WO2018037505A1 - Endoscope system - Google Patents

Endoscope system Download PDF

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Publication number
WO2018037505A1
WO2018037505A1 PCT/JP2016/074683 JP2016074683W WO2018037505A1 WO 2018037505 A1 WO2018037505 A1 WO 2018037505A1 JP 2016074683 W JP2016074683 W JP 2016074683W WO 2018037505 A1 WO2018037505 A1 WO 2018037505A1
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WO
WIPO (PCT)
Prior art keywords
light
special
emission
image data
reference light
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PCT/JP2016/074683
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French (fr)
Japanese (ja)
Inventor
佳宏 林
友輝 池田
祐哉 増川
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Hoya株式会社
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Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to PCT/JP2016/074683 priority Critical patent/WO2018037505A1/en
Publication of WO2018037505A1 publication Critical patent/WO2018037505A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/0655—Control therefor

Definitions

  • the present invention relates to an endoscope system that calculates and acquires a feature amount in a living tissue based on image data generated by imaging the living tissue.
  • An endoscope system having a function of obtaining, as a feature amount of a biological tissue, information on a biological substance in a biological tissue as a subject, for example, information on the amount of hemoglobin and oxygen saturation of hemoglobin, from image data obtained by the endoscope It has been known.
  • An example of such an endoscope system is described in Patent Document 1.
  • the endoscope system described in Patent Document 1 includes a light source device on which a rotary filter is mounted.
  • the rotary filter includes three optical bandpass filters (two optical bandpass filters that selectively transmit light in the 550 nm band and one optical bandpass filter that selectively transmits light in the 650 nm band) and white Normal observation filters that transmit light are arranged side by side in the circumferential direction.
  • the controller rotationally drives the rotary filter at a constant rotation period, sequentially inserts each filter into the white light optical path, and sequentially performs imaging of the living tissue with the irradiation light transmitted through each filter.
  • the controller generates a distribution image indicating the distribution of biomolecules in the biological tissue, for example, an oxygen saturation distribution image indicating the oxygen saturation distribution of hemoglobin, based on the image data captured using each optical bandpass filter.
  • the generated distribution image is displayed in the display screen side by side with the normal observation image captured using the normal observation filter.
  • the present invention has been made in view of the above circumstances, and is a distribution of feature amounts such as the amount of hemoglobin and oxygen saturation of biological tissue generated from captured image data of biological tissue illuminated with a plurality of lights.
  • feature amounts such as the amount of hemoglobin and oxygen saturation of biological tissue generated from captured image data of biological tissue illuminated with a plurality of lights.
  • the endoscope system of the present invention includes the following forms.
  • a light source device configured to repeat Color image data of the image of the biological tissue illuminated with the illumination light is obtained by imaging the biological tissue in accordance with the timing of emission of the illumination light each time the biological tissue is illuminated with each of the illumination light.
  • An endoscope comprising an imaging device configured to generate;
  • a processor comprising a feature amount acquisition unit configured to calculate the amount of hemoglobin in the living tissue and the oxygen saturation level of hemoglobin in the living tissue as the feature amount of the living tissue using the color image data;
  • An image of the biological tissue illuminated with the reference light and imaged by the imaging device, and a feature amount distribution image showing at least one distribution of the amount of the hemoglobin and the oxygen saturation are displayed.
  • the feature amount acquisition unit includes a component of the first special light color image data obtained by illumination of the first special light and the reference light color image data obtained by illumination of the reference light among the color image data.
  • a hemoglobin amount calculating unit configured to calculate the amount of the hemoglobin using a component, the component of the first special light color image data obtained by the illumination of the first special light, and the illumination of the second special light
  • An oxygen saturation calculator configured to calculate the oxygen saturation of the hemoglobin using the component of the second special light color image data obtained by
  • the light source device emits the reference light at least twice between one emission of the special light and another emission of the special light in the one cycle with respect to the order of the illumination light.
  • An endoscope system configured to perform the emission of reference light without continuing.
  • the light source device comprises a light source configured to emit a single light;
  • the light source device transmits the reference light and the special light by transmitting the light emitted from the light source through a plurality of optical filters having different pass wavelength bands so as to correspond to the order of emission of the reference light and the special light.
  • the endoscope system according to any one of Embodiments 1 to 3, wherein the endoscope system is configured to emit light.
  • the wavelength band of the reference light is wider than the wavelength band of the special light
  • the wavelength band of the reference light includes a wavelength band in which one of the components of the reference light color image data does not have sensitivity to a change in the amount of hemoglobin in the living tissue.
  • one of the components of the first special light color image data is sensitive to changes in the amount of hemoglobin in the living tissue, but sensitive to changes in the oxygen saturation.
  • the wavelength band of the second special light includes any one of modes 1 to 6, wherein one of the components of the second special light color image data includes a wavelength band having sensitivity to the change in oxygen saturation.
  • the endoscope system according to one.
  • the first special light is an optical filter that is filtered light of the reference light that transmits a first wavelength band within a range of 500 nm to 600 nm of the wavelength band of the reference light
  • the second special light is: The optical filter according to any one of Embodiments 1 to 7, wherein the reference light is a filtered light of the reference light that has been transmitted through a second wavelength band narrower than the first wavelength band within the first wavelength band. Endoscopic system.
  • the hemoglobin amount calculating unit is configured to calculate the amount of the hemoglobin based on a first ratio that is a ratio of the component of the reference light color image data and the component of the first special light color image data,
  • the oxygen saturation calculating unit calculates oxygen saturation of the hemoglobin based on a second ratio that is a ratio between the component of the first special light color image data and the component of the second special light color image data.
  • the reference light includes a first reference light and a second reference light having the same wavelength band
  • the light source device may be arranged between the emission of the first special light and the emission of the second special light, or between the emission of the second special light and the emission of the first special light with respect to the order of emission of the illumination light.
  • the first reference light is emitted and the first special light and the second reference light are emitted, or the second reference light and the first special light are emitted.
  • the feature amount acquisition unit calculates first feature color image data of an image of the biological tissue illuminated with the first reference light and the biological tissue illuminated with the second reference light for calculating the feature amount.
  • the endoscope system according to any one of Embodiments 1 to 11, further comprising a data selection unit configured to select and use any one of the second reference light color image data of the image.
  • the feature amount acquisition unit illuminates with the first reference light and illuminates with the second reference light with respect to the image of the biological tissue captured by the imaging element, and a positional deviation amount of the image of the biological tissue captured by the imaging element
  • a misregistration amount calculation unit configured to calculate
  • the data selection unit may use the first reference light color image data for calculating the feature amount instead of the second reference light color image data when the calculated positional deviation amount is out of an allowable range.
  • the endoscope system according to form 12, which is configured.
  • the endoscope has any one of forms 1 to 13, wherein the imaging device includes an optical system configured to receive reflected light of the living tissue in a wavelength band of the reference light and the special light. Endoscope system according to one.
  • the light source device includes: a light source configured to emit one light; and a plurality of light beams emitted from the light source having different pass wavelength bands so as to correspond to an order of emission of the reference light and the special light.
  • a rotary filter configured to emit the reference light and the special light by transmitting the optical filter, the optical filter being arranged on the circumference with an interval; and
  • the image sensor is a CMOS image sensor that exposes the light receiving surface with a rolling shutter;
  • the endoscope system according to any one of Embodiments 1 to 15, wherein the rotary filter has a blocking section that blocks light between the optical filters.
  • the light source device is configured to repeat emission of a plurality of cycles, with the emission of the reference light and the special light as one cycle.
  • the number of times that the image pickup device generates the reference light color image data in the one cycle is the number of times the image pickup device generates the first special light color image data and the image pickup device generates the second special light color image data.
  • the endoscope system according to any one of Embodiments 1 to 16, wherein the endoscope system is larger than the number of times of generating.
  • a biological tissue can be observed without stress for an operator who performs a procedure while operating the endoscope, and a focused position in a feature amount distribution image of the biological tissue with high accuracy is normally observed. It can be specified on the image of the living tissue in the image.
  • the endoscope system includes a light source device, an endoscope including an imaging element, a processor, and a display.
  • the light source device emits a plurality of special lights including reference light having different wavelength bands and at least first special light and second special light as one cycle, and uses the reference light and special light as illumination light for living tissue in one cycle. repeat.
  • the reference light and the plurality of special lights having different wavelength bands are different from each other in the wavelength band of the reference light and the plurality of special lights, and the wavelength bands of the plurality of special lights.
  • the imaging device picks up the image of the living tissue illuminated with each illumination light by imaging the living tissue with the timing of emitting the illumination light. Generate image data. Using this color image data, the processor calculates the amount of hemoglobin in the living tissue and the oxygen saturation of the hemoglobin in the living tissue.
  • the display connected to the processor displays an image of the biological tissue illuminated with the reference light, and a feature amount distribution image showing at least one distribution of the amount of hemoglobin and oxygen saturation.
  • the processor includes a component of the first special light color image data obtained by the illumination of the first special light and the reference light color image data obtained by the illumination of the reference light among the color image data. Of the first special light color image data obtained by illumination of the first special light and the second special light color image data obtained by illumination of the second special light.
  • the oxygen saturation of hemoglobin is calculated using the components.
  • the light source device is arranged between one emission of special light and another emission of special light with respect to the order of emission of illumination light in one cycle of emission of reference light and a plurality of special lights.
  • the reference light is emitted at least twice without continuing the emission of the reference light.
  • the emission of the reference light is not continued at least twice in the sequence of the special light emission order determined to emit the special light sequentially. It is the order of arrangement. In this way, normal observation obtained by imaging a biological tissue illuminated with the feature amount distribution image obtained in each cycle and the reference light by repeatedly emitting one cycle with a plurality of special light and reference light being emitted as one cycle.
  • the normal observation image is obtained by illuminating the living tissue with the reference light at least twice in one cycle. Therefore, the conventional observation image obtained only once in one cycle can be obtained. Compared to the endoscope system, the refresh rate of the normal observation image can be improved. In addition, since the refresh rate of the normal observation image is improved, the living tissue can be observed without stress for an operator who performs the procedure while operating the endoscope.
  • the refresh rate of the normal observation image is improved, the positional deviation between the image of the biological tissue in the feature distribution image obtained from the captured image of the biological tissue illuminated with special light and the image of the biological tissue in the normal observation image As a result, the operator who performs the procedure while operating the endoscope can easily specify the position of interest in the feature amount distribution image on the image of the biological tissue in the normal observation image.
  • the endoscope system of the present embodiment will be described in detail with reference to the drawings.
  • FIG. 1 is a block diagram illustrating a configuration of an endoscope system 1 according to the present embodiment.
  • the endoscope system 1 includes an electronic endoscope (endoscope) 100, a processor 200, a display 300, and a light source device 400.
  • the electronic endoscope 100 and the display 300 are detachably connected to the processor 200.
  • the processor 200 includes an image processing unit 500.
  • the light source device 400 is detachably connected to the processor 200. Note that the light source device 400 may be provided in the housing of the processor 200.
  • the electronic endoscope 100 has an insertion tube 110 that is inserted into the body of a subject. Inside the insertion tube 110, a light guide 131 extending over substantially the entire length of the insertion tube 110 is provided.
  • the distal end portion 131 a that is one end portion of the light guide 131 is located in the distal end portion of the insertion tube 110, that is, in the vicinity of the distal end portion 111 of the insertion tube, and the proximal end portion 131 b that is the other end portion of the light guide 131 is connected to the light source device 400.
  • the light guide 131 extends from the connection portion with the light source device 400 to the vicinity of the insertion tube distal end portion 111.
  • the light source device 400 includes a light source lamp 430 that generates a large amount of light, such as a xenon lamp, as a light source.
  • the light emitted from the light source device 400 enters the base end portion 131b of the light guide 131 as illumination light IL.
  • the light incident on the base end portion 131b of the light guide 131 is guided to the tip end portion 131a through the light guide 131, and is emitted from the tip end portion 131a.
  • a light distribution lens 132 disposed opposite to the distal end portion 131 a of the light guide 131 is provided at the insertion tube distal end portion 111 of the electronic endoscope 100.
  • the illumination light IL emitted from the distal end portion 131a of the light guide 131 passes through the light distribution lens 132 and illuminates the living tissue T in the vicinity of the insertion tube distal end portion 111.
  • An objective lens group 121 and an image sensor 141 are provided at the insertion tube tip 111 of the electronic endoscope 100.
  • the objective lens group 121 and the imaging element 141 form an imaging unit.
  • the illumination light IL the light reflected or scattered by the surface of the living tissue T is incident on the objective lens group 121, is condensed, and forms an image on the light receiving surface of the image sensor 141.
  • the image sensor 141 a known image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor having a color filter 141 a on the light receiving surface can be used. . Note that it is preferable to use a CMOS image sensor for the image sensor 141 in terms of low power consumption and low cost.
  • the color filter 141 a includes an R color filter that transmits red light, a G color filter that transmits green light, and a B color filter that transmits blue light, and is arranged on each light receiving element of the image sensor 141. It is a so-called on-chip filter formed directly.
  • FIG. 2 is a diagram illustrating an example of spectral characteristics of each of the red (R), green (G), and blue (B) filters of the image sensor used in the present embodiment.
  • the R color filter of the present embodiment is a filter that passes light having a wavelength longer than about 570 nm (for example, 580 nm to 700 nm)
  • the G color filter is a filter that passes light having a wavelength of about 470 nm to 620 nm.
  • the B color filter is a filter that allows light having a wavelength shorter than about 530 nm (for example, 420 nm to 520 nm) to pass therethrough.
  • the imaging element 141 is an imaging unit that images the living tissue T illuminated with each of a plurality of lights and generates color image data corresponding to each light, and the living tissue T with a plurality of lights having different wavelength ranges. It is an image data generation means for generating color image data corresponding to light reflected or scattered on the living tissue T by illuminating.
  • the image sensor 141 is controlled to be driven in synchronization with an image processing unit 500 described later, and periodically (for example, 1/30 second interval) color image data corresponding to the subject image formed on the light receiving surface. Output).
  • the color image data output from the image sensor 141 is sent to the image processing unit 500 of the processor 200 via the cable 142.
  • the image processing unit 500 mainly includes an A / D conversion circuit 502, a pre-image processing unit 504, a frame memory unit 506, a post image processing unit 508, a feature amount acquisition unit 510, a memory 512, an image display control unit 514, and a controller 516. Prepare for.
  • the A / D conversion circuit 502 performs A / D conversion on the color image data input from the image sensor 141 of the electronic endoscope 100 via the cable 142 and outputs digital image data. Digital data output from the A / D conversion circuit 502 is sent to the pre-image processing unit 504.
  • the pre-image processing unit 504 captures digital data by using the R digital image data captured by the light receiving element in the image sensor 141 with the R color filter and the light receiving element in the image sensor 141 with the G color filter.
  • the R, G, and B component color image data constituting the image by demosaic processing from the G digital image data and the B digital image data picked up by the light receiving element in the image pickup element 141 to which the B color filter is attached.
  • the pre-image processing unit 504 is a part that performs predetermined signal processing such as color correction, matrix calculation, and white balance correction on the generated color image data of R, G, and B components.
  • the frame memory unit 506 temporarily stores color image data for each image captured by the image sensor 141 and subjected to signal processing.
  • the post image processing unit 508 reads the color image data stored in the frame memory unit 506 or performs signal processing ( ⁇ correction or the like) on the image data generated by the image display control unit 514 (to be described later) for display display. Generate screen data.
  • the image data generated by the image display control unit 514 includes data of distribution images of feature amounts such as oxygen saturation of hemoglobin in the living tissue T.
  • the generated screen data (video format signal) is output to the display 300.
  • an image of the living tissue T, a feature amount distribution image indicating the distribution of the feature amount of the living tissue T, and the like are displayed on the display screen of the display 300.
  • the feature amount acquisition unit 510 calculates a feature amount of the imaged living tissue T, for example, the amount of hemoglobin, or the amount of hemoglobin and the oxygen saturation of hemoglobin, as will be described later.
  • the image data of the distribution image on the image of the captured tissue T of these feature amounts is generated. Since the feature quantity acquisition unit 510 calculates the feature quantity by calculating using the color image data of the living tissue T illuminated with a plurality of lights having different wavelength bands, the feature quantity acquisition unit 510 acquires the feature quantity from the frame memory unit 506 or the memory 512. Color image data and various information used in the unit 510 are called up.
  • the image display control unit 514 controls the display of the distribution image on the captured image of the biological tissue T of the feature amount calculated by the feature amount acquisition unit 510 in accordance with an instruction from the controller 516. For example, the image display control unit 514 displays the captured image of the living tissue T and the feature amount distribution image in parallel, or displays the feature amount distribution image so as to overlap the captured image of the living tissue T.
  • the controller 516 is a part that performs operation instruction and operation control of each part of the image processing unit 500, and performs operation instruction and operation control of each part of the electronic endoscope 100 including the light source device 400 and the imaging element 141.
  • the feature amount acquisition unit 510 and the image display control unit 514 may be configured by software modules that perform the above-described functions by starting and executing programs on a computer, or may be configured by hardware. Good.
  • the processor 200 instructs and controls the function of processing the color image data output from the image sensor 141 of the electronic endoscope 100 and the operation of the electronic endoscope 100, the light source device 400, and the display 300. Combines functionality.
  • the light source device 400 is a light emitting unit that emits reference light and special light as illumination light IL, and makes the reference light and special light enter the light guide 131.
  • the wavelength band of the reference light is different from the wavelength band of the plurality of special lights, and the wavelength bands of the plurality of special lights are different from each other.
  • the reference light includes first reference light and second reference light having the same wavelength band as described later, and the special light is different from the wavelength region of the reference light and has different wavelength bands from each other as described later. Includes special light and second special light.
  • the light source device 400 of the present embodiment emits four illumination lights IL, but may emit five or more illumination lights IL. In this case, the fifth light can be third special light different from the wavelength bands of the first special light and the second special light.
  • the light source device 400 includes a condenser lens 440, a rotation filter 410, a filter control unit 420, and a condenser lens 450.
  • the light that is substantially parallel light emitted from the light source lamp 430 is, for example, white light, is collected by the condenser lens 440, passes through the rotary filter 410, and is condensed again by the condenser lens 450.
  • the light enters the base end 131 b of the guide 131.
  • the rotary filter 410 is movable between a position on the optical path of light emitted from the light source 430 and a retracted position outside the optical path by a moving mechanism (not shown) such as a linear guide way.
  • the wavelength band of the illumination light IL emitted from the light source device 400 differs depending on the type of the rotary filter 410 that crosses the optical path of the light emitted from the light source lamp 430.
  • the special light is light that illuminates the biological tissue T in order to obtain color image data necessary for calculating the amount of hemoglobin in the biological tissue and the oxygen saturation of the hemoglobin
  • the wavelength band of the special light is Illumination light IL limited to a wavelength band having light absorption characteristics of hemoglobin.
  • the reference light is illumination light IL having a broad wavelength band, the wavelength band of which is not limited to the wavelength band having the light absorption characteristic of hemoglobin, and is white light in the present embodiment.
  • the configuration of the light source device 400 is not limited to that shown in FIG.
  • the light source lamp 430 may be a lamp that generates convergent light instead of parallel light.
  • a configuration may be adopted in which light emitted from the light source lamp 430 is collected before the condenser lens 440 and is incident on the condenser lens 440 as diffused light.
  • a configuration in which substantially parallel light generated by the light source lamp 430 is directly incident on the rotary filter 410 without using the condenser lens 440 may be employed.
  • a configuration in which a collimator lens is used instead of the condenser lens 440 and light is incident on the rotary filter 410 in a substantially parallel light state may be employed.
  • a collimator lens is used instead of the condenser lens 440 and light is incident on the rotary filter 410 in a substantially parallel light state.
  • an interference type optical filter such as a dielectric multilayer filter
  • the incident angle of the light to the optical filter is made uniform by causing substantially parallel light to enter the rotary filter 410.
  • a lamp that generates divergent light may be employed as the light source lamp 430.
  • the light source device 400 is configured to emit a plurality of lights having different wavelength bands by transmitting light emitted from one light source lamp 430 through an optical filter.
  • different wavelengths are used instead of the light source lamp 430.
  • a semiconductor light source such as a light emitting diode or a laser element that outputs laser light having different bands can be used as the light source of the light source device 400.
  • the rotation filter 410 may not be used.
  • the rotation filter 410 is a disc-shaped optical unit including a plurality of optical filters, and is configured such that the light passing wavelength region is switched according to the rotation angle.
  • the rotary filter 410 of the present embodiment includes four optical filters having different pass wavelength bands, but may include five, or six or more optical filters.
  • the rotation angle of the rotary filter 410 is controlled by a filter control unit 420 connected to the controller 516. When the controller 516 controls the rotation angle of the rotary filter 410 via the filter control unit 420, the wavelength band of the illumination light IL that passes through the rotary filter 410 and is supplied to the light guide 131 is switched.
  • FIG. 3 is an external view (front view) of the rotary filter 410.
  • the rotary filter 410 includes a total of four optical filters: a substantially disk-shaped frame 411, two optical filters Fn1, Fn2, one optical filter Fs1, and one optical filter Fs2.
  • the four optical filters are provided at intervals on the circumference.
  • the optical filters of the present embodiment are all dielectric multilayer filters, but other types of optical filters (for example, absorption optical filters and etalon filters using dielectric multilayer films as reflective films). May be used.
  • CMOS image sensor for the imaging element 141 of the electronic endoscope 100 from the viewpoint of low power consumption and low cost.
  • the CMOS image sensor is a rolling that repeats exposure and blocking of the light receiving surface. Since the image is taken by the shutter, it is preferable that the rotary filter 410 is rotated in accordance with the timing of the image pickup. However, the timing of exposure and the timing of emission of the illumination light IL may not match due to fluctuations in the rotation of the rotary filter 410, and the type of illumination light IL may change during exposure. For this reason, it is preferable that a blocking section where the illumination light IL is not emitted is provided between the optical filters on the frame 411 of the rotary filter 410.
  • the CMOS image sensor tends to generate a darker image than the CCD image sensor, it is necessary to lengthen the exposure time. It is preferable to increase the emission continuation time.
  • the wavelength bands of the optical filters Fs1 and Fs2 are narrower than the wavelength bands of the optical filters Fn1 and Fn2, as described later, the intensity of light transmitted through the optical filters Fs1 and Fs2 is weak, and the image is picked up by the image sensor 141. Images tend to be dark. For this reason, the accuracy of the feature quantity distribution image obtained using the color image data obtained from the light transmitted through the optical filters Fs1 and Fs2 tends to be low.
  • the ratio of the length along the circumference (circumferential direction) of each region of the cutoff section between the optical filters in the rotary filter 410 to the length along the circumference (circumferential direction) of each region of the optical filter is 0. It is preferably from super to 1, more preferably from 0.1 to 1.
  • a boss hole 412 is formed on the central axis of the frame 411.
  • An output shaft of a servo motor (not shown) provided in the filter control unit 420 is inserted into the boss hole 412 and fixed, and the rotary filter 410 rotates together with the output shaft of the servo motor.
  • the optical filter on which this light is incident is switched in the order of the optical filter Fs2, the optical filter Fn1, the optical filter Fs1, and the optical filter Fn2, thereby rotating the rotary filter.
  • the wavelength band of the illumination light IL passing through 410 is sequentially switched. Specifically, every time the rotary filter 410 makes one rotation, the light emitted from the light source lamp 430 passes through the optical filter Fs2 in turn, so that the second special light is generated, and the light emitted from the light source lamp 430 is optical.
