JP6172738B2 - Electronic endoscope and electronic endoscope system - Google Patents

Description

  The present invention relates to an electronic endoscope and an electronic endoscope system provided with an image sensor for capturing an image in a body cavity.

  2. Description of the Related Art Conventionally, electronic endoscopes that can observe and image a target site by inserting a long and narrow insertion portion into a patient's body cavity have been widely used. An imaging element (CCD image sensor, CMOS image sensor, etc.) and a light guide for irradiating illumination light into the body cavity are provided at the distal end of the insertion portion of the electronic endoscope. The light reflected by the target part is photoelectrically converted by the image sensor and output as an image signal, and is displayed on the monitor via a video processor connected to the electronic endoscope.

  In addition, in a conventional electronic endoscope, when the tip of the electronic endoscope approaches an observation target during work, the amount of light is adjusted by using the electronic shutter function to reduce image blurring. It has been known. Patent Document 1 discloses an electronic endoscope system having an electronic shutter function. In the electronic shutter function, the amount of light is adjusted by outputting a charge sweeping pulse at an arbitrary timing within the field and resetting the accumulated charge.

JP 2007-144143 A

  In general, when performing an electronic shutter, a charge sweeping pulse is input to a Vsub terminal to which a substrate voltage of an image sensor is applied. As a result, the rising edge of the charge sweeping pulse eliminates the potential difference between the anode and the cathode of each photodiode constituting the light receiving unit of the image sensor, and the charge accumulated therein is removed (reset). Thereafter, when the charge sweeping pulse falls, charge accumulation is resumed. However, after the charge sweep pulse is input, the substrate voltage of the image sensor may fluctuate over a certain period. In such a case, charges are not properly accumulated, and noise is generated in the acquired image data. In addition, the specifications (length, etc.) of an image pickup device and a cable (flexible tube) inserted into a body cavity vary depending on the type of electronic endoscope. Furthermore, the wiring resistance value and the parasitic capacitance value differ depending on the cable specifications. For this reason, the voltage drop of the substrate voltage due to the cable and the way the substrate voltage fluctuates when a charge sweep pulse is input differ depending on the type of electronic endoscope, making it difficult to drive the image sensor stably. It was.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic endoscope and an electronic device capable of appropriately controlling the substrate voltage of an image sensor according to the type of electronic endoscope. An endoscope system is provided.

  According to an embodiment of the present invention, an image sensor provided at the distal end of an electronic endoscope, a memory that stores unique information of the electronic endoscope, and a substrate voltage generation that generates a substrate voltage to be applied to the image sensor There is provided an electronic endoscope comprising means, detection means for detecting a substrate voltage value applied to the image sensor, and control means for controlling the substrate voltage generation means. Further, the control means of the present invention obtains a target substrate voltage value based on the unique information stored in the memory, so that the substrate voltage value detected by the detection means substantially matches the target substrate voltage value. The value of the substrate voltage generated by the substrate voltage generating means is adjusted.

  According to this configuration, it is possible to control the substrate voltage of the image sensor according to the type of electronic endoscope, and it is possible to deal with various electronic endoscopes using a common control substrate. In addition, by adjusting the substrate voltage value generated based on the detected substrate voltage value, it is possible to correct even when the substrate voltage fluctuates, driving the image sensor stably and reducing noise. Fewer images can be obtained.

  In addition, the imaging element and the substrate voltage generating means in the electronic endoscope of the present invention are connected via a long cable. Furthermore, the target board voltage value may be obtained based on the type of the image sensor and the cable length included in the unique information.

  The electronic endoscope of the present invention may have an electronic shutter function. In this case, the control means may be configured to adjust the value of the substrate voltage generated by the substrate voltage generating means only when the electronic shutter function is ON. According to this configuration, it is possible to correct the fluctuation of the substrate voltage due to the influence of the electronic shutter.

  Furthermore, the control means of the present invention is configured to generate a correction signal based on the substrate voltage value detected by the detection means and adjust the value of the substrate voltage generated by the substrate voltage generation means using the correction signal. Also good.

  Further, according to the present invention, an image sensor provided at the tip of the electronic endoscope, a memory that stores unique information of the electronic endoscope, a substrate voltage generating unit that generates a substrate voltage to be applied to the image sensor, An electronic endoscope system is provided that includes an electronic endoscope that includes a detection unit that detects a substrate voltage value applied to an imaging device, and a control unit that controls the substrate voltage generation unit. Further, the control means of the present invention obtains a target substrate voltage value based on the unique information stored in the memory, so that the substrate voltage value detected by the detection means substantially matches the target substrate voltage value. The value of the substrate voltage generated by the substrate voltage generating means is adjusted.

