JP2016129618A - Capsule type endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capsule type endoscope capable of accurately determining the shape of a subject.SOLUTION: A capsule type endoscope includes: an image pick-up device for subjecting light to photoelectric conversion to generate an imaging signal; an illumination part for emitting illumination light; a light distribution information storage part for storing light distribution information based on reception light luminance distribution of the image pick-up device according to the shape of a subject; a calculation part for calculating a difference between a representative light measurement value at a plurality of light measurement points set in a plurality of light measurement areas into which a picked-up image based on the imaging signal is divided concentrically, and a target light measurement value set for each of the plurality of light measurement areas; a determination part for generating a determination result for determining the shape of the subject by comparing the difference value with a reference difference value set for each of the plurality of light measurement areas, counting the difference values exceeding the reference difference value, and comparing the counted number with a shape determination value for determining the shape of the subject; and a setting part for determining the shape of the subject based on the result of determination by the determination part, and executing light control setting according to the determined shape of the subject.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a capsule endoscope that is introduced into a subject, moves inside the subject, and acquires information in the subject.

  2. Description of the Related Art Conventionally, in the field of endoscopes, capsule endoscopes that incorporate an imaging function, a wireless communication function, and the like in a capsule-shaped housing that is sized to be introduced into the digestive tract of a subject such as a patient are known. It has been. The capsule endoscope is swallowed from the subject's mouth and then sequentially moves inside the subject such as in the digestive tract by peristaltic movement to generate an imaging signal. Signals are transmitted wirelessly sequentially. The capsule endoscope includes a battery for driving the capsule endoscope, an imaging board on which an image sensor and a light emitting element are mounted, a signal processing board for performing signal processing of the captured imaging signal, and wirelessly transmitting the imaging signal Includes a wireless antenna for transmission.

  As such a capsule endoscope, a technique for adjusting the amount of illumination light according to the shape of a subject is disclosed (see Patent Document 1). According to the capsule endoscope disclosed in Patent Document 1, the average luminance value of a plurality of small regions set in the image region is calculated, and the subject of each of the lumen and the wall surface is calculated with respect to the calculated average luminance value. Multiply the coefficient set for each small area according to the shape of each area to obtain the multiplication value of each small area, and use the ratio between the maximum value and the minimum value of the multiplication value as the discrimination value. The size of the subject is determined by comparing the magnitude relationship, and the amount of illumination light is adjusted according to the determined shape of the subject.

JP 2010-17231 A

  However, in the determination of the shape of the subject disclosed in Patent Document 1, a discrimination value is obtained using the maximum value and the minimum value of the obtained multiplication values. When halation or blackout occurs, the halation or blackness is determined. The maximum value and the minimum value fluctuate due to crushing, and the shape of the subject cannot be accurately determined, and there is a possibility that optimal illumination of the subject cannot be performed.

  The present invention has been made in view of the above, and an object of the present invention is to provide a capsule endoscope that can perform optimal illumination corresponding to the shape of a subject.

  In order to solve the above-described problems and achieve the object, a capsule endoscope according to the present invention includes an imaging device that photoelectrically converts received light and generates the converted electrical signal as an imaging signal, and a subject. An illumination unit that emits illumination light to illuminate, a light distribution information storage unit that stores light distribution information based on a light-receiving luminance distribution of the imaging element according to the shape of the subject, and a captured image based on the imaging signal is concentric The difference between the representative metering value at the plurality of metering points set in the plurality of metering areas divided into the target metering value stored in the light distribution information storage unit and set for each of the plurality of metering areas is calculated. The calculation unit, the difference value, and the reference difference value stored in the light distribution information storage unit and set for each of the plurality of photometry areas are compared, and the difference value exceeding the reference difference value is counted. The cow And a determination unit that generates a determination result for determining the shape of the subject by comparing the number determined by the light distribution information storage unit and the shape determination value for determining the shape of the subject. , Determining the shape of the subject based on the determination result of the determination unit, performing dimming setting according to the determined shape of the subject, and outputting a control signal related to the dimming setting to the illumination unit And a setting unit.

  In the capsule endoscope according to the present invention as set forth in the invention described above, the determination unit determines whether the imaging element is close to the wall surface of the subject after determining the shape of the subject, and sets the setting. The unit is configured to set either a simple dimming setting that is not close to the wall surface or a wall surface proximity dimming setting that is close to the wall surface based on a determination result of the determination unit.

  In the capsule endoscope according to the present invention, in the above invention, the representative photometric value and the target photometric value are standardized values having the same maximum value and minimum value, respectively. Features.

  The capsule endoscope according to the present invention is characterized in that, in the above invention, the shape of the subject is planar, spherical, and cylindrical.

  According to the present invention, it is possible to perform optimal illumination corresponding to the shape of the subject.