  • the first reference light is generated by passing through the filter Fn1
  • the first special light is generated by passing the light emitted from the light source lamp 430 through the optical filter Fs1
  • the light emitted from the light source lamp 430 is converted into the optical filter Fn2.
  • the cycle in which the second reference light is generated by passing through is repeated.
  • the optical filters Fs1 and Fs2 are optical bandpass filters that selectively pass light in the 550 nm band. As shown in FIG. 4, the optical filter Fs1 allows light in a wavelength band R0 (W band) from equal absorption points E1 to E4, which will be described later, to pass through with low loss, and blocks light in other wavelength regions. It is configured.
  • the optical filter Fs2 is configured to pass light in a wavelength band R2 (N band) from equal absorption points E2 to E3, which will be described later, with low loss, and block light in other wavelength regions.
  • FIG. 4 is a diagram showing an example of an absorption spectrum of hemoglobin near 550 nm.
  • optical filters Fn1 and Fn2 are ultraviolet cut filters having the same transmission characteristics and passing light of the same wavelength band with low loss.
  • the optical filters Fn1 and Fn2 transmit light emitted from the light source lamp 430 in the wavelength region of 400 to 700 nm.
  • the wavelength band R1 shown in FIG. 4 is a band including the peak wavelength of the absorption peak P1 derived from oxygenated hemoglobin as described later, and the wavelength band R2 is the absorption peak P2 derived from reduced hemoglobin as described later.
  • the wavelength band R3 is a band including the peak wavelength of the absorption peak P3 derived from oxygenated hemoglobin, as will be described later.
  • the wavelength range R0 includes the peak wavelengths of the three absorption peaks P1, P2, and P3.
  • FIG. 4 is a diagram showing an example of an absorption spectrum of hemoglobin near 550 nm. A detailed description of the relationship between the amount of hemoglobin, the oxygen saturation of hemoglobin, and the wavelength band will be described later.
  • the light transmitted through the optical filters Fs1 and Fs2 is used as special light for illuminating the biological tissue T in order to obtain color image data for calculating the amount of hemoglobin of the captured biological tissue T and the oxygen saturation of the hemoglobin. .
  • the light transmitted through the optical filters Fn1 and Fn2 is used as reference light for illuminating the living tissue T in order to obtain color image data for generating a normal observation image.
  • the optical filters Fn1 and Fn2 may not be used, and the window on the frame 411 in which the optical filters Fn1 and Fn2 are arranged may be opened.
  • the first special light transmitted from the light source lamp 430 through the optical filter Fs1 is hereinafter referred to as Wide light
  • the second special light transmitted through the optical filter Fs2 from the light emitted from the light source lamp 430 Is referred to as “Narrow light” hereinafter
  • the reference light transmitted through the optical filters Fn1 and Fn2 among the light emitted from the light source lamp 430 is hereinafter referred to as “white light WL”.
  • the reference light generated when the light emitted from the light source lamp 430 passes through the optical filters Fn1 and Fn2 is transmitted from the light source device 400 to the first reference light and the second reference light.
  • the first reference light is hereinafter referred to as white light WL1
  • the second reference light is hereinafter referred to as white light WL.
  • the wavelength band R0 of the optical filter Fs1 and the wavelength band R2 of the optical filter Fs2 are included in the pass wavelength band (FIG. 2) of the G color filter of the color filter 141a. Therefore, the image of the living tissue T formed by the light that has passed through the optical filter Fs1 or Fs2 is obtained as an image of the G component of the color image data captured by the image sensor 141.
  • the optical filter Fs1 or the optical filter Fs1 or the optical filter Fs2 so that the light intensity of the special light generated by the optical filter Fs1 and the optical filter Fs2 is approximately the same so that an image with the same brightness can be obtained under the same exposure condition of the image sensor 414.
  • the transmittance of the optical filter Fs2 is adjusted.
  • a through hole 413 is formed in the peripheral edge of the frame 411.
  • the through-hole 413 is formed at the same position (phase) as the boundary between the optical filter Fn2 and the window where the optical filter Fs1 is arranged in the rotation direction of the frame 411.
  • a photo interrupter 422 for detecting the through hole 413 is arranged so as to surround a part of the peripheral edge of the frame 411.
  • the photo interrupter 422 is connected to the filter control unit 420.
  • the light source device 400 switches the four optical filters Fs2, Fn1, Fs1, and Fn2 in order in the optical path of the light emitted from the light source lamp 430, that is, light having different wavelength bands, that is, narrow light.
  • (Second special light), white light WL1 (first reference light), wide light (first special light), and white light WL2 (second reference light) are emitted as illumination light IL.
  • the light source device 400 of the present embodiment in one cycle in which the four illumination lights IL are sequentially emitted, is related to the order of emission of the illumination light IL between one emission of special light and another emission of special light.
  • the emission of the white light WL (reference light) is performed at least twice without continuing the emission of the white light WL (reference light).
  • the order of emission of the reference light and the special light is the sequence of the special light emission order determined for sequentially emitting the special light, specifically, the narrow light (second special light), the wide light ( This is the order in which the emission of the white light WL (reference light) is interrupted (disposed) twice in succession in the sequence of the emission of the first special light). As shown in FIG.
  • the light source device 400 includes narrow light (second special light), white light WL1 (first reference light), wide light (first special light), and white light WL2 (second reference light). Are sequentially emitted as the illumination light IL of the living tissue T, and the emission of the illumination light IL for one cycle is repeated.
  • FIG. 5 is a diagram illustrating an example of the order of emission of the reference light and the special light in the light source device 200 of the present embodiment.
  • the processor 200 acquires a normal observation image and a feature amount distribution image of the living tissue T and displays them on the display 300. Therefore, in this embodiment, since the white light WL is emitted twice in one cycle, the normal observation image is generated and displayed twice in one cycle.
  • the light source device 400 of the present embodiment emits two special lights, but may emit three or more special lights having different wavelength bands.
  • the white light WL reference light
  • the white light WL is not continuously emitted in two or more places, more than three places in the sequence of the emission order of three or more special lights. It is good to arrange (interrupt).
  • the emission of the Wide light (first special light) and the single emission of the white light WL (reference light) are performed.
  • the amount of hemoglobin is obtained as will be described later, that one emission of white light WL (reference light) and one emission of wide light (first special light) are continuous with each other. Therefore, when calculating the first ratio, it is preferable from the viewpoint that the positional deviation in the image of the image of the living tissue T can be suppressed.
  • the emission of narrow light (second special light) and one emission of white light WL (reference light), or white light WL (reference light) It is preferable that one emission of light) and the emission of narrow light (second special light) are continuous without interfering with other emission. Thereby, the white light WL (reference light) twice can be used as the illumination light IL of the living tissue T in one cycle, and the refresh rate of the normal observation image is improved.
  • the light source device 400 includes the light source lamp 430 that emits one light as a light source, and the light source device 400 includes white light WL (reference light), wide light, and narrow light ( The white light WL (reference light), the wide light, and the narrow light are transmitted by transmitting light in one wavelength band through a plurality of optical filters having different pass wavelength bands so as to correspond to the order of emission of the special light). It is preferable to be configured to emit (special light).
  • the wavelength band of the white light WL (reference light) of the present embodiment includes a wavelength band in which one of the components of the reference color image data does not have sensitivity to changes in the amount of hemoglobin in the living tissue T. It is preferable that it is set from the point that the influence of the scattering characteristics in the living tissue T can be appropriately removed in the first ratio.
  • the feature amount of the living tissue T is calculated by the feature amount acquisition unit 510 of the processor 500. Processing for calculating the amount of hemoglobin in the biological tissue T and the oxygen saturation Sat of hemoglobin as the feature amount from the captured image of the biological tissue T will be described below.
  • hemoglobin has a strong absorption band called a Q band derived from porphyrin near 550 nm.
  • the absorption spectrum of hemoglobin changes according to the oxygen saturation Sat representing the proportion of oxygenated hemoglobin HbO in the total hemoglobin.
  • the solid line waveform in FIG. 4 is an absorption spectrum of oxygen saturation Sat of 100%, that is, oxygenated hemoglobin HbO
  • the long broken line waveform is an absorption spectrum of oxygen saturation Sat of 0%, that is, reduced hemoglobin Hb. It is.
  • oxygenated hemoglobin HbO and reduced hemoglobin Hb have different peak wavelengths. Specifically, oxygenated hemoglobin HbO has an absorption peak P1 near a wavelength of 542 nm and an absorption peak P3 near a wavelength of 576 nm. On the other hand, reduced hemoglobin Hb has an absorption peak P2 near 556 nm.
  • FIG. 4 is an absorption spectrum when the sum of the concentrations of oxygenated hemoglobin HbO and reduced hemoglobin Hb is constant. Therefore, the ratio of oxygenated hemoglobin HbO and reduced hemoglobin Hb, that is, the absorbance is constant regardless of the oxygen saturation.
  • the isosbestic points E1, E2, E3, E4 appear.
  • the wavelength band sandwiched between the equal absorption points E1 and E2 is the wavelength band R1 described above, and the wavelength region sandwiched between the equal absorption points E2 and E3 is the wavelength band R2.
  • the wavelength band sandwiched between the equal absorption points E3 and E4 is the wavelength band R3, and the wavelength band sandwiched between the equal absorption points E1 and E4, that is, the combined band of the wavelength bands R1, R2, and R3 is the wavelength band. R0. Therefore, the wavelength band of the Wide light, which is the transmitted light that has passed through the optical filter Fs1 out of the light emitted from the light source lamp 430, is the wavelength band R0, and the light emitted from the light source lamp 430 is transmitted through the optical filter Fs2.
  • the wavelength band of the narrow light that is the transmitted light is the wavelength band R2.
  • the absorption of hemoglobin increases or decreases linearly with respect to the oxygen saturation.
  • the absorptions AR1 and AR3 of hemoglobin in the wavelength bands R1 and R3 increase linearly with respect to the oxygenated hemoglobin concentration, that is, the oxygen saturation.
  • the absorption AR2 of hemoglobin in the wavelength band R2 increases linearly with respect to the concentration of reduced hemoglobin.
  • the oxygen saturation is defined by the following equation (1).
  • formulas (2) and (3) representing the concentrations of oxygenated hemoglobin HbO and reduced hemoglobin Hb are obtained.
  • the absorption AR1, AR2, and AR3 of hemoglobin are characteristic amounts that depend on both the oxygen saturation and the amount of hemoglobin.
  • the total value of absorbance in the wavelength band R0 does not depend on the oxygen saturation Sat, but is a value determined by the amount of hemoglobin. Therefore, the amount of hemoglobin can be quantified based on the total absorbance in the wavelength band R0.
  • the oxygen saturation Sat can be quantified based on the total absorbance in the wavelength band R1, the wavelength band R2, or the wavelength band R3 and the amount of hemoglobin quantified based on the total value in the wavelength band R0. .
  • the feature amount acquisition unit 510 of the present embodiment calculates a hemoglobin amount of the biological tissue T based on a later-described first ratio having sensitivity to the amount of hemoglobin of the biological tissue T, and acquires a hemoglobin calculation unit 510a.
  • An oxygen saturation calculation unit 510b that calculates and acquires the oxygen saturation of hemoglobin in the living tissue T based on the calculated amount of hemoglobin and the second ratio described later having sensitivity to the oxygen saturation of hemoglobin, and a data selection unit 510c and a positional deviation amount calculation unit 510d.
  • the hemoglobin amount calculation unit 510a of the feature amount acquisition unit 510 of the form calculates the amount of hemoglobin based on the luminance component of the color image data in the wavelength band R0.
  • the luminance component is obtained by multiplying the R component of the color image data by a predetermined coefficient, multiplying the G component of the color image data by a predetermined coefficient, and multiplying the value of the B component of the color image data by a predetermined coefficient.
  • the result of multiplication can be calculated by adding them up.
  • the hemoglobin amount calculation unit 510a of the feature amount acquisition unit 510 includes color image data (first special light color image data) of the living tissue T using Wide light (first special light) as the illumination light IL.
  • the ratio Wide (Yh) / WL (R) or Wide (Yh) / ⁇ WL (R) + WL (G) ⁇ divided by the total component WL (R) + WL (G) of the G component WL (G) first The amount of hemoglobin is calculated based on the ratio.
  • WL (R) + WL (G) ⁇ is used to eliminate the change in the spectral characteristics of the living tissue T depending on the degree to which the illumination light IL is scattered on the surface of the living tissue T.
  • the reflection spectrum of the living tissue T such as the inner wall of the digestive tract has a wavelength characteristic of absorption by the components constituting the living tissue T (specifically, absorption spectrum characteristics of oxygenated hemoglobin and reduced hemoglobin), It is easily affected by the wavelength characteristic of scattering of illumination light by T.
  • R component WL (R) of color image data (reference light color image data) of living tissue T using white light WL (reference light) as illumination light IL, or total component WL (R) + WL of R component and G component (G) represents the degree of scattering of the illumination light IL in the living tissue T without being affected by the amount of hemoglobin or the oxygen saturation Sat.
  • the wavelength band of the white light WL is one of the components of the reference light color image data, It is preferable that the wavelength band is set so as not to be sensitive to changes in the amount of hemoglobin in the living tissue T. In addition, the wavelength band of the white light WL (reference light) is set so that one of the components of the reference light color image data includes a wavelength band that is not sensitive to changes in oxygen saturation. It is preferable.
  • a reference table representing the correspondence relationship between the information on the first ratio and the amount of hemoglobin in the living tissue T in which the amount of hemoglobin is known is stored in advance in the memory 512, and this reference table is used.
  • the amount of hemoglobin is calculated based on the value of the first ratio in the color image data captured by the living tissue T.
  • FIG. 6 is a diagram illustrating an example of a correspondence relationship between the first ratio and the amount of hemoglobin. In the figure, the amount of hemoglobin is normalized to be in the range of 0 to 1024, and the first ratio is normalized to be in the range of 0 to 1.
  • the luminance component of the color image data (first special light color image data) of the living tissue T using Wide light (first special light) as the illumination light IL as the first ratio.
  • G component Wide (G) instead of the luminance component Wide (Yh) of the color image data (first special light color image data) of the living tissue T using the illumination light IL.
  • the oxygen saturation calculation unit 510b of the feature amount acquisition unit 510 calculates the oxygen saturation Sat based on the second ratio defined below.
  • the oxygen saturation calculation unit 510b performs color image data (second special light color image data) of the living tissue T illuminated with the narrow light (second special light) that is the light in the wavelength band R2 that has passed through the optical filter Fs2.
  • the ratio Narrow (Yh) / Wide (Yh) is calculated as the second ratio.
  • the correspondence relationship obtained is obtained from a known sample and stored in the memory 512 in advance.
  • the oxygen saturation calculation unit 510b of the feature amount acquisition unit 510 uses the calculation result of the amount of hemoglobin obtained from the color image data generated by imaging the living tissue T and the above correspondence, and the lower limit value and the upper limit of the second ratio. A value is obtained, and the oxygen saturation Sat linearly changes according to the second ratio between the obtained lower limit value and upper limit value.
  • the second ratio Narrow (Yh) / Wide (Yh) of the imaged living tissue T Is calculated at which oxygen saturation Sat. In this way, the oxygen saturation calculation unit 510b of the feature amount acquisition unit 510 calculates the oxygen saturation Sat.
  • FIG. 7 is a diagram illustrating an example of the relationship between the upper limit value (Sat 100%) and the lower limit value (Sat 0%) of the second ratio that changes in accordance with the amount of hemoglobin.
  • the amount of hemoglobin is normalized to be in the range of 0 to 1024
  • the second ratio is normalized to be in the range of 0 to 1.
  • a reference table representing the correspondence relationship between the amount of hemoglobin and the value of the second ratio and the oxygen saturation Sat of hemoglobin is obtained from a known sample and stored in the memory 512 in advance, and this reference table is referred to.
  • the oxygen saturation Sat of hemoglobin can also be calculated from the calculated second ratio.
  • the second ratio is the luminance component Narrow (Yh) of the color image data (second special light color image data) of the living tissue T illuminated with the narrow light and the color of the living tissue T illuminated with the wide light.
  • G component Narrow of color image data (second special light color image data) of living tissue T illuminated with Narrow light which is used as a ratio with the luminance component Wide (Yh) of image data (first special light color image data).
  • the ratio between (G) and the G component Wide (G) of the color image data (first special light color image data) of the living tissue T illuminated with Wide light can also be used.
  • the narrow light in the wavelength band R2 is used for illumination of the living tissue T for the calculation of the second ratio, but is not limited to the narrow light.
  • special light having the wavelength band R1 or the wavelength band R2 as the wavelength band is used with the intention of using the wavelength band R1 or the wavelength band R2 in which the total absorbance changes with respect to the change in the oxygen saturation Sat.
  • the filter characteristic of the optical filter Fs2 may be set to the wavelength band R1 or the wavelength band R2.
  • the wavelength band of the narrow light may be included in the wavelength band of the wide light (first special light).
  • the wavelength band of Wide light is one of the components of the first special light color image data, for example, the luminance component and the G component are sensitive to changes in the amount of hemoglobin. It is preferable that the setting is made so as to include the wavelength band R0 that does not have sensitivity to the change in the saturation, because the oxygen saturation Sat can be accurately calculated.
  • the wavelength band of the narrow light (second special light) one of the components of the second special light color image data, for example, the luminance component and the G component is sensitive to a change in the oxygen saturation Sat of the living tissue T. It is preferable that the wavelength band R2 is set so as to include the oxygen saturation Sat accurately.
  • the above-mentioned Wide light is one of optical filters, and a wavelength band (first wavelength band) within a range of 500 nm to 600 nm in a wavelength band of white light WL (reference light),
  • the narrow light (second special light) is one of the optical filters.
  • a wavelength band (second wavelength band) narrower than the first wavelength band within the first wavelength band for example, a wavelength band between the equal absorption point E2 and the equal absorption point E3. It is preferably filtered light of the transmitted white light WL (reference light).
  • a feature amount distribution image such as an oxygen saturation distribution image showing the distribution of oxygen saturation Sat is required to have high image quality.
  • the feature amount distribution image is preferably 1 million pixels or more, more preferably 2 million pixels or more, and further preferably 8 million pixels or more.
  • the arithmetic circuit of the processor 200 increases and the processing load tends to increase. In particular, the above tendency is remarkable at a high pixel (high image quality) of 1 million pixels or more.
  • a reference table is provided in advance, and the amount of hemoglobin and the oxygen saturation Sat are calculated using this reference table.
  • the amount of hemoglobin and the oxygen saturation are obtained each time color image data is acquired.
  • the amount of hemoglobin and the oxygen saturation Sat can be calculated more efficiently than when Sat is calculated without using a reference table. For this reason, the arithmetic circuit of the processor 200 can be reduced. Accordingly, even when a high-quality image is generated, the low-cost, low heat generation, and low power-saving processor 200 can be provided.
  • the light source device 400 is configured to repeat the emission of a plurality of cycles, with the emission of white light WL (reference light), wide light, and narrow light (special light) as one cycle, and the image sensor 141 in one cycle includes
  • the number of times that the reference light color image data is generated is preferably larger than the number of times that the image sensor 141 generates the first special light color image data and the number of times that the image sensor 141 generates the second special light color image data. .
  • the ratio of the number of times of generating the reference light color image data to the number of times of generating the first special light color image data and the second special light color image data of the number of times of generating the reference light color image data are generated.
  • the ratio to the number of times is preferably 1.5 or more, and more preferably 2 or more.
  • the upper limit of this ratio is not particularly limited, but is preferably 4 or less from the viewpoint of securing a refresh rate of a feature amount distribution image obtained using the first and second special light color image data to a predetermined value or more. More preferably, it is 3 or less.
  • the refresh rate of the normal observation image is improved, the refresh rate of the feature amount distribution image is lowered relative to the refresh rate of the normal observation image. Since this is an auxiliary image for specifying the position of the lesion part in the inside, even if the refresh rate is relatively lowered, the stress applied to the operator who observes the living tissue T is small.
  • the electronic endoscope 100 is configured such that the imaging element 141 receives reflected light of the living tissue T in the wavelength bands of white light WL (reference light), wide light, and narrow light (special light).
  • the optical system includes the objective lens group 121 as described above, but does not include a cut filter that cuts at least part of the wavelength band of white light WL (reference light), wide light, and narrow light (special light). Accordingly, in the present embodiment, it is possible to obtain a highly accurate distribution image of the amount of hemoglobin and the oxygen saturation of hemoglobin by illuminating the living tissue T with the illumination light IL in the wavelength band described above. Therefore, it is preferable that the optical system is configured to transmit light in the wavelength bands of white light WL (reference light), wide light, and narrow light (special light).
  • the feature amount acquisition unit 510 of the present embodiment includes a data selection unit 510c and a positional deviation amount calculation unit 510d, so that the amount of highly reliable hemoglobin and oxygen saturation of hemoglobin are distributed. Is preferable in that it can be obtained.
  • the white light WL (reference light) and the wide light (first special light) emitted with a time interval are used for generating color image data used for calculating the first ratio.
  • white light WL (reference light) and Wide light (first special light) are used as other illumination light IL. It is preferable that the light is continuously emitted without interposing it.
  • the Wide light (first special light) and the narrow light (second special light) are used for generating color image data used for calculating the second ratio. It is preferable that (second special light) and Wide light (first special light) are continuously emitted without other emission.
  • the white light WL reference light
  • the white light WL1 is emitted from the light source device 200 between the narrow light emission and the wide light (first special light), and the wide light (first special light) is emitted and the white light.
  • the illumination light IL is emitted in the order in which the emission of WL2 (second reference light) is continued without interfering with other emission.
  • Narrow light second special light
  • white light WL1 first reference light
  • Wide light first special light
  • white light WL2 second special light
  • the light is emitted in the order of reference light.
  • the processor 200 obtains first reference light color image data by imaging the living tissue T illuminated with the white light WL1 (first reference light), and illuminates with the white light WL2 (second reference light).
  • the second reference light color image data is obtained by imaging the biological tissue T thus obtained. Therefore, the data selection unit 510c selects which of the first reference light color image data and the second reference light color image data is used for calculating the first ratio.
  • the selection by the data selection unit 510c is performed based on the amount of positional deviation between the image of the living tissue T in the first reference light color image data and the image of the living tissue T in the second reference light color image data in each cycle. Is called. For example, an image position shift may occur between the normal observation image and the oxygen saturation distribution image due to a rapid movement of the living tissue T or a hand shake during a procedure using the endoscope 100.
  • the feature amount calculation unit 510 uses the Wide light (first special light) without interposing other emission in order to suppress a decrease in reliability of the feature amount due to the displacement of the image of the living tissue T.
  • the first ratio is calculated using the second reference color image data and the first special light color image data obtained by continuously emitting the white light WL2 (second reference light).
  • the reliability of the first ratio due to the positional deviation of the image of the living tissue T may be reduced.
  • the emission of the white light WL2 (second reference light) is narrower than the emission of the white light WL1 (first reference light) (second special light). It is far from the emission of light.
  • the living tissue T represented by the first reference light color image data in each cycle. It is preferable to calculate the amount of positional deviation between the image of and the image of the living tissue T represented by the second reference light color image data. At this time, if the amount of positional deviation is outside the allowable range, the data selection unit 510c calculates the first ratio using the first reference color image data instead of the second reference color image data. Make a selection.
  • the image of the living tissue T illuminated with the white light WL1 (first reference light) and the image of the living tissue T illuminated with the narrow light (second special light) and the wide light (first special light) are used.
  • the possibility that the positional deviation amount is outside the allowable range with respect to the image of the illuminated living tissue T is quite low.
