JP2002263064A - Automatic light control device for endoscope and processor of electronic endoscope device including the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To calculate a luminance value appropriately indicating the brightness of a subject image and to perform automatic light control so as to maintain the desired brightness of the subject image regardless of the type of scope. A lamp (24) and a diaphragm (2) are provided in a processor (20).
2. A dimming circuit 34 is provided. E in the video scope 10
The mask shape data of the CCD 12 is read from the EPROM 14. An image signal for one field is read out from the CCD 12 at predetermined time intervals, converted into a luminance signal, and sent to the dimming circuit 34. Then, the dimming circuit 34 calculates an average luminance value indicating the average luminance of the subject image, compares the average luminance value with the reference luminance value set by the setting switch 46a, and adjusts the aperture 22 based on the difference. Open and close. At this time,
In consideration of the mask shape, an average luminance value is calculated for pixels in the effective area that are not masked in the CCD 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an image pickup device,
An electronic endoscope apparatus including a scope (endoscope) inserted into a body for observation and treatment of an organ such as a stomach, and a processor to which the scope is connected and which processes an image signal read from an imaging device. In particular, the present invention relates to automatic light control of an endoscope that automatically adjusts the amount of light emitted from a scope tip toward a subject.

[0002]

2. Description of the Related Art In a conventional electronic endoscope apparatus, light emitted from a light source in a processor is emitted from a distal end of a scope toward a subject through an optical fiber bundle provided in the scope. Then, when a subject image of the observation site is formed on an image pickup device such as a CCD via an objective lens on the distal end side of the scope, an image signal corresponding to the subject image is generated and sequentially sent to the processor. The processor generates a video signal such as a composite video signal from the image signal in order to display a subject image on a monitor.

The processor sequentially calculates a luminance value indicating the brightness of the subject image based on the read image signal. Usually, a stop for adjusting the amount of light is provided between the light source and the incident end of the fiber bundle, and a reference luminance value set as the brightness desired by the operator is compared with the aforementioned luminance value, and the luminance value is compared. Is driven so that is equal to the reference luminance value. Thus, the brightness of the subject image displayed on the monitor is maintained at an appropriate brightness. As a photometric method for obtaining the brightness of the subject image, for example, there is an average photometric method, and the average luminance of each pixel forming the subject image is calculated as the above-described luminance value.

[0004]

As an objective lens used in an endoscope, a wide-angle lens having a spherical shape and a large depth of focus is usually used. For this reason, in most of the imaging elements, a peripheral region having a small amount of light on the light receiving surface is masked, and the light does not reach the light receiving surface in the masked region. However, when calculating a luminance average value or the like, since the image signal including the masked area is read and the luminance calculation is performed, the calculated luminance value appropriately represents the actual brightness of the subject image. Not.

Further, the characteristics of the image pickup device and the objective lens differ depending on the type of the scope based on the observation site (the bronchus, the digestive tract, etc.), and the masked area in the image pickup device also differs. Therefore, the average brightness value calculated according to the type of scope connected to the processor also differs,
The brightness of the subject to be adjusted does not match for each scope.
In this case, the operator has to operate a panel switch provided in the processor to reset the reference luminance value as a reference every time the scope is replaced.

Accordingly, in the present invention, a brightness value that appropriately indicates the brightness of the subject image is calculated, and automatic light adjustment is performed so as to maintain the desired brightness of the subject image regardless of the type of scope. It is an object of the present invention to obtain an automatic light control device for an endoscope and a processor of an electronic endoscope device having such automatic light control function.

[0007]

A processor of an electronic endoscope apparatus according to the present invention comprises: an image pickup device masked so that a part of a light receiving surface on which a subject image is formed blocks light; A processor to which a scope having an objective optical system formed on a surface and an optical fiber bundle for transmitting light toward a subject is detachably connected. The processor generates a representative brightness value corresponding to the brightness of the subject image based on a light source that emits light toward the input end of the optical fiber bundle on the processor side and an image signal corresponding to the subject image sequentially read from the image sensor. Brightness value calculating means for sequentially calculating;
A light amount adjusting unit that adjusts a light amount of light emitted from the distal end side of the scope through the optical fiber bundle based on the representative luminance value, and a mask shape detecting unit that detects a mask shape in the image sensor. The representative brightness value is calculated according to the mask shape so that the brightness of the subject image in an effective area that is not masked on the light receiving surface is detected. Even if the mask area is different for each scope, the representative brightness value is calculated as the brightness of the subject image in the unmasked area, so that the brightness of the subject image is maintained at the desired brightness. However, the mask shape indicates the shape of the boundary between the effective area and the shielding area masked on the light receiving surface. In the case of an image sensor that is not masked, the shape of the light receiving surface is a mask shape.

