JPH1176157A - Automatic dimming device of electronic endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for the diaphragm of a light source device for an endoscope, the control device keeping a user from feeling the delay of response by driving the diaphragm more quickly in the event of halation. SOLUTION: In this automatic dimming device, a movable diaphragm 25 whose path of illuminating light can be blocked by a certain amount between a light source lamp 22 and the incident end face 4a of the light guide 4 of an endoscope 1 is driven by a stepping motor. In that case, the automatic dimming device has brightness detection means 21, 30 by which the brightness of the observation screen of the endoscope 1 is repeatedly detected in a predetermined cycle and output as brightness signal values and a control means 30 by which driving pulses for bringing the brightness of the observation image close to a reference value are imparted to the stepping motor at every detection of the brightness signal value and the control means 30 sets the number of driving pulses imparted to the stepping motor according to the magnitude of the brightness signal value and the difference between the brightness signal value and the reference value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope in which a movable stop capable of blocking an arbitrary amount of an illumination light path between a light source lamp and a light guide entrance end face of the endoscope is driven by a step motor. The present invention relates to an aperture control device of a light source device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, a movable aperture provided between a light source lamp and a light guide entrance end face is driven by a step motor in order to automatically adjust the amount of illumination light to be incident on a light guide of an endoscope. Is known.

In such an aperture control device for an endoscope light source device, a brightness signal indicating the brightness of an endoscope observation screen is repeatedly detected in a short cycle by a control process by a microcomputer. A drive pulse is given to the stepping motor based on a difference between the luminance signal value and a reference value representing a target luminance to drive the movable diaphragm,
The luminance signal value is made to approach the target value.

Japanese Patent Application Laid-Open No. Hei 8-50250 discloses that in such an aperture control device of a light source device for an endoscope, the number of drive pulses given to a step motor for each detection of a luminance signal is determined by the detected luminance and the detected luminance. A configuration is disclosed in which the luminance is quickly converged to the target value by changing the luminance in accordance with the difference from the target value.

[0005]

In the above-described aperture control device, aperture control is performed based only on the difference between the detected luminance value and the target value. Since the setting of the value was high, the aperture was not quickly stopped down, and the response was sometimes felt to be poor.

SUMMARY OF THE INVENTION Accordingly, the present invention provides an aperture control device for an endoscope light source device that drives an aperture faster when halation occurs, so that the user does not feel a response delay. With the goal.

[0007]

In order to achieve the above object, an aperture control device for an endoscope light source device according to the present invention comprises an illumination light path between a light source lamp and a light guide entrance end face of the endoscope. An automatic dimmer for an electronic endoscope system that drives a movable aperture that can be blocked by an arbitrary amount by a motor, and a luminance detecting unit that repeatedly detects the brightness of an observation screen of the endoscope and outputs the luminance as a luminance signal value. When outputting the luminance signal value, control means for providing to the motor a drive signal for bringing the brightness of the observation screen closer to a reference value, the control means, a drive signal to be provided to the motor, It is characterized in that it is set according to (1) the magnitude of the luminance signal value and (2) the difference between the luminance signal value and the reference value (claim 1).

With this configuration, the drive signal is set based not only on the difference between the luminance signal and the reference value but also on the luminance signal value itself. Therefore, when the luminance signal value is extremely large (or small), it is prompt. Drive control can be performed to eliminate such a state.

The luminance detecting means may detect the luminance in a predetermined cycle, and the control means may supply the drive signal to the motor every time the luminance signal value is output. 2). With such a configuration, since the luminance is periodically detected, the response to a change in the luminance can be made faster.

Note that a stepping motor can be used as the motor. In this case, the control unit outputs a drive pulse as the drive signal, and changes the number of pulses of the drive pulse according to the magnitude of the luminance signal value and a difference between the luminance signal value and the reference value. (Claim 3).