  • the feature amount acquisition unit 510 illuminates the image of the living tissue T illuminated with the white light WL1 (first reference light) and captured with the white light WL2 (second reference light) for the image of the living tissue T captured. It is preferable to include a positional deviation amount calculation unit 510d that calculates the positional deviation amount of the image. At this time, if the calculated displacement amount is outside the allowable range, the data selection unit 510c selects the first reference light color image data to be used for calculating the first ratio instead of the second reference light color image data. .
  • the amount of positional deviation of the image of the biological tissue T is, for example, two directions in the image based on the calculation result of the cross-correlation function between components at the same pixel position of the first reference light color image data and the second reference light image data Can be calculated.
  • the white light WL1 (first reference light) is emitted between the emission of the narrow light (second special light) and the emission of the wide light (first special light).
  • the white light WL1 (first special light) is emitted between the emission of the Wide light (first special light) and the second special light. It is preferable to emit reference light).
  • the white light WL2 (second reference light) is emitted before the Wide light (first special light)
  • the white light WL2 (second reference light)
  • the emission and the emission of the Wide light (first special light) be performed in the order in which the other emission is continued without being separated.
  • FIG. 8 is a diagram illustrating an example of a normal observation image displayed as a moving image on the display 300 of the endoscope system of the present embodiment and an oxygen saturation distribution image of hemoglobin.
  • the left image in the figure is a normal observation image
  • the right image is a distribution image of the oxygen saturation of hemoglobin.
  • the refresh rate of the normal observation image shown in FIG. 8 is such that no stress is given to the observation of the operator. For this reason, the operator who performs the procedure while operating the endoscope 100 can observe the living tissue T without stress, and the position of interest in the oxygen saturation distribution image of the hemoglobin of the living tissue T with high accuracy, for example, oxygen saturation.
  • a low-degree position can be identified on the image of the living tissue T in the normal observation image.
  • the endoscope system of the present invention has been described in detail above, the endoscope system of the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Of course it is also good.

Abstract

This endoscope system is provided with: a light source device which repeatedly emits, in a prescribed order and as illumination light for illuminating biological tissue, a reference light and multiple special lights, in different wavelength regions; an imaging element which generates color image data of an image of the biological tissue illuminated with the aforementioned illumination light; a processor which is provided with a feature value acquisition unit that uses the aforementioned color image data to calculate oxygen saturation of hemoglobin in the biological tissue; and a display which displays an image of the biological tissue and a distribution image of the oxygen saturation. Regarding the order of the illumination light in one cycle, emission of the reference light between one emission of the aforementioned special light and another emission of the special light is carried out by the light source device at least twice, without continuous emission of the reference light.

Description

内視鏡システムEndoscope system
　本発明は、生体組織の撮影により生成した画像データに基づいて、生体組織中の特徴量を算出し取得する内視鏡システムに関する。 The present invention relates to an endoscope system that calculates and acquires a feature amount in a living tissue based on image data generated by imaging the living tissue.
　内視鏡によって得られた画像データから、被写体である生体組織中の生体物質、例えば、ヘモグロビンの量やヘモグロビンの酸素飽和度の情報を生体組織の特徴量として求める機能を備えた内視鏡システムが知られている。このような内視システムの一例が特許文献１に記載されている。 An endoscope system having a function of obtaining, as a feature amount of a biological tissue, information on a biological substance in a biological tissue as a subject, for example, information on the amount of hemoglobin and oxygen saturation of hemoglobin, from image data obtained by the endoscope It has been known. An example of such an endoscope system is described in Patent Document 1.
　特許文献１に記載の内視鏡システムは、回転フィルタが搭載された光源装置を備えている。回転フィルタには、３つの光バンドパスフィルタ（５５０ｎｍ帯の光を選択的に透過させる光バンドパスフィルタが２つ、６５０ｎｍ帯の光を選択的に透過させる光バンドパスフィルタが１つ）と白色光を透過させる通常観察用フィルタが円周方向に並べて配置されている。コントローラは、回転フィルタを一定の回転周期で回転駆動させて、各フィルタを白色光の光路に順次挿入し、各フィルタを透過した照射光による生体組織の撮像を順次行う。コントローラは、各光バンドパスフィルタを用いて撮像された画像のデータに基づいて生体組織中の生体分子の分布を示す分布画像、例えばヘモグロビンの酸素飽和度の分布を示す酸素飽和度分布画像を生成し、生成された分布画像を、通常観察用フィルタを用いて撮像された通常観察画像と並べて表示画面内に表示する。 The endoscope system described in Patent Document 1 includes a light source device on which a rotary filter is mounted. The rotary filter includes three optical bandpass filters (two optical bandpass filters that selectively transmit light in the 550 nm band and one optical bandpass filter that selectively transmits light in the 650 nm band) and white Normal observation filters that transmit light are arranged side by side in the circumferential direction. The controller rotationally drives the rotary filter at a constant rotation period, sequentially inserts each filter into the white light optical path, and sequentially performs imaging of the living tissue with the irradiation light transmitted through each filter. The controller generates a distribution image indicating the distribution of biomolecules in the biological tissue, for example, an oxygen saturation distribution image indicating the oxygen saturation distribution of hemoglobin, based on the image data captured using each optical bandpass filter. The generated distribution image is displayed in the display screen side by side with the normal observation image captured using the normal observation filter.
国際公開第２０１４／１９２７８１号International Publication No. 2014/192781
　特許文献１に記載の内視鏡システムにおいて、回転フィルタに配置された３つの光バンドパスフィルタと１つの通常観察用フィルタの計４つは、フレームレートに同期したタイミングで白色光の光路に順次挿入される。しかし、この構成では、通常観察用フィルタによる通常観察画像の撮像が４フレーム毎にしか行われないことから、画面表示される通常観察画像のリフレッシュレートが低いという問題がある。 In the endoscope system described in Patent Document 1, a total of four optical bandpass filters and one normal observation filter arranged in a rotary filter are sequentially placed in the optical path of white light at a timing synchronized with the frame rate. Inserted. However, this configuration has a problem that the normal observation image displayed on the screen has a low refresh rate because the normal observation image is captured only every four frames by the normal observation filter.
　本発明は上記の事情に鑑みてなされたものであり、複数の光を用いて照明した生体組織の撮像画像データから生成される、生体組織のヘモグロビンの量や酸素飽和度等の特徴量の分布画像を通常観察画像とともにディスプレイに表示する際、内視鏡を操作しながら手技を行う操作者にとって生体組織の通常観察画像をストレスなく観察でき、精度の高い生体組織の特徴量の分布画像中の注目する位置を、通常観察画像中の生体組織の像上で特定することが容易にできる内視鏡システムを提供することを目的とする。 The present invention has been made in view of the above circumstances, and is a distribution of feature amounts such as the amount of hemoglobin and oxygen saturation of biological tissue generated from captured image data of biological tissue illuminated with a plurality of lights. When displaying an image together with the normal observation image on the display, the operator who performs the procedure while operating the endoscope can observe the normal observation image of the living tissue without stress, and the highly accurate distribution image of the characteristic amount of the living tissue It is an object of the present invention to provide an endoscope system that can easily identify a position of interest on an image of a biological tissue in a normal observation image.
　本発明の内視鏡システムは、以下の形態を含む。 The endoscope system of the present invention includes the following forms.
（形態１）
　お互いに波長帯域の異なる、基準光と少なくとも第１特殊光及び第２特殊光を含む複数の特殊光の出射を１サイクルとして、前記基準光と前記特殊光を生体組織の照明光として前記１サイクルを繰り返すように構成された光源装置と、
　前記照明光のそれぞれで前記生体組織が照明されるたびに前記生体組織を前記照明光の出射のタイミングに合わせて撮像することにより、前記照明光で照明した前記生体組織の像のカラー画像データを生成するように構成された撮像素子を備える内視鏡と、
　前記カラー画像データを用いて前記生体組織のヘモグロビンの量及び前記生体組織のヘモグロビンの酸素飽和度を前記生体組織の特徴量として算出するように構成された特徴量取得部を備えるプロセッサと、
　前記基準光で照明され前記撮像素子で撮像された前記生体組織の画像と、前記ヘモグロビンの量及び前記酸素飽和度の少なくとも一方の分布を示した特徴量分布画像とを表示するように構成されたディスプレイと、を備え、
　前記特徴量取得部は、前記カラー画像データのうち、前記第１特殊光の照明により得られた第１特殊光カラー画像データの成分と前記基準光の照明により得られた基準光カラー画像データの成分を用いて前記ヘモグロビンの量を算出するように構成されたヘモグロビン量算出部と、前記第１特殊光の照明により得られた第１特殊光カラー画像データの成分と前記第２特殊光の照明により得られた第２特殊光カラー画像データの成分を用いて前記ヘモグロビンの酸素飽和度を算出するように構成された酸素飽和度算出部を含み、
　前記光源装置は、前記照明光の順番に関して、前記１サイクルにおいて、前記特殊光の１つの出射と前記特殊光の別の出射の間に前記基準光の出射を行うことを、少なくとも２回、前記基準光の出射を続けることなく行うように構成されている、ことを特徴とする内視鏡システム。 (Form 1)
The reference light and a plurality of special lights including at least the first special light and the second special light, which are different in wavelength band from each other, are emitted as one cycle, and the reference light and the special light are used as illumination light for living tissue. A light source device configured to repeat
Color image data of the image of the biological tissue illuminated with the illumination light is obtained by imaging the biological tissue in accordance with the timing of emission of the illumination light each time the biological tissue is illuminated with each of the illumination light. An endoscope comprising an imaging device configured to generate;
A processor comprising a feature amount acquisition unit configured to calculate the amount of hemoglobin in the living tissue and the oxygen saturation level of hemoglobin in the living tissue as the feature amount of the living tissue using the color image data;
An image of the biological tissue illuminated with the reference light and imaged by the imaging device, and a feature amount distribution image showing at least one distribution of the amount of the hemoglobin and the oxygen saturation are displayed. A display, and
The feature amount acquisition unit includes a component of the first special light color image data obtained by illumination of the first special light and the reference light color image data obtained by illumination of the reference light among the color image data. A hemoglobin amount calculating unit configured to calculate the amount of the hemoglobin using a component, the component of the first special light color image data obtained by the illumination of the first special light, and the illumination of the second special light An oxygen saturation calculator configured to calculate the oxygen saturation of the hemoglobin using the component of the second special light color image data obtained by
The light source device emits the reference light at least twice between one emission of the special light and another emission of the special light in the one cycle with respect to the order of the illumination light. An endoscope system configured to perform the emission of reference light without continuing.
（形態２）
　前記基準光及び前記特殊光の出射の順番に関して、前記第１特殊光の出射と前記基準光の１回の出射とが、あるいは前記基準光の１回の出射と前記第１特殊光の出射とが、他の出射をはさまず連続している、形態１に記載の内視鏡システム。 (Form 2)
Regarding the order of emission of the reference light and the special light, the emission of the first special light and the single emission of the reference light, or the single emission of the reference light and the emission of the first special light, However, the endoscope system according to the first aspect, in which the other emission is continuous.
（形態３）
　前記基準光及び前記特殊光の出射の順番に関して、前記第２特殊光の出射と前記基準光の１回の出射とが、あるいは前記基準光の１回の出射と前記第２特殊光の出射とが、他の出射をはさまず連続している、形態２に記載の内視鏡システム。 (Form 3)
Regarding the order of emission of the reference light and the special light, the emission of the second special light and the single emission of the reference light, or the single emission of the reference light and the emission of the second special light, However, the endoscope system according to the second aspect, in which the other emission is continuous without being interrupted.
（形態４）
　前記光源装置は、１つの光を放射するように構成された光源を備え、
　前記光源装置は、前記基準光及び前記特殊光の出射の順番に対応するように、前記光源の放射光を、通過波長帯域の異なる複数の光学フィルタを透過させることにより前記基準光及び前記特殊光を出射するように構成されている、形態１～３のいずれか１つに記載の内視鏡システム。 (Form 4)
The light source device comprises a light source configured to emit a single light;
The light source device transmits the reference light and the special light by transmitting the light emitted from the light source through a plurality of optical filters having different pass wavelength bands so as to correspond to the order of emission of the reference light and the special light. The endoscope system according to any one of Embodiments 1 to 3, wherein the endoscope system is configured to emit light.
（形態５）
　前記基準光の波長帯域は前記特殊光の波長帯域に比べて広く、
　前記基準光の波長帯域は、前記基準光カラー画像データの成分の１つが、前記生体組織のヘモグロビンの量の変化に対して感度を有しないような波長帯域を含む、形態１～４のいずれか１つに記載の内視鏡システム。 (Form 5)
The wavelength band of the reference light is wider than the wavelength band of the special light,
The wavelength band of the reference light includes a wavelength band in which one of the components of the reference light color image data does not have sensitivity to a change in the amount of hemoglobin in the living tissue. The endoscope system according to one.
（形態６）
　前記第１特殊光の波長帯域は、前記第１特殊光カラー画像データの成分の１つが、前記生体組織のヘモグロビン量の変化に対して感度を有するが、前記酸素飽和度の変化に対して感度を有しないような波長帯域を含む、形態１～５のいずれか１つに記載の内視鏡システム。 (Form 6)
In the wavelength band of the first special light, one of the components of the first special light color image data is sensitive to changes in the amount of hemoglobin in the living tissue, but sensitive to changes in the oxygen saturation. The endoscope system according to any one of Embodiments 1 to 5, including a wavelength band that does not include
（形態７）
　前記第２特殊光の波長帯域は、前記第２特殊光カラー画像データの成分の１つが、前記酸素飽和度の変化に対して感度を有するような波長帯域を含む、形態１～６のいずれか１つに記載の内視鏡システム。 (Form 7)
The wavelength band of the second special light includes any one of modes 1 to 6, wherein one of the components of the second special light color image data includes a wavelength band having sensitivity to the change in oxygen saturation. The endoscope system according to one.
（形態８）
　前記第１特殊光は、光学フィルタで、前記基準光の波長帯域のうち５００ｎｍ～６００ｎｍの範囲内の第１波長帯域を透過させた前記基準光の濾過光であり、前記第２特殊光は、光学フィルタで、前記第１波長帯域の範囲内の前記第１波長帯域より狭い第２波長帯域を透過させた前記基準光の濾過光である、形態１～７のいずれか１つに記載の内視鏡システム。 (Form 8)
The first special light is an optical filter that is filtered light of the reference light that transmits a first wavelength band within a range of 500 nm to 600 nm of the wavelength band of the reference light, and the second special light is: The optical filter according to any one of Embodiments 1 to 7, wherein the reference light is a filtered light of the reference light that has been transmitted through a second wavelength band narrower than the first wavelength band within the first wavelength band. Endoscopic system.
（形態９）
　前記ヘモグロビン量算出部は、前記基準光カラー画像データの成分と前記第１特殊光カラー画像データの成分との比率である第１比率に基づいて前記ヘモグロビンの量を算出するように構成され、
　前記酸素飽和度算出部は、前記第１特殊光カラー画像データの成分と前記第２特殊光カラー画像データの成分との比率である第２比率に基づいて前記ヘモグロビンの酸素飽和度を算出するように構成されている、形態１～８のいずれか１つに記載の内視鏡システム。 (Form 9)
The hemoglobin amount calculating unit is configured to calculate the amount of the hemoglobin based on a first ratio that is a ratio of the component of the reference light color image data and the component of the first special light color image data,
The oxygen saturation calculating unit calculates oxygen saturation of the hemoglobin based on a second ratio that is a ratio between the component of the first special light color image data and the component of the second special light color image data. The endoscope system according to any one of Embodiments 1 to 8, which is configured as follows.
（形態１０）
　前記第１比率は、前記基準光カラー画像データの輝度成分と、前記第１特殊光カラー画像データのＲ成分、あるいはＲ成分及びＧ成分の合計成分との比率である、形態９に記載の内視鏡システム。 (Form 10)
The internal ratio according to claim 9, wherein the first ratio is a ratio between a luminance component of the reference light color image data and an R component of the first special light color image data, or a total component of the R component and the G component. Endoscopy system.
（形態１１）
　前記第２比率は、前記第２特殊光カラー画像データの輝度成分と前記第１特殊光カラー画像データの輝度成分との比率である、形態９または１０に記載の内視鏡システム。 (Form 11)
The endoscope system according to embodiment 9 or 10, wherein the second ratio is a ratio between a luminance component of the second special light color image data and a luminance component of the first special light color image data.
（形態１２）
　前記基準光は、同じ波長帯域の第１基準光と第２基準光を含み、
　前記光源装置は、前記照明光の出射の順番に関して、前記第１特殊光の出射と前記第２特殊光の出射の間に、あるいは前記第２特殊光の出射と前記第１特殊光の出射の間に、前記第１基準光の出射を行い、かつ前記第１特殊光の出射と前記第２基準光の出射とを、あるいは、前記第２基準光の出射と前記第１特殊光の出射とを、他の出射をはさまず連続させた順番で前記照明光を出射するように構成され、
　前記特徴量取得部は、前記特徴量の算出のために、前記第１基準光で照明した前記生体組織の像の第１基準光カラー画像データ及び前記第２基準光で照明した前記生体組織の像の第２基準光カラー画像データのいずれか一方を選択して用いるように構成されたデータ選択部を備える、形態１～１１のいずれか１つに記載の内視鏡システム。 (Form 12)
The reference light includes a first reference light and a second reference light having the same wavelength band,
The light source device may be arranged between the emission of the first special light and the emission of the second special light, or between the emission of the second special light and the emission of the first special light with respect to the order of emission of the illumination light. In between, the first reference light is emitted and the first special light and the second reference light are emitted, or the second reference light and the first special light are emitted. Is configured to emit the illumination light in an order in which the other emission is continued without being interrupted,
The feature amount acquisition unit calculates first feature color image data of an image of the biological tissue illuminated with the first reference light and the biological tissue illuminated with the second reference light for calculating the feature amount. The endoscope system according to any one of Embodiments 1 to 11, further comprising a data selection unit configured to select and use any one of the second reference light color image data of the image.
（形態１３）
　前記光源装置における前記照明光の出射の順番に関して、前記１サイクルにおいて、前前記第２基準光の出射は記第１基準光の出射に比べて前記第２特殊光の出射から離れており、
　前記特徴量取得部は、前記第１基準光で照明し前記撮像素子で撮像した前記生体組織の像に対する前記第２基準光で照明し前記撮像素子で撮像した前記生体組織の像の位置ずれ量を算出するように構成された位置ずれ量算出部を備え、
　前記データ選択部は、算出した前記位置ずれ量が許容範囲を外れる場合、前記第２基準光カラー画像データに代えて、前記第１基準光カラー画像データを、前記特徴量の算出に用いるように構成されている、形態１２に記載の内視鏡システム。 (Form 13)
Regarding the order of emission of the illumination light in the light source device, in the first cycle, the emission of the second reference light is farther from the emission of the second special light than the emission of the first reference light,
The feature amount acquisition unit illuminates with the first reference light and illuminates with the second reference light with respect to the image of the biological tissue captured by the imaging element, and a positional deviation amount of the image of the biological tissue captured by the imaging element A misregistration amount calculation unit configured to calculate
The data selection unit may use the first reference light color image data for calculating the feature amount instead of the second reference light color image data when the calculated positional deviation amount is out of an allowable range. The endoscope system according to form 12, which is configured.
（形態１４）
　前記内視鏡は、前記撮像素子が、前記基準光及び前記特殊光の波長帯域の、前記生体組織の反射光を受光するように構成された光学系を備える、形態１～１３のいずれか１つに記載の内視鏡システム。 (Form 14)
The endoscope has any one of forms 1 to 13, wherein the imaging device includes an optical system configured to receive reflected light of the living tissue in a wavelength band of the reference light and the special light. Endoscope system according to one.
（形態１５）
　前記光学系は、前記基準光及び前記特殊光の波長帯域の光を透過するように構成されている、形態１４に記載の内視鏡システム。 (Form 15)
The endoscope system according to aspect 14, wherein the optical system is configured to transmit light in a wavelength band of the reference light and the special light.
（形態１６）
　前記光源装置は、１つの光を放射するように構成された光源と、前記基準光及び前記特殊光の出射の順番に対応するように、前記光源の放射光を、通過波長帯域の異なる複数の光学フィルタを透過させることにより前記基準光及び前記特殊光を出射するように構成された、前記光学フィルタが円周上に間隔をあけて配置された回転フィルタと、を備え、
　前記撮像素子はローリングシャッタで受光面の露光を行うＣＭＯＳイメージセンサであり、
　前記回転フィルタは、前記光学フィルタ間に、光を遮断する遮断区間を有する、形態１～１５のいずれか１つに記載の内視鏡システム。 (Form 16)
The light source device includes: a light source configured to emit one light; and a plurality of light beams emitted from the light source having different pass wavelength bands so as to correspond to an order of emission of the reference light and the special light. A rotary filter configured to emit the reference light and the special light by transmitting the optical filter, the optical filter being arranged on the circumference with an interval; and
The image sensor is a CMOS image sensor that exposes the light receiving surface with a rolling shutter;
The endoscope system according to any one of Embodiments 1 to 15, wherein the rotary filter has a blocking section that blocks light between the optical filters.
（形態１７）
　前記光源装置は、前記基準光及び前記特殊光の出射を１サイクルとして、複数サイクルの出射を繰り返すように構成され、
　前記１サイクル中の前記撮像素子が前記基準光カラー画像データを生成する回数は、前記撮像素子が前記第１特殊光カラー画像データを生成する回数及び前記撮像素子が前記第２特殊光カラー画像データを生成する回数に比べて多い、形態１～１６のいずれか１つに記載の内視鏡システム。 (Form 17)
The light source device is configured to repeat emission of a plurality of cycles, with the emission of the reference light and the special light as one cycle.
The number of times that the image pickup device generates the reference light color image data in the one cycle is the number of times the image pickup device generates the first special light color image data and the image pickup device generates the second special light color image data. The endoscope system according to any one of Embodiments 1 to 16, wherein the endoscope system is larger than the number of times of generating.
（形態１８）
　前記１サイクルにおいて、前記基準光カラー画像データを生成する回数の、前記第１特殊光カラー画像データを生成する回数に対する比、及び前記基準光カラー画像データを生成する回数の、前記第２特殊光カラー画像データを生成する回数に対する比は、１．５以上である、形態１７に記載の内視鏡システム。 (Form 18)
The ratio of the number of times of generating the reference light color image data to the number of times of generating the first special light color image data and the number of times of generating the reference light color image data in the one cycle The endoscope system according to aspect 17, wherein a ratio to the number of times color image data is generated is 1.5 or more.
　上述の内視鏡システムによれば、内視鏡を操作しながら手技を行う操作者にとって生体組織をストレスなく観察でき、精度の高い生体組織の特徴量分布画像中の注目する位置を、通常観察画像中の生体組織の像上で特定することができる。 According to the above-described endoscope system, a biological tissue can be observed without stress for an operator who performs a procedure while operating the endoscope, and a focused position in a feature amount distribution image of the biological tissue with high accuracy is normally observed. It can be specified on the image of the living tissue in the image.