In order to apply the average photometry for obtaining the average luminance of the subject image as a photometric method, it is desirable that the representative luminance value is a luminance average value indicating the average brightness of the subject image. In this case, the average value of the pixels forming the subject image is calculated as the luminance average value, and the luminance value calculation means calculates the luminance average value from the pixels of the effective area excluding the masked shielding area on the light receiving surface. .

In a different mask shape for each scope,
In order to detect the mask shape of the scope connected to the processor, a scope-side non-volatile memory in which mask shape data indicating a mask shape in the image sensor mounted in the video scope is provided, and a mask shape detecting unit is provided. A processor-side non-volatile memory in which a plurality of mask shape data corresponding to a plurality of scopes each having a different mask shape are stored; It is desirable to read from memory. Then, the brightness value calculating means determines a pixel in the effective area based on the mask shape data, and calculates an average brightness value based on the pixels in the effective area. Since it is stored in advance in the non-volatile memory on the processor side in the processor, the mask shape corresponding to whatever scope is connected is detected, and the average luminance value is calculated from the pixels in the effective area according to the mask shape. Is done.

In order to use a stop as a structure for adjusting the light amount, the light amount adjusting means preferably includes a stop for adjusting the light amount of light incident on the incident end and a stop driving means for driving the stop. It is provided between the incident end of the optical fiber bundle and the light source. With such a configuration, the amount of light is adjusted by opening and closing the aperture. When calculating the average luminance value, it is preferable that the light amount adjusting unit opens and closes the aperture based on a luminance difference between the average luminance value and a reference luminance value set according to the viewing condition.

An automatic light control device for an endoscope according to the present invention includes an image pickup device masked so that a part of a light receiving surface on which a subject image is formed blocks light, and an object for forming the subject image on the light receiving surface. An automatic light control device for an endoscope provided in a processor to which a scope having an optical system and an optical fiber bundle for transmitting light toward a subject is detachably connected. The automatic light control device is provided between a light source provided in the processor for emitting light toward the incident end of the optical fiber bundle and the incident end of the optical fiber bundle, and is an aperture for adjusting the amount of light incident on the incident end. Aperture driving means for driving the aperture, and dimming means for controlling the aperture driving means so that the brightness of the subject image is constant based on an image signal read from the image sensor to open and close the aperture. . The dimming unit includes a luminance value calculating unit that sequentially calculates a representative luminance value corresponding to the brightness of the subject image based on an image signal corresponding to the subject image sequentially read from the imaging device, and a mask shape in the imaging device. And a brightness value calculation means for calculating a representative brightness value according to the mask shape so that the brightness of the subject image in an effective area that is not masked on the light receiving surface is detected. It is characterized by doing.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electronic endoscope apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an electronic endoscope apparatus according to the present embodiment.

The electronic endoscope apparatus includes a video scope 10 having a CCD 12 which is one of the image pickup devices, a processor 20 for processing an image signal read from the image pickup device,
And a monitor 52 for displaying a subject image. The video scope 10 is detachably connected to the processor 20, and a keyboard 50 is connected to the processor 20 together with a monitor 52. When an operation or an examination is started, the videoscope 10 is connected to the processor 20 and inserted into a body toward an observation site such as a stomach.

Light emitted from a lamp (light source) 24 controlled by a lamp control circuit 32
Through the input end 13a of the optical fiber bundle 13 provided in the video scope 10. Optical fiber bundle 1
Reference numeral 3 denotes an optical fiber for transmitting the light emitted from the lamp 24 to the distal end side of the video scope 10 having the observation site, and the light passing through the optical fiber bundle 13 is emitted from the emission end 13b. As a result, the observation site S is irradiated with light.

The light reflected at the observation site S reaches the light receiving surface of the CCD 12 through the objective lens 11, whereby an object image of the observation site S is formed on the light receiving surface of the CCD 12. In the present embodiment, a single-panel system of a simultaneous imaging system is applied as a color imaging system, and yellow (Ye), cyan (Cy), magenta (M)
g), a complementary color filter (not shown) composed of green (G) color elements is arranged in a checkered pattern corresponding to each pixel position on the light receiving surface. And in the CCD 12,
An image signal of a subject image corresponding to a color passing through the complementary color filter is generated by photoelectric conversion, and image signals for one frame or one field are sequentially read at predetermined time intervals. In the present embodiment, the NTSC system is applied as the color television system, and 1/30 (1/60)
Image signals for one frame (one field) are sequentially read out every second interval and sent to the initial signal processing circuit 16.

