JP4043559B2 - Automatic dimming device for electronic endoscope system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aperture control device for an endoscope light source device in which a movable aperture capable of blocking an arbitrary amount of an illumination optical path between a light source lamp and an endoscope light guide incident end surface is driven by a step motor. About.
[0002]
[Prior art]
Conventionally, in order to automatically adjust the amount of illumination light incident on an endoscope light guide, a movable diaphragm provided between the light source lamp and the light guide incident end face is driven by a step motor. It has been.
[0003]
In such a diaphragm control device for an endoscope light source device, a luminance signal indicating the brightness of the endoscope observation screen is repeatedly detected in a short cycle by a control process by a microcomputer, and the luminance is detected every time the luminance is detected. Based on the difference between the signal value and the reference value representing the target luminance, a driving pulse is applied to the step motor to drive the movable diaphragm so that the luminance signal value approaches the target value.
[0004]
In Japanese Patent Laid-Open No. 8-50250, in such a diaphragm control device for an endoscope light source device, the number of drive pulses given to a step motor every time a luminance signal is detected, and the detected luminance and target value are determined. A configuration is disclosed in which the luminance quickly converges to the target value by changing the difference according to the difference.
[0005]
[Problems to be solved by the invention]
In the diaphragm control device as described above, the diaphragm control is performed based only on the difference between the detected luminance value and the target value. There was a case where it was felt that the response was poor without being quickly squeezed.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an aperture control device for an endoscope light source device that, when halation occurs, drives the aperture faster so that the user does not feel a response delay. To do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the diaphragm control device for an endoscope light source device according to the present invention has a movable diaphragm capable of blocking an arbitrary amount of an illumination light path between a light source lamp and a light guide incident end surface of an endoscope. An automatic dimming device for an electronic endoscope system driven by a step motor, wherein brightness detecting means for repeatedly detecting the brightness of an observation screen of the endoscope and outputting it as a brightness signal value, and at the time of outputting the brightness signal value Control means for providing a driving pulse for bringing the brightness of the observation screen close to a reference value to the step motor, and the control means includes the luminance signal value and the reference value output by the luminance detection means. the difference was calculated, and based on the magnitude of the calculated issued difference and the output luminance signal value, and outputs the number of drive pulses corresponding to them to the step motor is obtained from the table, When the luminance signal value is higher than the first threshold value and lower than the second threshold value so that the state is quickly cleared when the luminance signal value is lower than the first threshold value or higher than the second threshold value. It is characterized by outputting a larger number of drive pulses .
[0008]
With this configuration, the drive signal is set not only based on the difference between the luminance signal and the reference value but also based on the luminance signal value itself, so that the state is promptly detected when the luminance signal value is extremely large (or small). It is possible to perform drive control that eliminates the above.
[0009]
Note that the luminance detection unit may detect the luminance in a predetermined cycle, and the control unit may supply the drive signal to the motor for each output of the luminance signal value. With such a configuration, since the luminance is periodically detected, it is possible to speed up the response to the luminance change.
[0010]
A step motor can be used as the motor. In this case, the control means outputs a driving pulse as the driving signal, and changes the number of the driving pulses according to the magnitude of the luminance signal value and the difference between the luminance signal value and the reference value. It can be.
[0011]
Further, for example, the luminance signal value below the first threshold is a value corresponding to a low luminance state in which the observation screen is dark or substantially dark, and the luminance signal value above the second threshold is the value on the observation screen. It is a value corresponding to halation or a white high brightness state. In this case, the control unit reads the table, and when the luminance signal value output from the luminance detection unit is a value corresponding to a low or high luminance state, the low or high luminance state is quickly resolved. More drive pulses are output than in the normal state that is not the low or high luminance state.
[0012]
The control means can further set the number of drive pulses according to which of the luminance signal value and the reference value is larger. That is, different control can be performed depending on whether the aperture is opened or narrowed, which is effective in preventing hunting.
[0013]
The control means does not drive the step motor when the difference between the luminance signal value and the reference value is smaller than a predetermined allowable value.
[0014]
The control unit may include a storage unit that stores a table that defines the relationship between the magnitude of the luminance signal value, the difference between the luminance signal value and the reference value, and the number of drive pulses.