本実施形態の内視鏡システムの一例の構成のブロック図である。It is a block diagram of an example of composition of an endoscope system of this embodiment. 本実施形態で用いる撮像素子に内蔵されるカラーフィルタの透過スペクトルである。It is a transmission spectrum of the color filter incorporated in the image pick-up element used by this embodiment. 本実施形態で用いる回転フィルタの外観図である。It is an external view of the rotary filter used in this embodiment. ５５０ｎｍ付近のヘモグロビンの吸収スペクトルの一例を示す図である。It is a figure which shows an example of the absorption spectrum of hemoglobin near 550 nm. 本実施形態の光源装置における基準光及び特殊光の出射の順番の一例を示す図である。It is a figure which shows an example of the output order of the reference light and special light in the light source device of this embodiment. 本実施形態で用いる第１比率とヘモグロビンの量の対応関係の一例を示す図である。It is a figure which shows an example of the correspondence of the 1st ratio used in this embodiment, and the quantity of hemoglobin. 本実施形態で用いる第２補正比率とヘモグロビンの酸素飽和度Ｓａｔとの関係の一例を示す図である。It is a figure which shows an example of the relationship between the 2nd correction ratio used in this embodiment, and the oxygen saturation Sat of hemoglobin. 本実施形態の内視鏡システムのディスプレイに動画として表示される通常観察画像とヘモグロビンの酸素飽和度の分布画像の一例を示す図である。It is a figure which shows an example of the normal observation image displayed as a moving image on the display of the endoscope system of this embodiment, and the distribution image of the oxygen saturation of hemoglobin.
（本実施形態の概説）
　本実施形態の内視鏡システムを概説すると以下の通りである。本実施形態の内視鏡システムは、光源装置、撮像素子を備える内視鏡、プロセッサ、及びディスプレイを備える。光源装置は、お互いに波長帯域が異なる基準光と少なくとも第１特殊光及び第２特殊光を含む複数の特殊光の出射を１サイクルとして、基準光と特殊光を生体組織の照明光として１サイクルを繰り返す。お互いに波長帯域が異なる基準光と複数の特殊光とは、基準光の波長帯域と複数の特殊光の波長帯域は異なり、複数の特集光の波長帯域もお互いに異なることをいう。この照明光のそれぞれで生体組織が照明されるたびに生体組織を照明光の出射のタイミングに合わせて撮像素子で撮像することにより、撮像素子は、各照明光で照明した生体組織の像のカラー画像データを生成する。このカラー画像データを用いて、プロセッサは、生体組織のヘモグロビンの量及び生体組織のヘモグロビンの酸素飽和度を算出する。プロセッサに接続されたディスプレイは、基準光で照明された生体組織の像と、ヘモグロビンの量及び酸素飽和度の少なくとも一方の分布を示した特徴量分布画像を表示する。
　この内視鏡システムでは、プロセッサは、カラー画像データのうち、第１特殊光の照明により得られた第１特殊光カラー画像データの成分と、基準光の照明により得られた基準光カラー画像データの成分を用いてヘモグロビンの量を算出し、第１特殊光の照明により得られた第１特殊光カラー画像データの成分と第２特殊光の照明により得られた第２特殊光カラー画像データの成分を用いてヘモグロビンの酸素飽和度を算出する。 (Outline of this embodiment)
An outline of the endoscope system of the present embodiment is as follows. The endoscope system according to the present embodiment includes a light source device, an endoscope including an imaging element, a processor, and a display. The light source device emits a plurality of special lights including reference light having different wavelength bands and at least first special light and second special light as one cycle, and uses the reference light and special light as illumination light for living tissue in one cycle. repeat. The reference light and the plurality of special lights having different wavelength bands are different from each other in the wavelength band of the reference light and the plurality of special lights, and the wavelength bands of the plurality of special lights. Each time the living tissue is illuminated with each of the illumination lights, the imaging device picks up the image of the living tissue illuminated with each illumination light by imaging the living tissue with the timing of emitting the illumination light. Generate image data. Using this color image data, the processor calculates the amount of hemoglobin in the living tissue and the oxygen saturation of the hemoglobin in the living tissue. The display connected to the processor displays an image of the biological tissue illuminated with the reference light, and a feature amount distribution image showing at least one distribution of the amount of hemoglobin and oxygen saturation.
In this endoscope system, the processor includes a component of the first special light color image data obtained by the illumination of the first special light and the reference light color image data obtained by the illumination of the reference light among the color image data. Of the first special light color image data obtained by illumination of the first special light and the second special light color image data obtained by illumination of the second special light. The oxygen saturation of hemoglobin is calculated using the components.
　このような内視鏡システムにおいて、光源装置は、基準光と複数の特殊光の出射の１サイクルにおいて、照明光の出射の順番に関して、特殊光の１つの出射と特殊光の別の出射の間に基準光の出射を行うことを、少なくとも２回、基準光の出射を続けることなく行うように構成されている。言い換えると、光源装置による基準光及び特殊光の出射の順番に関して、特殊光を順次出射するために定めた特殊光の出射の順番の列に、基準光の出射を少なくとも２回、連続することなく配置させた順番である。このように、複数の特殊光と基準光の出射を１サイクルとして、１サイクルを繰り返し行い、各サイクルで得られる特徴量分布画像と基準光で照明された生体組織を撮像して得られる通常観察画像をディスプレイに表示する。本実施形態では、基準光で生体組織を照明して通常観察画像を得ることを、１サイクル中少なくとも２回以上行うので、１サイクル中で１回しか通常観察画像を得られなかった従来の内視鏡システムに比べて通常観察画像のリフレッシュレートを向上させることができる。また、通常観察画像のリフレッシュレートが向上するので、内視鏡を操作しながら手技を行う操作者にとって生体組織をストレスなく観察できる。さらに、通常観察画像のリフレッシュレートが向上するので、特殊光で照明された生体組織の撮像画像から得られる特徴量分布画像中の生体組織の像と通常観察画像中の生体組織の像の位置ずれが抑制され、その結果、内視鏡を操作しながら手技を行う操作者は、特徴量分布画像中の注目する位置を、通常観察画像中の生体組織の像上で特定することが容易にできる。
　以下、本実施形態の内視鏡システムについて図面を参照しながら詳細に説明する。 In such an endoscope system, the light source device is arranged between one emission of special light and another emission of special light with respect to the order of emission of illumination light in one cycle of emission of reference light and a plurality of special lights. The reference light is emitted at least twice without continuing the emission of the reference light. In other words, with respect to the order of the emission of the reference light and the special light by the light source device, the emission of the reference light is not continued at least twice in the sequence of the special light emission order determined to emit the special light sequentially. It is the order of arrangement. In this way, normal observation obtained by imaging a biological tissue illuminated with the feature amount distribution image obtained in each cycle and the reference light by repeatedly emitting one cycle with a plurality of special light and reference light being emitted as one cycle. Show the image on the display. In the present embodiment, the normal observation image is obtained by illuminating the living tissue with the reference light at least twice in one cycle. Therefore, the conventional observation image obtained only once in one cycle can be obtained. Compared to the endoscope system, the refresh rate of the normal observation image can be improved. In addition, since the refresh rate of the normal observation image is improved, the living tissue can be observed without stress for an operator who performs the procedure while operating the endoscope. Furthermore, since the refresh rate of the normal observation image is improved, the positional deviation between the image of the biological tissue in the feature distribution image obtained from the captured image of the biological tissue illuminated with special light and the image of the biological tissue in the normal observation image As a result, the operator who performs the procedure while operating the endoscope can easily specify the position of interest in the feature amount distribution image on the image of the biological tissue in the normal observation image. .
Hereinafter, the endoscope system of the present embodiment will be described in detail with reference to the drawings.
　（内視鏡システムの構成）
　図１は、本実施形態に係る内視鏡システム１の構成を示すブロック図である。内視鏡システム１は、電子内視鏡（内視鏡）１００、プロセッサ２００、ディスプレイ３００、及び光源装置４００を備える。電子内視鏡１００及びディスプレイ３００は、プロセッサ２００に着脱可能に接続されている。また、プロセッサ２００は、画像処理部５００を備える。光源装置４００は、プロセッサ２００に着脱自在に接続されている。なお、光源装置４００は、プロセッサ２００の筐体内に設けられてもよい。 (Configuration of endoscope system)
FIG. 1 is a block diagram illustrating a configuration of an endoscope system 1 according to the present embodiment. The endoscope system 1 includes an electronic endoscope (endoscope) 100, a processor 200, a display 300, and a light source device 400. The electronic endoscope 100 and the display 300 are detachably connected to the processor 200. In addition, the processor 200 includes an image processing unit 500. The light source device 400 is detachably connected to the processor 200. Note that the light source device 400 may be provided in the housing of the processor 200.
　電子内視鏡１００は、被検者の体内に挿入される挿入管１１０を有する。挿入管１１０の内部には、挿入管１１０の略全長に亘って延びるライトガイド１３１が設けられている。ライトガイド１３１の一端部である先端部１３１ａは、挿入管１１０の先端部、すなわち挿入管先端部１１１近傍に位置し、ライトガイド１３１の他端部である基端部１３１ｂは、光源装置４００との接続部に位置する。したがって、ライトガイド１３１は、光源装置４００との接続部から挿入管先端部１１１近傍まで延びている。
　光源装置４００は、キセノンランプ等の光量の大きい光を生成する光源ランプ４３０を光源として備える。光源装置４００から出射した光は照明光ＩＬとして、ライトガイド１３１の基端部１３１ｂに入射する。ライトガイド１３１の基端部１３１ｂに入射した光は、ライトガイド１３１を通ってその先端部１３１ａに導かれ、先端部１３１ａから出射される。電子内視鏡１００の挿入管先端部１１１には、ライトガイド１３１の先端部１３１ａと対向して配置された配光レンズ１３２が設けられている。ライトガイド１３１の先端部１３１ａから出射する照明光ＩＬは、配光レンズ１３２を通過して、挿入管先端部１１１の近傍の生体組織Ｔを照明する。 The electronic endoscope 100 has an insertion tube 110 that is inserted into the body of a subject. Inside the insertion tube 110, a light guide 131 extending over substantially the entire length of the insertion tube 110 is provided. The distal end portion 131 a that is one end portion of the light guide 131 is located in the distal end portion of the insertion tube 110, that is, in the vicinity of the distal end portion 111 of the insertion tube, and the proximal end portion 131 b that is the other end portion of the light guide 131 is connected to the light source device 400. Located at the connection. Therefore, the light guide 131 extends from the connection portion with the light source device 400 to the vicinity of the insertion tube distal end portion 111.
The light source device 400 includes a light source lamp 430 that generates a large amount of light, such as a xenon lamp, as a light source. The light emitted from the light source device 400 enters the base end portion 131b of the light guide 131 as illumination light IL. The light incident on the base end portion 131b of the light guide 131 is guided to the tip end portion 131a through the light guide 131, and is emitted from the tip end portion 131a. A light distribution lens 132 disposed opposite to the distal end portion 131 a of the light guide 131 is provided at the insertion tube distal end portion 111 of the electronic endoscope 100. The illumination light IL emitted from the distal end portion 131a of the light guide 131 passes through the light distribution lens 132 and illuminates the living tissue T in the vicinity of the insertion tube distal end portion 111.
　電子内視鏡１００の挿入管先端部１１１には対物レンズ群１２１及び撮像素子１４１が設けられている。対物レンズ群１２１及び撮像素子１４１は撮像部を形成する。照明光ＩＬのうち、生体組織Ｔの表面で反射又は散乱された光は、対物レンズ群１２１に入射し、集光されて、撮像素子１４１の受光面上で結像する。撮像素子１４１は、その受光面にカラーフィルタ１４１ａを備えたカラー画像撮像用のＣＣＤ（Charge Coupled Device）イメージセンサ、あるいはＣＭＯＳ（Complementary Metal Oxide Semiconductor）イメージセンサ等の公知撮像素子を使用することができる。なお、撮像素子１４１にＣＭＯＳイメージセンサを用いることは、低消費電力及び低コストの点から好ましい。 An objective lens group 121 and an image sensor 141 are provided at the insertion tube tip 111 of the electronic endoscope 100. The objective lens group 121 and the imaging element 141 form an imaging unit. Of the illumination light IL, the light reflected or scattered by the surface of the living tissue T is incident on the objective lens group 121, is condensed, and forms an image on the light receiving surface of the image sensor 141. As the image sensor 141, a known image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor having a color filter 141 a on the light receiving surface can be used. . Note that it is preferable to use a CMOS image sensor for the image sensor 141 in terms of low power consumption and low cost.
　カラーフィルタ１４１ａは、赤色の光を通過させるＲカラーフィルタと、緑色の光を通過させるＧカラーフィルタと、青色の光を通過させるＢカラーフィルタとが配列され、撮像素子１４１の各受光素子上に直接形成された、いわゆるオンチップフィルタである。図２は、本実施形態で用いる撮像素子の赤（Ｒ）、緑（Ｇ）、青（Ｂ）の各フィルタの分光特性の一例を示す図である。本実施形態のＲカラーフィルタは、波長約５７０ｎｍより長波長、（例えば５８０ｎｍ～７００ｎｍ）の光を通過させるフィルタであり、Ｇカラーフィルタは、波長約４７０ｎｍ～６２０ｎｍの光を通過させるフィルタであり、Ｂカラーフィルタは、波長約５３０ｎｍより短波長（例えば４２０ｎｍ～５２０ｎｍ）の光を通過させるフィルタである。 The color filter 141 a includes an R color filter that transmits red light, a G color filter that transmits green light, and a B color filter that transmits blue light, and is arranged on each light receiving element of the image sensor 141. It is a so-called on-chip filter formed directly. FIG. 2 is a diagram illustrating an example of spectral characteristics of each of the red (R), green (G), and blue (B) filters of the image sensor used in the present embodiment. The R color filter of the present embodiment is a filter that passes light having a wavelength longer than about 570 nm (for example, 580 nm to 700 nm), and the G color filter is a filter that passes light having a wavelength of about 470 nm to 620 nm. The B color filter is a filter that allows light having a wavelength shorter than about 530 nm (for example, 420 nm to 520 nm) to pass therethrough.
　撮像素子１４１は、複数の光のそれぞれで照明された生体組織Ｔを撮像して、各光に対応したカラー画像データを生成する撮像手段であり、波長範囲が異なる複数の光で生体組織Ｔを照明することにより生体組織Ｔ上で反射したあるいは散乱した光に対応するカラー画像データを生成する画像データ生成手段である。撮像素子１４１は、後述する画像処理部５００と同期して駆動するように制御され、受光面上で結像した被写体像に対応するカラー画像データを、周期的に（例えば、１／３０秒間隔で）出力する。撮像素子１４１から出力されたカラー画像データは、ケーブル１４２を介してプロセッサ２００の画像処理部５００に送られる。 The imaging element 141 is an imaging unit that images the living tissue T illuminated with each of a plurality of lights and generates color image data corresponding to each light, and the living tissue T with a plurality of lights having different wavelength ranges. It is an image data generation means for generating color image data corresponding to light reflected or scattered on the living tissue T by illuminating. The image sensor 141 is controlled to be driven in synchronization with an image processing unit 500 described later, and periodically (for example, 1/30 second interval) color image data corresponding to the subject image formed on the light receiving surface. Output). The color image data output from the image sensor 141 is sent to the image processing unit 500 of the processor 200 via the cable 142.
　画像処理部５００は、Ａ／Ｄ変換回路５０２、プレ画像処理部５０４、フレームメモリ部５０６、ポスト画像処理部５０８、特徴量取得部５１０、メモリ５１２、画像表示制御部５１４、及びコントローラ５１６を主に備える。 The image processing unit 500 mainly includes an A / D conversion circuit 502, a pre-image processing unit 504, a frame memory unit 506, a post image processing unit 508, a feature amount acquisition unit 510, a memory 512, an image display control unit 514, and a controller 516. Prepare for.
　Ａ／Ｄ変換回路５０２は、電子内視鏡１００の撮像素子１４１からケーブル１４２を介して入力されるカラー画像データをＡ／Ｄ変換してデジタル画像データを出力する。Ａ／Ｄ変換回路５０２から出力されるデジタルデータは、プレ画像処理部５０４に送られる。 The A / D conversion circuit 502 performs A / D conversion on the color image data input from the image sensor 141 of the electronic endoscope 100 via the cable 142 and outputs digital image data. Digital data output from the A / D conversion circuit 502 is sent to the pre-image processing unit 504.
　プレ画像処理部５０４は、デジタルデータを、Ｒカラーフィルタが装着された撮像素子１４１中の受光素子によって撮像されたＲデジタル画像データ、Ｇカラーフィルタが装着された撮像素子１４１中の受光素子によって撮像されたＧデジタル画像データ、及びＢカラーフィルタが装着された撮像素子１４１中の受光素子によって撮像されたＢデジタル画像データからデモザイク処理により、画像を構成するＲ，Ｇ，Ｂ成分のカラー画像データを生成する。さらに、プレ画像処理部５０４は、生成したＲ，Ｇ，Ｂ成分のカラー画像データに対して、色補正、マトリックス演算、及びホワイトバランス補正等の所定の信号処理を施す部分である。 The pre-image processing unit 504 captures digital data by using the R digital image data captured by the light receiving element in the image sensor 141 with the R color filter and the light receiving element in the image sensor 141 with the G color filter. The R, G, and B component color image data constituting the image by demosaic processing from the G digital image data and the B digital image data picked up by the light receiving element in the image pickup element 141 to which the B color filter is attached. Generate. Further, the pre-image processing unit 504 is a part that performs predetermined signal processing such as color correction, matrix calculation, and white balance correction on the generated color image data of R, G, and B components.
　フレームメモリ部５０６は、撮像素子１４１で撮像され、信号処理の施された１画像毎のカラー画像データを一時記憶する。 The frame memory unit 506 temporarily stores color image data for each image captured by the image sensor 141 and subjected to signal processing.
　ポスト画像処理部５０８は、フレームメモリ部５０６に記憶されたカラー画像データを読み出して、あるいは後述する画像表示制御部５１４で生成された画像データを信号処理（γ補正等）してディスプレイ表示用の画面データを生成する。画像表示制御部５１４で生成された画像データは、後述するように、生体組織Ｔのヘモグロビンの酸素飽和度等の特徴量の分布画像のデータを含む。生成された画面データ（ビデオフォーマット信号）は、ディスプレイ３００に出力される。これにより、生体組織Ｔの画像や生体組織Ｔの特徴量の分布を示す特徴量分布画像等がディスプレイ３００の表示画面に表示される。 The post image processing unit 508 reads the color image data stored in the frame memory unit 506 or performs signal processing (γ correction or the like) on the image data generated by the image display control unit 514 (to be described later) for display display. Generate screen data. As will be described later, the image data generated by the image display control unit 514 includes data of distribution images of feature amounts such as oxygen saturation of hemoglobin in the living tissue T. The generated screen data (video format signal) is output to the display 300. As a result, an image of the living tissue T, a feature amount distribution image indicating the distribution of the feature amount of the living tissue T, and the like are displayed on the display screen of the display 300.
　特徴量取得部５１０は、コントローラ５１６の指示に応じて、後述するように、撮像された生体組織Ｔの特徴量、例えばヘモグロビンの量、あるいは、ヘモグロビンの量とヘモグロビンの酸素飽和度を算出し、これらの特徴量の、撮像した生体組織Ｔの像上の分布画像の画像データを生成する。
　特徴量取得部５１０は、波長帯域の異なる複数の光で照明した生体組織Ｔのカラー画像データを用いて演算することにより特徴量を算出するので、フレームメモリ部５０６あるいはメモリ５１２から、特徴量取得部５１０で用いるカラー画像データや各種情報を呼び出す。 In accordance with an instruction from the controller 516, the feature amount acquisition unit 510 calculates a feature amount of the imaged living tissue T, for example, the amount of hemoglobin, or the amount of hemoglobin and the oxygen saturation of hemoglobin, as will be described later. The image data of the distribution image on the image of the captured tissue T of these feature amounts is generated.
Since the feature quantity acquisition unit 510 calculates the feature quantity by calculating using the color image data of the living tissue T illuminated with a plurality of lights having different wavelength bands, the feature quantity acquisition unit 510 acquires the feature quantity from the frame memory unit 506 or the memory 512. Color image data and various information used in the unit 510 are called up.
　画像表示制御部５１４は、特徴量取得部５１０で算出した特徴量の、撮像した生体組織Ｔの像上の分布画像の表示を、コントローラ５１６の指示に応じて制御する。画像表示制御部５１４は、例えば、撮像した生体組織Ｔの像と特徴量分布画像を並列的に表示するように、あるいは撮像した生体組織Ｔの像に特徴量の分布画像を重ねて表示するように制御する。
　コントローラ５１６は、画像処理部５００の各部分の動作指示及び動作制御を行う他、光源装置４００、撮像素子１４１を含む電子内視鏡１００の各部分の動作指示及び動作制御を行う部分である。
　なお、特徴量取得部５１０及び画像表示制御部５１４は、コンピュータ上でプログラムを起動して実行することで上述した各機能を行うソフトウェアモジュールで構成されてもよいし、ハードウェアで構成されてもよい。 The image display control unit 514 controls the display of the distribution image on the captured image of the biological tissue T of the feature amount calculated by the feature amount acquisition unit 510 in accordance with an instruction from the controller 516. For example, the image display control unit 514 displays the captured image of the living tissue T and the feature amount distribution image in parallel, or displays the feature amount distribution image so as to overlap the captured image of the living tissue T. To control.
The controller 516 is a part that performs operation instruction and operation control of each part of the image processing unit 500, and performs operation instruction and operation control of each part of the electronic endoscope 100 including the light source device 400 and the imaging element 141.
The feature amount acquisition unit 510 and the image display control unit 514 may be configured by software modules that perform the above-described functions by starting and executing programs on a computer, or may be configured by hardware. Good.
　このように、プロセッサ２００は、電子内視鏡１００の撮像素子１４１から出力されるカラー画像データを処理する機能と、電子内視鏡１００、光源装置４００、及びディスプレイ３００の動作を指示し制御する機能とを兼ね備える。 As described above, the processor 200 instructs and controls the function of processing the color image data output from the image sensor 141 of the electronic endoscope 100 and the operation of the electronic endoscope 100, the light source device 400, and the display 300. Combines functionality.
　光源装置４００は、基準光及び特殊光の光を照明光ＩＬとして出射する光出射手段であり、基準光及び特殊光をライトガイド１３１に入射させる。基準光の波長帯域と複数の特殊光の波長帯域は異なり、複数の特集光の波長帯域は、お互いに異なる。基準光は、後述するように波長帯域が同じ第１基準光と第２基準光を含み、特殊光は、後述するように、基準光の波長地域と異なり、かつお互いに波長帯域の異なる第１特殊光及び第２特殊光を含む。本実施形態の光源装置４００は、４つの照明光ＩＬを出射するが、５つ以上の照明光ＩＬを出射させてもよい。この場合、５つ目の光は、第１特殊光及び第２特殊光の波長帯域と異なる第３特殊光とすることができる。光源装置４００は、光源ランプ４３０の他に、集光レンズ４４０、回転フィルタ４１０、フィルタ制御部４２０及び集光レンズ４５０を備えている。光源ランプ４３０から放射される略平行光である光は、例えば白色光であり、集光レンズ４４０によって集光され、回転フィルタ４１０を通過した後、集光レンズ４５０によって再度集光されて、ライトガイド１３１の基端１３１ｂに入射する。なお、回転フィルタ４１０は、リニアガイドウェイ等の図示されない移動機構によって、光源４３０から放射される光の光路上の位置と光路外の退避位置との間で移動可能になっている。回転フィルタ４１０は、透過特性の異なる複数のフィルタを含むので、光源ランプ４３０から放射される光の光路を横切る回転フィルタ４１０の種類によって、光源装置４００から出射する照明光ＩＬの波長帯域は異なる。これにより、基準光と特殊光が生成される。特殊光は、後述するように、生体組織のヘモグロビンの量やヘモグロビンの酸素飽和度の算出に必要なカラー画像データを得るために生体組織Ｔを照明する光であり、特殊光の波長帯域は、ヘモグロビンの光吸収特性を有する波長帯域に制限された照明光ＩＬである。基準光は、その波長帯域がヘモグロビンの光吸収特性を有する波長帯域に制限されない、広帯域の波長帯域を有する照明光ＩＬであり、本実施形態では白色光である。 The light source device 400 is a light emitting unit that emits reference light and special light as illumination light IL, and makes the reference light and special light enter the light guide 131. The wavelength band of the reference light is different from the wavelength band of the plurality of special lights, and the wavelength bands of the plurality of special lights are different from each other. The reference light includes first reference light and second reference light having the same wavelength band as described later, and the special light is different from the wavelength region of the reference light and has different wavelength bands from each other as described later. Includes special light and second special light. The light source device 400 of the present embodiment emits four illumination lights IL, but may emit five or more illumination lights IL. In this case, the fifth light can be third special light different from the wavelength bands of the first special light and the second special light. In addition to the light source lamp 430, the light source device 400 includes a condenser lens 440, a rotation filter 410, a filter control unit 420, and a condenser lens 450. The light that is substantially parallel light emitted from the light source lamp 430 is, for example, white light, is collected by the condenser lens 440, passes through the rotary filter 410, and is condensed again by the condenser lens 450. The light enters the base end 131 b of the guide 131. The rotary filter 410 is movable between a position on the optical path of light emitted from the light source 430 and a retracted position outside the optical path by a moving mechanism (not shown) such as a linear guide way. Since the rotary filter 410 includes a plurality of filters having different transmission characteristics, the wavelength band of the illumination light IL emitted from the light source device 400 differs depending on the type of the rotary filter 410 that crosses the optical path of the light emitted from the light source lamp 430. Thereby, the reference light and the special light are generated. As will be described later, the special light is light that illuminates the biological tissue T in order to obtain color image data necessary for calculating the amount of hemoglobin in the biological tissue and the oxygen saturation of the hemoglobin, and the wavelength band of the special light is Illumination light IL limited to a wavelength band having light absorption characteristics of hemoglobin. The reference light is illumination light IL having a broad wavelength band, the wavelength band of which is not limited to the wavelength band having the light absorption characteristic of hemoglobin, and is white light in the present embodiment.