In the initial signal processing circuit 16, the image signal is subjected to amplification processing and the like, and the luminance signal Yir
is is generated. The initial signal processing circuit 16 includes:
A CCD driver (not shown) for driving the CCD 12 is incorporated.
The drive signal is output to 2. The image signal subjected to the amplification processing and the like is sent to the signal processing circuit 44, and the generated luminance signal Yiris is sent to the dimming circuit 34. The vertical synchronizing signal rd, the horizontal synchronizing signal Hd, and the vertical synchronizing signal corresponding to the luminance signal for one frame (for one field) are adjusted in accordance with the luminance signal for one frame (for one field) sequentially sent to the light control circuit 34. The clock pulse signal Cl is sent to the dimming circuit 34 at a predetermined timing.

The signal processing circuit 44 performs gamma correction on the image signal sent from the initial signal processing circuit 16,
/ D conversion, white balance processing, and the like are performed to obtain a digital image signal. Then, a video signal such as an NTSC composite signal is generated based on the digital image signal, and sent to the monitor 52. As a result, the subject image is displayed on the monitor 52.

CPU in system control circuit 36
38 controls the entire processor 20 and controls the dimming circuit 34;
A control signal is output to each circuit such as the lamp control circuit 32 and the signal processing circuit 44. Timing control circuit 42
Then, a clock pulse for adjusting the signal processing timing is output to each circuit in the processor 20, and a synchronization signal attached to the video signal is sent to the signal processing circuit 44.

A stop 22 is provided between the incident end 13a of the light guide 13 and the condenser lens 26 for adjusting the amount of light irradiated to the subject S, and is opened and closed by driving a motor 28. In the present embodiment, a DSP (Digital
The light amount of light passing through the stop 22, that is, light applied to the subject S, is adjusted by a dimming circuit 34 including a signal processor. The luminance signal Yiris output from the initial signal processing circuit 16 is converted into a digital luminance signal by the A / D converter 35, and then the light control circuit 34
Is input to

The dimming circuit 34 sequentially calculates an average luminance value indicating the average luminance of the subject image for one frame (one field) based on the transmitted luminance signal. At this time, as will be described later, data relating to the mask shape of the CCD 12 is read from the dimming ROM 31 by the dimming circuit 34, and an average luminance value is calculated according to the read mask shape. Then, the reference luminance value, which is a reference for the brightness of the subject image, and the luminance average value are compared, and a control signal is output to the motor driver 30 based on the difference. However, the digital control signal output from the dimming circuit 34 is D / D
The signal is converted into an analog signal by an A converter (not shown) and sent to the motor driver 30. Motor driver 30
Then, a drive signal is sent to the motor 28 based on the control signal. As a result, the motor 28 is driven, and the aperture 22 is opened to a predetermined opening.

In the video scope 10, there are provided a microprocessor 15 for controlling the entire video scope 10, and an EEPROM 14 in which data relating to the characteristics of the video scope 10 is stored in advance. The microprocessor 15 sends a control signal to the initial signal processing circuit 16 and reads data from the EEPROM 14 as appropriate. Video scope 10 is processor 20
, Data is transmitted between the microprocessor 15 and the system control circuit 36, and data on scope characteristics is sent to the processor 20.

The front panel 46 is provided with a setting switch 46a for setting a reference luminance value which is a reference in automatic light control.
A signal corresponding to the value set by operating 6 is sent to the system control circuit 36. The data of the reference luminance value is temporarily stored in the RAM 40 and sent from the system control circuit 36 to the dimming circuit 34 as needed.

FIG. 2 is a diagram schematically showing the light receiving surface of the masked CCD 12 from the front.

A CCD provided in the video scope 10
An object image is formed on the light receiving surface PA of the object 12 by light passing through the objective lens 11. Since the objective lens 11 has a spherical shape, and it is difficult to install a zoom lens or the like at the distal end of the scope, a wide-angle lens having a large depth of focus is usually used as the objective lens 12. Therefore, since the amount of light reaching the periphery of the light receiving surface PA is extremely smaller than that of the central portion, a part of the light receiving surface PA of the CCD 12 is masked by the mask member MN, and the light receiving surface PA Light does not reach the shielding area MA (shown by oblique lines). The mask member MN is formed of, for example, a vapor-deposited aluminum film. Here, the light receiving surface PA is masked by the mask member MA so that the contour of the effective area EA to which light reaches becomes elliptical. , The contour shape of the effective area EA is set as a mask shape). Since the light is blocked in the shielded area MA, the level of the luminance signal detected from the pixel corresponding to the shielded area MA is almost zero.