[0015]
From another viewpoint, the automatic light control device of the electronic endoscope system according to the present invention includes a movable diaphragm capable of blocking an arbitrary amount of the illumination light path between the light source lamp and the light guide incident end surface of the endoscope. An automatic dimming device of an electronic endoscope system driven by a motor, wherein brightness detection means for repeatedly detecting the brightness of an observation screen of an endoscope and outputting it as a brightness signal value, and when outputting the brightness signal value, Control means for giving the motor a drive signal for bringing the brightness of the observation screen close to a reference value, and the control means sends a different drive signal to the motor depending on whether the movable diaphragm is narrowed or opened. It is characterized by giving. That is, different control can be performed depending on whether the aperture is opened or narrowed, which is effective in preventing hunting.
[0016]
A step motor can be used as the motor. In this case, the control means outputs a driving pulse as the driving signal, and changes the number of the driving pulses according to the magnitude of the luminance signal value and the difference between the luminance signal value and the reference value. It can be.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a system configuration of an electronic endoscope system 100 according to an embodiment of the present invention. The electronic endoscope system 100 includes an endoscope 1 and a light source device / video processor 20.
[0018]
At the distal end of the insertion portion of the electronic endoscope 1, a solid-state imaging device 3 made of, for example, a charge coupled device (CCD) is disposed at a subject imaging position by the objective lens 2. Facing the exit end of the illumination light guide fiber bundle 4 for illuminating the observation range of the endoscope 1 (i.e., the imaging range of the solid-state imaging device 3), the light distribution angle of the illumination light is widened and the subject is irradiated. An illumination lens 5 for this purpose is also disposed at the distal end of the insertion portion of the endoscope 1.
[0019]
The connector 6 of the endoscope 1 that is detachably connected to a light source / video processor (hereinafter abbreviated as “light source device”) 20 is connected to a signal line for transmitting a signal input / output to / from the solid-state imaging device 3. A connector 7 for connecting to the light guide, an incident end of the light guide fiber bundle 4 and the like are disposed.
[0020]
In the light source device 20, a video signal processing unit 21 for processing a video signal sent from the solid-state imaging device 3, a light source lamp 22 for generating illumination light to be supplied to the light guide fiber bundle 4, etc. Is provided. A TV monitor 49 is connected to the output end of the video signal processing unit 21, and an endoscopic observation image (that is, an image captured by the solid-state imaging device 3) is displayed on the TV monitor 49.
[0021]
Between the illumination light incident end 4 a of the light guide fiber bundle 4 and the light source lamp 22, a condenser lens 24 for converging the illumination light emitted from the light source lamp 22 on the incident end surface of the light guide fiber bundle 4 is disposed. Has been.
[0022]
In addition, a movable diaphragm 25 is disposed between the light source lamp 22 and the condenser lens 24 so as to change the amount of illumination light incident on the light guide fiber bundle 4 by blocking an arbitrary amount of illumination light path therebetween. ing. The movable diaphragm 25 is driven by a step motor 253 described later.
[0023]
A ROM 23 stores data unique to the endoscope 1 such as the type of the endoscope 1.
[0024]
The operation of the lamp control circuit 27 that drives the light source lamp 22, the diaphragm drive circuit 28 that drives the movable diaphragm 25, and the like is controlled by a microcomputer control unit 30 provided in the light source device 20. In addition, the control unit 30 and the ROM 23 inside the endoscope 1 are connected in a state where the endoscope 1 is connected to the light source device 20, and the control unit 30 reads data of the connected endoscope 1 from the ROM 23.
[0025]
FIG. 2 is a perspective view showing the outer shape of the movable diaphragm 25. The movable diaphragm is configured such that a thin plate is bent into a U-shaped cross section, a rotation shaft 251 connected to the center of the bottom surface is arranged perpendicular to the illumination optical axis, and is rotated by a step motor 253.
[0026]
FIG. 3 shows a state in which the movable diaphragm 25 is viewed from the illumination optical axis direction. As shown in FIG. 3, when the plate surface of the movable diaphragm 25 is parallel to the illumination optical axis, the illumination optical path L is hardly blocked.
[0027]
From this state, the illumination light path L is gradually interrupted corresponding to the rotation angle of the movable diaphragm 25 driven by the step motor 253, and the illumination beam bundle incident on the light guide fiber bundle 4 is reduced.