　なお、光源装置４００の構成は、図１に示されるものに限定されない。例えば、光源ランプ４３０に平行光でなく収束光を発生するランプを採用してもよい。この場合、例えば、光源ランプ４３０からの放射される光を集光レンズ４４０の手前で集光させ、拡散光として集光レンズ４４０に入射させる構成を採用してもよい。また、集光レンズ４４０を使用せず、光源ランプ４３０が発生する略平行光を直接回転フィルタ４１０に入射させる構成を採用してもよい。また、収束光を発生するランプを使用する場合、集光レンズ４４０の替わりにコリメータレンズを使用して、略平行光の状態で光を回転フィルタ４１０に入射させる構成を採用してもよい。例えば、回転フィルタ４１０に誘電体多層膜フィルタ等の干渉型の光学フィルタを使用する場合、略平行光の光を回転フィルタ４１０に入射させることで、光学フィルタへの光の入射角を均一にすることにより、より良好なフィルタ特性を得ることができる。また、光源ランプ４３０に発散光を発生するランプを採用してもよい。この場合にも、集光レンズ４４０の替わりにコリメータレンズを使用して、略平行光の光を回転フィルタ４１０に入射させる構成を採用することができる。 Note that the configuration of the light source device 400 is not limited to that shown in FIG. For example, the light source lamp 430 may be a lamp that generates convergent light instead of parallel light. In this case, for example, a configuration may be adopted in which light emitted from the light source lamp 430 is collected before the condenser lens 440 and is incident on the condenser lens 440 as diffused light. Further, a configuration in which substantially parallel light generated by the light source lamp 430 is directly incident on the rotary filter 410 without using the condenser lens 440 may be employed. When a lamp that generates convergent light is used, a configuration in which a collimator lens is used instead of the condenser lens 440 and light is incident on the rotary filter 410 in a substantially parallel light state may be employed. For example, when an interference type optical filter such as a dielectric multilayer filter is used as the rotary filter 410, the incident angle of the light to the optical filter is made uniform by causing substantially parallel light to enter the rotary filter 410. As a result, better filter characteristics can be obtained. In addition, a lamp that generates divergent light may be employed as the light source lamp 430. Also in this case, it is possible to employ a configuration in which a collimator lens is used instead of the condenser lens 440 so that substantially parallel light is incident on the rotary filter 410.
　また、光源装置４００は、１つの光源ランプ４３０から放射された光を光学フィルタに透過させることで、異なる波長帯域の複数の光を出射する構成であるが、光源ランプ４３０の代わりに、異なる波長帯域の異なる複数の光、例えば発光ダイオードやレーザ光を出力するレーザ素子等の半導体光源を光源装置４００の光源として用いることもできる。この場合、回転フィルタ４１０を用いなくてもよい。 The light source device 400 is configured to emit a plurality of lights having different wavelength bands by transmitting light emitted from one light source lamp 430 through an optical filter. However, instead of the light source lamp 430, different wavelengths are used. A semiconductor light source such as a light emitting diode or a laser element that outputs laser light having different bands can be used as the light source of the light source device 400. In this case, the rotation filter 410 may not be used.
　回転フィルタ４１０は、複数の光学フィルタを備えた円盤型の光学ユニットであり、その回転角度に応じて光の通過波長域が切り替わるように構成されている。本実施形態の回転フィルタ４１０は、通過波長帯域が異なる４つの光学フィルタを備えるが、５つ、または６以上の光学フィルタを備えてもよい。回転フィルタ４１０の回転角度は、コントローラ５１６に接続されたフィルタ制御部４２０によって制御される。コントローラ５１６がフィルタ制御部４２０を介して回転フィルタ４１０の回転角度を制御することにより、回転フィルタ４１０を通過してライトガイド１３１に供給される照明光ＩＬの波長帯域が切り替えられる。 The rotation filter 410 is a disc-shaped optical unit including a plurality of optical filters, and is configured such that the light passing wavelength region is switched according to the rotation angle. The rotary filter 410 of the present embodiment includes four optical filters having different pass wavelength bands, but may include five, or six or more optical filters. The rotation angle of the rotary filter 410 is controlled by a filter control unit 420 connected to the controller 516. When the controller 516 controls the rotation angle of the rotary filter 410 via the filter control unit 420, the wavelength band of the illumination light IL that passes through the rotary filter 410 and is supplied to the light guide 131 is switched.
　図３は、回転フィルタ４１０の外観図（正面図）である。回転フィルタ４１０は、略円盤状のフレーム４１１と、２つの光学フィルタＦｎ１，Ｆｎ２と、１つの光学フィルタＦｓ１と、１つの光学フィルタＦｓ２の計４つの光学フィルタを備えている。４つの光学フィルタは、円周上に間隔をあけて設けられている。フレーム４１１の中心軸の周りには４つの扇状の窓が等間隔で形成されており、各窓には、それぞれ光学フィルタＦｎ１，Ｆｓ１，Ｆｎ２，Ｆｓ２が嵌め込まれている。なお、本実施形態の光学フィルタは、いずれも誘電体多層膜フィルタであるが、他の方式の光学フィルタ（例えば、吸収型の光学フィルタや誘電体多層膜を反射膜として用いたエタロンフィルタ等）を用いてもよい。 FIG. 3 is an external view (front view) of the rotary filter 410. The rotary filter 410 includes a total of four optical filters: a substantially disk-shaped frame 411, two optical filters Fn1, Fn2, one optical filter Fs1, and one optical filter Fs2. The four optical filters are provided at intervals on the circumference. Around the central axis of the frame 411, four fan-shaped windows are formed at equal intervals, and optical filters Fn1, Fs1, Fn2, and Fs2 are fitted into the windows, respectively. The optical filters of the present embodiment are all dielectric multilayer filters, but other types of optical filters (for example, absorption optical filters and etalon filters using dielectric multilayer films as reflective films). May be used.
　上述したように、電子内視鏡１００の撮像素子１４１にＣＭＯＳイメージセンサを用いることは、低消費電力及び低コストの点から好ましく、この場合、ＣＭＯＳイメージセンサは受光面の露光と遮断を繰り返すローリングシャッタにより撮像するので、この撮像のタイミングに合わせて回転フィルタ４１０が回転することが好ましい。しかし、露光のタイミングと照明光ＩＬの出射のタイミングが回転フィルタ４１０の回転の変動等により合わず、露光中に照明光ＩＬの種類が変わる場合がある。このため、回転フィルタ４１０のフレーム４１１上の光学フィルタ間には照明光ＩＬが出射しない遮断区間が設けられていることが好ましい。一方、ＣＭＯＳイメージセンサでは、ＣＣＤイメージセンサに比べて暗い画像が生成される傾向にあるため、露光時間を長くする必要があり、これに合わせて光学フィルタの大きさを長くして、所望の光の出射継続時間を長くすることが好ましい。特に、光学フィルタＦｓ１，Ｆｓ２の波長帯域は、後述するように光学フィルタＦｎ１，Ｆｎ２の波長帯域に比べて狭いので、光学フィルタＦｓ１，Ｆｓ２を透過した光の強度は弱く、撮像素子１４１で撮像した画像は暗くなり易い。このため、光学フィルタＦｓ１，Ｆｓ２を透過した光により得られるカラー画像データを用いて求められる特徴量分布画像の精度は低くなり易い。このため、フレーム４１１中の光学フィルタの周方向に沿った領域を長くすることで特殊光の照明継続時間を長くして撮像素子１４１の受光量を増やすことが望ましい。しかし、上述したようにフレーム４１１において、回転フィルタ４１０の遮断区間の円周方向に沿った長さをある程度確保しなければならない。このような点から、複数の遮断区間が円周（周方向）に沿って設けられることが好ましい。複数の遮断区間の円周（周方向）に沿った長さはいずれも同じであり、複数の光学フィルタの領域の円周（周方向）に沿った長さもいずれも同じである。回転フィルタ４１０における光学フィルタ間にある遮断区間それぞれの領域の円周（周方向）に沿った長さの、光学フィルタの領域それぞれの円周（周方向）に沿った長さに対する比は、０超～１であることが好ましく、０．１～１であることがより好ましい。 As described above, it is preferable to use a CMOS image sensor for the imaging element 141 of the electronic endoscope 100 from the viewpoint of low power consumption and low cost. In this case, the CMOS image sensor is a rolling that repeats exposure and blocking of the light receiving surface. Since the image is taken by the shutter, it is preferable that the rotary filter 410 is rotated in accordance with the timing of the image pickup. However, the timing of exposure and the timing of emission of the illumination light IL may not match due to fluctuations in the rotation of the rotary filter 410, and the type of illumination light IL may change during exposure. For this reason, it is preferable that a blocking section where the illumination light IL is not emitted is provided between the optical filters on the frame 411 of the rotary filter 410. On the other hand, since the CMOS image sensor tends to generate a darker image than the CCD image sensor, it is necessary to lengthen the exposure time. It is preferable to increase the emission continuation time. In particular, since the wavelength bands of the optical filters Fs1 and Fs2 are narrower than the wavelength bands of the optical filters Fn1 and Fn2, as described later, the intensity of light transmitted through the optical filters Fs1 and Fs2 is weak, and the image is picked up by the image sensor 141. Images tend to be dark. For this reason, the accuracy of the feature quantity distribution image obtained using the color image data obtained from the light transmitted through the optical filters Fs1 and Fs2 tends to be low. For this reason, it is desirable to increase the amount of light received by the image sensor 141 by lengthening the special light illumination duration by lengthening the region along the circumferential direction of the optical filter in the frame 411. However, as described above, in the frame 411, a certain length along the circumferential direction of the blocking section of the rotary filter 410 must be ensured. From such a point, it is preferable that a plurality of blocking sections are provided along the circumference (circumferential direction). The lengths along the circumference (circumferential direction) of the plurality of blocking sections are all the same, and the lengths along the circumference (circumferential direction) of the regions of the plurality of optical filters are also the same. The ratio of the length along the circumference (circumferential direction) of each region of the cutoff section between the optical filters in the rotary filter 410 to the length along the circumference (circumferential direction) of each region of the optical filter is 0. It is preferably from super to 1, more preferably from 0.1 to 1.
　また、フレーム４１１の中心軸上にはボス穴４１２が形成されている。ボス穴４１２には、フィルタ制御部４２０が備える図示されないサーボモータの出力軸が差し込まれて固定され、回転フィルタ４１０はサーボモータの出力軸と共に回転する。 Also, a boss hole 412 is formed on the central axis of the frame 411. An output shaft of a servo motor (not shown) provided in the filter control unit 420 is inserted into the boss hole 412 and fixed, and the rotary filter 410 rotates together with the output shaft of the servo motor.
　回転フィルタ４１０が図３中の矢印で示される方向に回転すると、この光が入射する光学フィルタが、光学フィルタＦｓ２、光学フィルタＦｎ１、光学フィルタＦｓ１、光学フィルタＦｎ２の順番に切り替わり、これにより回転フィルタ４１０を通過する照明光ＩＬの波長帯域が順次切り替えられる。具体的に、回転フィルタ４１０が１回転するたびに、順番に、光源ランプ４３０の放射する光が光学フィルタＦｓ２を通過することにより第２特殊光が生成され、光源ランプ４３０の放射する光が光学フィルタＦｎ１を通過することにより第１基準光が生成され、光源ランプ４３０の放射する光が光学フィルタＦｓ１を通過することにより第１特殊光が生成され、光源ランプ４３０の放射する光が光学フィルタＦｎ２を通過することにより第２基準光が生成されるサイクルを繰り返す。 When the rotary filter 410 rotates in the direction indicated by the arrow in FIG. 3, the optical filter on which this light is incident is switched in the order of the optical filter Fs2, the optical filter Fn1, the optical filter Fs1, and the optical filter Fn2, thereby rotating the rotary filter. The wavelength band of the illumination light IL passing through 410 is sequentially switched. Specifically, every time the rotary filter 410 makes one rotation, the light emitted from the light source lamp 430 passes through the optical filter Fs2 in turn, so that the second special light is generated, and the light emitted from the light source lamp 430 is optical. The first reference light is generated by passing through the filter Fn1, the first special light is generated by passing the light emitted from the light source lamp 430 through the optical filter Fs1, and the light emitted from the light source lamp 430 is converted into the optical filter Fn2. The cycle in which the second reference light is generated by passing through is repeated.
　光学フィルタＦｓ１及びＦｓ２は、５５０ｎｍ帯の光を選択的に通過させる光バンドパスフィルタである。図４に示されるように、光学フィルタＦｓ１は、後述する等吸収点Ｅ１からＥ４までの波長帯域Ｒ０（Ｗ帯）の光を低損失で通過させ、それ以外の波長領域の光を遮断するように構成されている。また、光学フィルタＦｓ２は、後述する等吸収点Ｅ２からＥ３までの波長帯域Ｒ２（Ｎ帯）の光を低損失で通過させ、それ以外の波長領域の光を遮断するように構成されている。図４は、５５０ｎｍ付近のヘモグロビンの吸収スペクトルの一例を示す図である。
　また、光学フィルタＦｎ１，Ｆｎ２は、同じ透過特性を有し、紫外線カットフィルタであり、同じ波長帯域の光を低損失で通過させる光学フィルタである。光学フィルタＦｎ１，Ｆｎ２は、４００～７００ｎｍの波長領域では、光源ランプ４３０から放射された光を透過させる。 The optical filters Fs1 and Fs2 are optical bandpass filters that selectively pass light in the 550 nm band. As shown in FIG. 4, the optical filter Fs1 allows light in a wavelength band R0 (W band) from equal absorption points E1 to E4, which will be described later, to pass through with low loss, and blocks light in other wavelength regions. It is configured. The optical filter Fs2 is configured to pass light in a wavelength band R2 (N band) from equal absorption points E2 to E3, which will be described later, with low loss, and block light in other wavelength regions. FIG. 4 is a diagram showing an example of an absorption spectrum of hemoglobin near 550 nm.
Further, the optical filters Fn1 and Fn2 are ultraviolet cut filters having the same transmission characteristics and passing light of the same wavelength band with low loss. The optical filters Fn1 and Fn2 transmit light emitted from the light source lamp 430 in the wavelength region of 400 to 700 nm.
　なお、図４に示される波長帯域Ｒ１は後述するように酸素化ヘモグロビンに由来する吸収ピークＰ１のピーク波長が含まれる帯域であり、波長帯域Ｒ２は後述するように還元ヘモグロビンに由来する吸収ピークＰ２のピーク波長が含まれる帯域であり、波長帯域Ｒ３は後述するように酸素化ヘモグロビンに由来する吸収ピークＰ３のピーク波長が含まれる帯域である。また、波長域Ｒ０には、３つの吸収ピークＰ１、Ｐ２、Ｐ３の各ピーク波長が含まれている。図４は、５５０ｎｍ付近のヘモグロビンの吸収スペクトルの一例を示す図である。ヘモグロビンの量及びヘモグロビンの酸素飽和度と、波長帯域との関係についての詳細な説明は後述する。 The wavelength band R1 shown in FIG. 4 is a band including the peak wavelength of the absorption peak P1 derived from oxygenated hemoglobin as described later, and the wavelength band R2 is the absorption peak P2 derived from reduced hemoglobin as described later. The wavelength band R3 is a band including the peak wavelength of the absorption peak P3 derived from oxygenated hemoglobin, as will be described later. The wavelength range R0 includes the peak wavelengths of the three absorption peaks P1, P2, and P3. FIG. 4 is a diagram showing an example of an absorption spectrum of hemoglobin near 550 nm. A detailed description of the relationship between the amount of hemoglobin, the oxygen saturation of hemoglobin, and the wavelength band will be described later.
　光学フィルタＦｓ１，Ｆｓ２を透過した光は、撮像した生体組織Ｔのヘモグロビンの量及びヘモグロビンの酸素飽和度の算出のためのカラー画像データを得るために生体組織Ｔを照明する特殊光として使用される。光学フィルタＦｎ１、Ｆｎ２を透過した光は、通常観察像画像の生成のためのカラー画像データを得るために生体組織Ｔを照明する基準光として使用される。なお、光学フィルタＦｎ１，Ｆｎ２を使用せず、光学フィルタＦｎ１，Ｆｎ２を配置したフレーム４１１上の窓を開放した構成としてもよい。
　したがって、光源ランプ４３０から放射される光のうち光学フィルタＦｓ１を透過した第１特殊光を、以降Ｗｉｄｅ光といい、光源ランプ４３０か放射される光のうち光学フィルタＦｓ２を透過した第２特殊光を、以降Ｎａｒｒｏｗ光といい、光源ランプ４３０か放射される光のうち光学フィルタＦｎ１，Ｆｎ２を透過した基準光を、以降白色光ＷＬという。また、４つの照明光ＩＬが出射する１サイクルにおいて、光源ランプ４３０の放射する光が光学フィルタＦｎ１，Ｆｎ２を通過することにより生成される基準光は光源装置４００から第１基準光と第２基準光として出射するため、この２つの基準光を区別して説明する場合、第１基準光を以降白色光ＷＬ１といい、第２基準光を以降白色光ＷＬという。 The light transmitted through the optical filters Fs1 and Fs2 is used as special light for illuminating the biological tissue T in order to obtain color image data for calculating the amount of hemoglobin of the captured biological tissue T and the oxygen saturation of the hemoglobin. . The light transmitted through the optical filters Fn1 and Fn2 is used as reference light for illuminating the living tissue T in order to obtain color image data for generating a normal observation image. The optical filters Fn1 and Fn2 may not be used, and the window on the frame 411 in which the optical filters Fn1 and Fn2 are arranged may be opened.
Therefore, the first special light transmitted from the light source lamp 430 through the optical filter Fs1 is hereinafter referred to as Wide light, and the second special light transmitted through the optical filter Fs2 from the light emitted from the light source lamp 430. Is referred to as “Narrow light” hereinafter, and the reference light transmitted through the optical filters Fn1 and Fn2 among the light emitted from the light source lamp 430 is hereinafter referred to as “white light WL”. Further, in one cycle in which the four illumination lights IL are emitted, the reference light generated when the light emitted from the light source lamp 430 passes through the optical filters Fn1 and Fn2 is transmitted from the light source device 400 to the first reference light and the second reference light. When the two reference lights are described separately because they are emitted as light, the first reference light is hereinafter referred to as white light WL1, and the second reference light is hereinafter referred to as white light WL.
　また、光学フィルタＦｓ１の波長帯域Ｒ０及び光学フィルタＦｓ２の波長帯域Ｒ２は、カラーフィルタ１４１ａのＧカラーフィルタの通過波長域（図２）に含まれている。従って、光学フィルタＦｓ１又はＦｓ２を通過した光によって形成される生体組織Ｔの像は、撮像素子１４１で撮像されたカラー画像データのＧ成分の像として得られる。なお、撮像素子４１４の同じ露光条件で同程度の明るさの画像が得られるように、光学フィルタＦｓ１と光学フィルタＦｓ２により生成した特殊光の光強度が略同程度になるように光フィルタＦｓ１あるいは光学フィルタＦｓ２の透過率が調整されている。 The wavelength band R0 of the optical filter Fs1 and the wavelength band R2 of the optical filter Fs2 are included in the pass wavelength band (FIG. 2) of the G color filter of the color filter 141a. Therefore, the image of the living tissue T formed by the light that has passed through the optical filter Fs1 or Fs2 is obtained as an image of the G component of the color image data captured by the image sensor 141. Note that the optical filter Fs1 or the optical filter Fs1 or the optical filter Fs2 so that the light intensity of the special light generated by the optical filter Fs1 and the optical filter Fs2 is approximately the same so that an image with the same brightness can be obtained under the same exposure condition of the image sensor 414. The transmittance of the optical filter Fs2 is adjusted.
　フレーム４１１の周縁部には、貫通孔４１３が形成されている。貫通孔４１３は、フレーム４１１の回転方向において、光学フィルタＦｎ２と光学フィルタＦｓ１が配置される窓との境界部と同じ位置（位相）に形成されている。フレーム４１１の周囲には、貫通孔４１３を検出するためのフォトインタラプタ４２２が、フレーム４１１の周縁部の一部を囲むように配置されている。フォトインタラプタ４２２は、フィルタ制御部４２０に接続されている。 A through hole 413 is formed in the peripheral edge of the frame 411. The through-hole 413 is formed at the same position (phase) as the boundary between the optical filter Fn2 and the window where the optical filter Fs1 is arranged in the rotation direction of the frame 411. Around the frame 411, a photo interrupter 422 for detecting the through hole 413 is arranged so as to surround a part of the peripheral edge of the frame 411. The photo interrupter 422 is connected to the filter control unit 420.
　このように、本実施形態の光源装置４００は、４つの光学フィルタＦｓ２，Ｆｎ１，Ｆｓ１、Ｆｎ２を光源ランプ４３０の放射した光の光路中で順番に切り替えることにより波長帯域の異なる光、すなわちＮａｒｒｏｗ光（第２特殊光）、白色光ＷＬ１（第１基準光）、Ｗｉｄｅ光（第１特殊光）、及び白色光ＷＬ２（第２基準光）を照明光ＩＬとして出射する構成を備えている。 As described above, the light source device 400 according to the present embodiment switches the four optical filters Fs2, Fn1, Fs1, and Fn2 in order in the optical path of the light emitted from the light source lamp 430, that is, light having different wavelength bands, that is, narrow light. (Second special light), white light WL1 (first reference light), wide light (first special light), and white light WL2 (second reference light) are emitted as illumination light IL.