That is, the control means can set the number of drive pulses so that the halation state is quickly eliminated when the luminance signal value indicates the halation state (claim 4). When the luminance signal value indicates that the observed image is completely dark, the aperture can be quickly opened.

[0012] The control means can further set the number of drive pulses in accordance with which of the luminance signal value and the reference value is larger (claim 5). That is, different control can be performed when the aperture is opened and when the aperture is narrowed, which is effective in preventing hunting.

If the difference between the luminance signal value and the reference value is smaller than a predetermined allowable value, the control means does not drive the step motor (claim 6).

[0014] The control means may have a storage means for storing a table for defining a 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. (Claim 7).

From another viewpoint, the automatic dimmer of the electronic endoscope system according to the present invention can block an arbitrary amount of the illumination light path between the light source lamp and the light guide entrance end face of the endoscope. An automatic light control device of an electronic endoscope system that drives a movable diaphragm by a motor, a luminance detection unit that repeatedly detects the brightness of an observation screen of the endoscope and outputs the luminance signal value, and At the time of output, control means for giving a drive signal for bringing the brightness of the observation screen closer to a reference value to the motor, and the control means outputs a different drive signal depending on whether the movable aperture is narrowed or opened. It is provided to the motor (claim 8). That is, different control can be performed when the aperture is opened and when the aperture is narrowed, which is effective in preventing hunting.

Incidentally, a stepping motor can be used as the motor. In this case, the control unit outputs a drive pulse as the drive signal, and changes the number of pulses of the drive pulse according to the magnitude of the luminance signal value and a difference between the luminance signal value and the reference value. (Claim 9).

[0017]

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 the endoscope 1 and a light source device / video processor 20.

At the distal end of the insertion portion of the electronic endoscope 1, a solid-state image pickup device 3 composed of, for example, a charge-coupled device (CCD) is disposed at a position where an object is imaged 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 (that is, the imaging range of the solid-state imaging device 3), the light distribution angle of the illumination light is widened to irradiate the subject. Lens 5 is also arranged at the distal end of the insertion section of endoscope 1.

A signal line for transmitting signals input / output to / from the solid-state imaging device 3 is provided on the connector section 6 of the endoscope 1 which is detachably connected to a light source device / video processor (hereinafter abbreviated as a light source device) 20. The connector 7 for connecting to the light source device 20, the incident end of the light guide fiber bundle 4, and the like are arranged.

In the light source device 20, in addition to a video signal processing unit 21 for processing a video signal sent from the solid-state imaging device 3, a light source for generating illumination light to be supplied to the light guide fiber bundle 4. A lamp 22 and the like are provided. The TV monitor 4 is connected to the output terminal of the video signal processing unit 21.
9 is connected to the endoscope observation image (that is, the solid-state imaging device 3
Is displayed on the TV monitor 49.

The light source lamp 2 is provided 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 2 on the incident end face of the light guide fiber bundle 4 is arranged.

A movable diaphragm 25 is provided between the light source lamp 22 and the condenser lens 24 so that the illumination light path between them can be blocked by an arbitrary amount to change the amount of illumination light incident on the light guide fiber bundle 4. Is arranged.
The movable diaphragm 25 is driven by a step motor 253 described later.

Reference numeral 23 denotes a ROM that stores data unique to the endoscope 1, such as the type of the endoscope 1.

The operations of the lamp control circuit 27 for driving the light source lamp 22 and the diaphragm drive circuit 28 for driving the movable diaphragm 25 are controlled by a microcomputer control unit 30 provided in the light source device 20. The control unit 30 is connected to the ROM 23 inside the endoscope 1 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.

FIG. 2 is a perspective view showing the outer shape of the movable diaphragm 25. The movable diaphragm is obtained by bending a thin plate into a U-shaped cross section, disposing a rotating shaft 251 connected to the center of the bottom surface of the movable diaphragm perpendicular to the illumination optical axis, and is driven to rotate by a step motor 253.

