JP4014726B2 - Electronic endoscope apparatus and light source apparatus for electronic endoscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic endoscope apparatus including an electronic endoscope provided with an image pickup element and an emission end face of a light guide at a distal end portion, and a light source for an electronic endoscope that supplies illumination light to the electronic endoscope. Relates to the device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, one of electronic endoscope apparatuses that mainly photograph a patient's body cavity, for example, a state of a digestive tract or a blood vessel, has an imaging element and a light guide emission end face at the distal end portion of the electronic endoscope. In some cases, an imaging object is illuminated by emitting illumination light incident on an incident end face of a light guide from a single light source from the exit end face, and the imaging target is photographed by an imaging device.
[0003]
In this type of electronic endoscope apparatus, a solid-state image pickup device (CCD) is often used as an image pickup device, and its image pickup surface is arranged substantially parallel to the light guide exit surface, and these are at substantially the same angle as the object to be imaged. opposite. In some electronic endoscope apparatuses, the emission end faces of a plurality of light guides are arranged at a distance around the image sensor to reduce the influence of shadows due to the unevenness of the imaging target.
[0004]
By the way, the package outline of the CCD in recent years tends to be reduced in size, and accordingly, the tip portion of the electronic endoscope becomes thinner. For this reason, the burden of the patient examined using an electronic endoscope apparatus has been reduced.
[0005]
[Problems to be solved by the invention]
However, the electronic endoscope apparatus described above has the following problems. That is, when photographing an inside of a digestive tract or the like with an electronic endoscope device, the light beam from an object (proximity part: for example, a tube wall) that is close to the image sensor and the image sensor is far from the image sensor. Both the light beam from the object (distant view part: for example, the tube sky) enters the image sensor. In this case, the illuminance of the distant portion is lower than the illuminance of the proximity portion. For this reason, the illuminance with respect to the distant view portion is insufficient, the change in gradation of the luminance information in the distant view portion cannot be detected, and the image of the distant view portion may be blackened. Therefore, if the amount of light incident on the incident end face of the light guide is increased in order to increase the illuminance in the distant view area, the illumination light is strongly applied to the proximity portion. Range), and halation may occur in the image in the vicinity.
[0006]
In the electronic endoscope apparatus described above, the capacity of the charge storage element of each pixel is reduced with the miniaturization of the CCD, and the dynamic range is reduced. In view of this, the amount of illumination light tends to be reduced so that the charge amount of each pixel does not easily overflow. Therefore, there are many cases where the distant view portion is insufficient in illuminance and the contrast between the distant view portion and the close-up portion becomes high, resulting in an image that is difficult to observe.
[0007]
The present invention has been made in view of the above problems, and even when a portion having a high reflectance and a portion having a low reflectance enter the imaging range of the imaging device at the same time, it is possible to prevent halation from occurring in the image, and It is an object of the present invention to provide an electronic endoscope apparatus and a light source apparatus for an electronic endoscope that can obtain an image having a stable contrast.
[0008]
[Means for Solving the Problems]
The present invention employs the following configuration in order to solve the above-described problems. That is, the invention of claim 1 is an electronic endoscope apparatus, and is arranged in the vicinity of each of the plurality of light guides in which an emission end face of illumination light is arranged at a distal end portion of the endoscope, and each of the emission end faces. Based on an image sensor, a light source that supplies illumination light to the incident end face of each light guide, and a luminance signal obtained by the image sensor, the image sensor is an area where the highest luminance is detected. A luminance detection unit that identifies the first region and the second region that is the region where the lowest luminance is detected, and illumination that is incident on the incident end face of the light guide that has the greatest influence on the amount of light received by the first region A light amount distribution adjusting unit that reduces the light amount of light and increases the amount of illumination light incident on the incident end face of the light guide that has the greatest influence on the amount of light received in the second region.
[0009]
According to the first aspect of the present invention, the light amount distribution control unit reduces the light amount to the light guide that has the largest influence on the light reception amount of the first region, and the light that has the largest influence on the light reception amount of the second region. Increase the amount of light to the guide. As a result, the amount of light received in the first area is reduced, so that it is possible to prevent the occurrence of halation in the image taken by the first area and to remove the generated halation. At the same time, since the amount of light received in the second area increases, the image captured by the second area can be brightened, and the difference in the amount of light received between the first area and the second area can be reduced. I can make a difference. For this reason, an image having a stable luminance as a whole can be obtained.
According to a second aspect of the present invention, the light intensity distribution adjusting unit according to the first aspect provides the illumination light to be incident on the incident end face of the light guide that has the greatest influence on the received light amount of the first region from the light source. This is specified by being incident on the incident end face of the light guide that has the greatest influence on the amount of light received in the second region.
[0010]
According to the second aspect of the present invention, the distribution of the illumination light incident on the incident end face of each light guide can be changed in a state where the amount of illumination light emitted from the light source is constant.
[0011]
According to a third aspect of the present invention, when the light amount distribution adjusting unit according to the second aspect is disposed in an optical path from the light source to the incident end face of each of the light guides so as to freely advance and retract, Light that passes through a part of the region that should be incident on the incident end face of the light guide that includes the end of the light beam and has the greatest influence on the amount of light received in the first region in the region through which the light beam from the light source passes. And the reflected light reflected by the first reflecting member is the largest in the amount of light received by the second region. It has specified by having the 2nd reflective member reflected toward the incident end surface of the light guide which affects.
[0012]
According to a fourth aspect of the present invention, when the light source according to the third aspect emits a parallel light beam toward the incident end face of each light guide, and the first reflecting member enters the optical path, the first light source A reflection plane of the reflection member is disposed at an angle of approximately 45 degrees so as to face the traveling direction of the parallel light, and a reflection plane of the second reflection member is disposed in parallel to face the reflection plane of the first reflection member. It is something that has been identified.
[0013]
According to invention of Claim 4, the reflected light by the 1st reflective member and the 2nd reflective member turns into the parallel light which advances in the same direction as the light which is not reflected (direct light). For this reason, a space required as an optical path of the reflected light can be reduced (no useless space is generated), and the reflected light can be incident on the incident end face of the corresponding light guide in the same manner as the direct light.
[0014]
According to a fifth aspect of the present invention, two sets of the first reflecting member and the second reflecting member according to the third aspect are provided, and the second reflecting member in each set is disposed outside the optical path, and the first reflecting member in each set is provided. Can be moved integrally, and when the first reflecting member in one set enters the optical path, the first reflecting member in the other set is identified by retreating out of the optical path. It is.
