JP3696005B2 - Electronic endoscope device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic endoscope apparatus, and more particularly to an electronic endoscope apparatus characterized by a dimming control portion of illumination light.
[0002]
[Prior art]
Japanese Patent Laid-Open No. 10-201706 discloses a prior art example of an electronic endoscope apparatus that displays an image captured by an imaging unit provided in an endoscope as an endoscopic image on a display surface of a monitor.
[0003]
In Japanese Patent Laid-Open No. 10-201706, there is a difference in the target brightness level of the brightness of the image displayed on the display surface of the monitor by the brightness control (light control) of each of the auto iris, light source light control, and electronic shutter. Therefore, the target brightness changes depending on the selection of the dimming control means.
[0004]
For example, if the light source dimming control is not selected from the state in which the light source dimming control is prioritized and the selection is changed to the state in which the dimming control is performed with the next priority auto iris, the dimming control priority is changed and the light source dimming control is changed. When the target value by auto iris is set lower than the target value of light control, there is a problem that it becomes dark, and conversely, when it is set higher, it becomes brighter.
[0005]
In order to cope with this, it is conceivable to reset the target value of the dimming control according to the change of the priority order of the dimming control. That is, when the control of the second dimming control means of the second rank is selected without selecting the highest first dimming control means in the first priority of the dimming control, the dimming control is performed. The system shifts from the first priority to the second priority that gives the highest control of the second dimming control means. At this time, the target value of the second dimming control means in the first priority order is also reset to the target value of the second dimming control means in the second priority order. By doing in this way, optimal brightness control becomes possible irrespective of the selection of the dimming control means.
[0006]
[Problems to be solved by the invention]
However, even if optimal brightness control is performed by resetting the target value for dimming control according to the change in the priority order of dimming control, for example, in the case of dimming control using only an electronic shutter, Although it is possible to optimize the brightness control in the light quantity range, there is a problem that halation occurs when close to the subject. In other words, the shutter data (charge sweep time) of the electronic shutter has a limit (usually 1/100000 second) in consideration of the number of vertical lines of the CCD. Has a problem that the charge sweeping out in time and halation occurs.
[0007]
In addition, in the case of dimming control using only auto iris, the aperture is narrowed when close to the subject.However, if the aperture is too large, diffraction phenomenon occurs and depth improvement cannot be obtained. Therefore, there is a problem that halation occurs even in this case.
[0008]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an electronic endoscope apparatus capable of performing appropriate dimming control and preventing the occurrence of halation during close-up photography. .
[0009]
[Means for Solving the Problems]
An electronic endoscope apparatus according to the present invention includes a light source device that generates illumination light that illuminates a subject, an imaging unit that captures the subject image illuminated by the illumination light, and an imaging signal output from the imaging unit. A dimming signal generating unit for generating a dimming signal according to the signal level; and an imaging signal level output from the imaging unit in proportion to a signal level of the dimming signal output from the dimming signal generating unit. A dimming means for controlling, a limit value detecting means for detecting that the dimming signal has reached a control limit value of the dimming means based on the dimming signal, and a limit value detection signal by the limit value detecting means. The illumination light reducing means for reducing the illumination light generated by the light source means by a predetermined specified amount is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
1 to 11 relate to an embodiment of the present invention. FIG. 1 shows the configuration of the electronic endoscope apparatus of the first embodiment, FIG. 2 shows the configuration of the light source apparatus, and FIG. FIG. 4 shows the configuration of the CCU, FIG. 5 shows the configuration of the front panel SW unit, FIG. 6 shows the configuration of the detection circuit, and FIG. 7 shows the configuration of the target level setting circuit. 8 shows the configuration of the shutter data conversion circuit, FIG. 9 shows the configuration of a modified example of the shutter data conversion circuit, and FIG. 10 shows each dimming control at the first priority set by the priority determination circuit. A specific example of the target level of the means is shown, and FIG. 11 is an explanatory diagram of the relationship between the AGC gain and the DNR setting.