FIG. 1 is a schematic diagram showing a schematic configuration of a capsule endoscope system according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a configuration of the capsule endoscope according to the first embodiment of the present invention. FIG. 3 is a plan view showing a configuration of a main part of the capsule endoscope according to the first embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing a cross section taken along line AA shown in FIG. FIG. 5 is a diagram for explaining the photometry area setting in the light control processing performed by the capsule endoscope according to the first embodiment of the present invention. FIG. 6 is a diagram for explaining the received light luminance distribution obtained when images of subjects having different shapes are imaged. FIG. 7 is a flowchart showing the light control processing performed by the capsule endoscope according to the first embodiment of the present invention. FIG. 8 is a block diagram showing a configuration of a capsule endoscope according to the second embodiment of the present invention. FIG. 9 is a diagram for explaining a received light luminance distribution obtained when images of subjects having different shapes are picked up. FIG. 10 is a flowchart showing the light control processing performed by the capsule endoscope according to the second embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment. The drawings referred to in the following description only schematically show the shape, size, and positional relationship so that the contents of the present invention can be understood. That is, the present invention is not limited only to the shape, size, and positional relationship illustrated in each drawing. In the following description, a capsule type including a processing device that receives a radio signal from a capsule endoscope that is introduced into the body of the subject and captures an in-vivo image of the subject and displays the in-vivo image of the subject. Although an endoscope system is illustrated, this invention is not limited by this embodiment. Further, the same components are described with the same reference numerals.

(Embodiment 1)
First, FIG. 1 is a schematic diagram illustrating a schematic configuration of a capsule endoscope system according to the first embodiment. As shown in FIG. 1, this capsule endoscope system transmits from a capsule endoscope 2 that captures an in-vivo image of a subject 1 and a capsule endoscope 2 that is introduced into the subject 1. Receiving device 3 that receives the in-vivo image of subject 1 that has been received, image display device 4 that displays the in-vivo image of subject 1 received by receiving device 3, and data between receiving device 3 and image display device 4 And a portable recording medium 5 for delivering the data.

  After being swallowed from the mouth of the subject 1, the capsule endoscope 2 sequentially captures in-vivo images of the subject 1 while moving inside the organ of the subject 1 by peristaltic movement of the organ. The capsule endoscope 2 sequentially wirelessly transmits imaging information including the captured in-vivo image to the external receiving device 3 every time an in-vivo image of the subject 1 is captured. In this case, the capsule endoscope 2 sequentially wirelessly transmits each in-vivo image of the subject 1 at a time interval corresponding to its own unique function.

  The receiving device 3 receives the in-vivo image group of the subject 1 captured by the capsule endoscope 2 and accumulates the received in-vivo image group. Specifically, the receiving device 3 has a plurality of receiving antennas 3a to 3h, and is attached (carried) to the subject 1 into which the capsule endoscope 2 is introduced into the organ. The receiving device 3 sequentially receives imaging information wirelessly transmitted by the capsule endoscope 2 inside the subject 1 via the plurality of receiving antennas 3a to 3h, and acquires an in-vivo image group of the subject 1. The receiving device 3 has a portable recording medium 5 that is detachably inserted, and records the in-vivo image group of the subject 1 acquired from the capsule endoscope 2 on the portable recording medium 5.

  The receiving antennas 3a to 3h are distributed and arranged on the body surface of the subject 1 along the movement path of the capsule endoscope 2 introduced into the organ of the subject 1 (that is, the digestive tract of the subject 1), for example. , Connected to the receiving device 3 described above. The receiving antennas 3 a to 3 h capture imaging information sequentially wirelessly transmitted by the capsule endoscope 2 inside the subject 1, and sequentially transmit the captured imaging information to the receiving device 3. The receiving antennas 3a to 3h may be distributed on a jacket or the like worn by the subject 1. In addition, one or more receiving antennas that capture imaging information may be arranged with respect to the subject 1, and the number of arrangement is not particularly limited to eight.

  Here, the receiving device 3 demodulates the RF signals received by the plurality of receiving antennas 3 a to 3 h, generates image information and the like based on the demodulated signals, and stores them in the portable recording medium 5. The receiving device 3 selects the receiving antennas 3a to 3h having the highest received electric field strength based on the received electric field strength of the received RF signal, and stores the image information acquired through the selected receiving antenna in a portable recording format. Recorded on the medium 5. The receiving device 3 may include, for example, a touch panel as means for inputting or outputting various instruction information.

  The image display device 4 has a configuration such as a workstation that acquires various data such as an in-vivo image group of the subject 1 through the portable recording medium 5 and displays the acquired various data on a display. . Specifically, the image display device 4 removably inserts a portable recording medium 5 on which an in-vivo image group or the like of the subject 1 is recorded, and the subject 1 is attached from the inserted portable recording medium 5. Capture in-vivo images. In this case, the image display device 4 acquires the in-vivo image group in a state identified by the function unique to the capsule endoscope 2 by the receiving device 3 described above. The image display apparatus 4 holds and manages the acquired in-vivo image group for each function unique to the capsule endoscope 2 and displays each in-vivo image in a manner distinguished according to the function unique to the capsule endoscope 2. As described above, the image display device 4 distinguishes and displays each in-vivo image of the subject 1, so that a user such as a doctor or a nurse can observe (inspect) each in-vivo image of the subject 1 easily and efficiently. . The user diagnoses the subject 1 by observing each in-vivo image of the subject 1 displayed by the image display device 4.

  The portable recording medium 5 is a portable recording medium for transferring data between the receiving device 3 and the image display device 4 described above. Specifically, the portable recording medium 5 is detachable with respect to the receiving device 3 and the image display device 4, and has a structure capable of outputting and recording data when being inserted into both. When such a portable recording medium 5 is inserted into the receiving device 3, the in-vivo image group of the subject 1 received by the receiving device 3 from the capsule endoscope 2 is recorded on the image display device 4. When inserted, the recording data such as the in-vivo image group of the subject 1 is sent to the image display device 4.

