JP5997906B2 - Endoscope system and light source device for endoscope - Google Patents

Description

  The present invention relates to an endoscope system and an endoscope light source device capable of performing special light image observation such as narrow-band light observation.

  In an endoscope system, a technique called narrow-band light observation in which image observation is performed by irradiating an observation site with narrow-band light may be used in order to facilitate the detection of a lesion (see Patent Document 1, etc.). ). Conventionally, in order to perform narrow-band light observation with the same lamp as normal light image observation, for example, a filter that can be retracted from the optical path and transmits only light in a predetermined wavelength band is provided behind the lamp that emits white light. May be arranged.

JP 2010-184046 A

  However, when the above-described filter is used, a part of the light emitted from the lamp is cut by the filter, which causes a problem that the amount of narrowband light irradiated to the subject is reduced and the observation image becomes dark. Further, since the subject illumination becomes dark, the subject cannot be photographed with an electronic shutter having a fast shutter speed, and blurring is likely to occur in still image photographing.

  Therefore, the present invention provides an endoscope system and an endoscope that can prevent an observation image from becoming dark or blurring in still image shooting in special light image observation such as narrow-band light observation. An object of the present invention is to provide a light source device for an automobile.

  An endoscope system according to the present invention includes a lamp, a photographing element that captures an image of a subject irradiated by the lamp and generates a video signal, and a wavelength band of normal light that is disposed on the optical path of the lamp and emitted from the lamp. When a special light is generated by transmitting a part of the light and the subject is irradiated with the special light, and when the subject is irradiated with the special light, the emitted light amount of the lamp is relatively increased in the first period, and the first A lamp control unit that controls the lamp so as to relatively reduce the amount of emitted light in a second period that is continuous with the period, and acquires a video signal generated by imaging the subject in the first period as special light image data It is characterized by that.

  The special light image data is output to an output device such as a monitor, for example, and is preferably continuously output to the output device as an image obtained in the first and second periods. At this time, it is better to repeat the first and second periods to acquire a plurality of special light image data, and the plurality of special light image data are sequentially output to the output device and displayed as a moving image.

  For example, the imaging element captures a subject and generates a video signal in each of the first and second periods. The rate at which the special light image data is output to the output device is preferably ½ or less of the rate at which the image signal of the image sensor is generated. In this case, the video signal generated by imaging the subject in the second period is not output to the output device.

  The filter should be movable so as to selectively irradiate the subject with special light and normal light. In that case, a video signal generated by imaging a subject irradiated with normal light is acquired as normal light image data.

  The lamp control unit irradiates the subject with special light in the first period and emits the light emitted from the lamp when acquiring the special light image data. The lamp illuminates the subject with normal light and outputs the normal light image data. It is preferable to make it larger than the amount of light. In addition, the lamp control unit makes the emitted light amount of the lamp when the subject is irradiated with the special light in the second period smaller than the emitted light amount when the subject is irradiated with the normal light and the normal light image data is acquired. Is preferred. Further, for example, the lamp control unit controls the emitted light amount of the lamp to be constant when the subject is irradiated with normal light. The lamp is, for example, a xenon lamp.

  An endoscope light source device according to the present invention is arranged on a lamp and an optical path of the lamp, generates a special light by transmitting a part of the wavelength band of the normal light emitted from the lamp, and the subject by the special light. When irradiating the subject with special light and a filter that irradiates the light, the emitted light amount of the lamp is relatively increased in the first period, and the emitted light amount is relatively decreased in the second period that is continuous with the first period. And a lamp controller for controlling the lamp.

  In the present invention, by increasing the amount of light emitted from the lamp for a certain period, the observation image can be brightened during the special light image observation, and even if a still image is taken at a high shutter speed, the image is less likely to be blurred.

It is a block diagram for showing an electronic endoscope system concerning one embodiment of the present invention. It is a timing chart which shows the operation | movement at the time of normal light image observation. It is a timing chart which shows the operation | movement at the time of special light image observation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating an electronic endoscope system according to an embodiment of the present invention.