Generally, a videoscope is prepared according to an observation site such as a bronchus and a lower digestive organ, and the characteristics of a built-in objective lens and a CCD differ depending on the observation site. That is, the mask shape differs for each video scope. For example, in addition to the elliptical shape shown in FIG. 2, there are a chamfered square obtained by cutting four corners from a square, and a circular mask shape. In the present embodiment, a different CC
Data of a plurality of mask shapes related to the mask shape of D are stored in the light control ROM 31 in advance, and the EEPROM 14 in the video scope connected to the processor 20
Data matching the mask shape stored in the light control RO
It is read from M31. At this time, the CCD 12
, That is, the number of horizontal pixels Nh and the number of vertical pixels Nv are read out. Based on these data and the mask shape data, the pixels in the shielding area MA and the effective area E are read out.
Pixels within A are determined.

FIGS. 3 and 4 are flowcharts showing the automatic light control operation. This automatic dimming operation is started when the power is turned on or when a new scope is mounted due to replacement of the scope. Here, the videoscope 10 having the CCD 12 whose mask shape is elliptical is mounted. The calculation of the average luminance value is performed here for each field, and the luminance value of each pixel is 0 to 255.
Shall be in the range of

In step 101, the video scope 10
From the EEPROM 14, data on the mask shape of the CCD 12, data on the number of pixels Nv in the vertical direction and the number of pixels Nh in the horizontal direction on the light receiving surface PA of the CCD 12, and the like are read. Then, in step 102, a weighting table T corresponding to the mask shape is read based on the read data on the mask shape (elliptical shape) and the like.

This weighting table T is a table in which correction coefficients W corresponding to each pixel of the CCD 12 are arranged. The correction coefficient W is multiplied by a luminance signal corresponding to each pixel in the signal processing circuit 44 ( Weighted)
It is a coefficient. This is a process executed in accordance with a CCD color filter array system (color difference line sequential system) using a complementary color filter configured in units of arrays of cyan, yellow, green, and magenta elements. R, G, B constituting the read luminance signal
Are multiplied based on the weighting table W. Each value of the correction coefficient W is determined based on the optical characteristics of the objective lens 11 described above.
It is also possible to determine the value of the correction coefficient W in consideration of the occurrence of halation caused by the forceps channel (not shown) of the video scope 10. When the weighting table T corresponding to the elliptical mask shape is read in step 102, the process proceeds to step 103.

In step 103, the horizontal pixel position variables A,
The vertical pixel position variable B, the count variable C, and the luminance total variable S are set to 0, respectively. The horizontal pixel position variable A indicates a horizontal pixel position in the CCD 12, and the vertical pixel position variable B indicates a vertical pixel position. However, the origin is at the upper left of the light receiving surface PA. Also, the count variable C is
The variable for counting the pixels to which the luminance value is added, and the total luminance variable S is a variable indicating the total of the added luminance. When step 103 is executed, step 1
Move to 04.

In step 104, the initial signal processing circuit 1
6, the luminance value I (A, A) of the pixel corresponding to the horizontal and vertical pixel position variables A and B, that is, the pixel at the position (A, B) on the light receiving surface PA.
B) is extracted. At this time, signals other than the pixel signal of the CCD 12 are not sampled, and are extracted according to the pixel read clock pulse signal Cl sent from the initial signal processing circuit 16. Then, Step 105
Then, in the weighting table T, the pixel position (A, B)
It is determined whether or not the value of the correction coefficient W (A, B) corresponding to the pixel is zero. In the automatic light control operation of the present embodiment,
Regarding the weighting table T, the weighting coefficient W of the pixel in the shielding area MA is set to 0 by masking, and it is determined whether or not the pixel is in the masking area MA by the value of the weighting coefficient W. Lateral direction,
The correction coefficient W corresponding to the vertical pixel position variables A and B is 0,
That is, when it is determined that the pixel at the pixel position (A, B) is within the shielding area MA on the light receiving surface PA, steps 106 to 108 for calculating the average luminance value are not executed, and the process skips to step 108. .