  The various data recorded by the portable recording medium 5 includes, for example, the in-vivo image group of the subject 1, time information (imaging time, reception time, etc.) of each in-vivo image in the in-vivo image group, the patient of the subject 1 Information, examination information of the subject 1, imaging information, and the like. Here, the patient information of the subject 1 is specific information for identifying the subject 1, and is, for example, the patient name, patient ID, date of birth, sex, age, and the like of the subject 1. Further, the examination information of the subject 1 specifies the capsule endoscope examination performed on the subject 1 (the examination for introducing the capsule endoscope 2 inside the organ to observe the inside of the organ). Specific information, for example, inspection ID, inspection date, and the like. In addition, the imaging information refers to an imaging target such as whether an imaging target to be described later is captured with illumination light with plane dimming setting or captured with illumination light with cylindrical dimming setting. This is information indicating the dimming setting.

  FIG. 2 is a block diagram showing a configuration of the capsule endoscope according to the first embodiment. The capsule endoscope 2 is covered with a casing. The case is a capsule-type case formed in a size that can be easily introduced into the subject 1, and is formed by a cylindrical case body 10a and an optical dome 10b (see FIG. 4). The case body 10a is a case member having a cylindrical structure with one end opened and the other end closed in a dome shape. The optical dome 10b is a transparent optical member formed in a dome shape, and is attached to the case main body 10a so as to close an opening end which is one end of the case main body 10a. The casing formed by the case main body 10a and the optical dome 10b accommodates each component of the capsule endoscope 2 in a liquid-tight manner.

  The capsule endoscope 2 includes an imaging element 20, an image signal processing circuit 21, a transmission unit 22, a transmission antenna 23, an imaging element driving unit 24, a light emitting element 25, a light emitting element driving unit 26, a dimming control unit 27, and a power supply circuit. 28, a battery 29, a control unit 30, and a storage unit 31. The illumination unit according to the present invention includes a light emitting element 25 and a light emitting element driving unit 26.

  The image sensor 20 is realized using a solid-state image sensor such as a CMOS image sensor or a CCD. The imaging element 20 receives reflected light from the imaging field through the imaging surface, performs photoelectric conversion processing on the received light, and captures a subject image in the imaging field, that is, an in-vivo image of the subject 1. A lens 20a is provided on the light receiving surface side of the image sensor 20 (see FIGS. 3 and 4).

  The image signal processing circuit 21 has a signal processing function for generating an image signal. The image signal processing circuit 21 acquires in-vivo image data from the image sensor 20 and performs predetermined signal processing on the in-vivo image data each time to generate an image signal including the in-vivo image data.

  The transmission unit 22 performs a modulation process or the like on the imaging information including the image signal output from the image signal processing circuit 21, generates a radio signal obtained by modulating the image signal, and transmits the radio signal via the transmission antenna 23. The generated radio signal is output to the outside.

  The image sensor driving unit 24 controls the driving of the image sensor 20 based on the drive signal from the control unit 30. The image sensor 20, the image signal processing circuit 21, and the image sensor drive unit 24 function as an image capturing unit.

  Here, detailed configurations of the illumination unit and the imaging unit will be described. FIG. 3 is a plan view showing a configuration of a main part of the capsule endoscope according to the first embodiment, and is a view of the arrangement state of the light emitting elements 25 in the capsule endoscope as seen from the optical dome side. is there. FIG. 4 is a partial cross-sectional view showing a cross section taken along the line AA shown in FIG. As shown in FIG. 3, in the light emitting element 25, a plurality of light emitting elements are arranged at equal intervals around the imaging element 20 and the lens 20a. The light emitting element 25 includes four light emitting elements including a first light emitting element LA1, a second light emitting element LA2, a third light emitting element LA3, and a fourth light emitting element LA4, and is disposed on the light source substrate 25a. Here, the first light emitting element LA1 is opposed to the third light emitting element LA3 via the lens 20a, and the second light emitting element LA2 is opposed to the fourth light emitting element LA4 via the lens 20a.

  The first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 are white light sources that emit white illumination light. The peak wavelength may be different for each light emitting element, or the wavelength band of the emitted illumination light may be different.

  The orientation of the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 is adjusted so that the center of the imaging field of the imaging element 20 is brightest. For this reason, when a planar subject is imaged by the image sensor 20, the photometric value (luminance value) obtained is the largest at the center of the image.

  The lens 20 a is disposed in the lens barrel 20 b and above the image sensor 20. The lens 20 a collects the light emitted from the light emitting element 25 and reflected from the subject, and forms an image on the imaging element 20. The lens barrel 20b and the imaging device 20 are arranged and fixed on the imaging substrate 20c.

  The light emitting element driving unit 26 drives the light emitting element 25 based on a control signal from the dimming control unit 27. Specifically, the light emitting element driving unit 26 controls the power supplied to the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 based on the control signal, The amount of light emitted from the light emitting element, the light emission time, and the like are controlled.

  Based on the calculation result of the in-vivo image data obtained by the imaging element 20, the dimming control unit 27 determines whether the captured image is an image of a plane subject such as a stomach wall or a lumen (for example, a small intestine). It is determined whether the subject is an image of a cylindrical subject, and a dimming mode of illumination light is set according to the determined shape of the subject, and a control signal including the dimming mode is sent to the light emitting element driving unit 26. Output.

