JP2001137186A - Electronic endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a good quality optical image on the monitor even when distance between objective lens of an electronic endoscope and an object is different. SOLUTION: The first light guide 13 and the second light guide 14 are arranged with predetermined space so that they are optically independent at the incident end. The first diaphragm unit 23 and the second diaphragm unit 24 are arranged between the first light guide 13 and white light source 22 and between the second diaphragm 14 and light source 22 respectively. The light volume of the light flux guided to the first and second guides 13, 14 is controlled by driving, respectively, the first and the second diaphragms 33, 34 independently so that the luminance of each domain on the TV monitor corresponding to the observation sites irradiated by the first and second guide 13, 14 practically coincides with the reference luminance decided by the operation of the luminance control unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic endoscope comprising a scope and an image signal processing unit.

[0002]

2. Description of the Related Art In a conventional electronic endoscope, a charge coupled device (CCD) is provided at a distal end of a scope of the electronic endoscope.
e) An imaging unit is provided in which a solid-state imaging device such as an image sensor is combined with an objective lens. A light guide for illumination composed of a bundle of optical fibers is inserted into the scope. When the scope is connected to the image signal processing unit, the light guide is optically connected to an illumination light source such as a xenon lamp or a halogen lamp provided in the image signal processing unit. The light emitted from the illumination light source is guided to the distal end of the scope by the light guide, and passes through the light distribution lens provided near the light emitting end of the light guide to the object image in front of the light receiving surface of the CCD image sensor from the scope. Irradiated. Further, in a certain scope, in order to uniformly illuminate the front of the CCD image sensor, the light emitting end of the light guide is divided into a plurality of parts and arranged around the CCD image sensor. At the end they are put together.

When the distal end of the scope is inserted into the body cavity of a patient, an observation site illuminated by a light guide forms an image on a light receiving surface of a CCD image sensor by an objective lens, and is photoelectrically converted as a pixel signal. The pixel signal obtained by the CCD image sensor is sent to an image signal processing unit, and a video signal is created in the image signal processing unit based on the pixel signal. The video signal is output from the image signal processing unit to the TV monitor, and the optical
It is displayed on the V monitor device.

Normally, in such an electronic endoscope, the amount of illumination light at a site to be observed drives a single stop incorporated in a light source based on luminance information extracted from pixel signals of a CCD image sensor. Is adjusted by On the other hand, an objective lens provided at the distal end of the scope has a large depth of field. This is because it is necessary to observe the entire wide area including the affected part in order to find the affected part such as a lesion in a body cavity.

[0005]

However, in the endoscope in which the illumination light exit end is divided as described above, since the light guide entrance end is united into one, the exit of the divided light guide is divided into a plurality. The amount of illumination light emitted from each of the ends is the same. Therefore, in a field of view where a part near and far from the imaging unit are mixed, when taking an image with an objective lens having a large depth of field as described above, for example, C
If the light intensity of the illumination light is adjusted according to the observation part close to the CD image sensor, the observation part far from the CCD image sensor will not have sufficient light quantity, so the reproducibility on the TV monitor will be poor, and conversely, the observation part far from the CCD image sensor When the light amount is adjusted according to the above, there is a problem that an observation part close to the CCD image sensor exceeds the upper limit of the dynamic range of the CCD image sensor and causes halation on the TV monitor.

The present invention has been made to solve the above problems, and an electronic endoscope capable of obtaining a good optical observation image even when the object distance from the objective lens is different in the observable range of the observation object. It is intended to provide a mirror.

[0007]

According to the present invention, there is provided an electronic endoscope including a scope and an image signal processing unit to which the scope is detachably connected. Solid-state imaging means provided on the side, and a plurality of optically independent light guides for guiding the emitted light from the light source provided in the image signal processing unit to the distal end side of the scope and irradiating the object to be observed The image signal processing unit divides an imaging region of the solid-state imaging means based on a relative positional relationship between the plurality of light guides and the solid-state imaging means on the distal end side of the scope, and A luminance calculating means for calculating an average luminance value for each imaging region; and a light source guiding the light guide to the light guide such that the average luminance value for each divided imaging region substantially matches a predetermined luminance reference value. Adjusting the amount of emitted light, and having a light amount adjustment means provided for each of a plurality of light guides.

