JP3964507B2 - Aperture control 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 system in which, when halation occurs, the aperture is driven faster and the user does not feel a response delay.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, there is provided a diaphragm control 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 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 a drive signal for bringing the brightness of the observation screen close to the reference value when detecting the brightness signal value. Control means for giving to the motor according to the difference between the signal value and the reference value, and the control means has a luminance signal value when the luminance signal value is larger than the reference value and halation occurs. Regardless of the difference between the reference value and the reference value, the movable stop is driven to a predetermined target position determined according to the size of the reference value at a position where it is expected that no halation will occur. It is characterized by applying a driving signal of the order to the motor (claim 1).
[0008]
Thereby, even when the image is in the halation state, it is possible to quickly shift to an appropriate state.
[0009]
Further, the control means, the luminance signal value, Ru is configured to halation by whether the endoscope has been used is larger than the reference luminance signal value held to determine whether or not the generated ( Claim 2 ). That is, although the imaging conditions differ depending on the endoscope, if the control corresponding to the endoscope is performed, it is possible not only to quickly eliminate the halation state, but also to shift to an appropriate imaging state more quickly.
[0010]
Incidentally, the motor is a step motor, driving pulse as the drive signal can be configured to be applied to the step motor (claim 3).
[0011]
By using a step motor, it becomes possible to easily control the driving amount of the motor only by controlling the number of pulses.
[0012]
Further, the control means may be configured to drive-control the movable diaphragm so that the movable diaphragm is not narrowed beyond a predetermined diaphragm position when the number of drive pulses is a predetermined number or more. 4). With this configuration, it is possible to avoid a blackout state that occurs when the number of drive pulses is too large.
[0013]
In addition, the said brightness | luminance detection means can be comprised so that the said brightness | luminance signal value may be detected repeatedly in a predetermined cycle (Claim 5).
[0014]
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 (hereinafter abbreviated as a light source device) 20.
[0015]
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.
[0016]
The connector portion 6 of the endoscope 1 that is detachably connected to the light source device 20 has a connector 7 for connecting a signal line for transmitting signals to and from the solid-state imaging device 3 to the light source device 20, a light An incident end of the guide fiber bundle 4 is disposed.
[0017]
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.
[0018]
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.
[0019]
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.
[0020]
Reference numeral 23 denotes an EEPROM that stores data unique to the endoscope 1 such as the type of the endoscope 1. The EEPROM 23 also stores a reference luminance signal value that is a luminance signal value corresponding to the halation state when the endoscope 1 is used.
[0021]
The operation of the lamp control circuit 27 for driving the light source lamp 22 and the aperture driving circuit 28 for driving the movable aperture 25 are controlled by a microcomputer control unit 30 provided in the light source device 20. When the endoscope 1 is connected to the light source device 20, the control unit 30 reads the reference luminance signal value from the EEPROM 23 and sets the value in the variable vb. Therefore, when the endoscope 1 is used, it can be determined that halation has occurred if the luminance signal value exceeds the variable vb (reference luminance signal value).
[0022]
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.
[0023]
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.
[0024]
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.
[0025]
FIG. 4 is a block diagram showing the aperture driving circuit 28. As shown in FIG. Diaphragm drive circuit 28, and a pulse control circuit portion 28 2 and the motor drive circuit 28 3. Pulse control circuit unit 28 2, the control unit 30 via the output port 41 to be described later, the direction instruction signal instructing either forward to open reversing or for closing the movable diaphragm 25, the rotation amount In response to the corresponding drive pulse signal, a drive pulse to be given to the step motor 253 is set. The motor drive circuit 28 3 in accordance with the pulse signal input from the pulse control circuit portion 28 2, and outputs a driving pulse for driving the stepping motor 253.
[0026]
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. In the following description, the position of the movable diaphragm 25 is expressed using a variable m based on the pulse. That is, using the variable m as an index, m = 0 is a fully closed state, m = 120 is an intermediate state, and m = 240 is a fully open state. That is, m increases when the step motor 253 rotates forward and m decreases when the step motor 253 rotates backward. The number of pulses given to the step motor 253 is represented by a variable k. That is, the variable m corresponds to the position of the movable diaphragm 25, and the variable k represents a relative position indicating how much the movable diaphragm 25 moves from the current position.
[0027]
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.
[0028]
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.
[0029]
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.
[0030]
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 diaphragm 25. For example, a brightness adjustment switch is provided.
[0031]
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.
[0032]
When the luminance signal value is 0 to 30, the image is almost dark (blackout), when 20 to 50 is dark, 50 to 190 is a normal observation state, 180 to 230 is a halation state, and When the luminance signal value is 220 to 255 , the screen is almost white (white-out).
[0033]
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.
[0034]
Further, by connecting the connector portion 6 of the endoscope 1 to the light source device 20, the EEPROM 23 arranged in the endoscope 1 is connected to the microcomputer control portion 30 via the input / output port 43. As described above, the EEPROM 23 stores the type of the endoscope 1, data unique to the endoscope, and the reference luminance signal value.