  The dimming control unit 27 includes a calculation unit 27a, a determination unit 27b, and a setting unit 27c. The calculation unit 27a calculates normalized photometric values obtained by standardizing photometric values (luminance values) of a plurality of photometric points in a plurality of photometric areas set in the image display area of the in-vivo image data, and a plurality of standardized photometric values. Is calculated to calculate a representative standardized photometric value of the photometric area.

  FIG. 5 is a diagram for explaining photometry area setting in the light control processing performed by the capsule endoscope according to the first embodiment. In the present embodiment, circumferential areas Ec1 to Ec4 that are concentric photometric areas are set for the image display area 100 shown in FIG. 5, and a plurality of photometric points are equally spaced in each circumferential area. Is set to Specifically, photometry points Ep11 to Ep18 are set in the circumferential area Ec1. In the circumferential area Ec2, photometric points Ep21 to Ep28 are set. In the circumferential area Ec3, photometric points Ep31 to Ep38 are set. In the circumferential area Ec4, photometric points Ep41 to Ep48 are set.

  Based on the obtained in-vivo image data, the calculation unit 27a normalizes the photometric value of each photometric point and calculates it as a standardized photometric value, and calculates an average of a plurality of standardized photometric values for each circumferential area Ec1 to Ec4. A value is obtained and the average value is output as a representative standardized photometric value. Thereafter, the calculation unit 27a calculates a difference value between the plane dimming target value for each of the circumferential areas Ec1 to Ec4 stored in the storage unit 31 and the representative normalized photometric value. The standardized photometric value is a standardized value in which the maximum value and the minimum value of each photometric point are the same.

  The determination unit 27b is based on values based on the photometric values of the photometric points Ep11 to Ep48 in the circumferential areas Ec1 to Ec4 and the threshold values stored in the first threshold value storage unit 32a and the second threshold value storage unit 32b. Then, it is determined whether to perform planar dimming or cylindrical dimming on the imaged subject. In addition, the determination unit 27b determines whether to perform simple dimming where the wall surfaces are not close or wall surface proximity dimming where the wall surfaces are close in each setting of planar light control and cylindrical light control.

  The setting unit 27c sets a dimming mode based on the determination result of the determination unit 27b, generates a control signal for driving the light emitting element 25 in the dimming mode, and outputs the control signal to the light emitting element driving unit 26.

  The battery 29 is realized by a battery or the like. The power supply circuit 28 supplies power to each component using the battery 29.

  The control unit 30 controls each operation of the components of the capsule endoscope 2 and controls input / output of signals between the components. Specifically, the control unit 30 performs control for causing the image sensor 20 to capture an image of the subject. The control unit 30 also controls the transmission unit 22 to sequentially wirelessly transmit imaging information including the image signal output from the image signal processing circuit 21 to the outside along a time series.

  The storage unit 31 is realized by a semiconductor memory such as a flash memory. The storage unit 31 stores various types of information instructed to be stored by the control unit 30, and sends the information instructed to be read out by the control unit 30 from the stored various types of information to the control unit 30. Note that as various information stored in the storage unit 31, for example, a program for operating the capsule endoscope 2, an imaging condition (for example, a frame rate) by the capsule endoscope 2, and a dimming mode of illumination light Information related to.

  The storage unit 31 includes a light distribution information storage unit 32 that stores light distribution information. The light distribution information includes a photometric value obtained by imaging a plane subject corresponding to the stomach wall in advance and a photometric value obtained by imaging a cylindrical subject corresponding to a lumen (for example, the small intestine) in advance. Including a chart (light-receiving luminance distribution), a plane dimming target value for which plane dimming target values are set for each circumferential area Ec1 to Ec4, and a cylindrical dimming target value for each circumferential area Ec1 to Ec4 Includes cylindrical dimming target value. For example, the plane dimming target value is a value that is a value that corresponds to the brightness of each of the circumferential areas Ec1 to Ec4 when a plane subject is imaged, and is a standardized value. The dimming target value may be obtained using an actual measurement value, or may be obtained using a design value.

  The light distribution information storage unit 32 includes a first threshold storage unit 32a and a second threshold storage unit 32b that store thresholds set based on the charts described above. The first threshold value storage unit 32a stores various threshold values set based on a chart obtained by imaging a plane subject. Further, the second threshold storage unit 32b stores a threshold set based on a chart obtained by imaging a cylindrical subject.

  FIG. 6 is a diagram for explaining the received light luminance distribution obtained when images of subjects having different shapes are imaged. The graph shown in FIG. 6 shows the relationship between the position on the straight line passing through the imaging center and the normalized luminance obtained by standardizing the luminance curve so that the maximum luminance values obtained by imaging different subjects are equal. . In FIG. 6, a curve Lp indicates a luminance curve obtained with a planar object, and a curve Lr indicates a luminance curve obtained with a cylindrical object.

  As shown in FIG. 6, the luminance value of each luminance curve obtained by the planar and cylindrical subjects decreases as the distance from the peak position (imaging center position) increases. Here, the light reception luminance distribution by the planar subject has a larger difference between the luminance at the imaging center position and the luminance at the position away from the imaging center position than the light reception luminance distribution by the cylindrical subject. As shown in FIG. 6, in each of the circumferential areas Ec1 to Ec4, a circumferential area (for example, the circumferential area Ec4) that is farther from the imaging center than a circumferential area (for example, the circumferential area Ec1) that is closer to the imaging center position. ) Has a larger difference between the planar luminance and the cylindrical luminance.

