15, the pixel mixed read mode and all pixel read are performed via the a route. A mode switch 16 for switching modes and a digital signal processor (DVP) 17 for performing a predetermined color image processing on a video signal are provided. The DVP 17 includes a timing generator (TG) inside and performs various processes such as white balance, gamma correction, contour correction, image position control, and enlargement process.

In the subsequent stage of the DVP 17, a fourth memory 18 and a fifth memory 19 for storing odd field data and even field data, and a switching circuit 20, D
A / A converter 21 is provided. In the standard pixel mixed readout system, the system switching unit 16 selects the route a, and a moving image and a still image are formed with the above configuration based on the video signal input via the route a. .

A lamp 24 and a diaphragm 25 are provided in the light source section of the electronic endoscope apparatus, and the output light of the lamp 24 is guided to the distal end of the scope by a light guide 26.
The lamp 24 is turned on and driven by a lamp driving circuit 27, and the diaphragm 25 is controlled by a diaphragm control circuit 28. The diaphragm control circuit 28 controls the diaphragm 25 so that the brightness of the screen becomes constant based on the luminance signal. Variably control the opening amount of. In this example, a light shield plate 30 made of, for example, a semi-circular plate is arranged between the diaphragm 25 and the incident end of the light guide 26 for the processing of the all-pixel reading method. It is rotationally driven by the light shielding plate control circuit 31.
The shading plate 30 and the shading plate control circuit 31 alternately cut off the light during the period of the field O / E signal, which is a cycle of 1/60 seconds, when executing the all-pixel reading method, and obtains it by one exposure. All the read pixels can be read.

Thus, in this example, the all-pixel readout system circuit board 33 is already attached as shown in the figure, but this circuit board 33 is connected by a general connecting means such as a detachable connector. Mounted at a specified position on the device
It is connectable and this mounting is optional and optional. In this all-pixel readout system circuit board 33, for example, a first memory 34 for storing image data of odd lines, a second memory 35 for storing image data of even lines, and data of the first memory 34 are stored as they are, The third memory 36 for phase adjustment for delaying the read timing by 1/60 seconds, the mixing circuit 37, and the memory control circuit 38 are mounted.

That is, all pixel signals obtained by the CCD 11 are temporarily stored in the respective memories 34 and 35 in a state of being divided into odd line data and even line data, and the odd line data of the first memory 34 are stored. Is delayed by 1/60 seconds and made to have the same phase as the even line data in the second memory 35. Then, in the mixing circuit 37 in the next stage, the third memory 3
The pixel data of the odd lines of 6 and the pixel data of the even lines of the second memory 35 are added and mixed to form a pixel mixed signal similar to the above-described pixel mixed read method.

Such an all-pixel readout system circuit board 33
Will be discriminated by the microcomputer 14 in its mounting state. For example, by setting the output state of a predetermined terminal such as a connector when not connected to Low and setting the output state to switch from Low to High when the circuit board 33 is attached, the all-pixel readout method circuit board is set. The presence of 33 can be detected. When the presence of the circuit board 33 is confirmed, the microcomputer 14 switches the signal line from the route a to the route b (when the video signal is taken in) by the method switching device 16, and the CCD drive circuit 12 and the light shielding plate control circuit 31 As for the above, the process is switched to the all-pixel reading method. In addition, in this electronic endoscope apparatus, a freeze switch is provided in the operation portion of the scope, and the microcomputer 14 receives a freeze signal from the freeze switch to execute the still image forming operation.

The first example has the above-mentioned structure. First, referring to FIG. 2, the difference between the above-mentioned pixel mixture reading method and the all-pixel reading method will be described. As shown in FIG. 2A, in the CCD 11 provided with a color filter on a pixel-by-pixel basis, horizontal lines from 0 to N lines are provided corresponding to the number of scanning lines. It is configured to be transferred to the transfer line and read out. Then, in the pixel mixture reading method, as shown in FIG.
Directly from D11, an addition signal of 0 line + 1 line, 2 line + 3 line, 4 line + 5 line ... [O (odd line) + e (even line)] and 1 line + 2 line, 3 line
The added signals [(o + e) '] of lines +4 lines, 5 lines +6 lines, ... Are alternately read every one period (1/60 seconds) (these two signals are obtained in different exposure periods). Then, as shown in FIG. 2 (D), these signals have odd (Odd) field data and even (E) field data.
ven) fourth and fifth memories 1 as field data
It is output to 8 and 19.

On the other hand, in the all-pixel reading method, FIG.
As shown in Fig. 5, for all pixel signals obtained by one exposure, signals of odd lines of 1, 3, 5 ... (Light-shielding period)
Then, the signals of the even lines of 0, 2, 4, ... (Next period) are read. Thereafter, the mixing circuit 37 causes the signals on the odd line and the even line to be connected to each other by a solid line [o +
e] and a dotted line [(o + e) '] are added, and finally, the odd field data and the even field data of FIG. 2D are output to the fourth and fifth memories 18 and 19. .