[0035]
FIG. 7 shows the contents of the main program stored in the ROM 33 of the microcomputer control unit 30. 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, 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).
[0036]
8 to 11 are flowcharts showing interrupt processing executed during execution of the main program in FIG. 7 in order to automatically adjust the brightness of the endoscope observation screen to the brightness corresponding to the set brightness index. It is. That is, the process shown in FIGS. 8 to 11 is a process that is periodically executed at a constant interval, for example, 33 ms (milliseconds) to control the operation of the step motor 253.
[0037]
In FIG. 8, 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 corresponding to the input brightness index is within an allowable range (for example, 4) (S13: NO), the stepping motor 253 is not driven and the interruption process is terminated. If the difference between the luminance signal value and the reference value exceeds the allowable range (S13: YES), the following processing is executed to drive the step motor 253 so that the luminance signal value approaches the reference value.
[0038]
First, the reference value is compared with the luminance signal value (S15). If the luminance signal value is larger than the reference value (S15: YES), the process proceeds to FIG. If the luminance signal value is equal to or less than the reference value (S15: NO), the process proceeds to FIG.
[0039]
FIG. 9 is executed when it is determined in S15 of FIG. 8 that the luminance signal value is larger than the reference value (S15: YES). First, a reverse rotation signal is sent to the step motor 253 (S17), and it is determined which of the luminance signal value and the variable vb (that is, the reference luminance signal value unique to the connected endoscope 1) is larger (S19). That is, whether or not halation has occurred is determined by comparing the luminance signal value with the variable vb.
[0040]
If the luminance signal value is greater than the variable vb (S19: YES), it is determined whether the brightness index is greater than 5 (that is, whether the reference value is 128 or more) (S21). If the brightness index is greater than 5 (S21: YES), the variable k is set so that the aperture position is C1 (for example, C1 = 80) in the following processing. Here, the aperture position C1 is the aperture position indicated by the pulse number, and the variable k is the number of pulses required to move from the current aperture position (represented by the variable m) to the position C1.
[0041]
Therefore, first, in S23, it is determined whether or not the current position (variable m) is located on the open side with respect to the target position C1. If the current position is on the open side from the target position (S23: YES), the number of drive pulses (k) is calculated in S24. If the current position (m) of the movable diaphragm 25 is the target position (C1) or a position narrower than that (S23: NO), moving the diaphragm to the target position will open the diaphragm. Then, a predetermined value P1 (for example, 10 pulses) is set for the number of drive pulses (k) (S25), and the movable diaphragm 25 is driven by a predetermined amount (P1) in the direction of narrowing down.
[0042]
If it is determined in S21 that the brightness index is 5 or less (that is, the reference value is 120 or less) (S21: NO), the variable k is set so that the aperture position is C2 in the following processing. Here, C2 <C1, for example, C2 = 60.
[0043]
First, in S27, it is determined whether or not the current position (variable m) is located on the open side with respect to the target position C2. If the current position is closer to the target position C2 (S27: YES), the number of drive pulses (k) required to move from the current position (m) to the target position (C2) is calculated in S28. If the current position (m) of the movable diaphragm 25 is the target position (C2) or a position narrower than that (S27: NO), moving the diaphragm to the target position opens the diaphragm. A predetermined value P1 (for example, 10 pulses) is set to the number of drive pulses (k) (S29), and the movable diaphragm 25 is driven by a predetermined amount (P1) in the direction of narrowing down.
[0044]
After setting the drive pulse number k as described above, a pulse (k pulse) is applied to the step motor 253 to rotate the movable diaphragm 25 (S30). Since S <b> 17 to S <b> 29 are controls for reversing the stepping motor 253, the movable diaphragm 25 rotates in the narrowing direction by applying a k pulse to the stepping motor 25. In S31, the current position m changed by applying the k pulse to the step motor 253 is updated.
[0045]
If NO is determined in S19, that is, if the luminance signal value is equal to or less than the variable vb (less than the reference luminance signal value), halation has not occurred, and therefore, using the drive pulse table shown in FIG. A drive pulse k corresponding to the difference between the luminance signal value and the reference value is set (S32).
[0046]
In S33, in order to prevent the image from being blacked out due to excessive aperture, it is determined whether or not the current position (m) is on the open side with respect to the predetermined position C3. For example, C3 = 30. Here, if the current position m of the movable diaphragm is closer to the open side than the predetermined position C3 (S33: YES), it is next determined whether or not the number of drive pulses k is greater than a certain value P3. Here, for example, P3 = 20. If the drive pulse number k is larger than P3, it is determined whether or not the position m of the movable diaphragm 25 is a position narrowed by C3 by driving the amount movable diaphragm 25 (S35). If it is determined that the aperture position is moved to a position narrower than C3 by driving the step motor 253 by the drive pulse number k (S35: YES), the drive pulse number k is set to k = m−C3. Then, the movement position is set to the position of C3 (S36).