[0015]
According to the fifth aspect of the present invention, the incident end surface of each light guide is formed by either one of the first reflecting member and the second reflecting member regardless of which side of the image pickup device has an imbalance in the amount of received light. The position of the illumination light incident on is switched. For this reason, the imbalance in the amount of received light in each region is quickly resolved without loss of illumination light.
[0016]
According to a sixth aspect of the present invention, the luminance detection unit according to the first aspect of the present invention separates the luminance signal obtained by the imaging device in accordance with a predetermined plurality of regions, and compares the separated luminance signal to the first. This is specified by specifying the first area and the second area.
[0017]
The invention according to claim 7 is the first light guide and the second light guide in which the plurality of light guides according to claim 3 are arranged such that the respective emission end faces are symmetrical with respect to the center line of the imaging region of the image sensor. And the luminance detection unit compares the luminance of the imaging region on the first light guide side with the luminance on the second light guide based on the luminance signal obtained by the imaging device. When the first region and the second region are specified, and the first reflecting member and the second reflecting member are specified as the first light guide side imaging region as the first region In addition, illumination light emitted from the light source toward the incident end surface of the first light guide is incident on the incident end surface of the second light guide, and the imaging region on the second light guide side is used as the first region. If identified, before It is the illumination light emitted toward the incident end surface of the second light guide from the light source as specified in be incident on the incident end face of the first light guide.
[0018]
According to an eighth aspect of the present invention, the imaging device according to the seventh aspect is a solid-state imaging device, and the luminance detection unit detects an average luminance of each imaging region from a luminance signal output from the solid-state imaging device, The other average luminance is subtracted from the average luminance of the first light member, and when the first reflection member and the second reflection member have a negative subtraction result by the luminance detection unit, the light source to the incident end surface of the first light guide When the illumination light emitted toward the incident end surface of the second light guide is incident on the incident end surface of the second light guide and the subtraction result by the luminance detection unit is positive, the illumination light is emitted from the light source toward the incident end surface of the second light guide. The illumination light is specified by being incident on the incident end face of the first light guide.
[0019]
According to a ninth aspect of the present invention, there is provided a light guide which is disposed between the light source according to the first aspect and the incident end face of each light guide and has the greatest influence on the amount of light received by the second region by the light amount distribution adjusting unit. Specified by further including a light amount adjustment unit that uniformly increases the amount of illumination light incident on the incident end surface of each light guide from the light source when the amount of illumination light incident on the incident end surface increases. Is.
[0020]
A tenth aspect of the present invention is a light source device for an electronic endoscope that supplies illumination light to an electronic endoscope in which an imaging element and emission end faces of a plurality of light guides are provided at a distal end portion. Based on the light source that supplies the illumination light to the incident end face of the guide and the luminance signal obtained by the image sensor, the first area, which is the area where the highest luminance is detected, is the lowest among the image areas of the image sensor. A luminance detection unit that identifies a second region that is a region in which luminance is detected, and a light amount of illumination light that is incident on an incident end surface of the light guide that has the greatest influence on the amount of light received in the first region is reduced. And a light amount distribution adjusting unit for increasing the amount of illumination light incident on the incident end face of the light guide that has the greatest influence on the amount of light received in the second region.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
[Configuration of electronic endoscope device]
FIG. 1 is a configuration diagram of an electronic endoscope apparatus according to Embodiment 1 of the present invention. FIG. 1 shows an electronic endoscope apparatus using a color CCD 10 as an image sensor (solid-state image sensor). In FIG. 1, an electronic endoscope apparatus includes an electronic endoscope 1 having a color CCD 10, an illumination light to be imaged to the electronic endoscope 1, and an image of the image to be imaged captured by the color CCD 10. The light source device / video processor 2 for endoscope which generates a signal is connected to the television monitor 3 for displaying the video to be photographed.
<Electronic endoscope>
As shown in FIG. 1, the electronic endoscope 1 includes a cord-shaped insertion portion 4 whose distal end forms the distal end portion of the electronic endoscope 1, an operation portion 5 connected to the proximal end of the insertion portion 4, and an operation And a cord-like light guide connecting pipe 6 extending from the outer peripheral surface of the portion 5. A connector 7 is provided at the end of the light guide connecting tube 6, and the electronic endoscope 1 and the light source device / video processor 2 are detachably connected by the connector 7.
[0022]
Inside the electronic endoscope 1, two light guide fiber bundles (hereinafter referred to as “LCB”) 8 and 9 are provided from the distal end of the insertion portion 4 to the distal end of the connector 7. The end face on the insertion portion 4 side of each LCB 8, 9 forms an emission end face of illumination light, and the end face on the connector 7 side forms an incident end face of illumination light.
[0023]
FIG. 2A is a diagram showing the incident end faces of the LCBs 8 and 9 shown in FIG. As shown in FIG. 2A, the incident end faces of the LCBs 8 and 9 are formed in a semicircular shape that forms one circular end face. As shown in FIG. 1, the incident end faces of the LCBs 8 and 9 are arranged toward the light source device / video processor 2 when the connector 7 is connected to the light source device / video processor 2.
[0024]
FIG. 2B is a diagram showing a cut surface of the insertion portion 4 along the line BB shown in FIG. The LCBs 8 and 9 are separated inside the electronic endoscope 1, and the emission end faces of the LCBs 8 and 9 have a circular shape as shown in FIG. 2B, and the imaging surface (imaging region) of the color CCD 10. Are arranged symmetrically with respect to the center line. In front of the emission end faces of the LCBs 8 and 9, there are provided light distribution lenses 11 and 12 that spread the illumination light emitted from the LCBs 8 and 9, respectively.
[0025]
As shown in FIG. 1, the color CCD 10 is provided in the distal end portion of the insertion portion 4. The imaging area of the color CCD 10 is provided in parallel with the emission end faces of the LCBs 8 and 9. In front of the color CCD 10, an objective lens 13 that forms an image to be photographed in the imaging region of the color CCD 10 is disposed. The color CCD 10 is connected to an input terminal of a signal processing circuit 16 provided in the connector 7 through signal lines 14 and 15.
[0026]
In the present embodiment, the LCB 8 side area (each pixel) with the center line of the imaging area of the color CCD 10 as a boundary captures an image displayed on the right side of the screen of the TV monitor 3, and the LCB 9 side area ( An image in which each pixel) is displayed on the left side of the TV monitor 3 is taken. Further, each pixel of the color CCD 10 is affected by the illumination area and illuminance of the illumination light emitted from the LCB 8 as it is closer to the emission end face of the LCB 8 when the subject to be photographed is at a short distance, and the emission end face of the LCB 9 The closer it is, the more affected by the illumination area and illuminance of the illumination light emitted from the LCB 9.