  The first threshold value storage unit 32a determines a reference value for a difference between a photometric value obtained by imaging a plane subject and a plane dimming target value for each of the circumferential areas Ec1 to Ec4, and each normalized circumferential area A reference difference value of Ec1 to Ec4 and a threshold value that defines the number of measurement points at which the difference value exceeds the reference difference value, and a plane determination value that is a threshold value for determining whether or not the subject is a plane. In the planar light control, a first wall surface proximity determination value for determining whether or not the wall surfaces are close to each other is stored. The first wall surface proximity determination value is a value that defines the number of measurement points that exceed the reference difference value among the four measurement points adjacent to the measurement point whose difference value exceeds the reference difference value. Each determination value is set to a majority of all measurement points, for example.

  The second threshold value storage unit 32b is a value that defines the number of measurement points that exceed the reference difference value among the four measurement points adjacent to the measurement point whose difference value exceeds the reference difference value. In light, the second wall surface proximity determination value for determining whether or not the wall surface is close is stored.

  FIG. 7 is a flowchart showing the light control processing performed by the light control unit 27 of the capsule endoscope according to the embodiment of the present invention. First, the light control unit 27 acquires light distribution information (step S101). Specifically, the dimming control unit 27 refers to the light distribution information storage unit 32 and acquires light distribution information such as the above-described plane dimming target value.

  Subsequently, the dimming control unit 27 acquires representative normalized photometric values of the photometric points Ep11 to Ep48 based on the imaging signal generated by the imaging device 20 (step S102). Specifically, the computing unit 27a normalizes the pixel values (photometric values) of the pixels included in each of the photometric points Ep11 to Ep48, and obtains an average value as a representative normalized photometric value. The computing unit 27a, for example, normalizes pixel values (photometric values) of a plurality of pixels included in the photometric point Ep11, calculates an average value of a plurality of standardized photometric values, and calculates the calculated average The value is set as a representative normalized photometric value of the photometric point Ep11. Similarly, representative normalized photometric values are obtained for the photometric points Ep12 to Ep48.

  The calculating unit 27a calculates a difference (difference value) between the representative normalized photometric value calculated for each of the photometric points Ep11 to Ep48 and the planar light control target value (step S103). Specifically, the calculation unit 27a performs the representative standardized photometric values of the photometric points Ep11 to Ep48 in any one of the circumferential areas Ec1 to Ec4 and the plane tone set for each of the circumferential areas Ec1 to Ec4. The difference value with the light target value is calculated. For example, the difference between the photometric point Ep11 in the circumferential area Ec1 and the plane dimming target value in the circumferential area Ec1 is calculated, and the calculated difference value is output. Similarly, a difference value is calculated for each of the photometric points Ep12 to Ep48.

  When the light control point 27 outputs each difference value of the photometric points Ep11 to Ep48 from the calculation unit 27a, the light control unit 27 compares the difference value with a threshold value (reference difference value), and the number of difference values exceeding the threshold value ( The number of metering points is counted (step S104). Specifically, the determination unit 27b compares each difference value with the reference difference value, and determines whether or not the difference value exceeds the reference difference value. The determination unit 27b extracts a photometric point having a difference value that exceeds the reference differential value, and counts the extracted photometric points.

  Thereafter, the determination unit 27b determines whether or not the count number is equal to or less than the plane determination value (step S105). Here, when the determination unit 27b determines that the count number is equal to or less than the plane determination value (step S105: Yes), the dimming control unit 27 proceeds to step S106 and determines adjacent photometry points in the plane dimming setting. Process.

  When the dimming control unit 27 proceeds to step S106, the dimming control unit 27 determines whether or not the adjacent photometry point exceeds the reference difference value for the photometry point extracted in step S104. Specifically, the determination unit 27b determines, for each extracted photometry point, whether an adjacent photometry point (hereinafter also referred to as an adjacent photometry point) exceeds a reference difference value. For example, when the photometric point Ep23 is extracted, the determination unit 27b determines whether each of the four adjacent photometric points Ep13, Ep22, Ep24, and Ep33 exceeds the reference difference value.

  The determination unit 27b determines whether or not the number of adjacent metering points that exceed the reference difference value among the adjacent metering points adjacent to the extracted metering point is equal to or less than the first wall surface proximity determination value (step S107). ). Here, the first wall surface proximity determination value is a value that defines the number of adjacent photometric points for determining whether or not a planar object is close to the wall surface.

  When the determination unit 27b determines that the number of adjacent photometry points is equal to or less than the first wall surface proximity determination value (step S107: Yes), the setting unit 27c sets the plane (simple plane) dimming and sets the set dimming An optical mode control signal is generated and output to the light emitting element driving unit 26 (step S108). In the simple plane dimming setting, the amount of light emitted from the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 is constant, and uniform illumination light is irradiated to the subject.

  On the other hand, when the determination unit 27b determines that the number of adjacent photometry points exceeds the first wall surface proximity determination value (step S107: No), the setting unit 27c sets the plane (wall surface proximity) dimming. Then, the control signal of the set dimming mode is generated and output to the light emitting element driving unit 26 (step S109). In the wall surface proximity dimming setting, the first wall surface proximity determination among the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 with respect to the above-described simple plane dimming setting. By reducing the light emission amount of the light emitting element close to the photometry point determined to exceed the value, the amount of illumination light irradiated on the wall surface close to the capsule endoscope 2 is reduced. In addition, the wall surface may exist not only in a certain direction but also in a plurality of directions (for example, the right direction and the upward direction of the capsule endoscope 2).