[0008] Preferably, the light amount adjusting means has a stop provided between the incident end of the light guide and the light source, and a driving means for driving the stop.

The plurality of light guides are provided, for example, such that the end faces of the respective incident ends are arranged at predetermined intervals, and a condenser lens is provided between the incident end of the light guide and the corresponding stop. Will be arranged.

For example, the plurality of light guides are united at the entrance end while being optically independent from each other, and a single condenser lens is provided between the entrance ends of the plurality of light guides and the corresponding stop. Is arranged.

As described above, according to the present invention, a plurality of light guides are optically independent, and the amounts of guided light beams are adjusted independently of each other. Even if the object distance is not uniform in the region observed by the above, a good image of the object to be observed can be obtained.

If a plurality of light guides are optically independent of each other and are united at the entrance end, a single condenser lens may be provided between the entrance ends of the plurality of light guides and the corresponding stop. As a result, the number of parts can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electronic endoscope to which the first embodiment according to the present invention is applied. The scope 10 has a flexible conduit (flexible tube) and is detachably connected to the image signal processing unit 20. An image sensor 11 is provided on the distal end side of the scope 10. When the scope 10 is connected to the image signal processing unit 20, the image sensor 11 is connected to the video signal processing circuit of the image signal processing unit 20 via the CCD circuit 12. A first light guide 13 and a second light guide 1 are provided in a scope 10.
4 is inserted. First and second light guide 1
The emission ends of 3 and 14 extend to the tip of the scope 10.

The system controller 21 of the image signal processing unit 20 is a microcomputer that controls the entire electronic endoscope. That is, the system controller 21
Is a central processing unit (CPU), a program for executing various routines, a read-only memory (ROM) for storing constants and the like, and a write / read for temporarily storing data and the like.
It comprises a readable memory (RAM).

The scope 10 is connected to the image signal processing unit 20
Connected to the first and second light guides 13 and 14
Is a light source 22 such as a xenon lamp or a halogen lamp provided in the image signal processing unit 20.
Optically connected to the First and second light guide 1
A first aperture unit 23 and a second aperture unit 24 are provided so as to correspond to the entrance ends 3 and 14, respectively.

The image signal processing unit 20 is provided with an operation panel 25, and this operation panel 25 is provided with various display lights and various switches. Power switch (SW)
101 turns on / off a main power supply (not shown) of the image signal processing unit, and turns on a lighting switch (S
W) 102 controls lighting of the white light source 22.

The system controller 21 outputs a control signal to a lamp power supply circuit 26 based on a signal from the lighting SW 102. In accordance with a control signal from the system controller 21, power supply to the white light source 22 is appropriately controlled by the lamp power supply circuit 26. The lamp power supply circuit 26 is connected to a commercial power supply via a plug (not shown).

FIG. 2 is a view showing the correspondence between the distal end of the scope 10 and the insertion portion into the image signal processing unit 20. Note that some members are omitted in FIG. 2 for simplification of the drawing. A first light distribution lens 31 and a second light distribution lens 41 are disposed on the distal end side of the scope 10, that is, on the emission ends of the first and second light guides 13 and 14, respectively. The imaging sensor 11 is a CCD image sensor 110
And an objective lens group 111. On the distal end side of the scope 10, the first light guide 13 is disposed on the signal charge output end side (not shown) of the horizontal transfer unit of the CCD image sensor 110, and the second light guide 14 is disposed on the CCD image sensor 110. It is arranged on the side opposite to the signal charge output end of the horizontal transfer section.