[0012]
An electronic endoscope apparatus 1 shown in FIG. 1 includes a rigid endoscope 3 that is inserted into a body cavity and observes a subject 2, a light source apparatus 4 that supplies illumination light to the rigid endoscope 3, and the rigid endoscope 3. A camera head 6 that is detachably connected to the eyepiece of the camera and images the subject 2 and a camera control unit (hereinafter abbreviated as CCU) that is connected to the camera head 6 by a cable 23 and processes an image signal from the camera head 6. 7 and a monitor 8 for displaying an image of a subject signal-processed by the CCU 7.
[0013]
The rigid endoscope 3 has an elongated insertion portion 9, and an observation window 11 for entering an observation image of the subject 2 is provided at the distal end portion 10 of the insertion portion 9, and the observation image of the subject 2 is displayed in the observation window 11. An objective lens 12 for image formation is attached. In addition, a relay lens 13 that transmits an observation image as an optical image to the eyepiece unit 5 side is provided in the insertion unit 9, and the eyepiece unit 5 provided at the rear end of the insertion unit 9 is for observing the observation image in an enlarged manner. The eyepiece 14 is provided.
[0014]
Further, the rigid endoscope 3 is provided with a light guide 15 that transmits illumination light from the light source device 4 for illuminating the subject 2, so that the illumination light is emitted from the distal end portion 10 toward the subject 2. It has become. The light guide 15 is detachably attached to the light source device 4. In the light source device 4, the illumination light emitted from the lamp 16 is condensed by the lens 17 and supplied to the light guide 15. Further, the light source device 4 is provided with a diaphragm device 18 that adjusts the amount of light supplied from the lamp 16 to the light guide 15 (by the aperture of the diaphragm). The amount of illumination light emitted from the lamp 16 is appropriately set. The value can be controlled. Further, a turret 101 described later is provided between the lamp 16 and the aperture device 18. The diaphragm device 18 and the turret 101 are controlled by a dimming signal, which will be described later, provided from the CCU 7 via the light source cable 19.
[0015]
The image of the subject 2 transmitted by the relay lens 13 is magnified by the eyepiece lens 14, passes through a diaphragm (iris) 20, passes through an opposing imaging lens 21 in the camera head 6, and is a charge coupled device as a solid-state imaging device. An image is formed on the imaging surface 22 (hereinafter abbreviated as CCD). This image is converted into an electrical signal, that is, an imaging signal by the CCD 22.
[0016]
This imaging signal is transmitted to the CCU 7 via the cable 23, is subjected to signal processing by the CCU 7 and converted into a video signal, and the video signal is output to the monitor 8 via the cable 24. The image of the subject 2 displayed on the screen can be observed.
[0017]
In FIG. 2, the light source device 4 includes a lamp house unit 151 having a lamp 16. Further, a light quantity switching turret 101 having, for example, four filter portions 154a, 154b, 154c, and 154d (see FIG. 3) for reducing illumination light is provided adjacent to the lamp house unit 151. The turret 101 is rotationally driven via a gear 158 by a turret rotation motor 157. The turret 101 is rotated by a motor 157 so that any one of the filter portions 154a, 154b, 154c, and 154d can be inserted into the optical path.
[0018]
Note that a mesh-like filter is arranged in the filter unit 154a, no filter is arranged in the filter unit 154b, an emergency lamp is arranged in the filter unit 154c, and the filter unit 154d is a spare ( (See FIG. 3).
[0019]
Further, on the side of the turret 101, a filter proper position detection circuit 155 that detects which of the filter units 154a, 154b, 154c, and 154d is inserted on the optical path is provided. An optical system 159 that condenses the illumination light is provided on the optical path of the lamp 16, and the illumination light is irradiated to the incident end face of the light guide 15 connected to the light source device 4. Further, a diaphragm blade 162 and a shutter 163 constituting the diaphragm device 18 are provided on the optical axis.