  As described above, according to the present invention, the substrate voltage of the image sensor can be appropriately controlled according to the type of electronic endoscope, and the image sensor can be driven stably.

1 is a block diagram illustrating a schematic configuration of an electronic endoscope system according to an embodiment of the present invention. It is a block diagram which shows the detailed structure of the endoscope control part which concerns on embodiment of this invention. FIG. 3A shows the detected substrate voltage, FIG. 3B shows the correction signal, and FIG. 3C shows the corrected substrate voltage.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an electronic endoscope system 1 according to an embodiment of the present invention. As shown in FIG. 1, the electronic endoscope system 1 of this embodiment includes an electronic endoscope 100, an electronic endoscope processor 200, and a monitor 300.

  The electronic endoscope processor 200 includes a system controller 202 and a timing controller 206. The system controller 202 executes various programs stored in the memory 204 and integrally controls the entire electronic endoscope system 1. Further, the system controller 202 changes various settings of the electronic endoscope system 1 in accordance with instructions from the user (surgeon or assistant) input to the operation panel 208. The timing controller 206 outputs a clock pulse for adjusting the operation timing of each unit to various circuits in the electronic endoscope system 1.

  The electronic endoscope processor 200 includes a light source device 230 that supplies illumination light that is a white light beam to an LCB (Light Carrying Bundle) 102 of the electronic endoscope 100. The light source device 230 includes a lamp 232, a lamp power source 234, a condenser lens 236, and a light control device 240. The lamp 232 is a high-intensity lamp that emits illumination light when supplied with driving power from the lamp power supply 234. For example, a xenon lamp, a metal halide lamp, a mercury lamp, or a halogen lamp is used. The illumination light emitted from the lamp 232 is collected by the condenser lens 236 and then introduced into the LCB 102 via the light control device 240.

  The dimmer 240 is a device that adjusts the amount of illumination light introduced into the LCB 102 based on the control of the system controller 202, and includes a diaphragm 242, a motor 243, and a driver 244. The driver 244 generates a drive current for driving the motor 243 and supplies it to the motor 243. The diaphragm 242 is driven by a motor 243, and changes the opening through which the illumination light passes to adjust the amount of illumination light passing through the opening.

  Illumination light introduced into the LCB 102 from the incident end propagates through the LCB 102, exits from the exit end of the LCB 102 disposed at the tip of the electronic endoscope 100, and is irradiated onto the subject via the light distribution lens 104. . The reflected light from the subject forms an optical image on the light receiving surface of a CCD (Charge-Coupled DeVice) 108 via the objective lens 106.

  The CCD 108 is a single-plate color CCD image sensor in which various filters are arranged on the light receiving surface, and generates imaging signals of the three primary colors R, G, and B corresponding to the optical image formed on the light receiving surface. The generated imaging signal is converted into a digital image signal by the endoscope control unit 120 and sent to the image processing unit 220 of the processor for electronic endoscope 200. In addition, the endoscope control unit 120 accesses the memory 114 (ROM or nonvolatile memory) and reads out unique information of the electronic endoscope 100. The unique information of the electronic endoscope 100 recorded in the memory 114 includes, for example, the number of pixels of the CCD 108, sensitivity, an operable frame rate, a substrate voltage value described later, and the like. The endoscope control unit 120 outputs the unique information read from the memory 114 to the system controller 202.

  The system controller 202 performs various calculations based on the unique information of the electronic endoscope 100 and generates a control signal. The system controller 202 uses the generated control signal to perform various circuits in the electronic endoscope processor 200 so that processing suitable for the electronic endoscope 100 connected to the electronic endoscope processor 200 is performed. Control the operation and timing.

  The timing controller 206 supplies clock pulses to the endoscope control unit 120 and the image processing unit 220 according to the timing control by the system controller 202. In addition, the electronic endoscope system 1 of the present embodiment has an electronic shutter function, and the timing controller 206 outputs a charge sweep pulse to the endoscope control unit 120 in accordance with timing control by the system controller 202.

  The image processing unit 220 of the electronic endoscope processor 200 controls an endoscope image and the like based on an image signal sent from the endoscope control unit 120 of the electronic endoscope 100 under the control of the system controller 202. A video signal for monitor display is generated and output to the monitor 300. The surgeon performs observation and treatment in the digestive tract, for example, while confirming the endoscopic image displayed on the monitor 300.