  On the other hand, when it is determined by the determination unit 27b that the count number exceeds the plane determination value (step S105: No), the dimming control unit 27 proceeds to step S110 and is adjacent metering point in the cylindrical dimming setting. Judgment processing is performed.

  In step S110, the computing unit 27a calculates the difference (difference value) between the representative standardized photometric value calculated for each photometric point Ep11 to Ep48 and the cylindrical dimming target value, as in steps S102 to S104 described above. The determination unit 27b calculates the difference value and the threshold value (reference difference value), and extracts the difference value (photometric point) exceeding the threshold value.

  The determination unit 27b determines whether or not the number of adjacent metering points that exceed the reference difference value among the adjacent metering points adjacent to the extracted metering point is equal to or less than the second wall surface proximity determination value (step S111). . Here, the second wall surface proximity determination value is a value that defines the number of adjacent photometric points for determining whether or not a cylindrical subject is close to the wall surface.

  When the determination unit 27b determines that the number of adjacent metering points is equal to or less than the second wall surface proximity determination value (step S111: Yes), the setting unit 27c sets the cylindrical (simple cylindrical) light control and sets the setting. The control signal for the dimming mode thus generated is generated and output to the light emitting element driving unit 26 (step S112). In the simple cylindrical dimming setting, the light emission amounts of the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 are made constant, and the light amount is made smaller than that in the simple planar dimming setting. .

  On the other hand, when the determination unit 27b determines that the number of adjacent points exceeds the second wall surface proximity determination value (step S111: No), the setting unit 27c sets the tubular (wall surface proximity) dimming. Then, the control signal of the set dimming mode is generated and output to the light emitting element driving unit 26 (step S113). In the wall surface proximity dimming setting, the second wall surface proximity among the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 is different from the simple cylindrical light control setting described above. By reducing the light emission amount of the light emitting element that irradiates illumination light to the photometry point determined to exceed the determination value, the amount of illumination light irradiated on the wall surface close to the capsule endoscope 2 is reduced. Reduced.

  According to the first embodiment described above, the calculation unit 27a is set for each of the plurality of photometry areas and the representative photometry values at the plurality of photometry points set in the plurality of photometry areas obtained by dividing the captured image concentrically. The determination unit 27b compares the difference with a threshold value set for each of the plurality of photometric areas, and determines whether the subject has a planar shape based on the comparison result. The setting unit 27c sets either the plane dimming setting or the cylindrical dimming setting based on the determination result of the determining unit 27b, and sets the dimming setting to the set dimming setting. Since such a control signal is output to the light emitting element driving unit 26, it is possible to perform optimal illumination corresponding to the shape of the subject (planar shape or cylindrical shape).

  In addition, according to the first embodiment described above, the determination unit 27b determines whether the subject has a planar shape or a cylindrical shape, and then the capsule endoscope 2 (imaging device 20) moves the wall surface of the subject. The setting unit 27c is either simple dimming setting not close to the wall surface or wall surface proximity dimming setting close to the wall surface based on the determination result of the determining unit 27b. Therefore, it is possible to determine the shape of the subject in more detail and perform lighting control suitable for the scene.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. FIG. 8 is a block diagram showing a configuration of the capsule endoscope according to the second embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the structure same as the structure mentioned above. In the first embodiment described above, it has been described as determining whether the shape of the subject is planar or cylindrical. However, in the second embodiment, the shape of the subject is planar, cylindrical, or spherical. It is determined which one. The spherical shape includes a hemispherical shape and an elliptical shape.

  In the capsule endoscope 2a according to the second embodiment, the light distribution information storage unit 32 further stores a spherical dimming target value in which the spherical dimming target value is set for each of the circumferential areas Ec1 to Ec4. And a third threshold value storage unit 32c that stores various threshold values set based on a chart obtained by imaging a spherical subject. The first threshold storage unit 32a further stores a second plane determination value that is a threshold that defines the count number of the circumferential area and that is a threshold for determining whether or not the subject is a plane.

  The third threshold value storage unit 32c is a threshold value that defines the number of measurement points whose difference value exceeds the reference difference value, and a spherical determination value that is a threshold value for determining whether or not the subject is spherical, A value that defines the number of adjacent measurement points that exceed the reference difference value among adjacent measurement points, and a third wall surface proximity determination value for determining whether or not the wall surfaces are close in spherical dimming , Remember.

  FIG. 9 is a diagram for explaining a received light luminance distribution obtained when images of subjects having different shapes are picked up. The graph shown in FIG. 9 shows the relationship between the position on the straight line passing through the imaging center and the normalized luminance obtained by normalizing the luminance curve so that the maximum luminance values obtained by imaging different subjects are equal. . In FIG. 9, in addition to the above-described curves Lp and Lr, a curve Lb which is a luminance curve obtained by a spherical subject is shown.

  As shown in FIG. 9, in the luminance curve obtained from a spherical subject, the luminance value decreases as the distance from the peak position (imaging center position) increases. Here, the light reception luminance distribution by the spherical subject has a smaller difference between the luminance at the imaging center position and the luminance at the position away from the imaging center position than the light reception luminance distribution by the planar subject.