[0028]
FIG. 4 is a block diagram showing the aperture driving circuit 28. As shown in FIG. The aperture drive circuit 28 includes a pulse control circuit unit 281 and a motor drive circuit unit 282. The pulse control circuit unit 281 responds to the direction indication signal for instructing either the reverse rotation for closing the movable diaphragm 25 or the normal rotation for opening from the control unit 30 via the input / output port 41 described later, and the rotation amount. In response to the drive pulse signal to be transmitted, a drive pulse to be given to the step motor 253 is set. The motor drive circuit unit 282 outputs a drive pulse for driving the step motor 253 in accordance with the pulse signal input from the pulse control circuit unit 281.
[0029]
In the present embodiment, when the movable diaphragm 25 is in the state shown in FIG. 3, the movable diaphragm 25 can be fully closed by applying a reverse pulse 240 pulse to the step motor 253. When the step motor 253 is rotated forward, the movable diaphragm 25 rotates in a direction to increase the amount of light incident on the light guide fiber bundle 4.
[0030]
FIG. 5 is a block diagram showing the control unit 30 and its surroundings. In the control unit 30, a read-only memory (ROM) 33 storing a program and the like, a random access memory (RAM) 34, and the like are connected to a system bus 32 connected to a central processing unit (CPU) 31 for performing arithmetic processing. Has been.
[0031]
The display character data stored in the video random access memory (video RAM) 36 and the video data output from the video signal processing unit 21 are passed through a CRT controller (CRTC) 37 connected to the system bus 32. It is synthesized and output to the TV monitor 49.
[0032]
The panel switch 201 of the light source device 20, the lamp control circuit 27 for controlling the light source lamp 22, and the external keyboard 202 are connected to the system bus 32 via input / output ports 38, 39 and 40, respectively.
[0033]
The panel switch 201 adjusts the brightness of the observation screen or a self / hand switch for selecting whether to automatically or manually adjust the brightness of the observation screen by operating the movable aperture 25. For example, a brightness adjustment switch is provided.
[0034]
Signal output to the aperture drive circuit 28 is performed via the input / output port 41, and the luminance signal Y indicating the brightness of the observation screen taken out from the video signal processing unit 21 is 0 to 255 in the analog / digital converter 42. It is converted into a digital signal having a range value (luminance signal value) and input to the control unit 30. Note that the video signal processing unit 21 and the control unit 30 constitute luminance detecting means. Note that the average luminance value of the observation screen is basically calculated as the luminance, but it is also possible to detect only the luminance in a specific area in the observation screen using the keyboard 202 or the like. is there.
[0035]
When the luminance signal value is 0 to 20 , the image is almost dark, when 21 to 50 is dark, 51 to 180 is a normal observation state, 181 to 220 is a halation state, and the luminance signal value is In 221 to 255 , the screen is almost white.
[0036]
The value of the reference value that is the target value of brightness set by the above-described brightness adjustment switch is input by the brightness index. The relationship between the brightness index and the reference value is as shown in FIG. Therefore, the automatic light control device rotates the movable diaphragm 25 so that the luminance signal value approaches the selected reference value.
[0037]
Further, by connecting the connector unit 6 of the endoscope 1 to the light source device 20, the ROM 23 arranged in the endoscope 1 is connected to the microcomputer control unit 30 via the input / output port 43. As described above, the ROM 23 stores the type of the endoscope 1 and data unique to the endoscope.
[0038]
FIG. 6 shows the contents of the main program stored in the ROM 33 of the microcomputer control unit 30. In FIG. 6 , S indicates a processing step. In the main program, after performing various initial settings such as initial setting of each circuit, initial setting of each variable and aperture position (S1), processing corresponding to the state of the panel switch 201, such as pump on / off, etc. Processing is executed (S2). Next, processing corresponding to the input from the keyboard 202, for example, processing such as displaying characters input from the keyboard 202 on the monitor is performed (S3), and processing related to the lamp control circuit 27, for example, the panel switch 201 is performed. The lamp is turned on / off by scanning and monitoring the state of the lamp being lit (S4). Next, a process (S5) related to the endoscope 1 side is executed. Here, for example, when the endoscope is connected to the light source device, processing such as reading the contents of the ROM of the endoscope and displaying the endoscope name on the monitor is performed. Next, processing for displaying the date and time on the monitor 49 (S6), and other processing, for example, peripheral devices (VCR (video cassette recorder) , video printer, etc.) connected to the light source device 20 Various processes such as control are executed (S7).