On the other hand, if it is determined in step 105 that the correction coefficient W is not 0, that is, the pixel at the pixel position (A, B) is a pixel in the effective area EA on the light receiving surface PA, the process proceeds to step 106. Move on. Step 106
Then, the count variable C is incremented by one.
Then, in Step 107, the luminance value I (A, B) of the pixel at the pixel position (A, B) is multiplied by the correction coefficient W (A, B), and further, the luminance indicating the sum of the luminance values added so far. The sum variable S is added. As a result, the luminance values of the pixels in the effective area EA are sequentially added. Step 10
When Step 7 is executed, the process proceeds to Step 108.

In step 108, 1 is added to the horizontal pixel position variable A, and the pixel to be extracted moves to the pixel on the right. In step 109, it is determined whether or not the horizontal pixel position variable A is equal to the number of horizontal pixels Nh, that is, the light receiving surface PA
It is determined whether or not all the luminance values of the pixels for one line have been added. If it is determined that the horizontal pixel position variable A is equal to the horizontal pixel number Nh, the process proceeds to step 110 in FIG. On the other hand, the horizontal pixel position variable A is the number of horizontal pixels N
If it is not equal to h, the process returns to step 104, and steps 104 to 108 are repeatedly executed until the luminance values of the pixels for one line are added.

In step 110 (see FIG. 4), the vertical pixel position variable A is set to 0, and 1 is added to the vertical pixel position variable B. That is, the pixel on the next horizontal line is targeted. In step 111, it is determined whether or not the vertical pixel position variable B is equal to the number of vertical pixels Nv of the CCD 12, that is, whether or not the luminance values have been added for all the pixels. If it is determined that the vertical pixel position variable B is not equal to the vertical pixel number Nv of the CCD 12, the process returns to step 104, and steps 104 to 111 are repeatedly executed until the luminance values of all the pixels are added. On the other hand, if the vertical pixel position variable B is C
If it is determined that the number is equal to the number Nv of vertical pixels of the CD 12, the process proceeds to step 112.

In step 112, the average luminance value Ys for one field for the pixels in the effective area EA is obtained by the following equation. Ys = S / C (1) In step 113, the average luminance value Ys is compared with the reference luminance value Yr set by the operator. Here, the reference luminance value Yr is 128. In step 114, a control signal (voltage) is output from the dimming circuit 34 based on the difference between the average luminance value Ys and the reference luminance value Yr. When the reference luminance value Yr is larger than the average luminance value Ys, the control signal becomes positive, and the motor 28 is driven so that the aperture 22 is opened. Conversely, when the average luminance value Ys is larger than the reference luminance value Yr, the control signal becomes negative and the aperture 2
The motor 28 is driven so that 2 is closed. Step 11
At 5, it is detected whether the video scope 10 has been removed from the processor 20. If it is determined that the video scope 10 has not been removed, step 103 is performed again.
And again the average luminance value Y of the subject image for one field
s is calculated, and light amount adjustment is performed based on the difference from the reference luminance value Yr. On the other hand, if it is determined that the video scope 10 has been removed, this flowchart ends. Instead of calculating the average luminance value for one field, the average luminance value for one frame may be sequentially calculated. When a videoscope having an unmasked CCD is connected, the shape of the light receiving surface becomes a mask shape.

As described above, according to the present embodiment, the video scope 10 is connected to the processor 20 by executing the steps 101 and 102 shown in FIGS.
The data relating to the mask shape of D12 is read, and the processor 20 reads the weighting table T corresponding to the mask shape from the dimming ROM 31. Then, by executing steps 104 to 112, the weighting coefficient W
By determining whether (A, B) is 0, C
The pixels of the effective area EA on the light receiving surface PA of the CD 12 are determined, and only the pixels are subjected to the calculation of the average luminance Ys, and the average luminance Ys is calculated. The video scope 10 is removed and the CCD has a mask shape other than the elliptical shape.
Is connected, a weighting table corresponding to the mask shape is read out from the dimming ROM 31.

Although the average luminance value Ys is calculated in the present embodiment, a representative value other than the average value may be calculated in order to detect the brightness of the subject image. Further, instead of opening and closing the aperture 22 as the light amount adjustment, the light amount may be adjusted by controlling the output of the lamp 24. Further, a frame sequential method may be applied as a color imaging method.

[0038]

As described above, according to the present invention, a brightness value that appropriately indicates the brightness of a subject image is calculated, and an automatic brightness is maintained so as to maintain a desired brightness of the subject image regardless of the type of scope. Dimming is applied.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic endoscope apparatus according to an embodiment.