[0027]
The signal processing circuit 16 performs necessary processing on the output signal of the color CCD 10 input from its input terminal, and outputs a luminance signal (Y signal) and two color difference signals (RY signal and BY signal). Output from the output terminal.
<Light source device and video processor>
Inside the light source device / video processor 2, a light source lamp 17 using a xenon lamp is disposed at a position facing the incident end face of each LCB 8, 9. The light source lamp 17 is supplied with electric power generated from a lamp power supply 18 via a lamp wire 19. The light source lamp 17 emits white parallel light (light beam LF) having a constant light amount as illumination light toward the incident end faces of the LCBs 8 and 9. The optical axis OA of the light beam LF passes through the center of one circular end surface (see FIG. 2A) formed by the incident end surfaces of the LCBs 8 and 9.
[0028]
A condenser lens 20 that condenses the light beam LF emitted from the light source lamp 17 is disposed between the light source lamp 17 and the incident end faces of the LCBs 8 and 9. The condenser lens 20 causes the light beam LF to enter the incident end faces of the LCBs 8 and 9 while converging.
[0029]
An aperture device 21 is disposed between the condenser lens 20 and the light source lamp 17. The diaphragm device 21 is incident on the incident end faces of the LCBs 8 and 9 by uniformly shielding the light beam LF from the direction orthogonal to the X direction shown in FIG. 1 (+ Y direction and −Y direction: see FIG. 2). The amount of illumination light is adjusted (corresponding to the light amount adjustment unit of the present invention).
[0030]
Between the diaphragm device 21 and the light source lamp 17, a light quantity distribution adjusting unit 22 is disposed. The light amount distribution adjusting unit 22 enters the light beam LF from either the + X direction or the −X direction in FIGS. 1 and 2 and changes the distribution of the light amount incident on the incident end faces of the LCBs 8 and 9. . Thereby, the light quantity distribution adjusting unit 22 decreases the light quantity of the illumination light incident on one of the LCB 8 or the LCB 9 and increases the light quantity incident on the other. The configurations of the diaphragm device 21 and the light quantity distribution adjustment unit 22 will be described later.
The output terminals of the signal processing circuit 16 described above are connected to A / D converters 26 to 28 via signal lines 23 to 25. The above-described RY signal is input to the A / D converter 26, the above-described RB signal is input to the A / D converter 27, and the above-mentioned Y-signal is input to the A / D converter 28. A signal is input. Each A / D converter 26-28 performs analog-digital conversion on the input signal.
[0031]
Each A / D converter 26 to 28 is connected to the memory unit 29 via a signal line,
The memory unit 29 performs processing such as freeze and interpolation on the RY, RB, and Y digital signals input from the A / D converters 26 to 28.
[0032]
The memory unit 29 is connected to the D / A converters 30 to 32 via signal lines. The D / A converters 30 to 32 convert the RY, RB, and Y digital signals input from the memory unit 29 into analog signals.
[0033]
Each of the D / A converters 30 to 32 is connected to the signal processing unit 33 via a signal line. The signal processing unit 33 generates an analog RGB signal (including a synchronization signal) from the RY signal, the RB signal, and the Y signal input from each of the D / A converters 30 to 32 and supplies the analog RGB signal to the television monitor 3. Supply. As a result, an image (video) based on the RGB signal to be photographed, which is photographed by the color CCD 10, is displayed on the television monitor 3.
[0034]
The signal line 34 is connected to the signal line 25 described above. The signal line 34 is connected to the dimming circuit 35, and inputs the Y signal output from the signal processing circuit 16 to the dimming circuit 35. The light control circuit 35 is connected to the system control unit 36 via a signal line 37. The system control unit 36 inputs the reference voltage Vref for dimming the entire illumination light to the dimming circuit 35 via the signal line 37.
[0035]
The dimming circuit 35 generates the control signal α using the Y signal and the reference voltage Vref input to itself, and controls the diaphragm device 21 using the control signal α. In addition, the dimming circuit 35 generates a control signal β using the Y signal input thereto, and controls the light quantity distribution adjusting unit 22 using the control signal β. The details of the dimming circuit 35 will be described later.
[Configuration of diaphragm unit]
3A is a configuration diagram of the diaphragm device 21 shown in FIG. 1, and FIGS. 3A and 3B are views of the diaphragm device 21 as viewed from the condenser lens 20 side. As shown in FIG. 3A, the aperture device 21 includes a light reduction unit 40, a rotation shaft 41, a rotation mechanism 42, and a motor 43.
[0036]
As shown in FIG. 3 (a), the dimming part 40 is formed in a U shape in which the side edges of parallel plate-shaped light shielding plates 40a, 40b having the same rectangular planar shape are connected by a connecting plate 40c. Has been. The light shielding plate 40a and the light shielding plate 40b are arranged in parallel, and their central axes are on the same straight line. The connecting plate 40c is also formed in a parallel plate shape having a rectangular planar shape.
[0037]
The rotating shaft 41 is fixed to the connecting plate 40c coaxially with the central axis of the connecting plate 40c. As a result, the light reduction unit 40 rotates coaxially with the rotation shaft 41. The rotating mechanism 42 is connected to the motor 43 and rotates the rotating shaft 41 in conjunction with the driving of the motor 43. The motor 43 is adapted to receive a control signal α from the dimming circuit 35 shown in FIG. 1, and gives power to the rotating mechanism 42 according to the control signal α.
[0038]
As shown in FIG. 3B, the diaphragm device 21 is arranged in a state where the rotation axis 41 is on the same plane as the optical axis OA of the light beam LF shown in FIG. 1, and the center of each light shielding plate 40a, 40b. And the optical axis OA always maintain the same distance regardless of the rotation of the dimming unit 40. As shown in FIG. 3 (b), the aperture device 21 sets the state where the light shielding plates 40a and 40b and the optical axis OA are parallel to each other in the initial state, and in this initial state, enters the entrance end face of each LCB 8 and 9. The amount of illumination light emitted is maximized.
[0039]
Thereafter, when the control signal α is given to the motor 43 and the rotation shaft 41 is rotated by driving the motor 43, as shown in FIG. 3C, the light shielding plates 40a and 40b shield the light beam LF substantially evenly. . As a result, the amount of light incident on the incident end faces (see FIG. 1) of the LCBs 8 and 9 is reduced substantially evenly. Thus, the diaphragm device 21 adjusts the amount of light emitted from the emission end faces of the LCBs 8 and 9 according to the magnitude of the rotation angle from the initial state.