  Next, the drive control of the CCD 108 in this embodiment will be described in detail with reference to FIG. FIG. 2 is a block diagram showing the detailed configuration of the CCD 108 and the endoscope control unit 120 inside the electronic endoscope 100. The endoscope control unit 120 is provided in a connection portion of the electronic endoscope 100 and is connected to the CCD 108 via a long (for example, 2 m) cable 109. As shown in FIG. 2, the endoscope control unit 120 includes a CPU (Central Processing Unit) 121, a timing generator 122, a CCD vertical clock driver 123, a CCD horizontal clock driver 124, a power supply circuit 125, an A / D (Analogue / Digital). ) Converter 126, image processing circuit 127, substrate voltage generation circuit 130, D / A (Digital / Analogue) converter 131, A / D converter 132, and amplifiers 133 and 134.

  The CPU 121 performs data communication with the system controller 202 of the electronic endoscope processor 200 and controls each part of the endoscope control unit 120 in an integrated manner. The timing generator 122 drives and controls the CCD 108 at a timing synchronized with the frame rate of the video processed on the electronic endoscope processor 200 side according to the clock pulse supplied from the timing controller 206 under the control of the CPU 121. A drive signal is generated. Specifically, the timing generator 122 generates a vertical drive signal and outputs it to the CCD vertical clock driver 123, and generates a horizontal drive signal and outputs it to the CCD horizontal clock driver 124. The CCD vertical clock driver 123 receives the vertical drive signal and outputs a vertical clock to the Vdriv terminal of the CCD 108. The CCD horizontal clock driver 124 receives the horizontal drive signal and outputs a horizontal clock to the Hdriv terminal of the CCD 108. The power supply circuit 125 supplies a power supply voltage (for example, + 15V, −8V) for driving the CCD 108 to the CCD 108 at a predetermined timing.

  The CCD 108 reads out the photoelectrically converted image signal in accordance with the input vertical and horizontal clocks. The imaging signal read from the CCD 108 is converted into a digital signal by the A / D converter 126 and input to the image processing circuit 127. The image processing circuit 127 performs image processing such as blanking, clamping, white balance adjustment, and gamma correction on the input digital image data according to the control of the CPU 121. Data applied for the processing is stored in the memory 114 and read out by the CPU 121. Thereby, the dispersion | variation in the color spectral characteristic of CCD for every electronic endoscope and the spectral characteristic of the light guide 7 can be adjusted. The image signal processed by the image processing circuit 127 is output to the image processing unit 220 of the electronic endoscope processor 200.

  The substrate voltage generation circuit 130 generates a substrate voltage applied to the Vsub terminal of the CCD 108 under the control of the CPU 121. Here, the value of the substrate voltage is generally determined according to the type (specification) of the CCD 108. However, since the substrate voltage generation circuit 130 and the CCD 108 are connected by the long cable 109, the substrate voltage generated by the substrate voltage generation circuit 130 drops due to the wiring resistance of the cable 109 or the like. Further, the descending rate varies depending on the length of the cable 109 and the like. Further, when the electronic shutter is used, a charge sweep pulse is input to the Vsub terminal of the CCD 108 under the control of the CPU 121. Specifically, the substrate voltage generated by the substrate voltage generation circuit 130 is instantaneously increased according to the control of the CPU 121. In this case, the substrate voltage applied to the CCD 108 may fluctuate after the charge sweep pulse falls. For this reason, in this embodiment, the substrate voltage is controlled in consideration of the type of electronic endoscope and the variation of the substrate voltage due to the electronic shutter.

  Specifically, first, the CPU 121 reads the rated substrate voltage value Vsub-s of the CCD 108 from the unique information of the electronic endoscope 100 read from the memory 114. Subsequently, the CPU 121 reads information related to the specification of the cable 109 from the unique information of the electronic endoscope 100. Then, based on the length of the cable 109 and the wiring resistance, a voltage drop value Vsub-d by the cable 109 is calculated. Then, a voltage value obtained by adding the drop value Vsub-d to the rated substrate voltage value Vsub-s of the CCD 108 is set as a target substrate voltage Vsub-t, and the substrate generation circuit 130 is instructed. The substrate voltage generation circuit 130 generates a substrate voltage based on an instruction from the CPU 121. The substrate voltage generated by the substrate generation circuit 130 is converted into an analog signal by the D / A converter 131, amplified by the amplifier 133, and then input to the Vsub terminal of the CCD 108 through the cable 109.