FIG. 2 is a diagram schematically showing a light receiving surface of a masked CCD from the front.

FIG. 3 is a first half of a flowchart showing an automatic dimming operation.

FIG. 4 is a second half part of a flowchart showing an automatic dimming operation.

[Description of Signs] 10 Video scope (scope) 11 Objective lens (Objective optical system) 12 CCD (Imaging element) 14 EEPROM (Scope-side nonvolatile memory) 20 Processor 22 Aperture 24 Lamp (light source) 28 Motor 30 Motor driver 31 Adjustment Optical ROM (processor-side nonvolatile memory) 34 Light control circuit (light control means) MA Shielding area EA Effective area PA Light receiving surface Ys Average luminance value (representative luminance value) Yr Reference luminance value

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mitsuru Iida 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd. F-term (reference) 2H040 BA11 CA10 CA11 CA23 DA43 GA02 GA05 GA06 GA10 GA11 4C061 CC06 GG01 LL01 NN01 QQ09 RR02 RR15 RR17 RR22 YY02 5C022 AA09 AB04 AB06 AB12 AB15 AC42 AC54 AC69

Claims (6)

[Claims] An image pickup device masked such that a part of a light receiving surface on which a subject image is formed blocks light, an objective optical system for forming a subject image on the light receiving surface, and a light source for directing light toward the subject. A processor to which a scope having an optical fiber bundle for transmission is detachably connected, the light source emitting light toward an input end of the optical fiber bundle on a processor side, and a subject image sequentially read from the image sensor. Brightness value calculating means for sequentially calculating a representative brightness value corresponding to the brightness of the subject image based on the image signal, and light emitted from the distal end side of the scope via the optical fiber bundle based on the representative brightness value Light quantity adjusting means for adjusting the light quantity of the light, and mask shape detecting means for detecting a mask shape in the image sensor, wherein the luminance value calculating means is provided on the light receiving surface. As the brightness of the object image is detected in the effective area which is not masked There, processor of an electronic endoscope apparatus of the representative luminance value and calculates in accordance with the mask shape. 2. The method according to claim 1, wherein the representative brightness value is a brightness average value indicating a brightness average of a subject image, and the brightness value calculation unit includes:
The processor according to claim 1, wherein the luminance average value is calculated from pixels in the effective area excluding a masked shielding area on the light receiving surface. 3. A scope-side non-volatile memory in which mask shape data indicating a mask shape of the image sensor mounted in the video scope is stored, wherein the mask shape detecting means includes a plurality of mask shapes different from each other. A plurality of mask shape data corresponding to the scope are stored in the processor-side nonvolatile memory, and the mask shape data of the scope connected to the processor is read from the processor-side nonvolatile memory from the plurality of mask shape data. 3. The electronic endoscope apparatus according to claim 2, wherein the brightness value calculation means calculates the brightness average value by determining a pixel in the effective area based on the mask shape data. Processor. 4. A stop provided between the incident end of the optical fiber bundle and the light source for adjusting the amount of light incident on the incident end, and a diaphragm driving unit for driving the stop. The electronic endoscope apparatus according to any one of claims 1 to 3, further comprising: controlling the aperture driving unit to open and close the aperture to adjust a light amount. Processor. 5. The electronic device according to claim 4, wherein the light amount adjusting unit opens and closes the aperture based on a luminance difference between the luminance average value and a reference luminance value set as needed. Endoscope device processor. 6. An imaging device masked so that a part of a light receiving surface on which a subject image is formed blocks light, an objective optical system for forming a subject image on the light receiving surface, and a light source for the subject. An automatic dimmer for an endoscope provided in a processor to which a scope having an optical fiber bundle to be transmitted is detachably connected, wherein the processor emits light toward an incident end of the optical fiber bundle. An aperture provided between the light source provided on the optical fiber bundle and the incident end of the optical fiber bundle, for adjusting the amount of light incident on the incident end; aperture driving means for driving the aperture; and an image read from the image sensor. Light control means for controlling the aperture drive means to open and close the aperture based on the signal so that the brightness of the subject image is constant, wherein the light control means comprises: A brightness value calculation unit that sequentially calculates a representative brightness value corresponding to the brightness of the subject image based on an image signal corresponding to the subject image sequentially read out from; and a mask shape detection unit that detects a mask shape in the image sensor. Wherein the brightness value calculation means calculates the representative brightness value according to the mask shape so that the brightness of the subject image in an effective area that is not masked on the light receiving surface is detected. Automatic light control device for endoscopes.