[Configuration of light intensity distribution adjustment section]
FIG. 4 is a configuration diagram of the light quantity distribution adjusting unit 22 shown in FIG. As shown in FIG. 4, the light quantity distribution adjusting unit 22 includes a strip-shaped first mirror 45a tilted toward the light source lamp 17 at an angle of 45 ° with respect to the optical axis OA of the light beam LF (the traveling direction of the light beam LF). And a strip-shaped second mirror 45b inclined toward the diaphragm device 21 at an angle of 45 ° with respect to the optical axis OA. Each mirror surface of the first mirror 45 a and the second mirror 45 b is formed in a plane and is directed to the light source lamp 17. These first mirror 45a and second mirror 45b correspond to the first reflecting member of the present invention.
[0040]
The first mirror 45a and the second mirror 45b are integrally formed via L-shaped stays 45c and 45c. Each stay 45c, 45c is disposed along the X direction shown in FIG. 2, and one end (the end on the + X side) is connected to the side edge along the optical axis OA of the first mirror 45a. The other end (the end on the -X side) is connected to a side edge along the optical axis OA of the second mirror 45b.
[0041]
One of the stays 45c is supported by a support member (not shown). A rack 46 is carved on one outer surface of the stay 45c, and a pinion 47 that rotates while meshing with the rack 46 is provided. A rotation shaft 48 extends from the pinion 47, and the rotation shaft 48 is connected to a rotation mechanism 49. The rotation mechanism 49 is connected to the motor 50.
[0042]
The motor 50 receives the control signal β from the dimming circuit 35 shown in FIG. Then, the motor 50 gives power according to the control signal β to the rotation mechanism 49, and the rotation mechanism 49 rotates the rotation shaft 48. Then, the pinion 47 rotates while meshing with the rack 46. As a result, the first mirror 45a and the second mirror 45b can move integrally in the + X direction or the -X direction.
[0043]
FIG. 5 is a view of the light amount distribution adjusting unit 22 as viewed from the side, and FIG. 6 is a view of the light amount distribution adjusting unit 22 as viewed from the light source lamp 17 side. As shown in FIG. 5A, the light quantity distribution adjusting unit 22 further includes a third mirror 45d that forms a pair with the first mirror 45a and a fourth mirror 45e that forms a pair with the second mirror 45b. Yes.
[0044]
The third mirror 45d is fixedly disposed outside the light beam LF in the approach direction (−X direction) with respect to the light beam LF of the first mirror 45a. The mirror surface of the third mirror 45d is a flat surface, and is disposed in parallel to face the mirror surface of the first mirror 45a. The fourth mirror 45e is fixedly disposed outside the light beam LF in the approach direction (+ X direction) to the light beam LF of the second mirror 45b. The mirror surface of the fourth mirror 45e is a flat surface, and is disposed in parallel to face the mirror surface of the second mirror 45b. The third mirror 45d and the fourth mirror 45e correspond to the second reflecting member of the present invention.
[0045]
FIGS. 5A and 6A show the light amount distribution adjusting unit 22 in the case where the received light amounts of the respective regions (the LCB 8 side region and the LCB 9 side region) of the color CCD 10 are substantially equal. In this case, the light beam LF emitted from the light source lamp 17 passes between the stays 45c and 45c without coming into contact with the first mirror 45a and the second mirror 45b, and is distributed between the LCBs 8 and 9 with substantially equal light quantity distribution. Incident on the incident end face. This is a state in the case where, for example, a planar imaging object with uniform reflectance is illuminated from an equal distance. This state is the initial state of the light quantity distribution adjustment unit 22.
FIGS. 5B and 6B show the light amount distribution adjusting unit 22 when the amount of light received in the LCB 8 side region is larger than the amount of light received in the LCB 9 side region. In this case, the first mirror 45a and the second mirror 45b move in the −X direction, the first mirror 45a enters the light beam LF from the + X direction, and the second mirror 45b is retracted out of the light beam LF. .
[0046]
Then, the first mirror 45a has a part (see the shaded portion in FIG. 5B) including the end of the light beam LF in the region to be incident on the LCB 8 of the light beam LF in the −X direction at an angle of 45 °. Reflect toward you. Subsequently, the third mirror 45d reflects the light reflected by the first mirror 45a toward the diaphragm device 21 at an angle of 45 °. As a result, the reflected light of the third mirror 45d (see the hatched portion in FIG. 5B) becomes parallel light having the same traveling direction as the illumination light (direct light) emitted from the light source lamp 17, and the diaphragm device 21 and the condenser The light enters the incident end surface of the LCB 9 through the lens 20.
[0047]
As a result, the amount of illumination light incident on the LCB 8 decreases and the amount of illumination light incident on the LCB 9 increases. That is, the amount of illumination light emitted from the light source lamp 17 is distributed more to the LCB 9 than to the LCB 8. Accordingly, the amount of light received in the LCB 8 side area is reduced. On the other hand, since the amount of illumination light emitted from the LCB 9 increases, the illuminance of the subject to be illuminated illuminated by the illumination light from the LCB 9 increases, and the amount of light received in the LCB 9 side region increases. As a result, the amount of received light in the LCB 8 side region and the amount of received light in the LCB 9 side region are directed toward equalization.
[0048]
On the other hand, FIG. 5C and FIG. 6C show the light amount distribution adjusting unit 22 when the amount of light received in the LCB 9 side region is larger than the amount of light received in the LCB 8 side region. In this case, the first mirror 45a and the second mirror 45b move in the + X direction, the second mirror 45b enters the light beam LF from the −X direction, and the first mirror 45a is retracted from the outside of the light beam LF. Become.
[0049]
Then, the second mirror 45b directs a part including the end of the light beam LF in the region to be incident on the LCB 9 of the light beam LF (see the shaded portion in FIG. 5C) to the + X direction at an angle of 45 °. Reflect. Subsequently, the fourth mirror 45e reflects the light reflected by the second mirror 45b toward the diaphragm device 21 at an angle of 45 °. As a result, the reflected light of the fourth mirror 45e (see the hatched portion in FIG. 5C) becomes parallel light having the same traveling direction as the illumination light (direct light) emitted from the light source lamp 17, and the diaphragm device 21 and the condenser It enters the entrance end face of the LCB 8 through the lens 20.