  FIG. 10 is a flowchart showing the light control processing performed by the capsule endoscope according to the second embodiment. The dimming control unit 27 obtains light distribution information (step S201), similarly to steps S101 and S102 described above, and represents the photometric points Ep11 to Ep48 based on the imaging signals generated by the imaging device 20. A standardized photometric value is acquired (step S202). Thereafter, the calculation unit 27a calculates a difference (difference value) between the representative standardized photometric value calculated for each of the photometric points Ep11 to Ep48 and the plane dimming target value, similarly to steps S103 to S105 described above ( In step S203, the determination unit 27b compares the difference value with the threshold value (reference difference value), extracts the difference value (photometry point) exceeding the threshold value, and counts it (step S204). It is determined whether or not it is equal to or less than a determination value (step S205).

  Here, if the determination unit 27b determines that the count number is equal to or less than the plane determination value (step S205: Yes), the dimming control unit 27 proceeds to step S206 and determines adjacent photometry points in the plane dimming setting. Process. When the determination unit 27b proceeds to step S206, the determination unit 27b determines whether or not the adjacent photometry point exceeds the reference difference value for the photometry point extracted in step S204. Thereafter, the determination unit 27b determines whether or not the number of adjacent photometry points that exceed the reference difference value among the adjacent photometry points is equal to or less than the first wall surface proximity determination value (step S207).

  When the determination unit 27b determines that the number of adjacent photometry points is equal to or smaller than the first wall surface proximity determination value (step S207: Yes), the setting unit 27c sets the plane (simple plane) dimming and sets the set dimming An optical mode control signal is generated and output to the light emitting element driving unit 26 (step S208).

  On the other hand, when the determination unit 27b determines that the number of adjacent photometry points exceeds the first wall surface proximity determination value (step S207: No), the setting unit 27c sets the plane (wall surface proximity) dimming. Then, the control signal of the set dimming mode is generated and output to the light emitting element driving unit 26 (step S209).

  On the other hand, if the determination unit 27b determines that the count number exceeds the plane determination value (step S205: No), the dimming control unit 27 proceeds to step S210 and performs a circumferential area determination process.

  In step S210, the calculation unit 27a calculates an average value of the representative standardized photometric values of the photometric points in the circumferential areas Ec1 to Ec4. Thereafter, the determination unit 27b compares the average value for each circumferential area Ec1 to Ec4 with the planar dimming target value of each circumferential area, and determines the number of circumferential areas that exceed the planar dimming target value. Count.

  The determination unit 27b determines whether or not the counted number of circumferential areas is equal to or less than the second plane determination value (step S211). Here, when the determination unit 27b determines that the number of circumferential areas is equal to or less than the second plane determination value (step S211: Yes), the dimming control unit 27 proceeds to step S206 and sets the plane dimming setting. Adjacent photometric point determination processing is performed.

  On the other hand, when it is determined by the determination unit 27b that the number of circumferential areas exceeds the second plane determination value (step S211: No), the dimming control unit 27 proceeds to step S212 and performs the radial area determination process. Do.

  In step S212, the computing unit 27a performs a radial area determination process based on the photometric point of the radial area. Similar to steps S202 to S204 described above, the calculation unit 27a calculates a difference value between the representative standardized photometric value calculated for each of the photometric points Ep11 to Ep48 and the spherical light control target value, and the determination unit 27b The difference value and the reference difference value are compared, and a difference value (photometry point) exceeding the reference difference value is extracted. The determination unit 27b counts the number of radial areas where the extracted photometric points are present.

  Next, the determination unit 27b determines whether or not the counted number of radial areas is equal to or less than a spherical determination value (step S213). Here, when the determination unit 27b determines that the number of radial areas is equal to or less than the spherical determination value (step S213: Yes), the dimming control unit 27 proceeds to step S214 and is adjacent metering point in the spherical dimming setting. Judgment processing is performed. When the determination unit 27b proceeds to step S214, the determination unit 27b determines whether or not the difference value between the adjacent photometry points exceeds the reference difference value for the photometry point extracted in step S212. Thereafter, the determination unit 27b determines whether or not the number of adjacent metering points that exceed the reference difference value among the adjacent metering points adjacent to the extracted metering point is equal to or smaller than the third wall surface proximity determination value (step). S215). The third wall surface proximity determination value is a value for determining whether or not the wall surface is close in spherical light control.

  When the determination unit 27b determines that the number of adjacent photometry points is equal to or less than the third wall surface proximity determination value (step S215: Yes), the setting unit 27c sets spherical (simple spherical) light control, and the set light control An optical mode control signal is generated and output to the light emitting element driving unit 26 (step S216). In the simple spherical light control setting, the light emission amounts of the first light emitting element LA1, the second light emitting element LA2, the third light emitting element LA3, and the fourth light emitting element LA4 are made constant, and, for example, the amount of light is larger than the simple flat light control setting. The light amount is small and larger than the cylindrical plane dimming setting.

  On the other hand, when the determination unit 27b determines that the number of adjacent photometry points exceeds the third wall surface proximity determination value (step S215: No), it is set to spherical (wall surface proximity) light control, and the set control light is set. An optical mode control signal is generated and output to the light emitting element driving unit 26 (step S217).

  On the other hand, if the determination unit 27b determines that the number of radial areas is larger than the spherical determination value (step S213: No), the dimming control unit 27 proceeds to step S218 and determines adjacent metering points in the cylindrical dimming setting. Process.