FIG. 3 shows a method switching operation in the microcomputer 14, and as shown in the figure, step 1
In 01, it is determined whether or not the all-pixel readout system circuit board 33 exists. If "NO", the operation of the pixel mixture readout system is executed in step 102, and if "YES", the process proceeds to step 103. Then, the operation of the all-pixel reading method is executed.

FIG. 4 shows a black level signal extraction process in the case where the above-mentioned all-pixel reading system process is executed. In this example, even in the all-pixel reading system, the optical black signal is a. Clamp the black level signal obtained through the route. For example, the optical black pulse (OBP) of FIG. 4B is given to the horizontally synchronized video signal output from the CCD 11 as shown in FIG. 4A, and FIG.
4C, the signal input route is switched to the route a only during the optical black period, so that the color when returning from the still image display to the moving image display is displayed. Prevents deterioration of reproducibility.

That is, since the image data stored in the first and second memories 34 and 35 are repeatedly read in the still image forming process in the all-pixel reading method, the writing of the next data is prohibited, and the DVP 17 in the subsequent stage is prohibited. Old data
Clamp processing is executed based on (data of several years ago). Therefore, the black level of the signal may change significantly when the still image is changed to the moving image. In this example,
Only the black level signal, which is the reference for color processing, is input via the route a to suppress the fluctuation of the black level at the time of moving image to obtain good color reproducibility. .

Next, the operation of signal processing in each system will be described. 5 and 6, the pixel mixed read-out method (method A) is shown.
The image processing timing is shown, and as described above, when the presence of the all-pixel readout system circuit board 33 is not detected, the pixel mixture readout system is executed. Figure 5
Is a processing timing at the time of forming a moving image, and as shown in FIG. 5A, in the image processing, for example, a field O (Odd) / E (Even) signal is used every 1/60 seconds. Further, as shown in FIG. 5B, the light source light is emitted from the light guide 2.
5 is always given through 6, and the read pulses are the same as shown in FIGS. 5 (C) and 5 (D).

Then, the pixel mixture signal described in FIG. 2B is output from the CCD 11 through the route a, and
As in (E), in the fourth memory 18, (o + e) ₁ accumulated in the field period of O ₁ , (o + e) ₂ accumulated in the period of O ₂ , and (o + e) ₃ accumulated in the period of O _3.
The mixed signal of ... Is written in the fifth memory 19 and E
Mixed signal of (o + e) ₁ 'accumulated during 1 field period, (o + e) ₂ ' accumulated during E2 period, (o + e) ₃ 'accumulated during E3 period (different combination lines) Is written. Thereafter, these video signals are read out with a delay of one period as shown in FIGS. (G) and (H), and are output to the monitor to display a moving image on the monitor.

FIG. 6 shows the timing of a still image formed on the basis of the freeze signal. For example, if a freeze trigger is output at the timing shown in FIG. 6B, as shown in FIG. The (o + e) ₁ mixed signal accumulated in the exposure of the period (FIG. A) is written in the fourth memory 18, and is accumulated (o + e) in the exposure of the next E 1 period as shown in FIG. mixing signals ₁ 'fifth memory 1
9 and the subsequent writing to these memories 18 and 19 is prohibited. Then, these video signals are repeatedly read as shown in FIGS. (E) and (F), so that a still image is displayed on the monitor.

FIGS. 7 to 9 show the image processing timing of the all-pixel reading method (B method). When the presence of the all-pixel reading method circuit board 33 is detected, the all-pixel reading method is performed. Is executed by the microcomputer 14. 7 and 8 show processing timings when a moving image is formed. In this case, the light shielding plate 30 of FIG. 1 is rotationally driven according to the field O / E signal of FIG. 7B, light is output, for example, every odd field period (1/60 seconds). Further, as shown in FIG. 7C, a read pulse P1 for every 1/30 second and this pulse P1
The read pulse P2 in FIG.
Given to 1.

Then, from the CCD 11 as shown in FIG.
The signals of the odd line and the even line described in 1) are input through the b route, and as shown in FIG.
, O ₁ accumulated in the field period of O ₁ , o ₂ accumulated in the period of O ₂ , o ₃ accumulated in the period of O _3, ...
The odd line signal of is written in the second memory 35,
The even-line signals of e ₁ accumulated in the field period of E ₁ , e ₂ accumulated in the period of E ₂ , e ₃ accumulated in the period of E _{3, etc.} are written.

These odd and even line signals are read out twice each as shown in FIGS. 8G and 8H. Regarding the read signal indicated by the dotted circle in FIG. 8G, , Is written in the third memory 36, and the video signal in the third memory 36 is also read twice each as shown in FIG. Next, the signals of FIGS. 8H and 8I are pixel-mixed by the mixing circuit 37 as shown in FIG.
As in (J), in the fourth memory 18, o ₁ + e ₁ , o ₂
The signals + e ₂ , o ₃ + e ₃ ... Are written, and the fifth memory 19 stores (o ₁ + e ₁ ) ′, (o ₂ + e ₂ ) ′, (o ₃
+ E ₃ ) '... signal is written. Thereafter, these video signals are read out with a delay of one period as shown in FIGS. (L) and (M), and are output to the monitor to display a moving image on the monitor.