　本実施形態の光源装置４００は、言い換えると、４つの照明光ＩＬが順次出射する１サイクルにおいて、照明光ＩＬの出射の順番に関して、特殊光の１つの出射と特殊光の別の出射の間に白色光ＷＬ（基準光）の出射を行うことを、少なくとも２回白色光ＷＬ（基準光）の出射を続けることなく行う。さらに言い換えると、基準光及び特殊光の出射の順番は、特殊光を順次出射するために定めた特殊光の出射の順番の列、具体的にはＮａｒｒｏｗ光（第２特殊光）、Ｗｉｄｅ光（第１特殊光）の出射の順番の列に、白色光ＷＬ（基準光）の出射を２回、連続することなく割り込ませた（配置させた）順番である。光源装置４００は、図５に示すように、Ｎａｒｒｏｗ光（第２特殊光）、白色光ＷＬ１（第１基準光）、Ｗｉｄｅ光（第１特殊光）、及び白色光ＷＬ２（第２基準光）が順番に生体組織Ｔの照明光ＩＬとして出射することを１サイクルとして、この１サイクルの照明光ＩＬの出射を繰り返す。図５は、本実施形態の光源装置２００における基準光及び特殊光の出射の順番を示す一例を示す図である。各サイクルの照明光ＩＬの出射毎に、プロセッサ２００は、生体組織Ｔの通常観察画像と特徴量分布画像を取得し、ディスプレイ３００に表示させる。したがって、本実施形態では、１サイクルで２回の白色光ＷＬを出射するので、１サイクルで２回、通常観察画像が生成され画像表示されるので、通常観察画像のリフレッシュレートは従来に比べて向上する。
　本実施形態の光源装置４００は、２つの特殊光を出射するが、３つ以上の波長帯域の異なる特殊光を出射してもよい。この場合、３つ以上の特殊光の出射の順番の列に、白色光ＷＬ（基準光）を２箇所以上、さらには３箇所以上、白色光ＷＬ（基準光）の出射が連続することがないように配置させる（割り込ませる）とよい。 In other words, the light source device 400 of the present embodiment, in one cycle in which the four illumination lights IL are sequentially emitted, is related to the order of emission of the illumination light IL between one emission of special light and another emission of special light. The emission of the white light WL (reference light) is performed at least twice without continuing the emission of the white light WL (reference light). In other words, the order of emission of the reference light and the special light is the sequence of the special light emission order determined for sequentially emitting the special light, specifically, the narrow light (second special light), the wide light ( This is the order in which the emission of the white light WL (reference light) is interrupted (disposed) twice in succession in the sequence of the emission of the first special light). As shown in FIG. 5, the light source device 400 includes narrow light (second special light), white light WL1 (first reference light), wide light (first special light), and white light WL2 (second reference light). Are sequentially emitted as the illumination light IL of the living tissue T, and the emission of the illumination light IL for one cycle is repeated. FIG. 5 is a diagram illustrating an example of the order of emission of the reference light and the special light in the light source device 200 of the present embodiment. For each emission of the illumination light IL in each cycle, the processor 200 acquires a normal observation image and a feature amount distribution image of the living tissue T and displays them on the display 300. Therefore, in this embodiment, since the white light WL is emitted twice in one cycle, the normal observation image is generated and displayed twice in one cycle. Therefore, the refresh rate of the normal observation image is higher than that of the conventional case. improves.
The light source device 400 of the present embodiment emits two special lights, but may emit three or more special lights having different wavelength bands. In this case, the white light WL (reference light) is not continuously emitted in two or more places, more than three places in the sequence of the emission order of three or more special lights. It is good to arrange (interrupt).
　本実施形態で説明したように、白色光ＷＬ、Ｗｉｄｅ光、及びＮａｒｒｏｗ光の出射の順番に関して、Ｗｉｄｅ光（第１特殊光）の出射と白色光ＷＬ（基準光）の１回の出射とが、あるいは白色光ＷＬ（基準光）の１回の出射とＷｉｄｅ光（第１特殊光）の出射とが他の出射をはさまず連続していることが、後述するようにヘモグロビンの量を求めるために第１比率を算出する際、生体組織Ｔの像の画像中の位置ずれを抑制することができる点から好ましい。また、白色光ＷＬ、Ｗｉｄｅ光、及びＮａｒｒｏｗ光の出射の順番に関して、Ｎａｒｒｏｗ光（第２特殊光）の出射と白色光ＷＬ（基準光）の１回の出射とが、あるいは白色光ＷＬ（基準光）の１回の出射とＮａｒｒｏｗ光（第２特殊光）の出射とが、他の出射をはさまず連続していることが好ましい。これにより、１サイクル中で、２回の白色光ＷＬ（基準光）を生体組織Ｔの照明光ＩＬとして用いることができ、通常観察画像のリフレッシュレートが向上する。 As described in the present embodiment, regarding the order of the emission of the white light WL, the Wide light, and the narrow light, the emission of the Wide light (first special light) and the single emission of the white light WL (reference light) are performed. Alternatively, the amount of hemoglobin is obtained as will be described later, that one emission of white light WL (reference light) and one emission of wide light (first special light) are continuous with each other. Therefore, when calculating the first ratio, it is preferable from the viewpoint that the positional deviation in the image of the image of the living tissue T can be suppressed. Further, regarding the order of emission of white light WL, wide light, and narrow light, the emission of narrow light (second special light) and one emission of white light WL (reference light), or white light WL (reference light) It is preferable that one emission of light) and the emission of narrow light (second special light) are continuous without interfering with other emission. Thereby, the white light WL (reference light) twice can be used as the illumination light IL of the living tissue T in one cycle, and the refresh rate of the normal observation image is improved.
　また、本実施形態で説明したように、光源装置４００は、光源として１つの光を放射する光源ランプ４３０を備え、光源装置４００は、白色光ＷＬ（基準光）、Ｗｉｄｅ光、及びＮａｒｒｏｗ光（特殊光）の出射の順番に対応するように、１つの波長帯域の光を、通過波長帯域の異なる複数の光学フィルタを透過させることにより、白色光ＷＬ（基準光）、Ｗｉｄｅ光、及びＮａｒｒｏｗ光（特殊光）を出射するように構成されていることが好ましい。 Further, as described in the present embodiment, the light source device 400 includes the light source lamp 430 that emits one light as a light source, and the light source device 400 includes white light WL (reference light), wide light, and narrow light ( The white light WL (reference light), the wide light, and the narrow light are transmitted by transmitting light in one wavelength band through a plurality of optical filters having different pass wavelength bands so as to correspond to the order of emission of the special light). It is preferable to be configured to emit (special light).
　本実施形態の白色光ＷＬ（基準光）の波長帯域は、基準カラー画像データの成分の１つが、生体組織Ｔのヘモグロビンの量の変化に対して感度を有しないような波長帯域を含むように設定されていることが、第１比率において、生体組織Ｔにおける散乱特性の影響を適切に除去することができる点から、好ましい。 The wavelength band of the white light WL (reference light) of the present embodiment includes a wavelength band in which one of the components of the reference color image data does not have sensitivity to changes in the amount of hemoglobin in the living tissue T. It is preferable that it is set from the point that the influence of the scattering characteristics in the living tissue T can be appropriately removed in the first ratio.
（生体組織の特徴量の算出）
　生体組織Ｔの特徴量は、プロセッサ５００の特徴量取得部５１０で算出される。撮像した生体組織Ｔの画像から生体組織Ｔのヘモグロビンの量、及びヘモグロビンの酸素飽和度Ｓａｔを特徴量として算出する処理を以下説明する。 (Calculation of biological tissue features)
The feature amount of the living tissue T is calculated by the feature amount acquisition unit 510 of the processor 500. Processing for calculating the amount of hemoglobin in the biological tissue T and the oxygen saturation Sat of hemoglobin as the feature amount from the captured image of the biological tissue T will be described below.
　図４に示すように、ヘモグロビンは、５５０ｎｍ付近にポルフィリンに由来するＱ帯と呼ばれる強い吸収帯を有する。ヘモグロビンの吸収スペクトルは、全ヘモグロビンのうち酸素化ヘモグロビンＨｂＯが占める割合を表す酸素飽和度Ｓａｔに応じて変化する。図４における実線の波形は、酸素飽和度Ｓａｔが１００％、すなわち、酸素化ヘモグロビンＨｂＯの吸収スペクトルであり、長破線の波形は、酸素飽和度Ｓａｔが０％、すなわち、還元ヘモグロビンＨｂの吸収スペクトルである。また、短破線は、その中間の酸素飽和度Ｓａｔ＝１０、２０、３０、・・・９０％におけるヘモグロビン、すなわち酸素化ヘモグロビンＨｂＯと還元ヘモグロビンＨｂの混合物の吸収スペクトルである。 As shown in FIG. 4, hemoglobin has a strong absorption band called a Q band derived from porphyrin near 550 nm. The absorption spectrum of hemoglobin changes according to the oxygen saturation Sat representing the proportion of oxygenated hemoglobin HbO in the total hemoglobin. The solid line waveform in FIG. 4 is an absorption spectrum of oxygen saturation Sat of 100%, that is, oxygenated hemoglobin HbO, and the long broken line waveform is an absorption spectrum of oxygen saturation Sat of 0%, that is, reduced hemoglobin Hb. It is. The short dashed line is an absorption spectrum of hemoglobin at an intermediate oxygen saturation Sat = 10, 20, 30,... 90%, that is, a mixture of oxygenated hemoglobin HbO and reduced hemoglobin Hb.
　図４に示すように、Ｑ帯において、酸素化ヘモグロビンＨｂＯと還元ヘモグロビンＨｂは互いに異なるピーク波長を有する。具体的には、酸素化ヘモグロビンＨｂＯは、波長５４２ｎｍ付近の吸収ピークＰ１と、波長５７６ｎｍ付近の吸収ピークＰ３を有している。一方、還元ヘモグロビンＨｂは、５５６ｎｍ付近に吸収ピークＰ２を有している。図４は、酸素化ヘモグロビンＨｂＯ、還元ヘモグロビンＨｂの濃度の和が一定となる場合の吸収スペクトルであるため、酸素化ヘモグロビンＨｂＯ及び還元ヘモグロビンＨｂの比率、すなわち、酸素飽和度によらず吸光度が一定となる等吸収点Ｅ１、Ｅ２、Ｅ３、Ｅ４が現れる。以下の説明では、等吸収点Ｅ１とＥ２とで挟まれた波長帯域は、先に説明した波長帯域Ｒ１であり、等吸収点Ｅ２とＥ３とで挟まれた波長領域は波長帯域Ｒ２であり、等吸収点Ｅ３とＥ４とで挟まれた波長帯域は波長帯域Ｒ３であり、等吸収点Ｅ１とＥ４とで挟まれた波長帯域、すなわち波長帯域Ｒ１、Ｒ２及びＲ３を合わせた帯域は、波長帯域Ｒ０である。したがって、光源ランプ４３０から放射された光のうち光学フィルタＦｓ１を透過した透過光であるＷｉｄｅ光の波長帯域は、波長帯域Ｒ０であり、光源ランプ４３０から放射された光のうち光学フィルタＦｓ２を透過した透過光であるＮａｒｒｏｗ光の波長帯域は、波長帯域Ｒ２である。 As shown in FIG. 4, in the Q band, oxygenated hemoglobin HbO and reduced hemoglobin Hb have different peak wavelengths. Specifically, oxygenated hemoglobin HbO has an absorption peak P1 near a wavelength of 542 nm and an absorption peak P3 near a wavelength of 576 nm. On the other hand, reduced hemoglobin Hb has an absorption peak P2 near 556 nm. FIG. 4 is an absorption spectrum when the sum of the concentrations of oxygenated hemoglobin HbO and reduced hemoglobin Hb is constant. Therefore, the ratio of oxygenated hemoglobin HbO and reduced hemoglobin Hb, that is, the absorbance is constant regardless of the oxygen saturation. The isosbestic points E1, E2, E3, E4 appear. In the following description, the wavelength band sandwiched between the equal absorption points E1 and E2 is the wavelength band R1 described above, and the wavelength region sandwiched between the equal absorption points E2 and E3 is the wavelength band R2. The wavelength band sandwiched between the equal absorption points E3 and E4 is the wavelength band R3, and the wavelength band sandwiched between the equal absorption points E1 and E4, that is, the combined band of the wavelength bands R1, R2, and R3 is the wavelength band. R0. Therefore, the wavelength band of the Wide light, which is the transmitted light that has passed through the optical filter Fs1 out of the light emitted from the light source lamp 430, is the wavelength band R0, and the light emitted from the light source lamp 430 is transmitted through the optical filter Fs2. The wavelength band of the narrow light that is the transmitted light is the wavelength band R2.
　図４に示されるように、波長帯域Ｒ１，Ｒ２，Ｒ３では、ヘモグロビンの吸収は酸素飽和度に対して線形的に増加又は減少する。具体的には、波長帯域Ｒ１，Ｒ３におけるヘモグロビンの吸収ＡＲ１，ＡＲ３は、酸素化ヘモグロビンの濃度、すなわち酸素飽和度に対して線形的に増加する。また、波長帯域Ｒ２におけるヘモグロビンの吸収ＡＲ２は、還元ヘモグロビンの濃度に対して線形的に増加する。 As shown in FIG. 4, in the wavelength bands R1, R2, and R3, the absorption of hemoglobin increases or decreases linearly with respect to the oxygen saturation. Specifically, the absorptions AR1 and AR3 of hemoglobin in the wavelength bands R1 and R3 increase linearly with respect to the oxygenated hemoglobin concentration, that is, the oxygen saturation. In addition, the absorption AR2 of hemoglobin in the wavelength band R2 increases linearly with respect to the concentration of reduced hemoglobin.
　ここで、酸素飽和度は次の式（１）により定義される。 Here, the oxygen saturation is defined by the following equation (1).
式（１）：
Figure JPOXMLDOC01-appb-M000001
  
　　　但し、
　　　　Ｓａｔ：酸素飽和度
　　　　［Ｈｂ］：還元ヘモグロビンの濃度
　　　　［ＨｂＯ］：酸素化ヘモグロビンの濃度
　　　　［Ｈｂ］＋［ＨｂＯ］：ヘモグロビンの量（ｔＨｂ） Formula (1):
Figure JPOXMLDOC01-appb-M000001
However,
Sat: oxygen saturation [Hb]: concentration of reduced hemoglobin [HbO]: concentration of oxygenated hemoglobin [Hb] + [HbO]: amount of hemoglobin (tHb)
　また、式（１）より、酸素化ヘモグロビンＨｂＯ及び還元ヘモグロビンＨｂの濃度を表す式（２）、式（３）が得られる。 Further, from the formula (1), formulas (2) and (3) representing the concentrations of oxygenated hemoglobin HbO and reduced hemoglobin Hb are obtained.
式（２）：
Figure JPOXMLDOC01-appb-M000002
   Formula (2):
Figure JPOXMLDOC01-appb-M000002
式（３）：
Figure JPOXMLDOC01-appb-M000003
   Formula (3):
Figure JPOXMLDOC01-appb-M000003
　したがって、ヘモグロビンの吸収ＡＲ１、ＡＲ２及びＡＲ３は、酸素飽和度とヘモグロビンの量の両方に依存する特徴量となる。 Therefore, the absorption AR1, AR2, and AR3 of hemoglobin are characteristic amounts that depend on both the oxygen saturation and the amount of hemoglobin.
　ここで、波長帯域Ｒ０における吸光度の合計値は、酸素飽和度Ｓａｔには依存せず、ヘモグロビンの量によって決まる値となることが判明している。したがって、波長帯域Ｒ０における吸光度の合計値に基づいてヘモグロビンの量を定量することができる。また、波長帯域Ｒ１、波長帯域Ｒ２、あるいは波長帯域Ｒ３における吸光度の合計値と、波長帯域Ｒ０の合計値に基づいて定量したヘモグロビンの量とに基づいて、酸素飽和度Ｓａｔを定量することができる。 Here, it has been found that the total value of absorbance in the wavelength band R0 does not depend on the oxygen saturation Sat, but is a value determined by the amount of hemoglobin. Therefore, the amount of hemoglobin can be quantified based on the total absorbance in the wavelength band R0. In addition, the oxygen saturation Sat can be quantified based on the total absorbance in the wavelength band R1, the wavelength band R2, or the wavelength band R3 and the amount of hemoglobin quantified based on the total value in the wavelength band R0. .
　本実施形態の特徴量取得部５１０は、生体組織Ｔのヘモグロビンの量に対して感度を有する後述する第１比率に基づいて生体組織Ｔのヘモグロビンの量を算出し取得するヘモグロビン算出部５１０ａと、算出したヘモグロビンの量とヘモグロビンの酸素飽和度に対して感度を有する後述する第２比率に基づいて生体組織Ｔのヘモグロビンの酸素飽和度を算出し取得する酸素飽和度算出部５１０ｂと、データ選択部５１０ｃと、位置ずれ量算出部５１０ｄと、を含む。 The feature amount acquisition unit 510 of the present embodiment calculates a hemoglobin amount of the biological tissue T based on a later-described first ratio having sensitivity to the amount of hemoglobin of the biological tissue T, and acquires a hemoglobin calculation unit 510a. An oxygen saturation calculation unit 510b that calculates and acquires the oxygen saturation of hemoglobin in the living tissue T based on the calculated amount of hemoglobin and the second ratio described later having sensitivity to the oxygen saturation of hemoglobin, and a data selection unit 510c and a positional deviation amount calculation unit 510d.
　Ｗｉｄｅ光（光学フィルタＦｓ１を透過した波長帯域Ｒ０の光）で照明した生体組織Ｔのカラー画像データの輝度成分の値が、上述の波長帯域Ｒ０における吸光度の合計値に対応することから、本実施形態の特徴量取得部５１０のヘモグロビン量算出部５１０ａは、波長帯域Ｒ０のカラー画像データの輝度成分に基づいてヘモグロビンの量を算出する。ここで、輝度成分は、カラー画像データのＲ成分に所定の係数を掛け算し、カラー画像データのＧ成分に所定の係数を掛け算し、カラー画像データのＢ成分の値に所定の係数を掛け算し、これらの掛け算した結果を合算することで算出することができる。
　特徴量取得部５１０のヘモグロビン量算出部５１０ａは、具体的には、Ｗｉｄｅ光（第１特殊光）を照明光ＩＬとして用いた生体組織Ｔのカラー画像データ（第１特殊光カラー画像データ）の輝度成分Ｗｉｄｅ（Ｙｈ）を、白色光ＷＬ（基準光）を照明光ＩＬとして用いた生体組織Ｔのカラー画像データ（基準カラー画像データ）のＲ成分ＷＬ（Ｒ）、あるいはＲ成分ＷＬ（Ｒ）及びＧ成分ＷＬ（Ｇ）の合計成分ＷＬ（Ｒ）＋ＷＬ（Ｇ）で割った比率Ｗｉｄｅ（Ｙｈ）／ＷＬ（Ｒ）またはＷｉｄｅ（Ｙｈ）／｛ＷＬ（Ｒ）＋ＷＬ（Ｇ）｝（第１比率）に基づいてヘモグロビンの量を算出する。ヘモグロビンの量の算出において、輝度成分Ｗｉｄｅ（Ｙｈ）を、ＷＬ（Ｒ）あるいは｛ＷＬ（Ｒ）＋ＷＬ（Ｇ）｝で割った比率Ｗｉｄｅ（Ｙｈ）／ＷＬ（Ｒ）またはＷｉｄｅ（Ｙｈ）／｛ＷＬ（Ｒ）＋ＷＬ（Ｇ）｝を用いるのは、照明光ＩＬが生体組織Ｔの表面で散乱する程度によって生体組織Ｔの分光特性が変化することを除去するためである。特に、消化管内壁等の生体組織Ｔの反射スペクトルは、生体組織Ｔを構成する成分による吸収の波長特性（具体的には、酸素化ヘモグロビン及び還元ヘモグロビンの吸収スペクトル特性）に加えて、生体組織Ｔによる照明光の散乱の波長特性の影響を受け易い。白色光ＷＬ（基準光）を照明光ＩＬとして用いた生体組織Ｔのカラー画像データ（基準光カラー画像データ）のＲ成分ＷＬ（Ｒ）、あるいはＲ成分及びＧ成分の合計成分ＷＬ（Ｒ）＋ＷＬ（Ｇ）は、ヘモグロビンの量や酸素飽和度Ｓａｔの影響を受けず、照明光ＩＬの生体組織Ｔにおける散乱の程度を表す。したがって、生体組織Ｔの反射スペクトルから、照明光ＩＬの生体組織Ｔにおける散乱の影響を除去するために、白色光ＷＬ（基準光）の波長帯域は、基準光カラー画像データの成分の１つが、生体組織Ｔのヘモグロビンの量の変化に対して感度を有しないような波長帯域を含むように設定されていることが好ましい。これに加えて、白色光ＷＬ（基準光）の波長帯域は、基準光カラー画像データの成分の１つが、酸素飽和度の変化に対して感度を有しないような波長帯域を含むように設定されていることが好ましい。
　本実施形態では、ヘモグロビンの量が既知の生体組織Ｔにおける上述の第１比率の情報とヘモグロビンの量の対応関係を表した参照テーブルをメモリ５１２に予め記憶しておき、この参照テーブルを用いて、生体組織Ｔの撮像したカラー画像データにおける上記第１比率の値に基づいてヘモグロビンの量を算出する。図６は、第１比率とヘモグロビンの量の対応関係の一例を示す図である。図中のヘモグロビンの量の値は０～１０２４の範囲になるように規格化し、第１比率は０～１の範囲になるように規格化している。 Since the value of the luminance component of the color image data of the living tissue T illuminated with the Wide light (the light in the wavelength band R0 that has passed through the optical filter Fs1) corresponds to the total absorbance in the wavelength band R0 described above, this embodiment The hemoglobin amount calculation unit 510a of the feature amount acquisition unit 510 of the form calculates the amount of hemoglobin based on the luminance component of the color image data in the wavelength band R0. Here, the luminance component is obtained by multiplying the R component of the color image data by a predetermined coefficient, multiplying the G component of the color image data by a predetermined coefficient, and multiplying the value of the B component of the color image data by a predetermined coefficient. The result of multiplication can be calculated by adding them up.
Specifically, the hemoglobin amount calculation unit 510a of the feature amount acquisition unit 510 includes color image data (first special light color image data) of the living tissue T using Wide light (first special light) as the illumination light IL. R component WL (R) of color image data (reference color image data) of living tissue T using luminance component Wide (Yh) and white light WL (reference light) as illumination light IL, or R component WL (R) And the ratio Wide (Yh) / WL (R) or Wide (Yh) / {WL (R) + WL (G)} divided by the total component WL (R) + WL (G) of the G component WL (G) (first The amount of hemoglobin is calculated based on the ratio. In calculating the amount of hemoglobin, the ratio Wide (Yh) / WL (R) or Wide (Yh) / {divided by the luminance component Wide (Yh) divided by WL (R) or {WL (R) + WL (G)}. The reason why WL (R) + WL (G)} is used is to eliminate the change in the spectral characteristics of the living tissue T depending on the degree to which the illumination light IL is scattered on the surface of the living tissue T. In particular, the reflection spectrum of the living tissue T such as the inner wall of the digestive tract has a wavelength characteristic of absorption by the components constituting the living tissue T (specifically, absorption spectrum characteristics of oxygenated hemoglobin and reduced hemoglobin), It is easily affected by the wavelength characteristic of scattering of illumination light by T. R component WL (R) of color image data (reference light color image data) of living tissue T using white light WL (reference light) as illumination light IL, or total component WL (R) + WL of R component and G component (G) represents the degree of scattering of the illumination light IL in the living tissue T without being affected by the amount of hemoglobin or the oxygen saturation Sat. Therefore, in order to remove the influence of scattering of the illumination light IL in the living tissue T from the reflection spectrum of the living tissue T, the wavelength band of the white light WL (reference light) is one of the components of the reference light color image data, It is preferable that the wavelength band is set so as not to be sensitive to changes in the amount of hemoglobin in the living tissue T. In addition, the wavelength band of the white light WL (reference light) is set so that one of the components of the reference light color image data includes a wavelength band that is not sensitive to changes in oxygen saturation. It is preferable.