The image signal processing unit 20 of the scope 10
, Ie, the first and second light guides 13, 1
Condensing lenses 32 and 42 are provided at the entrance end of No. 4 respectively. The first aperture unit 23 provided between the incident end of the first light guide 13 and the white light source 22
A first diaphragm 33 and a first actuator 34 are provided.
The second aperture unit 24 disposed between the incident end of the second light guide 14 and the white light source 22 is provided with a second aperture 4.
3 and a second actuator 44. First and second
Of the actuators 34 and 44 include a motor such as a DC servomotor in the main body.

As shown in FIG. 3, the first stop 33 has a light blocking portion 330 and an arm portion 331. The light shielding portion 330 is a thin plate having a circular shape as a whole, and a light beam passing portion 330A cut out in a sector shape is formed in a part thereof. Further, a slit 330B is formed along the radial direction of the light shielding portion 330 so as to be continuous with the light beam passing portion 330A. The arm part 331 is molded integrally with the light-shielding part 330, and the end of the arm part 331 is a first actuator 3 such as a DC servomotor.
4 is fixedly supported by the output shaft 34A of the motor provided in the main body.

The first throttle 33 swings clockwise and counterclockwise in FIG. 3 according to the forward / reverse rotation of the output shaft 34A accompanying the operation of the motor of the actuator 34. The white light source 2 blocked by the light shielding unit 330 due to the swinging motion
The range of the optical path of the second emitted light is determined, and the amount of light guided to the first light guide 13 is adjusted. Note that the first aperture unit 23 is configured such that one point of an arc-shaped locus drawn by the center of the light-shielding portion 330 according to the swing accompanying the light amount adjustment substantially coincides with the center of the end face of the incident end of the first light guide 13. Will be arranged.

The configurations of the second diaphragm 43 and the second actuator 44 are the same as those of the first diaphragm 33 and the first actuator 34 described above, and therefore the description thereof is omitted. The second aperture unit 24 causes the center of the light-shielding portion to substantially coincide with the center of the end face of the incident end of the second light guide 14 when the amount of light to the second light guide 14 is adjusted to a predetermined amount. It is arranged as follows. The first and second actuators 3
Reference numerals 4 and 44 are supported by a predetermined support mechanism (not shown) in the image signal processing unit 20.

Referring to FIG. 1, in the image signal processing unit 20, a rotary RGB color filter 2 is provided on the light emission side of a white light source 22 as a rotary three primary color filter.
7 are interposed. Rotary RGB color filter 27
Is formed of a disc element as shown in FIG. 4, and provided with sector-shaped red filters 27R, green filters 27G, and blue filters 27B, respectively. Red filter 27R,
The green filter 27G and the blue filter 27B are arranged along the circumferential direction of the disk element such that the centers in the radial direction are at an angular interval of 120 °, and the area between the mutually adjacent filters is a light shielding area. is there.

The rotary RGB color filter 27 is provided with a driving motor 2 such as a servomotor or a stepping motor.
8 is rotated. The rotation frequency of the rotary RGB color filter 27 is determined according to a TV image reproduction method used in the electronic endoscope. For example, when the PAL method is adopted, the rotary RGB color filter 27 is used.
Has a rotation frequency of 25 Hz, and when the NTSC system is adopted, the rotation frequency is 30 Hz.

For example, a rotary RGB color filter 27
Is rotated at a rotation frequency of 30 Hz (NTSC
Method), the time required for one rotation is about 33.3msec (1 / 30se
c), and the illumination time of each color filter is almost 33.3 / 6
msec. Red light from the end face of the exit end of the light guide,
Green light and blue light are sequentially emitted for approximately 33.3 / 6 msec every 33.3 msec, the object to be observed is sequentially illuminated with red light, green light and blue light, and the optical object image of each color is captured. An image is sequentially formed on the light receiving surface of the CCD image sensor 110 (see FIG. 2) by the objective lens group 111 (see FIG. 2) of the sensor 11. The imaging sensor 11 is the CCD
The optical observation object image of each color formed on the light receiving surface of the image sensor 110 is photoelectrically converted into an analog pixel signal for one frame, and the analog pixel signal for one frame of each color is used for the illumination time of each color (33.3 / 6msec) followed by the next shading time (3
(3.3 / 6 msec) sequentially from the image sensor 11. Reading of the analog pixel signal from the image sensor 11 is performed by the CCD driver 12 provided in the scope 10.