[0020]
The control system of the light source device 4 will be described with reference to FIG. As shown in FIG. 3, the motor 157 for driving the turret 101 is controlled by a motor control circuit 164 so that the rotational drive is controlled. The motor control circuit 164 is connected to the arithmetic circuit 166, and drives the motor 157 by a control signal from the arithmetic circuit 166. The arithmetic circuit 166 is connected to a later-described light source control circuit 45 of the CCU 7 via the cable 19 and outputs a control signal to the motor control circuit 164 based on the control of the light source control circuit 45.
[0021]
Next, the configuration of the CCU 7 will be described with reference to FIG.
[0022]
An imaging signal obtained by the CCD 22 in the camera head 6 is amplified by an amplifier (AMP) 31 and input to a secondary circuit insulated from the patient circuit by a pulse transformer 32. The imaging signal is then converted into a baseband signal by a correlated double sampling (CDS) circuit 33 and converted to a digital signal by an A / D conversion circuit 34.
[0023]
The digitized video signal includes an auto gain control (AGC) circuit 35a, a digital noise reduction (DNR) circuit 35b, a color separation circuit 35c, a white balance (W / B) circuit 35d, an enhancement circuit 35e, which constitute a process circuit 35. After passing through processing circuits such as a color tone correction circuit 35f and a gamma correction (γ) circuit 35g, it is converted into an analog signal by a D / A conversion circuit 36, and further converted into an NTSC video signal by an encoder 37, and the monitor 8 And the subject image is displayed on the display surface of the monitor 8.
[0024]
The digital signal converted by the A / D conversion circuit 34 is further input to the detection circuit 38, and a plurality of (specifically, four) brightnesses having a function of adjusting the brightness of the subject image on the monitor 8 are provided. Control signals for electronic shutter, auto iris, light source device 4 (light control), and AGC, which constitute the control means (also referred to as light control control means), are generated.
[0025]
The AGC control signal is output to the AGC circuit 35a and the DNR circuit 35b, and is used to control the AGC gain setting of the AGC circuit 35a and the DNR setting of the DNR circuit 35b.
[0026]
In addition, the control data of the electronic shutter, auto iris, and light source device 4, that is, the shutter data, auto iris data, and light source dimming data are multiplexed by the data multiplexing circuit 39 and insulated from the secondary circuit by the photocoupler 41. The data is output to the data separation circuit 42 on the circuit side.
[0027]
The data separation circuit 42 separates control data of the electronic shutter, auto iris, and light source device 4 multiplexed by the data multiplexing circuit 39. The electronic shutter control data is output to a CCD drive circuit 43 that drives the CCD 22 to control the charge accumulation time of the CCD 22, that is, to control the time of the element shutter.
[0028]
Further, the auto iris data automatically controls the aperture of the diaphragm 20 provided in front of the CCD 22 via the auto iris drive circuit 44. Further, the light source control data is transmitted to the light source device 4 as a dimming signal via the light source control circuit 45, and the amount of light from the lamp 16 is controlled by the diaphragm device 18, that is, the light source device 4 is dimmed.
[0029]
Further, the data amount detection circuit 100 detects that the shutter data and the auto iris data have reached a predetermined limiter value (control limit value), and the turret 101 of the light source device 4 from the light source control circuit 45 via the cable 19. And a filter portion 154a having a mesh filter is inserted into the optical axis to reduce the emitted light.
[0030]
Further, the CCU 7 is provided with a front panel SW unit 46 as shown in FIG. The front panel SW unit 46 includes an electronic shutter switch (simply abbreviated as “shutter”) 46a, a light source switch (dimming switch) 46b, an auto iris switch 46c, and an AGC switch 46d. Operation of each function of AGC can be turned on / off (turned on / off).