In the present embodiment, a reference table representing the correspondence relationship between the information on the first ratio and the amount of hemoglobin in the living tissue T in which the amount of hemoglobin is known is stored in advance in the memory 512, and this reference table is used. The amount of hemoglobin is calculated based on the value of the first ratio in the color image data captured by the living tissue T. FIG. 6 is a diagram illustrating an example of a correspondence relationship between the first ratio and the amount of hemoglobin. In the figure, the amount of hemoglobin is normalized to be in the range of 0 to 1024, and the first ratio is normalized to be in the range of 0 to 1.
　本実施形態のヘモグロビンの量の算出では、第１比率として、Ｗｉｄｅ光（第１特殊光）を照明光ＩＬとして用いた生体組織Ｔのカラー画像データ（第１特殊光カラー画像データ）の輝度成分Ｗｉｄｅ（Ｙｈ）と、白色光ＷＬ（基準光）を照明光ＩＬとして用いた生体組織Ｔのカラー画像データ（基準光カラー画像データ）のＲ成分ＷＬ（Ｒ）、あるいはＲ成分及びＧ成分の合計成分ＷＬ（Ｒ）＋ＷＬ（Ｇ）の比率Ｗｉｄｅ（Ｙｈ）／ＷＬ（Ｒ）またはＷｉｄｅ（Ｙｈ）／｛ＷＬ（Ｒ）＋ＷＬ（Ｇ）｝を用いることが好ましいが、Ｗｉｄｅ光（第１特殊光）を照明光ＩＬとして用いた生体組織Ｔのカラー画像データ（第１特殊光カラー画像データ）の輝度成分Ｗｉｄｅ（Ｙｈ）の代わりにＧ成分Ｗｉｄｅ（Ｇ）を用いることも好ましい。 In the calculation of the amount of hemoglobin of the present embodiment, the luminance component of the color image data (first special light color image data) of the living tissue T using Wide light (first special light) as the illumination light IL as the first ratio. Wide (Yh) and R component WL (R) of color image data (reference light color image data) of biological tissue T using white light WL (reference light) as illumination light IL, or the sum of R component and G component It is preferable to use the ratio of the component WL (R) + WL (G) Wide (Yh) / WL (R) or Wide (Yh) / {WL (R) + WL (G)}. It is also preferable to use the G component Wide (G) instead of the luminance component Wide (Yh) of the color image data (first special light color image data) of the living tissue T using the illumination light IL.
　さらに、上述したように、酸素飽和度Ｓａｔの上昇とともに波長帯域Ｒ２における吸光度の合計値が低下すること、及び、波長帯域Ｒ０における吸光度の合計値はヘモグロビンの量に応じて変化するが、酸素飽和度Ｓａｔの変化に係わらず一定であることから、特徴量取得部５１０の酸素飽和度算出部５１０ｂは、以下に定める第２比率に基づいて酸素飽和度Ｓａｔを算出する。すなわち、酸素飽和度算出部５１０ｂは、光学フィルタＦｓ２を通過した波長帯域Ｒ２の光であるＮａｒｒｏｗ光（第２特殊光）で照明した生体組織Ｔのカラー画像データ（第２特殊光カラー画像データ）の輝度成分Ｎａｒｒｏｗ（Ｙｈ）と、Ｗｉｄｅ光（光学フィルタＦｓ１を透過した波長帯域Ｒ２の光）で照明した生体組織Ｔのカラー画像データ（第２特殊光カラー画像データ）の輝度成分Ｗｉｄｅ（Ｙｈ）との比率Ｎａｒｒｏｗ（Ｙｈ）／Ｗｉｄｅ（Ｙｈ）を、第２比率として算出する。一方、ヘモグロビンの量と、酸素飽和度Ｓａｔ＝０％における第２比率の下限値及び酸素飽和度Ｓａｔ＝１００％における第２比率Ｎａｒｒｏｗ（Ｙｈ）／Ｗｉｄｅ（Ｙｈ）の上限値との関係を表した対応関係を、既知の試料から求めてメモリ５１２に予め記憶しておく。特徴量取得部５１０の酸素飽和度算出部５１０ｂは、生体組織Ｔの撮像によって生成したカラー画像データから得られるヘモグロビンの量の算出結果と上記対応関係を用いて、第２比率の下限値及び上限値を求め、求めた下限値と上限値の間で酸素飽和度Ｓａｔは第２比率に応じて線形的に変化するとして、撮像した生体組織Ｔの第２比率Ｎａｒｒｏｗ（Ｙｈ）／Ｗｉｄｅ（Ｙｈ）の値がどの酸素飽和度Ｓａｔの位置にあるかを算出する。このようにして、特徴量取得部５１０の酸素飽和度算出部５１０ｂは、酸素飽和度Ｓａｔの算出を行う。図７は、ヘモグロビンの量に応じて変化する第２比率の上限値（Ｓａｔ１００％）及び下限値（Ｓａｔ０％）の関係の一例を示す図である。図中のヘモグロビンの量の値は０～１０２４の範囲になるように規格化し、第２比率は０～１の範囲になるように規格化している。
　また、ヘモグロビンの量及び第２比率の値とヘモグロビンの酸素飽和度Ｓａｔとの対応関係を表した参照テーブルを既知の試料から求めて予めメモリ５１２に記憶しておき、この参照テーブルを参照して、算出した第２比率からヘモグロビンの酸素飽和度Ｓａｔを算出することもできる。 Furthermore, as described above, the total absorbance value in the wavelength band R2 decreases with the increase in the oxygen saturation Sat, and the total absorbance value in the wavelength band R0 varies depending on the amount of hemoglobin. Since it is constant regardless of the change in the degree Sat, the oxygen saturation calculation unit 510b of the feature amount acquisition unit 510 calculates the oxygen saturation Sat based on the second ratio defined below. In other words, the oxygen saturation calculation unit 510b performs color image data (second special light color image data) of the living tissue T illuminated with the narrow light (second special light) that is the light in the wavelength band R2 that has passed through the optical filter Fs2. Brightness component Wide (Yh) and brightness component Wide (Yh) of color image data (second special light color image data) of living tissue T illuminated with Wide light (light in wavelength band R2 that has passed through optical filter Fs1). The ratio Narrow (Yh) / Wide (Yh) is calculated as the second ratio. On the other hand, the relationship between the amount of hemoglobin and the lower limit value of the second ratio at the oxygen saturation Sat = 0% and the upper limit value of the second ratio Narrow (Yh) / Wide (Yh) at the oxygen saturation Sat = 100% is shown. The correspondence relationship obtained is obtained from a known sample and stored in the memory 512 in advance. The oxygen saturation calculation unit 510b of the feature amount acquisition unit 510 uses the calculation result of the amount of hemoglobin obtained from the color image data generated by imaging the living tissue T and the above correspondence, and the lower limit value and the upper limit of the second ratio. A value is obtained, and the oxygen saturation Sat linearly changes according to the second ratio between the obtained lower limit value and upper limit value. The second ratio Narrow (Yh) / Wide (Yh) of the imaged living tissue T Is calculated at which oxygen saturation Sat. In this way, the oxygen saturation calculation unit 510b of the feature amount acquisition unit 510 calculates the oxygen saturation Sat. FIG. 7 is a diagram illustrating an example of the relationship between the upper limit value (Sat 100%) and the lower limit value (Sat 0%) of the second ratio that changes in accordance with the amount of hemoglobin. In the figure, the amount of hemoglobin is normalized to be in the range of 0 to 1024, and the second ratio is normalized to be in the range of 0 to 1.
Further, a reference table representing the correspondence relationship between the amount of hemoglobin and the value of the second ratio and the oxygen saturation Sat of hemoglobin is obtained from a known sample and stored in the memory 512 in advance, and this reference table is referred to. The oxygen saturation Sat of hemoglobin can also be calculated from the calculated second ratio.
　本実施形態では、第２比率を、Ｎａｒｒｏｗ光で照明した生体組織Ｔのカラー画像データ（第２特殊光カラー画像データ）の輝度成分Ｎａｒｒｏｗ（Ｙｈ）と、Ｗｉｄｅ光で照明した生体組織Ｔのカラー画像データ（第１特殊光カラー画像データ）の輝度成分Ｗｉｄｅ（Ｙｈ）との比率として用いるが、Ｎａｒｒｏｗ光で照明した生体組織Ｔのカラー画像データ（第２特殊光カラー画像データ）のＧ成分Ｎａｒｒｏｗ（Ｇ）と、Ｗｉｄｅ光で照明した生体組織Ｔのカラー画像データ（第１特殊光カラー画像データ）のＧ成分Ｗｉｄｅ（Ｇ）との比率を用いることもできる。 In the present embodiment, the second ratio is the luminance component Narrow (Yh) of the color image data (second special light color image data) of the living tissue T illuminated with the narrow light and the color of the living tissue T illuminated with the wide light. G component Narrow of color image data (second special light color image data) of living tissue T illuminated with Narrow light, which is used as a ratio with the luminance component Wide (Yh) of image data (first special light color image data). The ratio between (G) and the G component Wide (G) of the color image data (first special light color image data) of the living tissue T illuminated with Wide light can also be used.
　また、本実施形態では、第２比率の算出のために、生体組織Ｔの照明のために波長帯域Ｒ２のＮａｒｒｏｗ光を用いるが、Ｎａｒｒｏｗ光には限られない。例えば、酸素飽和度Ｓａｔの変化に対して吸光度の合計値が変化する波長帯域Ｒ１あるいは波長帯域Ｒ２を利用することを意図して、波長帯域Ｒ１あるいは波長帯域Ｒ２を波長帯域とする特殊光を用いることもできる。この場合、光学フィルタＦｓ２のフィルタ特性を波長帯域Ｒ１あるいは波長帯域Ｒ２に設定するとよい。 In the present embodiment, the narrow light in the wavelength band R2 is used for illumination of the living tissue T for the calculation of the second ratio, but is not limited to the narrow light. For example, special light having the wavelength band R1 or the wavelength band R2 as the wavelength band is used with the intention of using the wavelength band R1 or the wavelength band R2 in which the total absorbance changes with respect to the change in the oxygen saturation Sat. You can also. In this case, the filter characteristic of the optical filter Fs2 may be set to the wavelength band R1 or the wavelength band R2.
　このように、本実施形態では、酸素飽和度Ｓａｔを正確に算出するには、Ｎａｒｒｏｗ光（第２特殊光）の波長帯域は、Ｗｉｄｅ光（第１特殊光）の波長帯域に含まれることが好ましい。また、Ｗｉｄｅ光（第１特殊光）の波長帯域は、第１特殊光カラー画像データの成分の１つ、例えば輝度成分やＧ成分が、ヘモグロビンの量の変化に対して感度を有するが、酸素飽和度の変化に対して感度を有しないような波長帯域Ｒ０を含むように設定されていることが、正確に酸素飽和度Ｓａｔを算出することができる点から好ましい。Ｎａｒｒｏｗ光（第２特殊光）の波長帯域は、第２特殊光カラー画像データの成分の１つ、例えば輝度成分やＧ成分が、生体組織Ｔの酸素飽和度Ｓａｔの変化に対して感度を有するような波長帯域Ｒ２を含むように設定されていることが、正確に酸素飽和度Ｓａｔを算出することができる点から好ましい。 Thus, in the present embodiment, in order to accurately calculate the oxygen saturation Sat, the wavelength band of the narrow light (second special light) may be included in the wavelength band of the wide light (first special light). preferable. Further, the wavelength band of Wide light (first special light) is one of the components of the first special light color image data, for example, the luminance component and the G component are sensitive to changes in the amount of hemoglobin. It is preferable that the setting is made so as to include the wavelength band R0 that does not have sensitivity to the change in the saturation, because the oxygen saturation Sat can be accurately calculated. In the wavelength band of the narrow light (second special light), one of the components of the second special light color image data, for example, the luminance component and the G component is sensitive to a change in the oxygen saturation Sat of the living tissue T. It is preferable that the wavelength band R2 is set so as to include the oxygen saturation Sat accurately.
　また、上述のＷｉｄｅ光（第１特殊光）は、光学フィルタの１つで、白色光ＷＬ（基準光）の波長帯域のうち、５００ｎｍ～６００ｎｍの範囲内の波長帯域（第１波長帯域）、例えば等吸収点Ｅ１と等吸収点Ｅ４間の波長帯域を透過させた白色光ＷＬ（基準光）の濾過光であり、Ｎａｒｒｏｗ光（第２特殊光）は、光学フィルタの１つで、白色光ＷＬ（基準光）の波長帯域のうち、第１波長帯域の範囲内の、第１波長帯域より狭い波長帯域（第２波長帯域）、例えば等吸収点Ｅ２と等吸収点Ｅ３間の波長帯域を透過させた白色光ＷＬ（基準光）の濾過光であることが好ましい。 The above-mentioned Wide light (first special light) is one of optical filters, and a wavelength band (first wavelength band) within a range of 500 nm to 600 nm in a wavelength band of white light WL (reference light), For example, the filtered light of the white light WL (reference light) that transmits the wavelength band between the equal absorption point E1 and the equal absorption point E4, and the narrow light (second special light) is one of the optical filters. Among the wavelength bands of WL (reference light), a wavelength band (second wavelength band) narrower than the first wavelength band within the first wavelength band, for example, a wavelength band between the equal absorption point E2 and the equal absorption point E3. It is preferably filtered light of the transmitted white light WL (reference light).
　本実施形態では、精度の高い診断を行うために、酸素飽和度Ｓａｔの分布を示す酸素飽和度分布画像等の特徴量分布画像は高画質であることが求められる。このため、特徴量分布画像は、好ましくは１００万画素以上、より好ましくは２００万画素以上、さらに好ましくは８００万画素以上である。一方、取り扱う画像の画素数が多くなる程、プロセッサ２００の演算回路は大きくなり、処理負荷も大きくなる傾向にある。特に、１００万画素以上の高画素（高画質）では上記傾向は顕著である。本実施形態では、予め参照テーブルを設け、この参照テーブルを用いてヘモグロビンの量及び酸素飽和度Ｓａｔを算出するので、本実施形態は、カラー画像データの取得の度にヘモグロビンの量及び酸素飽和度Ｓａｔを、参照テーブルを用いずに算出する場合に比べて効率よくヘモグロビンの量及び酸素飽和度Ｓａｔを算出することができる。このため、プロセッサ２００の演算回路を小さくすることができ、これにより、高画質な画像を生成するとしても、低コストで、低発熱量で、低省電力のプロセッサ２００を提供することができる。 In the present embodiment, in order to perform highly accurate diagnosis, a feature amount distribution image such as an oxygen saturation distribution image showing the distribution of oxygen saturation Sat is required to have high image quality. For this reason, the feature amount distribution image is preferably 1 million pixels or more, more preferably 2 million pixels or more, and further preferably 8 million pixels or more. On the other hand, as the number of pixels of the image to be handled increases, the arithmetic circuit of the processor 200 increases and the processing load tends to increase. In particular, the above tendency is remarkable at a high pixel (high image quality) of 1 million pixels or more. In this embodiment, a reference table is provided in advance, and the amount of hemoglobin and the oxygen saturation Sat are calculated using this reference table. Therefore, in this embodiment, the amount of hemoglobin and the oxygen saturation are obtained each time color image data is acquired. The amount of hemoglobin and the oxygen saturation Sat can be calculated more efficiently than when Sat is calculated without using a reference table. For this reason, the arithmetic circuit of the processor 200 can be reduced. Accordingly, even when a high-quality image is generated, the low-cost, low heat generation, and low power-saving processor 200 can be provided.
　また、光源装置４００は、白色光ＷＬ（基準光）及びＷｉｄｅ光、Ｎａｒｒｏｗ光（特殊光）の出射を１サイクルとして、複数サイクルの出射を繰り返すように構成され、１サイクル中の撮像素子１４１が基準光カラー画像データを生成する回数は、撮像素子１４１が第１特殊光カラー画像データを生成する回数及び撮像素子１４１が前記第２特殊光カラー画像データを生成する回数に比べて多いことが好ましい。
　このとき、基準光カラー画像データを生成する回数の、第１特殊光カラー画像データを生成する回数に対する比、及び基準光カラー画像データを生成する回数の、第２特殊光カラー画像データを生成する回数に対する比は、１．５以上であることが好ましく、２以上であることがより好ましい。また、この比の上限は特に制限されないが、第１及び第２特殊光カラー画像データを用いて得られる特徴量分布画像のリフレッシュレートを所定値以上確保する点から、４以下であることが好ましく、３以下であることがより好ましい。
　通常観察画像のリフレッシュレートを向上させると、これに伴って、特徴量分布画像のリフレッシュレートは、通常観察画像のリフレッシュレートに対して相対的に低下するが、特徴量分布画像は、生体組織Ｔ中の病変部の位置を特定するための補助画像であるので、リフレッシュレートが相対的に低下しても、生体組織Ｔを観察する操作者に与えるストレスは小さい。 The light source device 400 is configured to repeat the emission of a plurality of cycles, with the emission of white light WL (reference light), wide light, and narrow light (special light) as one cycle, and the image sensor 141 in one cycle includes The number of times that the reference light color image data is generated is preferably larger than the number of times that the image sensor 141 generates the first special light color image data and the number of times that the image sensor 141 generates the second special light color image data. .
At this time, the ratio of the number of times of generating the reference light color image data to the number of times of generating the first special light color image data and the second special light color image data of the number of times of generating the reference light color image data are generated. The ratio to the number of times is preferably 1.5 or more, and more preferably 2 or more. The upper limit of this ratio is not particularly limited, but is preferably 4 or less from the viewpoint of securing a refresh rate of a feature amount distribution image obtained using the first and second special light color image data to a predetermined value or more. More preferably, it is 3 or less.
When the refresh rate of the normal observation image is improved, the refresh rate of the feature amount distribution image is lowered relative to the refresh rate of the normal observation image. Since this is an auxiliary image for specifying the position of the lesion part in the inside, even if the refresh rate is relatively lowered, the stress applied to the operator who observes the living tissue T is small.
　本実施形態の電子内視鏡１００は、撮像素子１４１が、白色光ＷＬ（基準光）及びＷｉｄｅ光及びＮａｒｒｏｗ光（特殊光）の波長帯域の、生体組織Ｔの反射光を受光するように構成された光学系を備えることが好ましい。この光学系は、上述したように対物レンズ群１２１を含むが、白色光ＷＬ（基準光）及びＷｉｄｅ光及びＮａｒｒｏｗ光（特殊光）の波長帯域の少なくとも一部をカットするカットフィルタを含まない。これにより、本実施形態では、上述した波長帯域の照明光ＩＬによる生体組織Ｔの照明により、精度の高いヘモグロビンの量及びヘモグロビンの酸素飽和度の分布画像を求めることができる。したがって、上記光学系は、白色光ＷＬ（基準光）及びＷｉｄｅ光及びＮａｒｒｏｗ光（特殊光）の波長帯域の光を透過するように構成されていることが好ましい。 The electronic endoscope 100 according to the present embodiment is configured such that the imaging element 141 receives reflected light of the living tissue T in the wavelength bands of white light WL (reference light), wide light, and narrow light (special light). It is preferable that the optical system is provided. This optical system includes the objective lens group 121 as described above, but does not include a cut filter that cuts at least part of the wavelength band of white light WL (reference light), wide light, and narrow light (special light). Accordingly, in the present embodiment, it is possible to obtain a highly accurate distribution image of the amount of hemoglobin and the oxygen saturation of hemoglobin by illuminating the living tissue T with the illumination light IL in the wavelength band described above. Therefore, it is preferable that the optical system is configured to transmit light in the wavelength bands of white light WL (reference light), wide light, and narrow light (special light).
　本実施形態の特徴量取得部５１０は、図１に示すように、データ選択部５１０ｃと、位置ずれ量算出部５１０ｄを備えることが、信頼度の高いヘモグロビンの量やヘモグロビンの酸素飽和度の分布を求めることができる点で好ましい。
　上述したように、時間間隔を設けて出射する白色光ＷＬ（基準光）とＷｉｄｅ光（第１特殊光）は第１比率の算出に用いるカラー画像データの生成のために用いられので、生体組織Ｔの急激な動きや手振れに起因する画像中の生体組織Ｔの像の位置ずれを抑制するには、白色光ＷＬ（基準光）とＷｉｄｅ光（第１特殊光）は、他の照明光ＩＬの出射を挟まず、続けて出射されることが好ましい。さらに、Ｗｉｄｅ光（第１特殊光）とＮａｒｒｏｗ光（第２特殊光）は第２比率の算出に用いるカラー画像データの生成のために用いられので、上記位置ずれを抑制するには、Ｎａｒｒｏｗ光（第２特殊光）とＷｉｄｅ光（第１特殊光）は他の出射をはさまず連続して出射されることが好ましい。しかし、上述したように、通常観察画像のリフレッシュレートの向上のために、本実施形態では、１サイクル中で、少なくとも２回の白色光ＷＬ（基準光）の出射を行うので、本実施形態では、光源装置２００から、Ｎａｒｒｏｗ光の出射とＷｉｄｅ光（第１特殊光）の間に白色光ＷＬ１（第１基準光）の出射を行い、かつＷｉｄｅ光（第１特殊光）の出射と白色光ＷＬ２（第２基準光）の出射を他の出射をはさまず連続させた順番で照明光ＩＬを出射する。本実施形態では、１サイクルにおいて、図５に示すように、Ｎａｒｒｏｗ光（第２特殊光）、白色光ＷＬ１（第１基準光）、Ｗｉｄｅ光（第１特殊光）、白色光ＷＬ２（第２基準光）の順番で出射を行う。プロセッサ２００は、各サイクルにおいて、白色光ＷＬ１（第１基準光）で照明された生体組織Ｔを撮像することにより第１基準光カラー画像データを得、白色光ＷＬ２（第２基準光）で照明された生体組織Ｔを撮像することにより第２基準光カラー画像データを得る。したがって、データ選択部５１０ｃは、第１比率の算出のために、第１基準光カラー画像データと第２基準光カラー画像データのいずれを用いるかを選択する。 As shown in FIG. 1, the feature amount acquisition unit 510 of the present embodiment includes a data selection unit 510c and a positional deviation amount calculation unit 510d, so that the amount of highly reliable hemoglobin and oxygen saturation of hemoglobin are distributed. Is preferable in that it can be obtained.
As described above, the white light WL (reference light) and the wide light (first special light) emitted with a time interval are used for generating color image data used for calculating the first ratio. In order to suppress the displacement of the image of the living tissue T in the image due to the rapid movement of T and the camera shake, white light WL (reference light) and Wide light (first special light) are used as other illumination light IL. It is preferable that the light is continuously emitted without interposing it. Furthermore, the Wide light (first special light) and the narrow light (second special light) are used for generating color image data used for calculating the second ratio. It is preferable that (second special light) and Wide light (first special light) are continuously emitted without other emission. However, as described above, in this embodiment, since the white light WL (reference light) is emitted at least twice in one cycle in this embodiment in order to improve the refresh rate of the normal observation image, in this embodiment. The white light WL1 (first reference light) is emitted from the light source device 200 between the narrow light emission and the wide light (first special light), and the wide light (first special light) is emitted and the white light. The illumination light IL is emitted in the order in which the emission of WL2 (second reference light) is continued without interfering with other emission. In the present embodiment, in one cycle, as shown in FIG. 5, Narrow light (second special light), white light WL1 (first reference light), Wide light (first special light), white light WL2 (second special light) The light is emitted in the order of reference light). In each cycle, the processor 200 obtains first reference light color image data by imaging the living tissue T illuminated with the white light WL1 (first reference light), and illuminates with the white light WL2 (second reference light). The second reference light color image data is obtained by imaging the biological tissue T thus obtained. Therefore, the data selection unit 510c selects which of the first reference light color image data and the second reference light color image data is used for calculating the first ratio.