FIG. 3 shows a state where the movable diaphragm 25 is viewed from the direction of the illumination optical axis. 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 obstructed.

From this state, the illumination light path L is gradually blocked in accordance with the rotation angle of the movable stop 25 driven by the step motor 253, and the light guide fiber bundle 4
Are reduced.

FIG. 4 is a block diagram showing the aperture driving circuit 28. The aperture driving circuit 28 includes a pulse control circuit unit 281
And a motor drive circuit section 282. The pulse control circuit unit 281 responds to the direction instruction signal for instructing either the reverse rotation for closing the movable diaphragm 25 or the normal rotation for opening the movable diaphragm 25 from the control unit 30 via an input / output port 41 described later, and the rotation amount. The drive pulse signal to be supplied to the step motor 253 is set in response to the received drive pulse signal. Then, the motor drive circuit section 282 outputs a drive pulse for driving the step motor 253 according to the pulse signal input from the pulse control circuit section 281.

In this embodiment, when the movable diaphragm 25 is in the state shown in FIG.
Can be fully closed. Step motor 253
, The movable stop 25 rotates in a direction to increase the amount of light incident on the light guide fiber bundle 4.

FIG. 5 is a block diagram showing the control unit 30 and its periphery. In the control unit 30, a read only memory (ROM) 33 storing programs and the like, a random access memory (RAM) 3 are stored in a system bus 32 connected to a central processing unit (CPU) 31 for performing arithmetic processing.
4 etc. are connected.

The CR connected to the system bus 32
Through the T controller (CRTC) 37, 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 combined and output to the TV monitor 49. You.

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 provided with input / output ports 38, 3 respectively.
It is connected to the system bus 32 via 9 and 40.

The panel switch 201 has a movable diaphragm 25
To select whether to automatically or manually adjust the brightness of the observation screen by operating
A hand switch and a brightness adjustment switch for adjusting the brightness of the observation screen are provided.

The signal output to the aperture driving 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 section 21 is converted to 0 by the analog-to-digital converter 42. It is converted into a digital signal having a value (luminance signal value) in the range of ~ 255 and input to the control unit 30. Note that the video signal processing unit 21 and the control unit 30 constitute a luminance detecting unit. Although the average luminance value of the observation screen is basically calculated as the luminance, 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.

When the luminance signal value is 0 to 30, the image is almost completely dark, when it is 20 to 50, it is dark,
At 190, a normal observation state, at 180-230, a halation state, and at a luminance signal value of 220-250, the screen is almost completely white.

The value of the reference value, which is the target value of the brightness set by the brightness adjustment switch, is input by a brightness index. The relationship between the brightness index and the reference value is as shown in FIG. The automatic dimmer is
Therefore, the movable aperture 25 is rotated so that the luminance signal value approaches the selected reference value.

Further, by connecting the connector section 6 of the endoscope 1 to the light source device 20, the ROM 23 disposed in the endoscope 1 is connected to the microcomputer control section 30 via the input / output port 43. . In the ROM 23, as described above,
The type of the endoscope 1 and data unique to the endoscope are stored.

FIG. 6 shows the ROM 33 of the microcomputer control unit 30.
2 shows the contents of the main program stored in. In FIG. 7, 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, for example, ON / OFF of a pump, etc. The process is executed (S2). Next, a process corresponding to an input from the keyboard 202, for example, a process of displaying characters input from the keyboard 202 on a monitor is performed (S3), and a process related to the lamp control circuit 27, for example, the panel switch 201 The on / off of the lamp by the scanning of, and the state of the lamp being lit are performed (S4). Next, processing (S) related to the endoscope 1 side
5) 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 or the like on a monitor is performed. Next, various processes such as a process (S6) for displaying the date and time on the monitor 49 and other processes such as control of peripheral devices (such as a VCR and a video printer) connected to the light source device 20 are performed. The processing is executed (S
7).