[0039]
FIG. 7 is a flowchart showing interrupt processing executed during execution of the main program of FIG. 6 in order to automatically adjust the brightness of the endoscope observation screen to the brightness corresponding to the set brightness index. . That is, the process shown in FIG. 7 is a process for controlling the operation of the step motor 253 periodically executed at regular intervals after the start of imaging, for example, 33 ms (milliseconds).
[0040]
In FIG. 7, first, a luminance signal is input from the video signal processing unit 21 (S11). If the difference between the luminance signal value and the reference value is within an allowable range (for example, 4) (S12: NO), the stepping motor 253 is not driven and the interruption process is terminated. If the difference between the two exceeds the allowable range (S12: YES), the following processing is executed to drive the step motor 253 so that the luminance signal value approaches the reference value. First, the reference value is compared with the luminance signal value (S13). When the luminance signal value is larger than the reference value (S13: YES), a reverse rotation signal is sent to the step motor 253 (S14), and a pulse is sent to the step motor 253 according to Table 1 (S15). When the luminance signal value is less than or equal to the reference value (S13: NO), a forward rotation signal is sent to the step motor 253 (S16), and a pulse is sent to the step motor 253 according to Table 2 (S17).
[0041]
FIG. 8 is a diagram showing the contents of the table 1. In Table 1, when the luminance signal value is 181 to 220, that is, when the screen is in a halation state, and when the luminance signal value is 221 or more and the screen is in a pure white state, the difference between the luminance signal value and the reference value is Is relatively small, a large number of pulses are sent to the step motor 253 so that the halation state and the white screen state can be quickly resolved.
[0042]
For example, when the reference value is 128 and the luminance signal value is 198, the difference between the two is 70. At this time, according to Table 1, 40 pulses are sent to the step motor 253.
[0043]
FIG. 9 is a diagram showing the contents of the table 2. In Table 2, when the luminance signal value is 20 or less and the screen is almost dark, and when the screen is relatively dark and the luminance signal value is 21 to 50, a large number of pulses are sent to the step motor 253, and the screen is The dark state is quickly resolved. Tables 1 and 2 are stored in the ROM 33.
[0044]
In the present embodiment, different tables are used for opening and closing the aperture.
If the driving amount of the step motor 253 is controlled by a single table, the following state may occur. For example, assume that when a reference value is set, the luminance signal value is larger by a predetermined amount. Then, the step motor 253 is driven so that the luminance signal value decreases. As a result, if the decreased luminance signal value becomes smaller than the reference value by the predetermined amount, the step motor 253 is driven so that the luminance signal value increases. At this time, if the control is based on a single table, the same number of pulses as the number of pulses sent to the step motor 253 to decrease the luminance signal value are sent to increase the luminance signal value. Is likely to be. Then, a hunting state in which the luminance signal value continues to alternately take a value that is larger by a predetermined amount and a value that is smaller by a predetermined amount, with the reference value as the center.
[0045]
However, in the present embodiment, since different tables are used for opening and closing the aperture, it is possible to reliably converge the luminance signal value to the reference value without entering the hunting state.
[0046]
In the above embodiment, only two tables are shown. However, even if the detected luminance signal value and the difference between the luminance signal value and the reference value are the same, it may be better to change the driving amount of the movable diaphragm depending on the type of endoscope. Since the type of the endoscope 1 can be acquired from the ROM 23, if the table 1 and the table 2 corresponding to various endoscopes are stored in the ROM 33 of the light source device 20 in advance, the connection acquired by the CPU 31 is obtained. By using the table 1 and the table 2 corresponding to the endoscope 1 that has been used, it is possible to realize an automatic aperture adjustment device with a faster response speed. Further, as a configuration in which the user can select Table 1 and Table 2 from a plurality of tables, the characteristics of the automatic light control device may be set freely. Further, the table 1 and the table 2 unique to the endoscope 1 may be stored in the ROM 23 of the endoscope 1.