[0031]
The on / off setting state is acquired by the CPU 48, and the setting state is output to a priority order determination circuit 49 for determining the priority order of the plurality of brightness control or dimming control means. The priority order determination circuit 49 determines the priority order of a plurality of dimming controls, and sets the target value of each dimming control according to the priority order, and outputs it to the detection circuit 38 and turns on the dimming control turned on. Brightness adjustment is performed so that the target value of the highest-priority dimming control in the light control unit is held at the target value of the highest-priority dimming control unit determined by the priority order determination circuit 49. .
[0032]
Next, the configuration of the detection circuit 38 will be described with reference to FIG.
[0033]
The video signal output from the A / D conversion circuit 34 is input to the 1-field averaging circuit 51, and the 1-field averaging circuit 51 calculates an average value for each field of the video signal (determines an average value for each frame). 1 frame average circuit may be used).
[0034]
The average signal of the average value is a loop filter for each dimming that determines the response speed of each dimming control, that is, an AGC loop filter 52a, a light source dimming loop filter 52b, an auto iris loop filter 52c, and an electronic shutter. The signal is input to the loop filter 52d and is converted into an average signal suitable for each dimming control.
[0035]
Each average signal is input to each of target level setting circuits 53a, 53b, 53c, and 53d for setting a target luminance level for each dimming control, and is converted into a control signal according to each target level. Each target level is obtained from the priority order determination circuit 49 described above.
[0036]
The output of the target level setting circuit 53a that has passed through the AGC loop filter 52a is input to the AGC circuit 35a and the DNR circuit 35b through the gain setting circuit 54.
[0037]
The outputs of the target level setting circuits 53b and 53c that have passed through the light source dimming loop filter 52b and the auto iris loop filter 52c are input to the data multiplexing circuit 39. The output of the target level setting circuit 53d that has passed through the electronic shutter loop filter 52d is input to the data multiplexing circuit 39 via the shutter data conversion circuit 55.
[0038]
The target level setting circuit 53i (i = a, b, c, d) is configured as shown in FIG. From the target level obtained from the priority determining circuit 49, a shift amount to be given to the average signal that has passed through the loop filter is created by the shift amount setting circuit 56. This shift amount is input to the level shift circuit 57. The level shift circuit 57 shifts the average signal in accordance with the shift amount, and creates and outputs a control signal for each light control.
[0039]
The shutter data conversion circuit 55 is configured as shown in FIG. The shutter data conversion circuit 55 includes a look-up table (LUT) 58 and a 1-field delay circuit 59 that delays the output data of the LUT 58 by 1 field.
[0040]
The LUT 58 constitutes a table for deriving new (electronic) shutter data from the electronic shutter data output one field before the data output from the target level setting circuit 53d. In this case, the LUT 58 obtains shutter data output one field before by passing through the one-field delay circuit 59.
[0041]
Shutter data to be given to the CCD drive circuit 43 is created from the table data of the LUT 58. The shutter data conversion circuit 55 may be configured as shown in FIG. 9 including the target level conversion circuit 53d.
[0042]
That is, a plurality of shutter data conversion circuits 55j including LUTs 58j (j = a, b,..., N) configured as shown in FIG. 8 and one-field delay circuits 59j are prepared, and multiplexers 60a provided at the input and output terminals thereof. And 60b are switched according to the change of the target level, and shutter data is created using the LUT 58j selected by the switching.
[0043]
Note that the priority determination circuit 49 is not used for dimming control, that is, when information on the dimming control means that is off is received via the CPU 48, for example, a control signal in that case is sent from the detection circuit 38 to the data multiplexing circuit 39 side. Do not send. For example, when auto iris is turned off, auto iris data is not sent to the data multiplexing circuit 39. Therefore, when data is separated by the data separation circuit, there is no auto iris data and the function of the auto iris is stopped. Therefore, the dimming control means turned off does not perform dimming. Instead of not sending data, data to be turned off may be sent.
[0044]
In other words, the priority determining circuit 49 is used for dimming control, that is, when the information of the on dimming control means is received via the CPU 48, the control signal of the on dimming control means is data multiplexed from the detection circuit 38. It is sent to the circuit 39 side. Further, according to the priority order, the brightness adjustment is preferentially performed by the dimming control unit having the highest priority in the dimming control unit that is turned on.