FIG. 9 shows the timing of a still image formed based on the freeze signal. For example, if the freeze trigger is output at the timing shown in FIG. 9B (either the solid line position or the dotted line position), As shown in FIG. 9C, the signal o ₁ accumulated by the exposure in the O ₁ period is written in the first memory 34, and the write is prohibited for the subsequent 3 periods, for example, and as shown in FIG. 9D. Then, the signal of e ₁ accumulated by the exposure in the O 1 period is written in the second memory 35, and the writing is prohibited in the subsequent 3 periods, for example.

Then, these signals are shown in FIG.
As in (F) and (G), the data is repeatedly read and added and mixed in the mixing circuit 37. Next, as shown in FIG.
The signal of o ₁ + e ₁ is written in the fourth memory 18, the signal of (o ₁ + e ₁ ) ′ is written in the fifth memory 19, and the writing is prohibited thereafter. Next, as shown in FIGS. (J) and (K), these video signals are repeatedly read out with a delay of one period to display a still image on the monitor.

In the all-pixel reading method of the embodiment as described above, one image can be formed by the pixel signal obtained by one-time exposure, so that the image quality is high, and it is particularly useful in observing a still image. . Further, since the latest black level signal is always input via the route a, it is possible to maintain good color reproducibility even after displaying a still image.

FIGS. 10 and 11 show the configuration of a second example in which the processing method currently in operation is displayed on the monitor.
This second example has the same configuration as the first example shown in FIG.
As shown in, the DVP 17 and the fourth and fifth memories 1
A character mixing circuit 40 including a character generator is provided between 8 and 19, and the character mixing circuit 40 can add a character image to a video signal. According to this, as shown in FIG. 11, characters or the like indicating the method are displayed on the upper right or the like of the screen of the monitor 41, and in this example, for example, the pixel mixture reading method is represented by N and the all pixel reading method is represented by H. It The display may be a design or the like.

In the above embodiment, the all-pixel read-out type circuit board 33 can be selectively attached. However, this circuit board 33 is mounted as a standard and, conversely, a pixel mixed read-out type circuit board can be attached. Good.

[0036]

As described above, according to the present invention,
The pixel mixture read-out circuit section and the all-pixel read-out circuit section for reading out all pixel signals from the image sensor while utilizing the light-shielding period are selectively attachable, and whether or not these circuit sections exist Therefore, if the above-mentioned all-pixel reading method circuit unit is present, the operation of the method is executed. Therefore, instead of the conventional pixel-mixing reading method, the all-pixel reading method can be easily used. In addition, the user can select a high quality image in consideration of various situations.

According to the second aspect of the present invention, it is possible to easily confirm on the monitor screen whether the current display image is obtained by the pixel mixture reading method or the all pixel reading method. There are advantages.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an electronic endoscope apparatus according to a first example of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a color filter structure of a CCD and both processes of a pixel mixed read system and an all pixel read system in the embodiment.

FIG. 3 is a diagram showing an operation in the microcomputer of the embodiment.

FIG. 4 is a waveform diagram showing an operation of capturing a black level signal in the embodiment.

FIG. 5 is a waveform diagram showing an operation at the time of forming a moving image in the pixel mixed read method (method A) of the embodiment.

FIG. 6 is a waveform chart showing an operation at the time of forming a still image in the pixel mixture reading method (method A).

FIG. 7 is a waveform diagram showing an operation at the time of forming a moving image in the all pixel reading method (B method) of the embodiment.

FIG. 8 is a waveform chart showing a continuation of the operation of FIG. 7 when forming a moving image in the all-pixel reading method (B method).

FIG. 9 is a waveform chart showing an operation at the time of forming a still image in the all-pixel reading method (B method).

FIG. 10 is a block diagram showing a circuit configuration of a second example of the embodiment.

FIG. 11 is a diagram showing a display state on a monitor in the second example.

[Explanation of symbols]

11 ... CCD, 12 ... CCD driving circuit, 14 ... Microcomputer, 16 ... system switching circuit, 18, 19, 34, 35, 36 ... Memory, 30 ... Light shield, 31 ... Light shield control circuit, 33 ... All pixel readout system circuit board, 37 ... Mixing circuit.

Claims (2)

(57) [Claims] 1. A circuit unit of a pixel mixed read system for reading pixel signals from an image sensor by mixing them between upper and lower horizontal lines, and an all pixel read system for reading all pixel signals from the image sensor while utilizing a predetermined light-shielding period. One of the circuit parts is attached as a standard, and the other is configured to be selectively attachable, and it is determined whether or not the above-mentioned circuit part that can be selectively attached is present. An electronic endoscope apparatus comprising a control circuit for controlling the operation of the method of the circuit unit when the presence is detected. 2. The monitor screen is provided with a display indicating which one of the pixel mixed read-out method and the all-pixel read-out method is in operation.
The described electronic endoscope apparatus.