Strictly speaking, the color filter 27
Since the output powers of the respective colors from R, 27G and 27B and the spectral sensitivity characteristics of the CCD image sensor 110 are different, the illumination times by the red light, the green light and the blue light are slightly different from each other. Reading of the analog pixel signals for one frame of each color from the image sensor 110 is performed within the light shielding time in the same manner.

As shown in FIG. 1, when the scope 10 is connected to the image signal processing unit 20, the CCD driver 12
Is connected to the video signal processing circuit 29. Image sensor 11
The pixel signal read out from is transmitted to the video signal processing circuit 29 via the CCD driver 12. In the video signal processing circuit 29, RGB color analog video signals are generated from the sent pixel signals, and sent to the TV monitor 50.

Further, the operation panel 25 has a brightness adjustment unit 103. The brightness adjustment unit 103
Specifically, it is composed of an UP button switch for increasing the luminance of the entire video reproduction screen of the TV monitor 50 due to illumination, a DOWN button switch for decreasing the luminance, and a luminance level display. Pressing the UP button switch outputs a brightness increase pulse signal to the system controller 21, and pressing the DOWN button switch outputs a brightness decrease pulse signal to the system controller 21. A luminance reference value, which will be described later, is increased stepwise by a predetermined amount every time the luminance increase pulse signal is output,
Each time the luminance reduction pulse signal is output, the luminance reference value is reduced stepwise by a predetermined amount. The luminance level designated by operating the DOWN button switch and the UP button switch is displayed stepwise on the luminance level display, and is recognized by the operator of the electronic endoscope.

FIG. 5 is a diagram showing a main part of the video signal processing circuit 29 of the image signal processing unit 20. Scope 10
The analog pixel signal for one frame of each color read from the image sensor 11 by the CCD driver 12 is input to the pre-stage signal circuit 201. The pre-stage signal circuit 201 is provided with a preamplifier, a band limiting video filter, a gamma circuit, and the like, and performs predetermined image processing such as amplification and gamma correction of an analog pixel signal output from the CCD driver 12.

The 1 of each color processed by the pre-stage signal circuit 201
The analog pixel signals for the frames are sequentially sent to an analog / digital (A / D) converter 202 and converted into digital pixel signals. Then, the digital pixel signals for one frame of each color are stored in the R image memory 203R and the G image memory, respectively. 2
03G, B image memory 203B. The digital pixel signals of each color stored in each image memory are read out simultaneously, and a horizontal synchronizing signal and a vertical synchronizing signal are added to the read digital pixel signals of each color. That is,
The three primary color digital pixel signals for one frame are stored in the R image memory 203R, the G image memory 203G, and the B image memory 20.
3B is output as a color digital video signal (R, G, B) and sent to the digital process circuit 204.
Note that the timing of conversion in the A / D converter 202, the capture of pixel signals into each image memory, the generation of a synchronization signal, and the like are controlled by the timing controller 30.

In the digital process circuit 204, processes such as enlargement, reduction, and noise reduction are performed on the color digital video signals of each color, and the signals are input to digital / analog (D / A) converters 205R, 205G, and 205B, respectively. The color digital video signal for one frame of each color is converted into a color analog video signal for one frame by the D / A converters 205R, 205G, and 205B, and is input to the subsequent signal processing circuit 206. The color analog video signal for one frame of each color is supplied to the subsequent signal processing circuit 206.
After passing through the low-pass filter in, the output level is adjusted appropriately and sent to the TV monitor 50, where the optical observation object image is reproduced as a color image.