[0050]
As a result, the amount of illumination light incident on the LCB 9 decreases and the amount of illumination light incident on the LCB 8 increases. That is, the amount of illumination light emitted from the light source lamp 17 is distributed more to the LCB 8 than to the LCB 9. Accordingly, the amount of light received in the LCB 9 side area is reduced. On the other hand, since the amount of illumination light emitted from the LCB 8 increases, the illuminance of the subject to be illuminated illuminated by the illumination light from the LCB 8 increases, and the amount of light received in the LCB 8 side region increases. As a result, the amount of received light in the LCB 8 side region and the amount of received light in the LCB 9 side region are directed toward equalization.
[0051]
As described above, the light quantity distribution adjusting unit 22 translates a part of the light beam LF to be incident on either one of the LCB 8 and the LCB 9 and causes the translated light to enter one of the LCB 8 and the LCB 9. Thus, the light quantity distribution of the illumination light emitted from the light source lamp 17 is changed.
[Configuration of light control circuit]
FIG. 7 is a configuration diagram of the dimming circuit 35 shown in FIG. As shown in FIG. 7, the light control circuit 17 includes a light amount control unit 52 that controls the diaphragm device 21 and a light amount distribution control unit 53 that controls the light amount distribution adjustment unit 22.
<Light control unit>
The light quantity control unit 52 includes an amplifier 54, a detection circuit 55, a differential amplifier 56, and a motor driver 57. The input terminal of the amplifier 54 is connected to the signal line 34 shown in FIG. 1, and the output terminal of the amplifier 54 is connected to the input terminal of the detection circuit 55. The output terminal of the detection circuit 55 is connected to the inverting input terminal of the differential amplifier 56, and the non-inverting input terminal of the differential amplifier 56 is connected to the signal line 37 shown in FIG. The output terminal of the differential amplifier 56 is connected to the input terminal of the motor driver 57. The motor driver 57 outputs the control signal α described above from its output terminal, and the control signal α is given to the motor 43 of the diaphragm device 21 shown in FIG.
[0052]
A Y signal (luminance signal) is input to the amplifier 54 from the signal line 34. FIG. 8A shows an input signal waveform to the amplifier 54. The amplifier 54 amplifies the Y signal input to itself and outputs it to the detection circuit 55. The detection circuit 55 integrates the luminance signal input from the amplifier 54 and outputs a signal indicating the average voltage level of the luminance signal. FIG. 8B shows the output signal waveform of the detection circuit 55. The differential amplifier 56 amplifies and outputs a differential voltage between the signal input from the detection circuit 55 and the reference voltage Vref input from the signal line 37.
[0053]
While the differential voltage signal input from the differential amplifier 56 is positive (while the average voltage level of the Y signal exceeds the reference voltage Vref), the motor driver 57 receives the amount of light incident on the incident end faces of the LCBs 8 and 9 ( The control signal α for closing the diaphragm device 21 is given to the motor 43 on the assumption that the total amount of light that illuminates the imaging target is too much. As a result, as shown in FIG. 3C, the light shielding unit 40 rotates in the direction of shielding the light beam LF by the light shielding plates 40a and 40b, and the amount of light incident on the incident end faces of the LCBs 8 and 9 is reduced.
[0054]
On the other hand, the motor driver 57 is incident on the incident end faces of the LCBs 8 and 9 while the differential voltage signal input from the differential amplifier 56 is negative (while the average voltage level of the Y signal is lower than the reference voltage Vref). Assuming that the amount of light is insufficient, a control signal α for opening the diaphragm device 21 is given to the motor 43. As a result, as shown in FIG. 3B, the light shielding unit 40 rotates in a direction to return to the initial state, and the amount of light incident on the incident end faces of the LCBs 8 and 9 is increased.
[0055]
Thus, the motor driver 57 gives the control signal α based on the signal input from the differential amplifier 56 to the motor 43, and feeds back the diaphragm device 21 so that the differential voltage signal from the differential amplifier 56 becomes zero. Control (see FIG. 8C). With the above configuration, the light quantity control unit 52 controls the diaphragm device 21 to uniformly adjust the light quantity incident on the LCBs 8 and 9.
<Light intensity distribution control unit>
As shown in FIG. 7, the light quantity distribution control unit 53 includes signal removal circuits 59 and 60, amplifiers 61 and 62, detection circuits 63 and 64, a differential amplifier 65, and a motor driver 67. The input terminals of the signal removal circuits 59 and 60 are connected to the signal line 34. The output terminal of the signal removal circuit 59 is connected to the input terminal of the amplifier 61, and the output terminal of the signal removal circuit 60 is connected to the input terminal of the amplifier 62. The output terminal of the amplifier 61 is connected to the input terminal of the detection circuit 63, and the output terminal of the amplifier 61 is connected to the input terminal of the detection circuit 64.
[0056]
The output terminal of the detection circuit 63 is connected to the inverting input terminal of the differential amplifier 65, and the output terminal of the detection circuit 64 is connected to the non-inverting input terminal of the differential amplifier 65. The output terminal of the differential amplifier 65 is connected to the input terminal of the integrating circuit 66, and the output terminal of the integrating circuit 66 is connected to the input terminal of the motor driver 67. The motor driver 67 outputs the control signal β described above from its output terminal, and the control signal β is given to the motor 50 of the light quantity distribution adjusting unit 22 shown in FIG.
[0057]
A Y signal is input to each of the signal removal circuits 59 and 60. FIG. 9A shows the input signal waveform to each of the signal removal circuits 59 and 60. In one cycle of the Y signal shown in FIG. 9A, the first half shows the luminance (light reception amount) obtained by the LCB9 side region, and the second half shows the luminance (light reception) obtained by the LCB8 side region. Amount).
[0058]
The signal removal circuit 59 inputs to the amplifier 61 a signal (a signal indicating the luminance of the LCB 8 side region) from which the latter half of one cycle of the input Y signal has been removed. FIG. 9B shows the output signal waveform of the signal removal circuit 59. On the other hand, the signal removal circuit 60 inputs to the amplifier 62 a signal (a signal indicating the luminance of the LCB 9 side region) from which the first half of one cycle of the input Y signal has been removed. FIG. 9C shows the output signal waveform of the signal removal circuit 59.