  The endoscope system includes an endoscope (scope) 10 that images an observation site (subject) in the body or the like and generates a video signal, a processor 11 that performs image processing on the video signal, and a monitor 12. The endoscope 10 includes a flexible tube and an insertion portion 14 that is inserted into the body and the like, and is connected to the processor 11 via a connector portion 15. A light guide 16 is inserted into the endoscope 10, and an emission end thereof is disposed at the distal end portion 10 </ b> A of the insertion portion 14, and an incident end is disposed inside the processor 11.

  The endoscope 10 includes an image sensor 17 formed of a simultaneous type CCD or the like at the distal end portion 10A. In addition, the endoscope 10 includes a pre-stage signal processing circuit 18, a microcomputer 19 that controls the operation of the entire endoscope 10, and a driver 20 that drives and controls the image sensor 17 in the connector unit 15.

  The processor 11 includes a lamp 21 and has a function as a light source device. The processor 11 includes a system controller 31, a processor signal processing circuit 32, a timing controller 33, and a peripheral controller 34. The system controller 31 controls the entire processor 11 and outputs a control signal to the microcomputer 19 of the endoscope 10. The timing controller 33 outputs a timing signal to the signal processing circuit 32, the peripheral controller 34, and the microcomputer 19 of the endoscope 10, and controls the operation timing of the endoscope 10 and the processor 11. The peripheral controller 34 controls driving of the lamp 21, a filter 27 and a diaphragm 28 described later, and the like.

  The lamp 21 is supplied with power from a lamp power source 23 including a lamp control unit 22. The lamp controller 22 controls the amount of light emitted from the lamp 21 by controlling the current value input to the lamp 21. The lamp 21 is composed of a discharge lamp such as a xenon lamp, and emits white light (normal light). The rated current of the lamp 21 in this embodiment is 20A.

  The light emitted from the lamp 21 is incident on the incident end of the light guide 16 through the condenser lens 25 and is transmitted to the emission end by the light guide 16, and irradiates the subject from the distal end portion 10 </ b> A of the endoscope 10. Is done.

  Between the lamp 21 and the condenser lens 25, a filter 27 and a diaphragm 28 are arranged in this order from the lamp 21 side. The filter 27 is disposed on the optical path of the lamp 21 when observing the special light image, and transmits light in a part of the wavelength band of the white light emitted from the lamp 21. That is, the light transmitted through the filter 27 is light having a narrower wavelength band than the light emitted from the lamp 21. The light having a narrow wavelength band is irradiated as special light from the distal end portion 10A toward the subject through the light guide 16.

  The filter 27 can be withdrawn from the optical path of the lamp 21 and is withdrawn from the optical path during normal light image observation, whereby the light from the lamp 21 is not cut by the filter 27 and white light (normal light) is emitted from the tip portion 10A. Is emitted. The diaphragm 28 further adjusts the amount of special light or normal light.

  A subject irradiated with special light or normal light is imaged by the image sensor 17. That is, a subject image is formed on the image sensor 17 by an imaging lens (not shown), and a video signal is generated by photoelectric conversion. The video signal is subjected to amplification processing by an amplifier (not shown), and then subjected to predetermined front-stage signal processing by the front-stage signal processing circuit 18, and then transmitted to the processor 11 as a digital signal, for example. The video signal is further subjected to predetermined post-stage image processing by the processor signal processing circuit 32 to be converted into image data (normal light image data or special light image data), and is output to the monitor 12 as a moving image. When the operation switch 38 of the endoscope 10 is pressed, still image shooting is performed, and the image data is displayed on the monitor 12 as a still image. Note that image data of moving images and still images may be appropriately recorded on a storage medium or the like.

  FIG. 2 is a timing chart showing a state of image output when normal light is irradiated on the subject and normal light image observation is performed. Hereafter, the operation | movement at the time of normal light image observation is demonstrated using FIG.

  As shown in FIG. 2, the image sensor 17 is driven at a driving rate of 30 fps (frames per second), and one frame period is 1/30 second. Each frame period includes an odd field period (first period) of 1/60 seconds in the first half and an even field period (second period) of 1/60 seconds in the latter half, and these odd and even fields are repeated. .