[0047]
If it is determined in S35 that the aperture position is located at the position C3 or on the open side as a result of giving the drive pulse number k (S35: NO), the drive pulse number k is not changed. In S34, even when the drive pulse number k is equal to or less than the predetermined value P3 (S34: NO), the drive pulse number k is not changed.
[0048]
If it is determined in S33 that the current position m coincides with or is narrower than the predetermined position C3 (S33: NO), the drive pulse number k is set to a predetermined value P2 in S37. Here, P2 is a relatively small value, for example, P2 = 2.
[0049]
As described above, when the number of drive pulses k is set in S32 to S37 when no halation has occurred, the process proceeds to S30 in FIG. 9, the step motor 253 is driven (S30), and the current position m Update.
[0050]
If it is determined in S15 of FIG. 8 that the luminance signal value is equal to or less than the reference value (S15: NO), the process proceeds to S38 of FIG. Here, first, since the luminance signal value is smaller than the reference value, which is the target value, it is necessary to drive the movable diaphragm 25 to the open side, a forward rotation signal is sent to the step motor 253 (S38). Next, based on the difference between the luminance signal value and the reference value, the drive pulse number k is set with reference to the drive pulse table of FIG. 12 (S39).
[0051]
Next, after the set drive pulse number k is given to the step motor 253 (S40), the current position m is updated (S41). In step S41, since the step motor 253 is rotated forward by an amount corresponding to the drive pulse number k, a new current position is obtained by adding the drive pulse number k to the current position m.
[0052]
In the above embodiment, the drive pulse number k is set using a single drive pulse table. However, depending on the type of endoscope, it is better to change the drive amount of the movable diaphragm. There is. Since the type of the endoscope 1 can be acquired from the ROM 23, if a table corresponding to various endoscopes is stored in the ROM 33 of the light source device 20 in advance, the CPU 31 acquires the connected internal connection. By using a table corresponding to the endoscope 1, it is possible to realize an aperture control device with better response. Alternatively, as a configuration in which the user can select an arbitrary table from a plurality of tables, the characteristics of the aperture control device may be set freely. Alternatively, a table unique to the endoscope 1 may be stored in the ROM 23 of the endoscope 1, and the number of drive pulses k may be set using the table. Furthermore, each constant (C1 to P3) may be a value corresponding to the connected endoscope.
[0053]
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 table showing a relationship between a brightness index and a reference value.
FIG. 7 is a flowchart showing the contents of a main program according to the embodiment.
FIG. 8 is a flowchart showing the contents of interrupt processing for drive pulse control of the embodiment together with FIGS.
FIG. 9 is a flowchart showing the contents of interrupt processing for drive pulse control according to the embodiment together with FIGS.
FIG. 10 is a flowchart showing the contents of interrupt processing for drive pulse control according to the embodiment together with FIGS.
FIG. 11 is a flowchart showing the contents of interrupt processing for drive pulse control according to the embodiment together with FIGS.
FIG. 12 is a table that is referred to when the movable diaphragm is driven.
[Explanation of symbols]
100 Electronic Endoscope System 1 Endoscope 20 Light Source Device 21 Video Signal Processing Unit 23 EEPROM
27 Lamp control circuit 25 Movable aperture 28 Aperture drive circuit 30 Control unit 33 ROM
253 Step motor 282 Pulse control circuit unit 283 Motor drive circuit unit

Claims (5)

A diaphragm control device for an electronic endoscope system that drives a movable diaphragm that can block an arbitrary amount of an illumination light path between a light source lamp and a light guide incident end surface of an endoscope by a 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 a drive signal for bringing the brightness of the observation screen close to a reference value to the motor according to a difference between the luminance signal value and the reference value when detecting the luminance signal value. And
When the luminance signal value is larger than the reference value and halation is occurring , the control means causes the movable diaphragm after driving to halate regardless of the difference between the luminance signal value and the reference value. An electronic device characterized in that a drive signal for narrowing the movable diaphragm to a predetermined target position determined according to the size of the reference value is provided to the motor where the motor is expected not to occur. A diaphragm control device for an endoscope system. Wherein, claims wherein the luminance signal value, characterized in that the halation by whether the endoscope has been used is larger than the reference luminance signal value held to determine whether or not occurred 2. A diaphragm control device for an electronic endoscope system according to 1. The diaphragm control apparatus for an electronic endoscope system according to claim 1 or 2 , wherein the motor is a step motor, and the drive signal is a drive pulse. Wherein, the number of pulses of the drive pulse when more than a predetermined number, according to claim 3, wherein the movable stop is characterized in that the drive control of the movable diaphragm so as not narrowed beyond a predetermined stop position A diaphragm control device for an electronic endoscope system. The diaphragm control apparatus for an electronic endoscope system according to any one of claims 1 to 4 , wherein the luminance detection means repeatedly detects the luminance signal value in a predetermined cycle.

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