[0059]
The amplifier 61 amplifies the output signal of the signal removal circuit 59 and inputs it to the detection circuit 63. On the other hand, the amplifier 62 amplifies the output signal of the signal removal circuit 60 and inputs it to the detection circuit 64. The detection circuit 63 inputs a signal obtained by integrating the output signal of the amplifier 61 to the differential amplifier 65. FIG. 9D shows the output signal waveform of the detection circuit 63. On the other hand, the detection circuit 64 inputs a signal obtained by integrating the output signal of the amplifier 62 to the differential amplifier 65. FIG. 9D shows the output signal waveform of the detection circuit 64. The differential amplifier 65 amplifies the difference (difference between the luminance on the LCB 9 side and the luminance on the LCB 8 side) between the output signal of the detection circuit 63 and the output signal of the detection circuit 64 and inputs the amplified difference to the integration circuit 66. FIG. 9E shows the output signal waveform of the differential amplifier 65. The integration circuit 66 integrates the output signal of the differential amplifier 65 to input a differential amplification signal indicating the average voltage level of the difference between the luminance on the LCB 9 side and the luminance on the LCB 8 side to the motor driver 67. FIG. 9F shows the output signal waveform of the integrating circuit 66.
The motor driver 67 assumes that too much light is incident on the LCB 8 (right light guide) while the signal input from the integrating circuit 66 is negative (while the luminance on the LCB 8 side exceeds the luminance on the LCB 9 side). The control signal β for reducing the amount of light incident on the LCB 8 is given to the motor 50 shown in FIG. Then, the pinion 47 is rotated by driving the motor 50, and the first mirror 45a enters the light beam LF from the + X direction. As a result, as shown in FIGS. 5B and 6B, a part of the light beam LF is translated in the −X direction by the first and third mirrors 45a and 45c. As a result, the amount of light incident on the LCB 8 decreases and the amount of light incident on the LCB 9 increases.
[0060]
On the other hand, while the differential amplification signal input from the integration circuit 66 is positive (while the brightness of the LCB9 side area exceeds the brightness of the LCB8 side area), the motor driver 67 is in LCB9 (left light guide). Assuming that the amount of incident light is too large, a control signal β for reducing the amount of incident light on the LCB 9 is given to the motor 50. Then, the pinion 47 is rotated by driving of the motor 50, and the second mirror 45b enters the light beam LF from the −X direction. Accordingly, as shown in FIGS. 5C and 6C, a part of the light beam LF is translated in the + X direction by the second and fourth mirrors 45b and 45e. As a result, the amount of light incident on the LCB 9 decreases and the amount of light incident on the LCB 8 increases.
[0061]
Thus, the motor driver 67 gives the control signal unit β based on the differential amplification signal input from the integration circuit 66 to the motor 50, and distributes the light amount so that the differential amplification signal from the integration circuit 66 becomes zero. The adjustment unit 22 is feedback controlled (see FIG. 9G).
[0062]
With the above configuration, when the luminance of the LCB 8 side region is higher than the luminance of the LCB 9 side region, the light amount distribution control unit 53 operates the light amount distribution adjustment unit 22 to illuminate the light to be incident on the LCB 8. Is incident on LCB9. On the other hand, when the luminance of the LCB 9 side region is higher than the luminance of the LCB 8 side region, the illumination light to be incident on the LCB 9 is incident on the LCB 8.
[0063]
In this manner, the light quantity distribution control unit 53 equalizes the luminance (light reception amount) of the LCB 8 side region and the luminance (light reception amount) of the LCB 9 side region. When the luminance of both is equalized (when the difference between the two becomes zero), the output signal waveform from the signal processing circuit 16 is the signal as shown in FIG. The first half and the second half are almost equal.
[Operation of electronic endoscope device]
Next, the operation of the electronic endoscope apparatus described above will be described. Here, as an example, the operation when the insertion portion 4 of the electronic endoscope 1 shown in FIG. 1 is inserted in the digestive tract will be described. It is assumed that the light source device / video processor 2 and the TV monitor 3 are powered on, the diaphragm device 21 is in the state shown in FIG. 3C, and the light quantity distribution adjusting unit 22 is in the initial state described above. .
[0064]
When the power of the light source device / video processor 2 shown in FIG. 1 is turned on, power is supplied from the lamp power source 18 to the light source lamp 17. Then, the light source lamp 17 emits illumination light (light flux LF) toward the incident end faces of the LCBs 8 and 9. At this time, since the light amount distribution adjusting unit 22 is in the initial state, the light beam LF passes through the light amount distribution adjusting unit 22 without contacting the first and second mirrors 45a and 45b (see FIG. 5A).
[0065]
On the other hand, since the diaphragm device 21 is in a state of narrowing the light beam LF, a part of the light beam LF passes through the diaphragm device 21 while being partially shielded by the light shielding plates 40a and 40b (see FIG. 3C). Thereafter, the light beam LF is incident on the condenser lens 20 and is incident on the incident end surfaces of the LCBs 8 and 9 while being converged.
[0066]
Illumination light incident on the LCBs 8 and 9 is emitted from the emission end face, and illuminates the subject to be photographed via the light distribution lenses 11 and 12. Then, the color CCD 10 captures an image of the subject to be imaged formed by the objective lens 13. At this time, the LCB 9 side area of the color CCD 10 captures a close-up portion (for example, digestive tract wall) to be imaged, and the LCB 8-side area captures a distant view portion (for example, a state behind the digestive tract (tube empty)). Suppose you were.
[0067]
In this case, since the illumination light strikes the proximity portion strongly and the illumination light hardly reaches the distant view portion, the region on the LCB 9 side receives more light from the photographing target than the region on the LCB 8 side. For this reason, the Y signal obtained by the LCB9 side region is higher than the Y signal obtained by the LCB8 side region (see FIGS. 8A and 9A). Such a Y signal is output from the color CCD 10 and input to the signal processing circuit 16 via the signal line 15.
[0068]
Then, the signal processing circuit 16 generates and outputs an RY signal, a BY signal, and a Y signal. These signals are converted into analog RGB signals through processing by the A / D converters 26 to 28, the memory unit 29, the D / A converters 30 to 32, and the signal processing unit 33. Supplied. At this time, the image of the proximity portion displayed on the screen of the television monitor 3 is the one in which halation has occurred due to the strong illumination light. On the other hand, the image in the distant view is crushed black due to insufficient illuminance. That is, an image with high contrast is obtained between the close-up portion and the distant view portion.