FIG. 7 shows an interrupt process executed during execution of the main program of FIG. 6 in order to automatically adjust the brightness of the endoscope observation screen to a brightness corresponding to the set brightness index. It is a flowchart. That is, the processing shown in FIG. 7 is performed at a fixed interval after the start of imaging, for example, 33 ms.
(Milliseconds), periodically executed by the step motor 2
This is a process for controlling the operation of 53.

In FIG. 7, first, a luminance signal is input from the video signal processing section 21 (S11). If the difference between the luminance signal value and the reference value is within an allowable range (for example, 4) (S1
2: NO) The step motor 253 is not driven, and the interrupt processing ends. 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 magnitude of the reference value is compared with the luminance signal value (S13). If 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). If the luminance signal value is equal to or less than 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).

FIG. 8 is a diagram showing the contents of the table 1. In Table 1, the luminance signal values are 181-222.
When the value is 0, 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, even when the difference between the luminance signal value and the reference value is relatively small, the stepping motor 253 is also used. A large number of pulses are sent to the camera so that the halation state and the white screen are quickly eliminated.

For example, when the reference value is 128 and the luminance signal value is 198, the difference between them is 70. At this time, 40 pulses are sent to the step motor 253 according to Table 1.

FIG. 9 is a diagram showing the contents of the table 2.
In Table 2, when the luminance signal value is 20 or less, the screen is almost completely dark, and when the screen is relatively dark and the luminance signal values are 21 to 50, a large number of pulses are sent to the step motor 253, and the screen is displayed. The dark state is resolved quickly. Table 1 and Table 2 are stored in the ROM 33.

In this embodiment, different tables are used when the aperture is opened and when the aperture is stopped. If the drive amount of the step motor 253 is controlled by a single table, the following situation may occur. For example, it is assumed that when a certain 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 reduced luminance signal value is 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,
It is more likely that the same number of pulses as the number of pulses sent to the step motor 253 to decrease the luminance signal value will be sent to increase the luminance signal value. Then
A hunting state is established in which the luminance signal value continues to alternate between a value larger by a predetermined amount and a value smaller by a predetermined amount centering on the reference value.

However, in this embodiment, since different tables are used when the aperture is opened and when the aperture is stopped, it is possible to surely converge the luminance signal value to the reference value without hunting. Becomes

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 drive amount of the movable diaphragm depending on the type of endoscope. Since the type of the endoscope 1 can be obtained from the ROM 23, the tables 1 and 2 corresponding to various endoscopes are previously stored in the RO of the light source device 20.
If stored in M33, an automatic iris adjustment device with a higher response speed can be realized by using the tables 1 and 2 corresponding to the connected endoscope 1 acquired by the CPU 31. Further, the configuration may be such that the user can select Table 1 and Table 2 from a plurality of tables, so that the characteristics of the automatic light control device can be freely set. Further, the tables 1 and 2 specific to the endoscope 1 may be stored in the ROM 23 of the endoscope 1.

In the present embodiment, emphasis is particularly placed on preventing halation, and a setting is made such that a larger number of pulses are transmitted when the aperture is stopped down than when the aperture is opened. But if your focus is on preventing dark screens,
It is sufficient to send more pulses when opening the aperture.

In this 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. , Can be applied to various types of apertures.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating 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 a 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 an interrupt process for drive pulse control according to the embodiment;

FIG. 8 is a table 1 referred to when narrowing the movable diaphragm
It is.

FIG. 9 is a table 2 referred to when a movable aperture is opened.