[0045]
For example, when the auto iris is set to the highest priority in the priority order determined by the priority order determination circuit 49 and the auto iris and the light source dimming are actually selected, the target value of the dimming control with the auto iris is prioritized. Then, the dimming control is performed by other dimming control means so that the higher priority is given priority to the level close to the target value.
[0046]
Further, in the present embodiment, when the dimming control means having the highest priority in the priority order determined by the priority order determination circuit 49 is not selected, the dimming control means that is selected is the highest among the selected dimming control means. The target value of the dimming control means having the highest priority is level-shifted, for example, so as to match the target value of the dimming control means having the highest priority in the priority order determined by the priority order determination circuit 49. It is a feature.
[0047]
In other words, in the present embodiment, a plurality of dimming control units for adjusting the brightness of the image displayed on the monitor 8, and a priority order determining unit that determines a plurality of dimming control priorities, The target value of the dimming control means having the highest priority among the selected (that is, operating) dimming control means is changed to the target value of the highest priority dimming control means determined by the priority order determining means. It is characterized by providing means.
[0048]
Next, the operation of this embodiment will be described.
[0049]
The priority order of each dimming control means is determined in advance by the priority order determination circuit 49. There are a plurality of combinations of priorities. Here, for example, in order from the highest priority, auto iris> light control by light source> light control by electronic shutter (abbreviated as ELC) (this is simply referred to as auto iris> light source> ELC). (Abbreviation) is the first priority.
[0050]
Next, the target level of each dimming control means in the first priority order is determined. In the present embodiment, each target level can be individually set according to the ON / OFF (ON / OFF) state of each dimming control means by the front panel SW unit 46 shown in FIG. Was set as follows.
[0051]
First, in the first priority order, the target levels when all dimming control means are ON are set to 60 IRE for the auto iris, 65 IRE for the light source, and 70 IRE for the ELC.
[0052]
Further, in the first priority order, the target levels when only the auto iris is turned off are 60 IRE as the light source of the next priority order after the auto iris and 65 IRE as the ELC.
[0053]
In this case, when only the auto iris with the highest priority is turned off, the target level of the light source with the highest priority in all the dimming control means that actually perform the dimming control operation is set to all dimming. The target level of auto iris having the highest priority among the control means is shifted to 60 IRE.
[0054]
In the first priority, the target level of ELC when auto iris and light source are turned off is set to 60 IRE. That is, when the auto iris with the highest priority and the light source with the next priority are turned off, the remaining dimming control means has the highest priority ELC (in this case, the remaining dimming control means is 1). However, the target level of the auto iris having the highest priority among all the dimming control means, that is, 60 IRE is shifted.
[0055]
The above settings are as shown in FIG.
[0056]
With the above setting, when all the dimming means are turned on in the first priority order by the front panel SW unit 46, the information is sent to the priority order decision circuit 49 via the CPU 48. The target level determination circuit 53c of the detection circuit 38 is set so that the target level is set with the highest priority.
[0057]
Since dimming control is performed by light source dimming or the like so as to maintain the target level where auto iris is given the highest priority, an image with an improved depth of field obtained by reducing the auto iris is obtained, and the monitor 8 The brightness is 60 IRE.
[0058]
In addition, when only the auto iris having the highest priority is turned off as necessary in the first priority order, the information that the auto iris is turned off is sent to the priority order decision circuit 49 via the CPU 48.
[0059]
The priority order determination circuit 49 disables the target level setting by the auto iris, and sets the target level of the target level setting circuit 53b for the light source dimming control with the highest priority in the remaining dimming control means other than the auto iris as the target of the auto iris. Control is performed so that light control is performed at the shifted target level. Accordingly, in this case as well, the brightness on the monitor 8 becomes the target level 60 IRE of the light source that has the highest priority in the dimming control means in operation.