On the other hand, the Y signal output from the signal processing circuit 16 is input to the light amount control unit 52 and the light amount distribution control unit 53 (see FIG. 7) of the dimming circuit 35. Then, the light quantity control unit 52 controls the diaphragm device 21 based on the Y signal obtained from the entire imaging region of the color CCD 10 with the configuration shown in FIG. At this time, the light amount control unit 52 reduces the aperture as an appropriate amount of light when the average voltage level is almost equal to the reference voltage Vref (difference is zero) even if the luminance is uneven between the LCB 8 side and the LCB 9 side. The device 21 is not operated.
[0069]
On the other hand, in the light quantity distribution control unit 52, since a positive signal is output from the integrating circuit 66, the motor driver 67 adjusts the light quantity distribution of the control signal β for causing the illumination light to be incident on the LCB 8 to enter the LCB 9. Part 22 is given. Then, the second mirror 45b moves in the + X direction by the operation of the motor 50, the rotation mechanism 49, the rotation shaft 48, and the pinion 47 (see FIG. 4), and the second and fourth mirrors 45b and 45e The part is translated in the + X direction (see FIG. 5C).
[0070]
As a result, the amount of light incident on the LCB 9 decreases and the amount of light incident on the LCB 8 increases. Accordingly, the amount of illumination light emitted from the LCB 8 increases, and the amount of light received in the LCB 8 side region increases. On the other hand, the amount of illumination light emitted from the LCB 9 decreases, and the amount of light received in the LCB 9 side area decreases.
[0071]
Thereafter, the movement of the second mirror 45b in the + X direction is continued by feedback control of the light quantity distribution control unit 53. When the Y signal output from the color CCD 10 is almost unchanged between the LCB8 side area and the LCB9 side area, the light quantity distribution control unit 53 stops the second mirror 45b.
[0072]
In this way, halation is removed from the image of the proximity portion displayed on the screen of the television monitor 3, and the contrast is stabilized. On the other hand, the total amount of light emitted from the LCBs 8 and 9 hardly changes, so that the entire screen is displayed brighter than when, for example, part of the illumination light incident on the LCB 9 is shielded.
[0073]
However, when the illumination light to be incident on the LCB 9 is assigned to the LCB 8, the average luminance level of the entire imaging area of the color CCD 10 is lowered. For this reason, the screen of the television monitor 3 is a little dark to be called proper. That is, the average voltage level of the Y signal output from the color CCD 10 is lower than the reference voltage Vref.
[0074]
Then, the light quantity control unit 52 rotates the diaphragm device 21 in the direction to return to the initial state until the average voltage level of the Y signal becomes substantially equal to the reference voltage Vref. As a result, the amount of light incident on the LCBs 8 and 9 increases substantially evenly. Therefore, the Y signal output from the color CCD 10 has an average voltage level substantially equal to the reference voltage Vref, and the difference between the luminance of the LCB8 side region and the luminance of the LCB9 side region is substantially zero. As a result, the television monitor 3 displays an image of a subject to be photographed that suppresses the occurrence of halation, is bright as a whole, and has a stable contrast.
[Operation of Embodiment 1]
As described above, according to the electronic endoscope apparatus according to the first embodiment, when a difference occurs between the luminance (light reception amount) of the LCB8 side region and the luminance (light reception amount) of the LCB9 side region, The light quantity distribution control unit 53 causes a part of the illumination light to be incident on the LCB having the higher luminance to enter the LCB having the lower luminance. As a result, the luminance of the LCB8 side region and the luminance of the LCB9 side region are averaged, and the halation is removed and the contrast is stabilized.
[0075]
When the luminance level of the entire color CCD 10 is reduced by supplying the illumination light supplied to one of the LCBs 8 and 9 to the other, the light quantity control unit 52 and the diaphragm device 21 send the light to the LCBs 8 and 9. Increase the amount of light evenly. For this reason, a bright and uniformly stable image is displayed on the television monitor 3. Therefore, a user (for example, a doctor) of the electronic endoscope apparatus can comfortably use an image (video) obtained by the electronic endoscope apparatus.
[0076]
Further, according to the first embodiment, the illumination light supplied to one of the LCBs 8 and 9 is assigned to the other, so that the illumination light emitted from the light source lamp 17 is not wasted. Therefore, a low-cost lamp with a low rating can be used as the light source lamp 17.
[0077]
Further, according to the first embodiment, the reflected light from the first and third mirrors 45a and 45c (second and fourth mirrors 45b and 45e) becomes parallel light of the illumination light emitted from the light source lamp 17, The space required for the optical path of the reflected light can be reduced, and the reflected light can be appropriately incident on the LCB.
[0078]
Further, according to the first embodiment, the set of the first and third mirrors 45a and 45c for making the illumination light to be incident on the LCB 9 incident on the LCB 8, and the second and second for making the illumination light to be incident on the LCB 8 incident on the LCB 9. Since a set of four mirrors 45b and 45e is provided, the imbalance between the amount of received light in the LCB8 side region and the amount of received light in the LCB9 side region can be quickly resolved without loss of the amount of illumination light. .
[Embodiment 2]
FIG. 10 is a configuration diagram of an electronic endoscope apparatus according to Embodiment 2 of the present invention. The electronic endoscope apparatus according to the second embodiment uses a monochrome CCD 70 and acquires color information of a subject to be photographed by a so-called frame sequential method. That is, as shown in FIG. 10, the RGB rotation filter 71 is inserted on the optical path of the illumination light between the condenser lens 20 and the LCBs 8 and 9. The RGB rotation filter 71 is rotated by a motor 72, whereby red (R) light, green (G) light, blue ( B) Light is incident.
[0079]
Accordingly, the monochrome CCD 70 outputs a signal in which the luminance signal indicating R, the luminance signal indicating G, and the luminance signal indicating B are arranged in time series (referred to as “time series RGB signal”). This time-series RGB signal is input to the memory unit 29 via the signal processing circuit 16, the signal line 25, and the A / D. The memory unit 29 performs processing such as freezing and interpolation on the signal input to itself, and then inputs the R signal, the G signal, and the B signal to each of the D / A converters 30 to 32. Thereafter, the R signal, the G signal, and the B signal are digital / analog converted, subjected to necessary processing by the signal processing unit 33, and then supplied to the television monitor 3. As a result, an image (video) based on the RGB signals is displayed on the screen of the television monitor 3.