Further, the digital video processing circuit 20
4, the first and second light guides 13 and 14 (FIG. 2)
CCD image sensor 11 (see FIG. 2) and the CCD image sensor 110 (see FIG. 2).
The imaging region of 0 is divided, and an average luminance signal of each divided region is generated. A luminance signal for each pixel is generated from the R, G, and B color digital video signals, and a luminance signal of a pixel belonging to each divided region is extracted and integrated to calculate an average luminance signal of each divided region. .

As described above, in the first embodiment, the CCD
Viewed from the vertical transfer unit substantially at the center of the image sensor 110,
The first light guide 13 is a CCD image sensor 110
The second light guide 14 is disposed on the side opposite to the signal charge output end of the horizontal transfer unit. Accordingly, in the digital video process circuit 204, the imaging area of the CCD image sensor 110 is divided into two substantially at the center along the vertical transfer unit, and an average luminance signal for each divided area is generated.

In the divided image pickup area of the CCD image sensor 110, the image pickup area on the side opposite to the signal charge output end side of the horizontal transfer section, that is, the right area 51R of the image display area 51 of the TV monitor 50 (see FIG. 1). The average luminance signal of the corresponding imaging region is sent to the D / A converter 207, converted into an analog average luminance signal, and sent to the motor driver 208.
Similarly, of the divided imaging regions of the CCD image sensor 110, an imaging region on the signal charge output end side of the horizontal transfer unit,
That is, the left area 51L of the image display area 51 of the TV monitor 50
The average luminance signal of the imaging region corresponding to (see FIG. 1) is D
The signal is sent to the / A converter 209, converted into an analog luminance signal, and sent to the motor driver 210.

On the other hand, the UP button switch of the light amount adjustment unit 103 (see FIG. 1) of the front panel 25,
The reference luminance value determined by operating the DOWN button switch is sent to the D / A converter 211 via the system controller 21 and is converted into an analog reference luminance value. The analog reference luminance value is sent to motor drivers 208 and 210, respectively.

In the motor driver 208, the analog average luminance signal input from the D / A converter
The analog reference luminance value input from the / A converter 211 is compared and amplified, and the direction and amount of rotation of the motor of the first actuator 34 are calculated based on the result. Similarly, in the motor driver 210, the D / A converter 20
9 is compared with the analog reference luminance value input from the D / A converter 211, and the direction and amount of rotation of the motor of the second actuator 44 are calculated based on the result. Is done.

That is, the amount of light guided to the first light guide 13 determined by the direction and amount of swing of the first diaphragm 33 is adjusted, and as a result, the signal charge output of the horizontal transfer unit of the CCD image sensor 110 is adjusted. The direction and amount of rotation of the motor of the first actuator 34 are calculated such that the analog average luminance signal of the imaging area opposite to the end substantially matches the analog reference luminance value. Similarly, the amount of light guided to the second light guide 14 determined by the swing direction and amount of the second aperture 43 is adjusted, and the CCD image sensor 11
The direction and amount of rotation of the motor of the second actuator 44 are calculated so that the analog average luminance signal of the imaging region at the signal charge output end of the horizontal transfer unit of 0 substantially matches the analog reference luminance value.

As described above, the brightness of the left area 51L and the right area 51R of the image display area 51 of the TV monitor device 50 match the brightness level specified by the DOWN button and the UP button of the brightness adjustment unit 103. Adjusted.

FIG. 6 is a diagram schematically showing the positional relationship between the light guide entrance end, the white light source, and the aperture unit in the electronic endoscope to which the second embodiment according to the present invention is applied. First light guide 61, second light guide 62
The shape of the end face of the incident end is a semicircle, and they are bundled together so as to be optically independent so that the respective linear portions come into contact with each other. The amount of white light emitted from a white light source 63 such as a halogen lamp or a xenon lamp similar to that of the first embodiment is adjusted by a first aperture unit 65 and a second aperture unit 66 to form a single condensing lens. The light is guided to the entrance ends of the first and second light guides 61 and 62 through the 67.

