JP2006034796A - Electronic endoscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display an image of a body to be observed by brightness suitable for an operation by a treatment tool in an electronic endoscope apparatus. <P>SOLUTION: One field of a body to be observed is divided into prescribed nine regions and an average luminance level for each region is calculated (step S100). The output of a detection element disposed at the insertion distal end of an electronic scope is checked whether or not the treatment tool such as forceps is used for the electronic scope. In the case that the treatment tool is not used, the normal weighting processing of a luminance value according to the area of each region is executed (S104). When the use of the treatment tool is confirmed, the special weighting processing of the luminance value for which the weighting of the center region of the image of the body to be observed is relatively increased is executed (S106). The weighted luminance value is compared with a reference value (S108), the opening degree of a diaphragm is adjusted, and the light quantity of illumination light is adjusted (S110). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to automatic light control that adjusts the brightness of an object image obtained from an electronic scope in an electronic endoscope apparatus.

  In the electronic endoscope apparatus, a light guide made of an optical fiber bundle is inserted into an electronic scope (electronic endoscope), and a treatment instrument insertion passage through which a treatment instrument such as forceps is inserted is provided. Further, a solid-state image sensor such as a CCD is provided at the distal end of the insertion portion of the electronic scope. A white light source such as a xenon lamp is provided in the image processor to which the electronic scope is connected. White light emitted from this white light source is guided to the tip of the insertion part of the electronic scope by the light guide, and irradiated forward as illumination light through a light distribution optical system disposed at the exit end of the light guide at the tip of the insertion part. Is done.

  When the illumination light is irradiated onto the object to be observed in this way, the reflected light is imaged on the light receiving surface of the solid-state imaging device by the objective optical system. The optical image of the object to be observed is photoelectrically converted in the solid-state image sensor, and an image signal is output from the solid-state image sensor. This image signal is subjected to predetermined image signal processing in an image processor, and is output to a TV monitor, and the object to be observed is displayed on the TV monitor. The practitioner operates the treatment tool protruding from the opening of the treatment tool insertion path at the distal end of the insertion portion of the electronic scope while visually recognizing the TV monitor, and performs treatment such as excision of the lesion site.

In such an electronic endoscope apparatus, automatic dimming, that is, control of the diaphragm provided on the optical path of the emitted light of the white light source is performed so that a good image is always obtained on the TV monitor. Specifically, in the image processor, the luminance level of one frame or one field of image data is calculated by average metering, peak metering, or the like based on the luminance component included in the image signal, and the luminance level is determined according to a predetermined reference. Compared with the value (reference value), the aperture of the throttle is controlled based on the comparison result. As a result, the amount of light emitted from the white light source is appropriately adjusted. Even when the same object is imaged, the luminance level varies depending on whether or not the treatment tool is used. Therefore, in automatic light control, a reference value to be compared is switched depending on the presence or absence of a treatment tool (for example, Patent Document 1).
JP-A-7-171098

  However, in the above-described automatic light control, the brightness value calculation is affected by the reflected light from the treatment instrument, and thus the brightness at the center of the object to be observed may not be appropriate brightness. On the other hand, in the treatment using the electronic endoscope, the distal end of the insertion portion is operated so that the site to be treated is projected at the center of the TV monitor. Therefore, in the above-described automatic light control, there is a case where the treatment target portion displayed in the center of the TV monitor does not have an appropriate light amount, and the treatment is difficult.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to always reproduce an object image to be observed with appropriate brightness in an electronic endoscope apparatus.

  An electronic endoscope apparatus according to the present invention includes an illumination light source for irradiating an observation object with illumination light, an electronic scope provided with a solid-state image sensor at the distal end of an insertion portion, and an object acquired by the solid-state image sensor. An area luminance value calculation unit that divides an observation body image into a plurality of areas and calculates an area luminance value for each area, a treatment instrument detection unit that detects use of a treatment instrument inserted into the electronic scope, and a plurality of Weighting each area brightness value of the area, and calculating the overall brightness value of the entire object image, and the amount of illumination light emitted from the illumination light source based on the overall brightness value And a light intensity adjusting means for adjusting the weight, and when the use of the treatment tool is detected by the treatment tool detection means, the overall luminance value calculation means is weighted so that the area where the treatment by the treatment tool is performed has a brightness suitable for observation. Adjusting The features. For example, the illumination light source may be provided at the distal end of the insertion portion of the electronic scope.