[0080]
Further, the light amount control unit 52 and the light amount distribution control unit 53 of the adjustment circuit 35 have the same configuration as that shown in FIG. However, instead of the Y signal, the above-described time-series RGB signals are input to the light amount control unit 52 and the light amount distribution control unit 53 (see FIGS. 13A and 14A). The light quantity control unit 52 and the light quantity distribution control unit 53 control the diaphragm device 21 and the light quantity distribution adjustment unit 22 by the same processing as in the first embodiment using the time-series RGB signals input to itself (see FIG. 11 and FIG. 11). (See FIG. 12). Except for the points described above, the configuration and operation of the second embodiment are the same as those of the first embodiment. The second embodiment has almost the same effect as the first embodiment.
[0081]
【The invention's effect】
According to the electronic endoscope device and the electronic endoscope light source device according to the present invention, halation occurs in an image when a high-reflectance portion and a low-reflectance portion enter the imaging region of the image sensor at the same time. This can be prevented or the generated halation can be removed. In addition, a bright and stable image can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an electronic endoscope apparatus according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram of the color CCD and LCB shown in FIG.
FIG. 3 is a configuration diagram of the diaphragm device shown in FIG. 1;
4 is a configuration diagram of a light quantity distribution adjustment unit shown in FIG. 1. FIG.
FIG. 5 is a diagram for explaining the operation of the light quantity distribution adjustment unit shown in FIG. 4;
6 is a diagram for explaining the operation of the light intensity distribution adjustment unit shown in FIG. 4;
7 is a block diagram of the dimming circuit shown in FIG.
8 is a waveform diagram of an output signal in the light amount control unit shown in FIG.
FIG. 9 is an output signal waveform diagram in the light quantity distribution control unit shown in FIG. 7;
FIG. 10 is a configuration diagram of an electronic endoscope apparatus according to Embodiment 2 of the present invention.
FIG. 11 is a waveform diagram of an output signal in a light amount control unit according to the second embodiment.
FIG. 12 is an output signal waveform diagram in the light quantity distribution control unit according to the second embodiment.
[Explanation of symbols]
1 Electronic endoscope (endoscope)
2 Light source device and video processor (Light source device for electronic endoscope)
8 LCB (1st light guide)
9 LCB (2nd light guide)
10 Color CCD (Image sensor)
17 Light source lamp (light source)
21 Aperture device (light quantity adjustment unit)
22 Light intensity distribution adjustment unit
45a First mirror (first reflecting member)
45b Second mirror (first reflecting member)
45d third mirror (second reflecting member)
45e Fourth mirror (second reflecting member)
52 Light intensity controller
53 Light intensity distribution control unit (luminance detection unit)
70 Monochrome CCD (Image sensor)

Claims (7)

A plurality of light guides in which an emission end face of illumination light is arranged at the distal end portion of the endoscope;
An image sensor disposed in the vicinity of each of the emission end faces;
A light source for supplying illumination light to the incident end face of each light guide;
Based on the luminance signal obtained by the imaging device, the first region that is the highest luminance region and the second region that is the lowest luminance region are identified among the imaging regions of the imaging device. A luminance detection unit to
Illumination light to be incident on the incident end face of the light guide that has the greatest influence on the received light amount of the first area from the light source, and the incident end face of the light guide that has the greatest influence on the received quantity of light in the second area. The amount of illumination light incident on the incident end face of the light guide that has the greatest influence on the amount of light received in the first region is reduced, and the amount of light received in the second region has the greatest effect. An electronic endoscope apparatus comprising: a light amount distribution adjustment unit that increases a light amount of illumination light incident on an incident end face of a light guide to be applied. The light quantity distribution adjusting unit is
The light source is disposed in an optical path from the light source to the incident end face of each light guide so as to freely move back and forth. A first reflecting member that reflects light passing through a part of the region to be incident on the incident end face of the light guide that has the greatest influence on the amount of light received in the first region;
The reflected light that is disposed outside the light flux in the approach direction of the first reflecting member and reflected by the first reflecting member is directed to the incident end face of the light guide that has the greatest influence on the amount of light received by the second region. the electronic endoscope apparatus according to claim 1, characterized in that it has a second reflecting member for reflecting. The light source emits a parallel light beam toward the incident end face of each light guide,
When the first reflecting member enters the optical path, the reflecting plane of the first reflecting member is disposed at an angle of approximately 45 degrees facing the traveling direction of the parallel light, and the second reflecting member 3. The electronic endoscope apparatus according to claim 2, wherein a reflection plane is disposed in parallel to face the reflection plane of the first reflection member. Two sets of the first reflecting member and the second reflecting member are provided,
The second reflecting member in each set is disposed outside the optical path,
The first reflecting member in each group can move integrally,
3. The electronic endoscope according to claim 2, wherein when the first reflecting member in one set enters the optical path, the first reflecting member in the other set is retracted out of the optical path. apparatus. The plurality of light guides includes a first light guide and a second light guide in which each emission end face is arranged symmetrically with respect to the center line of the imaging region of the image sensor,
The luminance detection unit compares the luminance of the imaging region on the first light guide side with the central line as a boundary and the luminance on the second light guide side based on the luminance signal obtained by the imaging element. When the first region and the second region are specified, and the first reflecting member and the second reflecting member are specified as the first region, the imaging region on the first light guide side is specified as the first region, When the imaging region on the second light guide side is specified as the first region by being incident on the incident end surface of the first light guide from the light source, the light source is directed toward the incident end surface of the second light guide. The electronic endoscope apparatus according to claim 2 , wherein the illumination light emitted in this manner is incident on an incident end face of the first light guide. The image sensor is a solid-state image sensor;
The luminance detection unit calculates the average luminance of each imaging region from the luminance signal output from the solid-state imaging device, subtracts the other average luminance from one average luminance,
The first reflection member and the second reflection member emit illumination light emitted from the light source toward the incident end surface of the first light guide when the subtraction result by the luminance detection unit is negative. 6. The electronic endoscope according to claim 5 , wherein the light is incident on an incident end face of the guide and is incident on the incident end face of the second light guide from the light source when a subtraction result by the luminance detection unit is positive. apparatus. A light source device that supplies illumination light to an electronic endoscope in which an imaging element and emission end surfaces of a plurality of light guides are provided on a distal end surface,
A light source for supplying illumination light to the incident end face of each light guide;
Based on the luminance signal obtained by the imaging device, the first region that is the highest luminance region and the second region that is the lowest luminance region are identified among the imaging regions of the imaging device. A luminance detection unit to
Increasing the amount of illumination light incident on the incident end face of the light guide that has the greatest influence on the amount of light received in the first area, and the incidence of the light guide having the greatest influence on the amount of light received in the second area An electronic endoscope light source device, comprising: a light amount distribution adjustment unit that increases a light amount of illumination light incident on an end surface.

Images