FIG. 10 is a table showing a relationship between a brightness index and a reference value.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 electronic endoscope system 1 endoscope 20 light source device 21 video signal processing unit 27 lamp control circuit 25 movable stop 28 stop drive circuit 30 control unit 33 ROM 253 step motor 281 pulse control circuit unit 282 motor drive circuit unit

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[Procedure amendment]

[Submission date] April 17, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

FIG. 6 shows the ROM 33 of the microcomputer control unit 30.
2 shows the contents of the main program stored in. Figure
In 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, for example, ON / OFF of a pump, etc. The process is executed (S2). Next, a process corresponding to an input from the keyboard 202, for example, a process of displaying characters input from the keyboard 202 on a monitor is performed (S3), and a process related to the lamp control circuit 27, for example, the panel switch 201 The on / off operation of the lamp and the monitoring of the state of the lamp being lit are performed by scanning (S4). Next, processing (S) related to the endoscope 1 side
5) 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 or the like on a monitor is performed. Next, a process (S6) for displaying the date and time on the monitor 49 and other processes, for example, a peripheral device (VCR (video cassette) connected to the light source device 20 )
Various processes such as control of a recorder (recorder) and a video printer) are executed (S7).

Claims (9)

[Claims] 1. An automatic dimmer for an electronic endoscope system in which a movable stop capable of blocking an arbitrary amount of an illumination light path between a light source lamp and a light guide entrance end face of an endoscope is driven by a motor, Brightness detection means for repeatedly detecting the brightness of the observation screen of the endoscope and outputting it as a brightness signal value; and detecting the drive signal for bringing the brightness of the observation screen closer to a reference value when detecting the brightness signal value. Control means for providing a drive signal to the motor; (1) a magnitude of the luminance signal value; and (2) a difference between the luminance signal value and the reference value. An automatic light control device for an electronic endoscope system, wherein the automatic light control device is set according to the condition. 2. The apparatus according to claim 1, wherein said luminance detecting means detects said luminance in a predetermined cycle, and said control means supplies said drive signal to said motor every time said luminance signal value is output. An automatic light control device for the electronic endoscope system according to the above. 3. The motor is a step motor, and the control means outputs a drive pulse as the drive signal,
The electronic endoscope system according to claim 1, wherein the number of the drive pulses is changed according to a magnitude of the luminance signal value and a difference between the luminance signal value and the reference value. Automatic light control device. 4. The apparatus according to claim 3, wherein the control means sets the number of drive pulses so that the halation state is quickly eliminated when the luminance signal value indicates a halation state. Automatic light control device for electronic endoscope system. 5. The electronic endoscope according to claim 3, wherein the control unit further sets the number of drive pulses according to which of the luminance signal value and the reference value is larger. Automatic dimmer for mirror system. 6. The control unit according to claim 3, wherein the control unit does not drive the step motor when a difference between the luminance signal value and the reference value is smaller than a predetermined allowable value. 6. The automatic light control device of the electronic endoscope system according to 4. 7. The control unit includes a storage unit that stores a table that defines a 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 automatic light control device of the electronic endoscope system according to claim 3, wherein 8. An automatic light control device of an electronic endoscope system, wherein a movable stop capable of blocking an arbitrary amount of an illumination light path between a light source lamp and a light guide incident end face of an endoscope is driven by a motor, Brightness detection means for repeatedly detecting the brightness of the observation screen of the endoscope and outputting the brightness signal value as a brightness signal value; and when outputting the brightness signal value, the driving signal for bringing the brightness of the observation screen closer to a reference value is used in the step. Control means for providing the motor with a motor, wherein the control means supplies a different drive signal to the motor depending on whether the movable aperture is stopped down or opened. 9. An automatic light control device for an electronic endoscope system in which a movable stop capable of blocking an arbitrary amount of an illumination light path between a light source lamp and a light guide incident end face of an endoscope is driven by a step motor. A brightness detection unit that repeatedly detects the brightness of the observation screen of the endoscope in a predetermined cycle and outputs the brightness signal value, and for each detection of the brightness signal value, to bring the brightness of the observation screen closer to a reference value. Control means for providing the drive pulse to the step motor, wherein the control means provides a different number of drive pulses to the step motor depending on whether the movable aperture is narrowed or opened. Automatic dimmer for mirror system.