  The image sensor 17 is exposed in each exposure period (charge accumulation period) of each field period (odd field period, even field period), and accumulates charges corresponding to the subject image formed on the light receiving surface. Thereafter, the image sensor 17 outputs the accumulated charges as video signals of odd and even fields, respectively. Here, since the endoscope 10 radiates normal light, the image sensor 17 has the odd field and even field video signals (ODD1, EVEN1, ODD2,...) Corresponding to the normal light image formed by the reflected light of the normal light.・ ・) Is repeatedly generated. As described above, the image sensor 17 generates a video signal in each field and generates a video signal at a rate of 60 times / second.

  Each of the odd-numbered and even-field video signals is subjected to a predetermined preceding signal processing by the preceding signal processing circuit 18 and then input to the processor signal processing circuit 32. The odd-numbered and even-field video signals are each subjected to predetermined post-stage image processing in the processor signal processing circuit 32 to be converted into normal light image data, and sequentially output to the monitor 12 as odd-numbered and even-field normal light images. . As described above, during normal light image observation, the display update rate of the monitor 12 is 60 times / second, which is the same as the rate at which the image sensor 17 generates the video signal.

  During normal light image observation, the current input to the lamp 21 is controlled to a constant value 20A, which is the rated current, and therefore the emitted light quantity of the lamp is the same in the odd and even field periods. Therefore, the normal light image data in the odd and even fields both have appropriate luminance values, and an appropriate normal light image is displayed on the monitor 12.

  FIG. 3 is a timing chart showing how the image is output when the subject is irradiated with special light and special light image observation is performed. Hereinafter, the operation when special light image observation is performed will be described with reference to FIG.

  The image sensor 17 is controlled so as to be driven at a drive rate of 30 fps even when observing the special light image, and similarly to the normal light image observation, the image signal 17 (ODD1, EVEN1,. ODD2 ...) is generated at a rate of 60 times / second. Further, since the endoscope 10 emits special light during special light image observation, the video signals in the odd and even fields correspond to special light images representing a subject irradiated with the special light.

  Here, the amount of light emitted from the lamp 21 is relatively large in the odd field and relatively small in the even field. Specifically, in the odd field period, the current input to the lamp 21 is controlled to 30 A, which is larger than the rated current (20 A), and is controlled to 10 A, which is smaller than the rated current, in the even field period. For this reason, in the odd field, a video signal having a sufficiently large luminance value is generated in the image sensor 17, while in the even field, a video signal having a small luminance value is generated.

  Note that the emitted light quantity of the lamp does not need to be relatively increased over the entire odd field period, and may be relatively increased in the exposure period as shown in FIG. Further, at the time of observing the special light image, the arithmetic average of the current input to the lamp 21 is controlled to be equal to or less than the rated current 20A, and the lamp 21 is driven at the rated current or less as a total amount.

  The odd-numbered and even-field video signals are subjected to pre-stage signal processing by the pre-stage signal processing circuit 18 in the same manner as in normal light image observation, and then the processor signal processing circuit 32 performs signal processing corresponding to the special light image. .

  Specifically, the video signal in the odd field is subjected to predetermined post-stage video signal processing in the processor signal processing circuit 32, and is stored in the memory (not shown) as the special light image data in the odd field and is also displayed on the monitor 12. Is output. On the other hand, the video signal of the even field is deleted without being subjected to the subsequent image processing in the signal processing circuit 32 and is not output as an image to the monitor 12. Instead, the video signal of the odd field stored in a memory (not shown) is used. The special light image data is read out and output to the monitor 12 as an even field image. Thereby, at the time of special light image observation, the image data obtained in the odd field is continuously output to the monitor 12 over one frame period as image data photographed in the odd / even field.

  This operation is repeated, and the plurality of special light image data obtained in the odd field are sequentially updated every frame period, output to the monitor, and displayed as a moving image. That is, when the special light image is captured, the display update rate of the monitor 12 is 30 times / second, which is ½ of the rate (60 fields / second) for generating the video signal of the image sensor 17, and the normal light image is captured. Slower than the display update rate.

  As described above, in the present embodiment, in special light image observation, it is possible to output a bright special light image to the monitor by increasing the amount of light emitted from the lamp during exposure of the image sensor in the odd field. In the even field, the lamp light intensity is suppressed, and the lamp current as a whole is prevented from exceeding the rating. The video signal in the even field is not used for image observation, so an unnatural image is displayed on the monitor. It never happens.