  The total luminance value calculating means may set the area luminance value weighting value of the area corresponding to the center of the observed object image to be relatively large when the treatment tool is used, and the center of the observed object image. The overall brightness value may be calculated based only on the area brightness value of the area corresponding to.

  As described above, according to the present invention, when the treatment tool is used, the amount of illumination light is adjusted so that the region where the treatment is performed has brightness suitable for observation. Therefore, it becomes easy for the user who is viewing the TV monitor to perform the treatment with the treatment tool.

  FIG. 1 is a block diagram of an electronic endoscope apparatus to which an embodiment according to the present invention is applied. A light guide 11 made of a large number of optical fibers is inserted into the electronic scope 10, and the light guide 11 extends to the distal end 12 </ b> A of the insertion portion 12 of the electronic scope 10. The light guide 11 has two exit ends at the distal end 12A of the insertion portion, and a pair of light distribution lenses 13A and 13B are arranged corresponding to each exit end, as will be described later. The electronic scope 10 is provided with a treatment instrument insertion passage 14 into which a treatment instrument such as forceps is inserted.

  The system controller 31 of the image processor 30 is, for example, a microprocessor that controls the entire electronic endoscope system, and includes a CPU 31A, a ROM 31B, and a RAM 31C. In the image processor 30, a lamp 32 that is a xenon lamp or the like that emits white light is provided. The lamp 32 is driven to light based on the output from the lamp drive circuit 33.

  When the electronic scope 10 is connected to the image processor 30, the light guide 11 is optically connected to the lamp 32. When the user performs a lamp lighting operation, a driving signal is output from the lamp driving circuit 33 to the lamp 32 based on a control signal from the CPU 31 </ b> A, and white light is emitted from the lamp 32. White light enters the incident end of the light guide 11 through the condenser lens 34 and the diaphragm 60. The incident white light is guided to the insertion portion distal end 12A by the light guide 11, and irradiated to the object to be observed as illumination light through the pair of light distribution lenses 13A and 13B.

  The reflected light from the object to be observed enters the CCD 16 through the objective lens 15 provided at the insertion portion distal end 12A of the electronic scope 10. Thereby, an optical image of the object to be observed is formed on the light receiving surface of the CCD 16. The scope CPU 17 in the electronic scope 10 transmits / receives control information and the like to / from the CPU 31A of the system controller 31 of the image processor 30 by SCI (Serial Communication Interface). Further, a CCD drive signal is output from the image processing IC 18 based on a control signal from the scope CPU 17. In the CCD 16, the optical image of the object to be observed is photoelectrically converted during the charge accumulation time. As a result, an analog image signal of the object to be observed is output from the CCD 16 for each field.

  An analog image signal for one field output from the CCD 16 is input to an image processing IC 18 via an AGC (Auto Gain Controller) 19. The image signal input to the image processing IC 18 is subjected to predetermined image signal processing and then transmitted to the processor signal processing circuit 35 of the image processing processor 30.

  The processor signal processing circuit 35 subjects the input image signal to predetermined image signal processing such as amplification processing, gamma correction, and contour enhancement, and stores image data in an image memory (not shown) provided in the processor signal processing circuit 35. Stored as The image data in the image memory is read out in a timely manner, subjected to video signal conversion processing conforming to a predetermined video signal specification, and output to the TV monitor 50. As a result, the observed object image is displayed on the TV monitor 50.

  Further, as shown in FIG. 2, the image processing IC 18 divides image data for one field into nine regions, extracts luminance signals from image signals of pixels constituting each region, and obtains a luminance value for each region. Is calculated. The calculated luminance value is output to the dimming circuit 61 of the image processor 30. The dimming circuit 61 calculates the opening degree of the diaphragm 60 based on the input luminance value and outputs it to the motor driver 62. The motor driver 62 calculates the driving amount of the motor 63 for driving the diaphragm 60 based on the opening degree of the diaphragm 60 and drives the motor 63. As a result, the amount of white light incident on the incident end of the light guide 11 is adjusted.

  The front panel 36 of the image processor 30 is provided with an adjustment switch 36 </ b> A that adjusts the brightness level of the video displayed on the TV monitor 50. The brightness level is 8-bit data and ranges from 0 level to 255 level. The ROM 31B of the system controller 31 stores a luminance table indicating the correspondence between the brightness level and the actual luminance value. When the user operates the adjustment switch 36A to set the brightness level, the brightness value corresponding to the set brightness level is retrieved from the brightness table and set as a reference value. This reference value is used in the automatic light control processing described later. In the present embodiment, the range of the brightness level that can be adjusted by the user is a range of 70 to 170 levels.