[0047]
In the present embodiment, the emphasis is particularly on the prevention of halation, and it is set so that a larger number of pulses are sent when the aperture is reduced than when the aperture is opened. However, if the emphasis is on preventing dark screens, more pulses may be sent when the aperture is opened.
[0048]
In the present embodiment, the shape of the movable diaphragm 25 is a U-shaped diaphragm, and the amount of light is adjusted by rotating the movable diaphragm by a step motor. However, the present invention is not limited to this configuration, It can be applied to the structure aperture.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an electronic endoscope system according to an embodiment of the present invention.
FIG. 2 is a perspective view of a movable diaphragm according to the embodiment.
FIG. 3 is a front view of the movable diaphragm according to the embodiment.
FIG. 4 is a block diagram of an aperture driving circuit according to the embodiment.
FIG. 5 is a block diagram of a control circuit according to the embodiment.
FIG. 6 is a flowchart showing the contents of a main program according to the embodiment.
FIG. 7 is a flowchart showing the contents of interrupt processing for drive pulse control according to the embodiment;
FIG. 8 is a table 1 that is referred to when the movable aperture is narrowed down.
FIG. 9 is a table 2 referred to when the movable diaphragm is opened.
FIG. 10 is a table showing a relationship between a brightness index and a reference value.
[Explanation of symbols]
100 Electronic Endoscope System 1 Endoscope 20 Light Source Device 21 Video Signal Processing Unit 27 Lamp Control Circuit 25 Movable Aperture 28 Aperture Drive Circuit 30 Control Unit 33 ROM
253 Step motor 281 Pulse control circuit unit 282 Motor drive circuit unit

Claims (6)

An automatic dimming device for an electronic endoscope system in which a movable diaphragm capable of blocking an arbitrary amount of an illumination light path between a light source lamp and a light guide incident end surface of an endoscope is driven by a step motor,
Luminance detection means for repeatedly detecting the brightness of the observation screen of the endoscope and outputting it as a luminance signal value;
Control means for providing the step motor with a driving pulse for bringing the brightness of the observation screen close to a reference value when detecting the luminance signal value;
Storage means for storing a table that defines the relationship between the magnitude of the luminance signal value, the difference between the luminance signal value and the reference value, and the number of drive pulses,
The control unit calculates a difference between the luminance signal value output by the luminance detection unit and a reference value, and responds to the difference based on the calculated difference and the magnitude of the output luminance signal value. The number of drive pulses is acquired from the table and output to the step motor. When the luminance signal value is equal to or lower than the first threshold value or equal to or higher than the second threshold value, the luminance signal value is An automatic dimming device for an electronic endoscope system, characterized in that a larger number of drive pulses are output than when the first threshold is higher and the second threshold is lower .   2. The electronic internal device according to claim 1, wherein the luminance detecting unit detects the luminance in a predetermined cycle, and the control unit supplies the driving pulse to the step motor every time the luminance signal value is output. Automatic dimmer for endoscope system. The luminance signal value below the first threshold is a value corresponding to a low luminance state in which the observation screen is dark or almost completely dark,
The luminance signal value equal to or higher than the second threshold is a value corresponding to a high luminance state where the observation screen is halation or white,
The control unit reads the table, and when the luminance signal value output from the luminance detection unit is a value corresponding to a low or high luminance state, the low or high luminance state is quickly reduced. 3. The automatic light control device for an electronic endoscope system according to claim 1, wherein a larger number of drive pulses are output than in a normal state that is not a high luminance state .   The tables include different first and second tables, and the control means sets the number of drive pulses using the first table when the luminance signal value is larger than the reference value, 4. The electronic endoscope according to claim 1, wherein when the reference value is larger than the luminance signal value, the number of driving pulses is set using the second table. 5. Automatic dimmer for mirror system.   The table includes different first and second tables, and the control means sets the number of drive pulses using the first table when narrowing the movable diaphragm, and opens the movable diaphragm. 4. The automatic light control device for an electronic endoscope system according to claim 1, wherein the number of drive pulses is set using the second table. 5.   The said control means does not drive the said step motor, when the difference of the said brightness | luminance signal value and the said reference value is smaller than predetermined | prescribed allowable value, The said motor is any one of Claim 1-5 Automatic dimming device for electronic endoscope system.

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