  In the above description, a mode in which a moving image is shot is shown. However, the same applies when a still image is shot, and a still image can be obtained by a video signal obtained in an odd field. At this time, if the exposure period is shortened by the electronic shutter, it becomes easy to prevent blurring of the still image. In still image shooting, when the exposure period is shortened, the period during which the amount of emitted light is relatively increased may be shortened in accordance with the exposure period.

  In the above description, the video signal is generated by the CCD by the interlace method and is output to the monitor. However, the progressive method may be used. Even in the progressive method, the amount of emitted light from the lamp is relatively increased when the first image is acquired (first period), and the amount of emitted light from the lamp is relatively increased when the second image is subsequently acquired (second period). This is repeated, and special light image observation is performed in the same manner.

  In the present embodiment, the display update rate of the monitor 12 at the time of capturing the special light image is ½ of the drive rate of the image sensor 17, but may be lower, for example, １ ／ or ¼. It may be. In this case, the same image is output to the monitor 12 over 3 to 4 field periods. Further, the image sensor 17 may be driven at a driving rate other than the above-described driving rate.

10 Endoscope 11 Processor (Light source device)
12 Monitor (output device)
17 Image sensor 18 Pre-stage signal processing circuit 21 Lamp 22 Lamp control unit 23 Lamp power supply 27 Filter 32 Processor signal processing circuit

Claims (11)

A lamp,
An imaging element for imaging a subject illuminated by a lamp and generating a video signal;
A filter that is arranged on the optical path of the lamp, transmits a part of the wavelength band of the normal light emitted from the lamp, generates special light, and irradiates the subject with the special light; and
When illuminating the subject with the special light, the lamp emits a relatively large amount of light in the first period, and relatively reduces the amount of emitted light in a second period that is continuous with the first period. A lamp control unit for controlling
The lamp control unit makes the current input to the lamp larger than the rated current in the first period and smaller than the rated current in the second period, and calculates the current over the first and second periods. Control the average below the rated current,
An endoscope system, wherein a video signal generated by imaging a subject in the first period is acquired as special light image data.   The endoscope system according to claim 1, wherein the special light image data is continuously output to an output device as an image obtained in the first and second periods.   3. The plurality of special light image data are acquired by repeating the first and second periods, and the plurality of special light image data are sequentially output to the output device and displayed as a moving image. The endoscope system described in 1.   In each of the first and second periods, the imaging device captures a subject and generates a video signal, and a rate at which the special light image data is output to the output device generates the video signal of the imaging device. The endoscope system according to claim 3, wherein the endoscope system is ½ or less of the rate.   The endoscope system according to claim 1, wherein a video signal generated by imaging a subject in the second period is not output to an output device.   The endoscope system according to claim 1, wherein the filter is movable so as to selectively irradiate the subject with the special light and the normal light.   The endoscope system according to claim 6, wherein a video signal generated by imaging the subject irradiated with the normal light is acquired as normal light image data.   The lamp control unit is configured to determine the amount of light emitted from the lamp when the subject is irradiated and acquire the special light image data in the first period, and the normal light image data when the subject is irradiated with the normal light. The endoscope system according to claim 7, wherein the endoscope system is larger than the amount of emitted light.   The endoscope system according to claim 6, wherein the lamp control unit controls the emitted light amount of the lamp to be constant when the subject is irradiated with the normal light.   The endoscope system according to claim 1, wherein the lamp is a xenon lamp. A lamp,
A filter that is arranged on the optical path of the lamp, transmits a part of the wavelength band of the normal light emitted from the lamp, generates special light, and irradiates the subject with the special light; and
When illuminating the subject with the special light, the lamp emits a relatively large amount of light in the first period, and relatively reduces the amount of emitted light in a second period that is continuous with the first period. A lamp control unit for controlling
The lamp control unit makes the current input to the lamp larger than the rated current in the first period and smaller than the rated current in the second period, and calculates the current over the first and second periods. Control the average below the rated current ,
An endoscope light source device, wherein a video signal generated by imaging a subject in the first period is acquired as special light image data .

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