  A keyboard 37 is connected to the image processor 30 and various control signals can be input.

  FIG. 3 is an enlarged view showing a portion where the treatment instrument insertion passage 14 is formed in the insertion portion distal end 12A. The treatment instrument insertion path 14 is provided with a photo interrupter 41 for detecting a treatment instrument 40 such as forceps. The photo interrupter 41 has a light emitting part 41A made of a light emitting diode or the like and a light receiving part 41B made of a phototransistor or the like. A predetermined voltage is applied to the light emitting unit 41A via the resistor R1, and thereby, detection light is emitted from the light emitting unit 41A toward the light receiving unit 41B. On the other hand, a predetermined voltage is also applied to the light receiving unit 41B via the resistor R2, and the detection terminal 42 extending from the wiring between the resistor R2 and the light receiving unit 41B is connected to the scope CPU 17.

  While the light receiving unit 41B receives the detection light from the light emitting unit 41A, the light receiving unit 41B is in an energized state, and the potential of the detection terminal 42 at this time is at a low level. On the other hand, when the treatment tool 40 such as forceps is interposed between the light emitting part 41A and the light receiving part 41B, the light receiving part 41B is blocked from receiving the detection light. Is at a high level. Therefore, by detecting the potential level of the detection terminal 42, it can be determined whether or not the treatment tool 40 such as forceps is used and is taken by the CCD 16.

  In the present embodiment, the use of the treatment instrument 40 is determined by the photo interrupter 41, but the present invention is not limited to this. For example, instead of the photo interrupter 41, a micro switch may be provided so as to be able to contact the treatment instrument 40 interposed in the treatment instrument insertion path 14. Moreover, it is good also as a structure which mounts the software which discriminate | determines the presence or absence of use of the treatment tool 40 instead of providing detection devices, such as a photo interrupter and a micro switch. That is, in the image obtained by the electronic scope 10, the presence or absence of the use of the treatment instrument 40 may be determined by comparing the luminance value of the region where the treatment instrument 40 is reflected with a predetermined threshold value.

  FIG. 4 is a flowchart showing the processing procedure of the automatic light control routine. This automatic dimming routine is an interrupt process executed by the microcomputer in the dimming circuit 61 once per field in the dimming circuit 61. In step S100, one field is divided into nine areas shown in FIG. 2, and the average luminance level calculated for each area is input from the image processing IC 18. Next, the process proceeds to step S102, where the potential of the detection terminal 42 is checked to check whether or not the treatment instrument 40 is being used. In step S102, if it is confirmed that the treatment instrument 40 is not being used, the process proceeds to step S104, and normal weighting processing of luminance values (hereinafter, normal processing) is performed. In step S102, if it is confirmed that the treatment instrument 40 is being used, the process proceeds to step S106, and a special weighting process for luminance values (hereinafter, special process) is performed.

  Here, the luminance value weighting process will be described with reference to Table 1. The luminance value weighting process is performed by multiplying the luminance value of each area acquired in step S100 by a predetermined weighting value. Table 1 is stored in the ROM 31B of the system controller 31. Table 1 shows the weight values for each area used in the normal process and the special process. In Table 1, the last line indicates the total weight value in each process.

  In the normal process executed in step S104, the weight values shown in the “normal process” column of Table 1 are assigned to the areas 1 to 9 on the screen. In the normal process, the weight value is determined according to the size of the area of the region. For example, when comparing the region 1 in the upper left corner with the region 2 adjacent to the right, the area of the region 2 is approximately twice as large as the area of the region 1. In the normal process, the weighting value of the area 2 is “2”, and the weighting value of the area 1 is “1”. The area of the region 5 at the center of the screen is approximately twice as large as the region 2 and approximately four times as large as the region 1. The weighting value of the area 5 is “4”. That is, in the normal process, a substantially uniform weight value is used.

  The luminance value of the entire image is calculated based on Expression (1).

  In the present embodiment, in the special process executed in step S106, the weight values shown in the “case 1” column of Table 1 are assigned to the areas 1 to 9 on the screen, respectively. Comparing the weighting of case 1 with the normal processing, the weighting value of region 5 in the normal processing is “4”, whereas the weighting value of region 5 in case 1 is “10”. The weight values of the areas other than the area 5 are the same in both the normal process and the case 1. As described above, in case 1, the luminance value of the entire screen is calculated by relatively increasing the weighting value of the area in the center of the object to be observed, that is, the area displayed in the center of the TV monitor. Even in the special processing, the luminance value of the entire screen is calculated based on the above formula (1).