[0060]
That is, even when the plurality of dimming control units are switched to the mode in which the dimming unit with the highest priority is turned off and the dimming is performed with the remaining plural dimming units, the brightness before switching can be maintained.
[0061]
Further, in the first priority, when the auto iris and the light source are turned off as necessary, the ELC target level is shifted to the auto iris target level in the same manner as described above. The target level is 60IRE. In this case as well, even if the dimming control means performs the dimming, the brightness on the monitor 8 does not change and the brightness before switching can be maintained.
[0062]
In the above description, in a plurality of dimming control means, when dimming control with high priority is switched from ON to OFF, the target value of dimming control by the remaining dimming control means is kept constant so as not to change. Although the operation has been described, the target value of the dimming control does not change in the same manner even when the dimming control with a high priority is turned ON by the reverse.
[0063]
As the priority order of the dimming control means, for example, the light source> auto iris>ELC> may be set as the second priority order, or for example, ELC> light source> auto iris> may be set as the third priority order. In these cases as well, by setting the target level of each dimming control means in the same manner as described above, even if a plurality of dimming control means having a higher priority is turned from ON to OFF, etc., in that case The target level of the highest-priority dimming control means operating at the same time can be held at the target value of the highest-priority dimming control means determined by the priority order determination circuit 49, so that the brightness of the image on the monitor 8 is kept constant. Can do.
[0064]
Further, the AGC function by the AGC circuit 35a may be included in the priority order of the dimming control means.
[0065]
Next, the relationship between AGC gain and DNR setting will be described. As shown in FIG. 6, the gain of the AGC circuit 35a is set by the gain setting circuit 54 from the output of the target level setting circuit 53a. This set value is output to the AGC circuit 35a and the DNR circuit 35b in FIG. 4 to perform the AGC operation and to perform noise removal by the DNR with the setting as shown in FIG. 11, for example.
[0066]
That is, when the AGC gain is 0 dB, the DNR setting of the DNR circuit 35b is OFF, and when the AGC gain is 0 dB to 6 dB, the DNR setting of the DNR circuit 35b is weak, and the AGC gain is 6 dB or more. By setting the DNR setting of the DNR circuit 35b to be strong, even when the AGC gain is variably set, the influence of noise becomes inconspicuous and good image quality can be maintained.
[0067]
When the data amount detection circuit 100 detects that the shutter data and the auto iris data have reached a predetermined limit value (control limit value) during the above control operation, the light source control circuit 45 is connected to the light source device 4 via the cable 19. The turret 101 is controlled to insert a filter unit 154a provided with a mesh filter into the optical axis, and the emitted light is dimmed.
[0068]
The present embodiment has the following effects.
[0069]
With the above configuration and operation, in the present embodiment, when the shutter data and the auto iris data reach a predetermined limit value (control limit value), the filter unit 154a including a mesh filter is inserted into the optical axis. It is possible to diminish the incident light and prevent the occurrence of halation.