  Furthermore, in this embodiment, the value of the substrate voltage actually input to the Vsub terminal of the CCD 108 is detected and fed back to the CPU 121. Specifically, the substrate voltage value Vsub-a input to the Vsub terminal of the CCD 108 is amplified by the amplifier 134, converted into a digital signal by the A / D converter 132, and input to the CPU 121. In the CPU 121, the detected substrate voltage value Vsub-a fed back is compared with the target substrate voltage value Vsub-t, and the substrate is set so that the detected substrate voltage value Vsub-a matches the target substrate voltage value Vsub-t. The value of the substrate voltage generated by the voltage generation circuit 130 is adjusted and the substrate voltage generation circuit 130 is instructed. Specifically, a voltage value obtained by adding (or subtracting) the difference between the target substrate voltage value Vsub-t and the detected substrate voltage value Vsub-a to the target substrate voltage value Vsub-t is instructed to the substrate voltage generation circuit 130. As a result, a stable substrate voltage can be supplied to the CCD 108.

  Thus, in this embodiment, it is possible to set an appropriate substrate voltage according to the type of electronic endoscope based on the unique information of the electronic endoscope stored in the memory 114. In addition, by detecting the substrate voltage input to the CCD 108 and performing feedback control, the substrate voltage value can be adjusted (increased or decreased) to the target value even when the substrate voltage varies due to the electronic shutter. As a result, the CCD 108 can be driven stably, and image noise can be reduced.

  The above is the description of the embodiment of the present invention, but the present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the technical idea of the present invention. For example, an image sensor (such as a CMOS) other than a CCD can be used as the image sensor. Further, the system controller 202 of the electronic endoscope processor 200 may be configured to control the value of the substrate voltage generated in the substrate voltage generation circuit 130.

  Further, the substrate voltage feedback control in the above embodiment may be performed only when the electronic shutter function is ON. Thereby, when the possibility that the substrate voltage fluctuates is low, the processing in the endoscope control unit 120 can be reduced.

  Further, the CPU 121 may be configured to adjust the substrate voltage using a correction signal corresponding to the variation in the substrate voltage caused by the electronic shutter. Specifically, the CPU 121 detects a change in the substrate voltage when the charge sweep pulse is first input. The substrate voltage detected in this case is shown in FIG. Then, the detected fluctuation portion of the substrate voltage is inverted to generate a correction signal shown in FIG. When the electronic shutter function is ON, the substrate voltage generation circuit 130 is instructed to output a substrate voltage obtained by adding the correction signal stored in the memory 114 to the target substrate voltage value Vsub-t. By providing such a configuration, it is possible to supply a stable substrate voltage as shown in FIG. 3C to the CCD 108 without always performing feedback control.

1 Electronic Endoscope System 100 Electronic Endoscope 108 CCD
114 Memory 120 Endoscope control unit 121 CPU
130 Substrate voltage generation circuit 200 Electronic endoscope processor 202 System controller 206 Timing controller 220 Image processing unit 300 Monitor

Claims (5)

An image sensor provided at the tip of an electronic endoscope having an electronic shutter function ;
A memory for storing unique information of the electronic endoscope;
Substrate voltage generating means for generating a substrate voltage to be applied to the image sensor;
Detecting means for detecting a substrate voltage value applied to the image sensor;
Control means for controlling the substrate voltage generating means;
With
The control means includes
Based on the unique information stored in the memory, a target substrate voltage value is obtained,
Only when the electronic shutter function is ON, the value of the substrate voltage generated by the substrate voltage generating unit is adjusted so that the substrate voltage value detected by the detecting unit substantially matches the target substrate voltage value. to,
Electronic endoscope. The imaging device and the substrate voltage generating means are connected via a long cable ,
The electronic endoscope according to claim 1. The target substrate voltage value is obtained based on the type of the image sensor included in the unique information and the length of the cable .
The electronic endoscope according to claim 2. The control means includes
Generating a correction signal based on the substrate voltage value detected by the detection means, and adjusting the value of the substrate voltage generated by the substrate voltage generation means using the correction signal ;
The electronic endoscope according to any one of claims 1 to 3 . An image sensor provided at the tip of an electronic endoscope having an electronic shutter function ;
A memory for storing unique information of the electronic endoscope;
Substrate voltage generating means for generating a substrate voltage to be applied to the image sensor;
Detecting means for detecting a substrate voltage value applied to the image sensor;
An electronic endoscope comprising:
Control means for controlling the substrate voltage generating means;
An electronic endoscope system comprising:
The control means includes
Based on the unique information stored in the memory, a target substrate voltage value is obtained,
Only when the electronic shutter function is ON, the value of the substrate voltage generated by the substrate voltage generating unit is adjusted so that the substrate voltage value detected by the detecting unit substantially matches the target substrate voltage value. to,
Electronic endoscope system.

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