  In step S218, the calculation unit 27a calculates the difference between the representative standardized photometric value calculated for each photometric point Ep11 to Ep48 and the cylindrical dimming target value in the same manner as in steps S202 to S204 described above. The unit 27b compares the difference value with a threshold value (reference difference value), and extracts a difference value (photometric point) exceeding the threshold value.

  The determination unit 27b determines whether or not the number of adjacent metering points that exceed the reference difference value among the adjacent metering points adjacent to the extracted metering point is equal to or less than the second wall surface proximity determination value (step S219). . When it is determined by the determination unit 27b that the number of adjacent photometry points is equal to or less than the second wall surface proximity determination value (step S219: Yes), the setting unit 27c sets the cylindrical (simple cylindrical) light control and sets the setting. The control signal for the dimming mode thus generated is generated and output to the light emitting element driving unit 26 (step S220).

  On the other hand, when the determination unit 27b determines that the number of adjacent photometry points exceeds the second wall surface proximity determination value (step S219: No), the setting unit 27c sets the cylindrical (wall surface proximity) light control. Then, the control signal of the set dimming mode is generated and output to the light emitting element driving unit 26 (step S221).

  According to the second embodiment described above, the calculation unit 27a is set for each of the plurality of photometry areas and the representative photometry values at the plurality of photometry points set in the plurality of photometry areas obtained by concentrating the captured image. The determination unit 27b compares the difference with a threshold value set for each of the plurality of photometric areas, and determines whether the subject has a planar shape based on the comparison result. The setting unit 27c sets one of the plane dimming setting, the spherical dimming setting, and the cylindrical dimming setting based on the determination result of the determining unit 27b, and the set dimming is determined. Since the control signal relating to the light setting is output to the light emitting element driving unit 26, it is possible to perform optimal illumination corresponding to the shape of the subject (planar, spherical, or cylindrical).

  In the first and second embodiments described above, it has been described that the determination process is performed based on the plane dimming and the dimming is set. However, even if the determination process is performed based on the cylindrical shape or the spherical shape, Good.

  Further, in the first and second embodiments described above, each shape is described as using one determination value, but two or more determination values (for example, two threshold values having different plane determination values) are used. Different dimming settings may be performed. For example, a plurality of determination values may be provided for cases where the diameters of the cylinders are different so that the light amounts are different from each other. In this case, since the photometric value obtained becomes larger as the diameter of the cylinder becomes larger, the dimming setting is made such that the light quantity becomes smaller as the diameter becomes smaller.

  In the first and second embodiments described above, the dimming target value is described as being stored in advance in the light distribution information storage unit 32. However, the dimming target value is calculated every time measurement is performed. May be.

  In the first and second embodiments described above, the capsule endoscopes 2 and 2a have been described as determining the shape of the subject. However, the capsule endoscopes such as the receiving device 3 and the image processing device 4 are external to the capsule endoscope. The shape determination process and the dimming setting process may be performed. In this case, the capsule endoscope is provided with an antenna or the like for performing wireless communication with an external device that outputs setting information.

  As described above, the capsule endoscope according to the present invention is useful for accurately determining the shape of a subject.

DESCRIPTION OF SYMBOLS 1 Subject 2, 2a Capsule endoscope 3 Receiving device 4 Image display device 5 Portable recording medium 20 Image sensor 21 Image signal processing circuit 22 Transmitter 23 Transmitting antenna 24 Image sensor driving unit 25 Light emitting element 26 Light emitting element driving unit 27 Light control unit 27a Calculation unit 27b Determination unit 27c Setting unit 28 Power supply circuit 29 Battery 30 Control unit 31 Storage unit 32 Light distribution information storage unit 32a First threshold storage unit 32b Second threshold storage unit 32c Third threshold storage unit

Claims (4)

An image sensor that photoelectrically converts received light and generates the converted electrical signal as an imaging signal;
An illumination unit that emits illumination light to illuminate the subject;
A light distribution information storage unit that stores light distribution information based on a light-receiving luminance distribution of the image sensor according to the shape of the subject;
Representative photometric values at a plurality of photometry points set in a plurality of photometry areas obtained by concentrically dividing a captured image based on the image pickup signal, and stored in the light distribution information storage unit, are set for each of the plurality of photometry areas. A calculation unit for calculating a difference between the target metering value and
The difference value is stored in the light distribution information storage unit and compared with a reference difference value set for each of a plurality of light metering areas, and the difference value exceeding the reference difference value is counted and counted. A determination unit that generates a determination result for determining the shape of the subject by comparing the number and a shape determination value that is stored in the light distribution information storage unit and determines the shape of the subject;
Setting that determines the shape of the subject based on the determination result of the determination unit, performs dimming setting according to the determined shape of the subject, and outputs a control signal related to the dimming setting to the illumination unit And
A capsule endoscope characterized by comprising: The determination unit determines whether the imaging element is close to the wall surface of the subject after determining the shape of the subject,
The setting unit is configured to set either a simple dimming setting that is not close to the wall surface or a near wall dimming setting that is close to the wall surface based on a determination result of the determination unit. Item 2. The capsule endoscope according to Item 1.   The capsule endoscope according to claim 1, wherein the representative photometric value and the target photometric value are standardized values having the same maximum value and minimum value.   The capsule endoscope according to claim 1, wherein the subject has a planar shape, a spherical shape, or a cylindrical shape.

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