  When the luminance value of the entire screen is calculated in step S104 or S106, the process proceeds to step S108. In step S108, the brightness value of the entire screen is compared with the reference value obtained by searching the brightness table described above. Next, the process proceeds to step S110.

  In step S110, light amount adjustment calculation processing is executed based on the result of the comparison processing in step S108. When the calculated brightness value of the entire screen is larger than the reference value, a control signal for controlling the diaphragm 60 is supplied to the motor driver 62 so that the amount of white light output from the lamp 32 and incident on the incident end of the light guide 11 is reduced. Is output. When the calculated luminance value of the entire screen is smaller than the reference value, a control signal for controlling the diaphragm 60 is output to the motor driver 62 so that the amount of white light is increased. When a drive signal is output from the motor driver 62 to the motor 63 in accordance with the control signal from the light control circuit 61, the diaphragm 60 is driven by the motor 63, the opening degree thereof is adjusted, and the light amount is increased or decreased.

  As described above, in the present embodiment, in the calculation of the luminance value that determines the opening of the diaphragm 60, when the treatment tool 40 is used, the observation object image is compared with when the treatment tool 40 is not used. The weight of the central area is made heavier. Usually, when using the treatment tool, the insertion portion distal end 12A of the electronic scope 10 is operated so that the center of the treatment is projected on the center of the TV monitor 50. Therefore, according to the present embodiment, it is possible to always maintain a good illuminance at the center of the observed object image to be treated by the treatment tool 40 without imposing a burden on the user.

  In the present embodiment, in the special process executed in step S106, the weight values shown in the column “Case 1” in Table 1 are assigned to each area of the screen, and the central area of the object image to be observed is compared with the normal process. The weight of is increased. However, the mode of weighting in the special processing is not limited to this. The weight shown in the column of “Case 2” in Table 1 may be used. The weight value of the area 5 is “1”, and the weight values of the other areas are all “0”. That is, in the special process of case 2, only the luminance value of the region 5 is adopted as the luminance value of the entire screen, and the opening degree of the diaphragm 60 is adjusted.

  Further, instead of providing the lamp 32 in the image processor 30, a lamp such as an LED may be provided at the distal end 12A of the insertion portion of the electronic scope 10, and light control may be performed by controlling the driving current of the LED.

1 is a block diagram of an electronic endoscope apparatus to which an embodiment according to the present invention is applied. It is a figure which shows the aspect of the area division | segmentation in luminance value calculation. It is a figure which expands and shows the insertion part front-end | tip of an electronic scope centering on a treatment tool insertion path. It is a flowchart which shows the process sequence of an automatic light control routine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic scope 13A, 13B Light distribution lens 14 Treatment tool insertion path 15 Objective lens 16 CCD
17 Scope CPU
18 Image processing IC
20 EEPROM
50 TV monitor 60 Aperture 61 Dimming circuit 62 Motor driver 63 Motor

Claims (4)

An illumination light source for irradiating the observation object with illumination light;
An electronic scope provided with a solid-state image sensor at the distal end of the insertion section;
An area luminance value calculating means for dividing an object image acquired by the solid-state imaging device into a plurality of areas and calculating an area luminance value for each area;
A treatment instrument detection means for detecting the use of a treatment instrument inserted into the electronic scope;
An overall brightness value calculating means for weighting each area brightness value of each of the plurality of areas and calculating an overall brightness value of the entire object image;
A light amount adjusting means for adjusting the amount of illumination light emitted from the illumination light source based on the overall luminance value,
When the use of the treatment tool is detected by the treatment tool detection means, the overall luminance value calculation means adjusts the weighting so that a region where the treatment by the treatment tool is performed has brightness suitable for observation. An electronic endoscope apparatus that is characterized.   The overall brightness value calculating means sets a relatively large weighting value of the area brightness value of the area corresponding to the center of the observed object image when the treatment tool is used. The electronic endoscope apparatus according to 1.   The overall brightness value calculating means calculates the overall brightness value based only on the area brightness value of the area corresponding to the center of the observed object image when the treatment tool is used. The electronic endoscope apparatus according to 1. The electronic endoscope apparatus according to claim 1, wherein the illumination light source is provided at a distal end of an insertion portion of the electronic scope.

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