Note that, in the second embodiment, the first and second
The configuration of the light guides 61 and 62 at the entrance ends and the configuration other than the mechanisms of the first and second aperture units 65 and 66 are the same as those of the first embodiment. The system configuration in the image signal processing unit is also the same as in the first embodiment.
Therefore, the observation region illuminated by the first light guide 61 is displayed in the right region obtained by vertically dividing the center of the image display region of the TV monitor, and the observation region illuminated by the second light guide 62 is displayed on the left side. Is displayed in the area.

FIG. 7 shows the first and second aperture units 65,
FIG. 66 is a front view showing a light source 66 from a white light source 63 side. The first diaphragm 70 of the first diaphragm unit 65 has a semicircular light shielding portion 7.
00 and an arm 7 integrally formed with the light shielding unit 700.
01. A semicircular notch 700A is formed substantially at the center of the linear end of the light shielding portion 700. An end of the arm 701 is fixedly supported on an output shaft 71A of a motor such as a DC servomotor provided in the first actuator 71. Similarly, the second aperture unit 6
6, the second diaphragm 80 includes a semicircular light shielding unit 800 and an arm unit 801 integrally formed with the light shielding unit 800.
A semicircular notch 800A is formed substantially at the center of the linear end of the light shielding portion 801 and the end of the arm portion 801 is the second end.
Is fixedly supported on an output shaft 81A of a motor such as a DC servomotor provided in the actuator 81.
The first and second actuators 71 and 81 are supported in the image signal processing unit by a support mechanism (not shown), as in the first embodiment.

FIG. 7 shows a state where the first and second apertures 70 and 80 are most closed. That is, when the amount of light guided to the first and second light guides 61 and 62 is minimized, the linear portion of the light blocking portion 700 of the first aperture 70 and the second
Are arranged so that the linear portions of the light blocking portion 800 of the stop 80 abut on each other. Also, this contact portion is a white light source 63.
The first and second light guides 61 and 62 and the first light guide 61 and 62 overlap with the contact portions of the end faces at the incident ends of the first and second light guides 61 and 62 when viewed from the side of FIG.
The second aperture units 65 and 66 are provided in the image signal processing unit.

In FIG. 7, when the output shaft 71A rotates clockwise by the operation of the motor of the first actuator 71, the first diaphragm 70 swings in the direction A, and the amount of light guided to the first light guide 61 increases. I do. Also, the output shaft 71A
In a state where the first diaphragm 70 swings in the direction A by the clockwise rotation of and is positioned at a predetermined angle, the motor of the actuator 71 is operated to rotate the output shaft 71A counterclockwise. The diaphragm 70 swings in the direction A ', and the amount of light guided to the first light guide 61 decreases. Similarly, when the motor of the actuator 81 operates and the output shaft 81A rotates clockwise, the second diaphragm 80 swings in the B direction, and the amount of light guided to the second light guide 62 increases. The second rotation is performed according to the clockwise rotation of the output shaft 81A.
When the motor of the actuator 81 is operated and the output shaft 81A is rotated counterclockwise in a state where the stop 80 of the first stop swings in the direction B and is positioned at a predetermined angle, the second stop 80 swings in the direction B '. And the amount of light guided to the second light guide 62 decreases.

The operation of the actuator 71 is controlled by a system controller in the image signal processing unit so that the first stop 70 does not swing toward the second stop 80 from the state shown in FIG. Similarly, the operation of the actuator 81 is controlled by the system controller so that the second diaphragm 80 does not swing from the state shown in FIG. 7 toward the first diaphragm 70.