[0070]
[Appendix]
(Additional Item 1) a light source device that generates illumination light for illuminating a subject;
Imaging means for capturing the subject image illuminated with the illumination light;
A dimming signal generating means for generating a dimming signal according to the signal level of the imaging signal output from the imaging means;
A light receiving period control means for controlling the light receiving period of the imaging means in proportion to the signal level of the dimming signal output from the dimming signal generating means;
Based on the dimming signal, limit value detecting means for detecting that the dimming signal has reached the control limit value of the light receiving period control means;
Illumination light reduction means for reducing the illumination light generated by the light source means by a predetermined amount based on a limit value detection signal from the limit value detection means;
An electronic endoscope apparatus comprising:
[0071]
(Additional Item 2) A light source device that generates illumination light for illuminating a subject;
Imaging means for capturing the subject image illuminated with the illumination light;
A dimming signal generating means for generating a dimming signal according to the signal level of the imaging signal output from the imaging means;
Illumination light quantity control means for controlling the illumination light quantity generated by the light source means in proportion to the signal level of the dimming signal output from the dimming signal generation means;
Based on the dimming signal, limit value detecting means for detecting that the dimming signal has reached the control limit value of the illumination light amount control;
Illumination light reduction means for reducing the illumination light generated by the light source means by a predetermined amount based on a limit value detection signal from the limit value detection means;
An electronic endoscope apparatus comprising:
[0072]
(Additional Item 3) a light source device that generates illumination light for illuminating a subject;
Imaging means for capturing the subject image illuminated with the illumination light;
A dimming signal generating means for generating a dimming signal according to the signal level of the imaging signal output from the imaging means;
A diaphragm means provided on the light receiving surface of the imaging means;
Aperture control means for controlling the aperture amount of the aperture means in proportion to the signal level of the dimming signal output from the dimming signal generation means;
Based on the dimming signal, limit value detecting means for detecting that the dimming signal has reached the control limit value of the aperture control means;
Illumination light reduction means for reducing the illumination light generated by the light source means by a predetermined amount based on a limit value detection signal from the limit value detection means;
An electronic endoscope apparatus comprising:
[0073]
【The invention's effect】
As described above, according to the electronic endoscope apparatus of the present invention, the dimming means sets the imaging signal level output from the imaging means in proportion to the signal level of the dimming signal output from the dimming signal generation means. The limit value detecting means detects that the dimming signal has reached the control limit value of the dimming means based on the dimming signal, and the illumination light reducing means is based on the limit value detection signal by the limit value detecting means. Since the illumination light generated by the light source means is reduced by a predetermined amount, it is possible to perform appropriate light control and to prevent the occurrence of halation during close-up photography.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an electronic endoscope apparatus according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram showing a configuration of a light source device.
FIG. 3 is a block diagram showing a configuration of a control system of the light source device.
FIG. 4 is a block diagram showing a configuration of a CCU.
FIG. 5 is a block diagram showing a configuration of a detection circuit.
FIG. 6 is a front view showing a configuration of a front panel SW unit.
FIG. 7 is a block diagram showing a configuration of a target level setting circuit.
FIG. 8 is a block diagram showing a configuration of a shutter data conversion circuit.
FIG. 9 is a block diagram showing a configuration of a modified example of the shutter data conversion circuit.
FIG. 10 is a diagram showing a specific example of target levels of each dimming control means at the first priority set by the priority determining circuit.
FIG. 11 is a diagram showing an example of the relationship between AGC gain and DNR setting.
[Explanation of symbols]
1. Electronic endoscope device
3 ... Rigid endoscope
4. Light source device
6 ... Camera head
7 ... CCU
8 ... Monitor
12 ... Objective lens
18 ... Aperture device
20 ... Iris (Iris)
22 ... CCD
35 ... Process circuit
38 ... Detection circuit
39. Data multiplexing circuit
42. Data separation circuit
43 ... CCD drive circuit
44 ... Auto iris drive circuit
45. Light source control circuit
46 ... Front panel SW section
48 ... CPU
49. Priority determining circuit
51 ... 1 field average circuit
52a, 52b, 52c, 52d... Loop filter
53a, 53b, 53c, 53d... Target level setting circuit
55. Shutter data conversion circuit
56: Shift amount setting circuit
57. Level shift circuit
100: Data amount detection circuit
101 ... Turret

Claims (1)

A light source device for generating illumination light for illuminating a subject;
Imaging means for capturing the subject image illuminated with the illumination light;
A dimming signal generating means for generating a dimming signal according to the signal level of the imaging signal output from the imaging means;
A dimming means for controlling an imaging signal level output from the imaging means in proportion to a signal level of the dimming signal output from the dimming signal generation means;
Based on the dimming signal, limit value detecting means for detecting that the dimming signal has reached the control limit value of the dimming means;
An electronic endoscope apparatus comprising: illumination light reduction means for reducing the illumination light generated by the light source means by a predetermined amount based on a limit value detection signal from the limit value detection means. .

Images