In the first and second embodiments, the observation sites displayed in the left and right regions obtained by vertically dividing the center of the image display region 51 are the first and second light guides 13 (6).
1) and the first and second light guides 13 (61) and 14 (62) and the CCD so as to be irradiated by 14 (62).
Although the relative positional relationship with the image sensor 110 is determined, it is not limited to this. For example, the first and second light guides 13 (61) and 14 (62) illuminate observation sites displayed in upper and lower regions obtained by dividing the center of the image display region 51 horizontally along a horizontal scanning line. Thus, the first and second light guides 13 (61), 14
The relative positional relationship between (62) and the CCD image sensor 110 may be determined. As described above, in a field of view in which a part near and far from the image sensor 11 are mixed,
A portion having a short distance is connected to the first and second light guides 13 (6
1) and 14 (62), while mainly illuminating, and distant portions to the first and second light guides 13 (61) and 14 (14).
If the posture of the distal end of the scope 10 is adjusted so as to mainly illuminate on the other side of (62), appropriate light amount adjustment for obtaining a good observation image is automatically performed.

[0046]

As described above, according to the present invention, even when the object distance from the objective lens is different within the range observable by the objective lens, an electronic endoscope capable of reproducing a good optical observation image is provided. Is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic endoscope to which a first embodiment of the present invention is applied.

FIG. 2 is a diagram schematically illustrating a configuration near an emission end and an incidence end of the light guide according to the first embodiment.

FIG. 3 is a front view of the aperture unit according to the first embodiment.

FIG. 4 is a front view of an RGB rotary color filter.

FIG. 5 is a block diagram illustrating a main part of a video signal processing circuit.

FIG. 6 is a diagram illustrating a configuration near an incident end of a light guide according to a second embodiment of the present invention.

FIG. 7 is a front view of an aperture unit according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 10 scope 11 imaging sensor 13, 61 first light guide 14, 62 second light guide 20 image signal processing unit 21 system controller 22 white light source 23, 65 first aperture unit 24, 66 second aperture unit 25 operation Panel 26 Lamp power supply circuit 27 Rotating RGB color filter 29 Video signal processing circuit 30 Timing controller 50 TV monitor device 101 Power switch 102 Lighting switch 103 Brightness adjustment unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H04N 5/238 H04N 5/238 Z 7/18 7/18 MF term (Reference) 2H040 BA11 BA13 CA04 CA10 CA11 GA02 4C061 AA00 BB00 CC06 DD03 FF35 FF46 GG01 JJ06 JJ11 LL02 NN01 PP12 QQ07 RR02 RR15 RR17 RR23 SS23 5C022 AA08 AB03 AB12 AB15 AC01 AC42 AC54 AC69 AC78 5C054 AA01 CA04 CC02 EA01 EA05 ED02

Claims (6)

[Claims] 1. An electronic endoscope comprising a scope and an image signal processing unit to which the scope is detachably connected, wherein the scope is a solid-state imaging means provided at a distal end thereof, and the image signal A plurality of optically independent light guides for guiding emitted light from a light source provided in the processing unit to the distal end side of the scope and irradiating the object to be observed with the image signal processing unit, The imaging region of the solid-state imaging unit is divided based on a relative positional relationship between the plurality of light guides and the solid-state imaging unit on the distal end side of the scope, and each divided imaging region corresponding to the plurality of light guides is divided. Brightness calculating means for calculating an average brightness value; and the light source and the light source so that an average brightness value for each of the divided imaging regions substantially matches a predetermined brightness reference value. An electronic endoscope comprising: a light amount adjusting unit provided for each of the plurality of light guides, for adjusting a light amount of the emitted light guided to the guide. 2. The apparatus according to claim 1, wherein said light amount adjusting means includes a stop disposed between an incident end of said light guide and said light source, and a drive means for driving said stop. 2. The electronic endoscope according to 1. 3. The electronic endoscope according to claim 2, wherein the plurality of light guides are provided such that end faces of respective incident ends are disposed at a predetermined interval. 4. The electronic endoscope according to claim 3, wherein a condenser lens is provided between the entrance end of the light guide and the corresponding stop. 5. The electronic endoscope according to claim 2, wherein the plurality of light guides are integrated into one at an incident end while being optically independent of each other. 6. The electronic endoscope according to claim 5, wherein a single condenser lens is disposed between the entrance ends of the plurality of light guides and the corresponding stop.