　データ選択部５１０ｃによる選択は、各サイクル中の第１基準光カラー画像データにおける生体組織Ｔの像と第２基準光カラー画像データにおける生体組織Ｔの像との間の位置ずれ量に基づいて行われる。例えば、生体組織Ｔの急激な動きあるいは内視鏡１００を用いた手技中の手振れ等により、通常観察画像と酸素飽和度分布画像との間で、像の位置ずれが生じる場合がある。本実施形態の特徴量算出部５１０は、生体組織Ｔの像の位置ずれに起因した特徴量の信頼度の低下を抑制するために、他の出射を挟まずＷｉｄｅ光（第１特殊光）と白色光ＷＬ２（第２基準光）を続けて出射させることで得られる第２基準カラー画像データと第１特殊光カラー画像データを用いて第１比率を算出する。しかし、上記位置ずれ量が許容範囲をはずれた場合、生体組織Ｔの像の位置ずれに起因した第１比率の信頼度は低下する可能性がある。上述したように、照明光ＩＬの出射の順番に関して、１サイクルにおいて、白色光ＷＬ２（第２基準光）の出射は白色光ＷＬ１（第１基準光）の出射に比べてＮａｒｒｏｗ光（第２特殊光）の出射から離れている。このため、第２基準光カラー画像データにおける生体組織Ｔの像の位置ずれの有無を判断するために、本実施形態では、各サイクル中の第１基準光カラー画像データで表される生体組織Ｔの像と第２基準光カラー画像データで表される生体組織Ｔの像との間の位置ずれ量を算出することが好ましい。このとき、位置ずれ量が許容範囲を外れる場合、第２基準カラー画像データに代えて第１基準カラー画像データを用いて第１比率を算出するように、データ選択部５１０ｃは第１カラー画像データの選択を行う。この場合、白色光ＷＬ１（第１基準光）で照明し撮像した生体組織Ｔの像は、Ｎａｒｒｏｗ光（第２特殊光）で照明した生体組織Ｔの像及びＷｉｄｅ光（第１特殊光）で照明した生体組織Ｔの像に対して位置ずれ量が許容範囲を外れている可能性はかなり低い。 The selection by the data selection unit 510c is performed based on the amount of positional deviation between the image of the living tissue T in the first reference light color image data and the image of the living tissue T in the second reference light color image data in each cycle. Is called. For example, an image position shift may occur between the normal observation image and the oxygen saturation distribution image due to a rapid movement of the living tissue T or a hand shake during a procedure using the endoscope 100. The feature amount calculation unit 510 according to the present embodiment uses the Wide light (first special light) without interposing other emission in order to suppress a decrease in reliability of the feature amount due to the displacement of the image of the living tissue T. The first ratio is calculated using the second reference color image data and the first special light color image data obtained by continuously emitting the white light WL2 (second reference light). However, when the amount of positional deviation deviates from the allowable range, the reliability of the first ratio due to the positional deviation of the image of the living tissue T may be reduced. As described above, regarding the order of emission of the illumination light IL, in one cycle, the emission of the white light WL2 (second reference light) is narrower than the emission of the white light WL1 (first reference light) (second special light). It is far from the emission of light. For this reason, in order to determine the presence or absence of the positional deviation of the image of the living tissue T in the second reference light color image data, in this embodiment, the living tissue T represented by the first reference light color image data in each cycle. It is preferable to calculate the amount of positional deviation between the image of and the image of the living tissue T represented by the second reference light color image data. At this time, if the amount of positional deviation is outside the allowable range, the data selection unit 510c calculates the first ratio using the first reference color image data instead of the second reference color image data. Make a selection. In this case, the image of the living tissue T illuminated with the white light WL1 (first reference light) and the image of the living tissue T illuminated with the narrow light (second special light) and the wide light (first special light) are used. The possibility that the positional deviation amount is outside the allowable range with respect to the image of the illuminated living tissue T is quite low.
　上述の理由から、特徴量取得部５１０は、白色光ＷＬ１（第１基準光）で照明し撮像した生体組織Ｔの像に対する白色光ＷＬ２（第２基準光）で照明し撮像した生体組織Ｔの像の位置ずれ量を算出する位置ずれ量算出部５１０ｄを備えることが好ましい。このとき、データ選択部５１０ｃは、算出した位置ずれ量が許容範囲を外れる場合、第２基準光カラー画像データに代えて第１基準光カラー画像データを第１比率の算出に用いるように選択する。上記生体組織Ｔの像の位置ずれ量は、例えば、第１基準光カラー画像データと第２基準光画像データの同じ画素位置における成分間の相互相関関数の算出結果に基づいて画像中の２方向に関して算出することができる。 For the above-described reason, the feature amount acquisition unit 510 illuminates the image of the living tissue T illuminated with the white light WL1 (first reference light) and captured with the white light WL2 (second reference light) for the image of the living tissue T captured. It is preferable to include a positional deviation amount calculation unit 510d that calculates the positional deviation amount of the image. At this time, if the calculated displacement amount is outside the allowable range, the data selection unit 510c selects the first reference light color image data to be used for calculating the first ratio instead of the second reference light color image data. . The amount of positional deviation of the image of the biological tissue T is, for example, two directions in the image based on the calculation result of the cross-correlation function between components at the same pixel position of the first reference light color image data and the second reference light image data Can be calculated.
　なお、本実施形態の照明光ＩＬの出射の順番に関して、Ｎａｒｒｏｗ光（第２特殊光）の出射とＷｉｄｅ光（第１特殊光）の出射の間に白色光ＷＬ１（第１基準光）の出射を行うが、Ｗｉｄｅ光（第１特殊光）を第２特殊光より先に出射させる場合、Ｗｉｄｅ光（第１特殊光）の出射と第２特殊光の出射の間に白色光ＷＬ１（第１基準光）の出射を行うことが好ましい。また、本実施形態の照明光ＩＬの出射の順番に関して、白色光ＷＬ２（第２基準光）をＷｉｄｅ光（第１特殊光）より先に出射させる場合、白色光ＷＬ２（第２基準光）の出射とＷｉｄｅ光（第１特殊光）の出射とを、他の出射をはさまず連続させた順番で出射を行うことも好ましい。 In addition, regarding the order of emission of the illumination light IL of the present embodiment, the white light WL1 (first reference light) is emitted between the emission of the narrow light (second special light) and the emission of the wide light (first special light). However, when the Wide light (first special light) is emitted before the second special light, the white light WL1 (first special light) is emitted between the emission of the Wide light (first special light) and the second special light. It is preferable to emit reference light). In addition, regarding the order of emission of the illumination light IL of the present embodiment, when the white light WL2 (second reference light) is emitted before the Wide light (first special light), the white light WL2 (second reference light) It is also preferable that the emission and the emission of the Wide light (first special light) be performed in the order in which the other emission is continued without being separated.
　図８は、本実施形態の内視鏡システムのディスプレイ３００に動画として表示される通常観察画像とヘモグロビンの酸素飽和度の分布画像の一例を示す図である。
　図中左の画像が通常観察画像であり、右の画像がヘモグロビンの酸素飽和度の分布画像である。図８に示す通常観察画像のリフレッシュレートは操作者の観察にストレスを与えない程度である。このため、内視鏡１００を操作しながら手技を行う操作者にとって生体組織Ｔをストレスなく観察でき、精度の高い生体組織Ｔのヘモグロビンの酸素飽和度の分布画像中の注目する位置、例えば酸素飽和度の低い位置を、通常観察画像中の生体組織Ｔの像上で特定することができる。 FIG. 8 is a diagram illustrating an example of a normal observation image displayed as a moving image on the display 300 of the endoscope system of the present embodiment and an oxygen saturation distribution image of hemoglobin.
The left image in the figure is a normal observation image, and the right image is a distribution image of the oxygen saturation of hemoglobin. The refresh rate of the normal observation image shown in FIG. 8 is such that no stress is given to the observation of the operator. For this reason, the operator who performs the procedure while operating the endoscope 100 can observe the living tissue T without stress, and the position of interest in the oxygen saturation distribution image of the hemoglobin of the living tissue T with high accuracy, for example, oxygen saturation. A low-degree position can be identified on the image of the living tissue T in the normal observation image.
　以上、本発明の内視鏡システムについて詳細に説明したが、本発明の内視鏡システムは上記実施形態に限定されず、本発明の主旨を逸脱しない範囲において、種々の改良や変更をしてもよいのはもちろんである。 Although the endoscope system of the present invention has been described in detail above, the endoscope system of the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Of course it is also good.
１　　内視鏡システム
１００　　電子内視鏡
１１０　　挿入管
１１１　　挿入管先端部
１２１　　対物レンズ群
１３１　　ライトガイド
１３１ａ　先端部
１３１ｂ　基端部
１３２　　レンズ
１４１　　撮像素子
１４１ａ　カラーフィルタ
１４２　　ケーブル
２００　　プロセッサ
３００　　ディスプレイ
４００　　光源部
４１０　　回転フィルタ
４２０　　フィルタ制御部
４３０　　光源ランプ
４４０　　集光レンズ
４５０　　集光レンズ
５００　　画像処理部
５０２　　Ａ／Ｄ変換回路
５０４　　プレ画像処理部
５０６　　フレームメモリ部
５０８　　ポスト画像処理部
５１０　　特徴量取得部
５１０ａ　ヘモグロビン算出部
５１０ｂ　酸素飽和度算出部
５１０ｃ　データ選択部
５１０ｄ　位置ずれ量算出部
５１２　　メモリ
５１４　　画像表示制御部
５１６　　コントローラ DESCRIPTION OF SYMBOLS 1 Endoscope system 100 Electronic endoscope 110 Insertion tube 111 Insertion tube front-end | tip part 121 Objective lens group 131 Light guide 131a Front end part 131b Base end part 132 Lens 141 Image pick-up element 141a Color filter 142 Cable 200 Processor 300 Display 400 Light source part 410 Rotation filter 420 Filter control unit 430 Light source lamp 440 Condensing lens 450 Condensing lens 500 Image processing unit 502 A / D conversion circuit 504 Pre-image processing unit 506 Frame memory unit 508 Post-image processing unit 510 Feature amount acquisition unit 510a Hemoglobin calculation unit 510b Oxygen saturation calculation unit 510c Data selection unit 510d Position shift amount calculation unit 512 Memory 514 Image display control unit 516 Controller

Claims (15)

  1. 　お互いに波長帯域の異なる、基準光と少なくとも第１特殊光及び第２特殊光を含む複数の特殊光の出射を１サイクルとして、前記基準光と前記特殊光を生体組織の照明光として前記１サイクルを繰り返すように構成された光源装置と、
    　前記照明光のそれぞれで前記生体組織が照明されるたびに前記生体組織を前記照明光の出射のタイミングに合わせて撮像することにより、前記照明光で照明した前記生体組織の像のカラー画像データを生成するように構成された撮像素子を備える内視鏡と、
    　前記カラー画像データを用いて前記生体組織のヘモグロビンの量及び前記生体組織のヘモグロビンの酸素飽和度を前記生体組織の特徴量として算出するように構成された特徴量取得部を備えるプロセッサと、
    　前記基準光で照明され前記撮像素子で撮像された前記生体組織の画像と、前記ヘモグロビンの量及び前記酸素飽和度の少なくとも一方の分布を示した特徴量分布画像とを表示するように構成されたディスプレイと、を備え、
    　前記特徴量取得部は、前記カラー画像データのうち、前記第１特殊光の照明により得られた第１特殊光カラー画像データの成分と前記基準光の照明により得られた基準光カラー画像データの成分を用いて前記ヘモグロビンの量を算出するように構成されたヘモグロビン量算出部と、前記第１特殊光の照明により得られた第１特殊光カラー画像データの成分と前記第２特殊光の照明により得られた第２特殊光カラー画像データの成分を用いて前記ヘモグロビンの酸素飽和度を算出するように構成された酸素飽和度算出部を含み、
    　前記光源装置は、前記照明光の順番に関して、前記１サイクルにおいて、前記特殊光の１つの出射と前記特殊光の別の出射の間に前記基準光の出射を行うことを、少なくとも２回、前記基準光の出射を続けることなく行うように構成されている、ことを特徴とする内視鏡システム。     The reference light and a plurality of special lights including at least the first special light and the second special light, which are different in wavelength band from each other, are emitted as one cycle, and the reference light and the special light are used as illumination light for living tissue. A light source device configured to repeat
    Color image data of the image of the biological tissue illuminated with the illumination light is obtained by imaging the biological tissue in accordance with the timing of emission of the illumination light each time the biological tissue is illuminated with each of the illumination light. An endoscope comprising an imaging device configured to generate;
    A processor comprising a feature amount acquisition unit configured to calculate the amount of hemoglobin in the living tissue and the oxygen saturation level of hemoglobin in the living tissue as the feature amount of the living tissue using the color image data;
    An image of the biological tissue illuminated with the reference light and imaged by the imaging device, and a feature amount distribution image showing at least one distribution of the amount of the hemoglobin and the oxygen saturation are displayed. A display, and
    The feature amount acquisition unit includes a component of the first special light color image data obtained by illumination of the first special light and the reference light color image data obtained by illumination of the reference light among the color image data. A hemoglobin amount calculating unit configured to calculate the amount of the hemoglobin using a component, the component of the first special light color image data obtained by the illumination of the first special light, and the illumination of the second special light An oxygen saturation calculator configured to calculate the oxygen saturation of the hemoglobin using the component of the second special light color image data obtained by
    The light source device emits the reference light at least twice between one emission of the special light and another emission of the special light in the one cycle with respect to the order of the illumination light. An endoscope system configured to perform the emission of reference light without continuing.
  2. 　前記基準光及び前記特殊光の出射の順番に関して、前記第１特殊光の出射と前記基準光の１回の出射とが、あるいは前記基準光の１回の出射と前記第１特殊光の出射とが、他の出射をはさまず連続している、請求項１に記載の内視鏡システム。 Regarding the order of emission of the reference light and the special light, the emission of the first special light and the single emission of the reference light, or the single emission of the reference light and the emission of the first special light, The endoscope system according to claim 1, wherein the other outputs are continuous without intervening.
  3. 　前記基準光及び前記特殊光の出射の順番に関して、前記第２特殊光の出射と前記基準光の１回の出射とが、あるいは前記基準光の１回の出射と前記第２特殊光の出射とが、他の出射をはさまず連続している、請求項２に記載の内視鏡システム。 Regarding the order of emission of the reference light and the special light, the emission of the second special light and the single emission of the reference light, or the single emission of the reference light and the emission of the second special light, The endoscope system according to claim 2, wherein the other outputs are continuous without being interrupted.
  4. 　前記光源装置は、１つの光を放射するように構成された光源を備え、
    　前記光源装置は、前記基準光及び前記特殊光の出射の順番に対応するように、前記光源の放射光を、通過波長帯域の異なる複数の光学フィルタを透過させることにより前記基準光及び前記特殊光を出射するように構成されている、請求項１～３のいずれか１項に記載の内視鏡システム。     The light source device comprises a light source configured to emit a single light;
    The light source device transmits the reference light and the special light by transmitting the light emitted from the light source through a plurality of optical filters having different pass wavelength bands so as to correspond to the order of emission of the reference light and the special light. The endoscope system according to any one of claims 1 to 3, wherein the endoscope system is configured so as to emit light.
  5. 　前記基準光の波長帯域は前記特殊光の波長帯域に比べて広く、
    　前記基準光の波長帯域は、前記基準光カラー画像データの成分の１つが、前記生体組織のヘモグロビンの量の変化に対して感度を有しないような波長帯域を含む、請求項１～４のいずれか１項に記載の内視鏡システム。     The wavelength band of the reference light is wider than the wavelength band of the special light,
    The wavelength band of the reference light includes a wavelength band in which one of the components of the reference light color image data has no sensitivity to a change in the amount of hemoglobin in the living tissue. The endoscope system according to claim 1.
  6. 　前記第１特殊光の波長帯域は、前記第１特殊光カラー画像データの成分の１つが、前記生体組織のヘモグロビン量の変化に対して感度を有するが、前記酸素飽和度の変化に対して感度を有しないような波長帯域を含む、請求項１～５のいずれか１項に記載の内視鏡システム。 In the wavelength band of the first special light, one of the components of the first special light color image data is sensitive to changes in the amount of hemoglobin in the living tissue, but sensitive to changes in the oxygen saturation. The endoscope system according to any one of claims 1 to 5, including a wavelength band that does not include
  7. 　前記第２特殊光の波長帯域は、前記第２特殊光カラー画像データの成分の１つが、前記酸素飽和度の変化に対して感度を有するような波長帯域を含む、請求項１～６のいずれか１項に記載の内視鏡システム。 The wavelength band of the second special light includes a wavelength band in which one of the components of the second special light color image data is sensitive to the change in oxygen saturation. The endoscope system according to claim 1.
  8. 　前記第１特殊光は、光学フィルタで、前記基準光の波長帯域のうち５００ｎｍ～６００ｎｍの範囲内の第１波長帯域を透過させた前記基準光の濾過光であり、前記第２特殊光は、光学フィルタで、前記第１波長帯域の範囲内の前記第１波長帯域より狭い第２波長帯域を透過させた前記基準光の濾過光である、請求項１～７のいずれか１項に記載の内視鏡システム。 The first special light is an optical filter that is filtered light of the reference light that transmits a first wavelength band within a range of 500 nm to 600 nm of the wavelength band of the reference light, and the second special light is: The filtered light of the reference light transmitted through a second wavelength band narrower than the first wavelength band within the first wavelength band by an optical filter, according to any one of claims 1 to 7. Endoscope system.
  9. 　前記ヘモグロビン量算出部は、前記基準光カラー画像データの成分と前記第１特殊光カラー画像データの成分との比率である第１比率に基づいて前記ヘモグロビンの量を算出するように構成され、
    　前記酸素飽和度算出部は、前記第１特殊光カラー画像データの成分と前記第２特殊光カラー画像データの成分との比率である第２比率に基づいて前記ヘモグロビンの酸素飽和度を算出するように構成されている、請求項１～８のいずれか１項に記載の内視鏡システム。     The hemoglobin amount calculating unit is configured to calculate the amount of the hemoglobin based on a first ratio that is a ratio of the component of the reference light color image data and the component of the first special light color image data,
    The oxygen saturation calculating unit calculates oxygen saturation of the hemoglobin based on a second ratio that is a ratio between the component of the first special light color image data and the component of the second special light color image data. The endoscope system according to any one of claims 1 to 8, which is configured as follows.
  10. 　前記第１比率は、前記基準光カラー画像データの輝度成分と、前記第１特殊光カラー画像データのＲ成分、あるいはＲ成分及びＧ成分の合計成分との比率である、請求項９に記載の内視鏡システム。 The first ratio is a ratio between a luminance component of the reference light color image data and an R component of the first special light color image data, or a total component of the R component and the G component. Endoscope system.
  11. 　前記第２比率は、前記第２特殊光カラー画像データの輝度成分と前記第１特殊光カラー画像データの輝度成分との比率である、請求項９または１０に記載の内視鏡システム。 The endoscope system according to claim 9 or 10, wherein the second ratio is a ratio between a luminance component of the second special light color image data and a luminance component of the first special light color image data.
  12. 　前記基準光は、同じ波長帯域の第１基準光と第２基準光を含み、
    　前記光源装置は、前記照明光の出射の順番に関して、前記第１特殊光の出射と前記第２特殊光の出射の間に、あるいは前記第２特殊光の出射と前記第１特殊光の出射の間に、前記第１基準光の出射を行い、かつ前記第１特殊光の出射と前記第２基準光の出射とを、あるいは、前記第２基準光の出射と前記第１特殊光の出射とを、他の出射をはさまず連続させた順番で前記照明光を出射するように構成され、
    　前記特徴量取得部は、前記特徴量の算出のために、前記第１基準光で照明した前記生体組織の像の第１基準光カラー画像データ及び前記第２基準光で照明した前記生体組織の像の第２基準光カラー画像データのいずれか一方を選択して用いるように構成されたデータ選択部を備える、請求項１～１１のいずれか１項に記載の内視鏡システム。     The reference light includes a first reference light and a second reference light having the same wavelength band,
    The light source device may be arranged between the emission of the first special light and the emission of the second special light, or between the emission of the second special light and the emission of the first special light with respect to the order of emission of the illumination light. In between, the first reference light is emitted and the first special light and the second reference light are emitted, or the second reference light and the first special light are emitted. Is configured to emit the illumination light in an order in which the other emission is continued without being interrupted,
    The feature amount acquisition unit calculates first feature color image data of an image of the biological tissue illuminated with the first reference light and the biological tissue illuminated with the second reference light for calculating the feature amount. The endoscope system according to any one of claims 1 to 11, further comprising a data selection unit configured to select and use any one of the second reference light color image data of the image.
  13. 　前記光源装置における前記照明光の出射の順番に関して、前記１サイクルにおいて、前前記第２基準光の出射は記第１基準光の出射に比べて前記第２特殊光の出射から離れており、
    　前記特徴量取得部は、前記第１基準光で照明し前記撮像素子で撮像した前記生体組織の像に対する前記第２基準光で照明し前記撮像素子で撮像した前記生体組織の像の位置ずれ量を算出するように構成された位置ずれ量算出部を備え、
    　前記データ選択部は、算出した前記位置ずれ量が許容範囲を外れる場合、前記第２基準光カラー画像データに代えて、前記第１基準光カラー画像データを、前記特徴量の算出に用いるように構成されている、請求項１２に記載の内視鏡システム。     Regarding the order of emission of the illumination light in the light source device, in the first cycle, the emission of the second reference light is farther from the emission of the second special light than the emission of the first reference light,
    The feature amount acquisition unit illuminates with the first reference light and illuminates with the second reference light with respect to the image of the biological tissue captured by the imaging element, and a positional deviation amount of the image of the biological tissue captured by the imaging element A misregistration amount calculation unit configured to calculate
    The data selection unit may use the first reference light color image data for calculating the feature amount instead of the second reference light color image data when the calculated positional deviation amount is out of an allowable range. The endoscope system according to claim 12, wherein the endoscope system is configured.
  14. 　前記内視鏡は、前記撮像素子が、前記基準光及び前記特殊光の波長帯域の、前記生体組織の反射光を受光するように構成された光学系を備える、請求項１～１３のいずれか１項に記載の内視鏡システム。 The endoscope according to any one of claims 1 to 13, wherein the imaging device includes an optical system configured to receive reflected light of the living tissue in a wavelength band of the reference light and the special light. The endoscope system according to item 1.
  15. 　前記光学系は、前記基準光及び前記特殊光の波長帯域の光を透過するように構成されている、請求項１４に記載の内視鏡システム。 The endoscope system according to claim 14, wherein the optical system is configured to transmit light in a wavelength band of the reference light and the special light.
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Citations (5)

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JP2011188929A (en) * 2010-03-12 2011-09-29 Olympus Corp Fluorescent endoscope apparatus
WO2014192781A1 (en) * 2013-05-30 2014-12-04 Hoya株式会社 Method and device for generating image showing concentration distribution of biological substances in biological tissue
JP2016019569A (en) * 2014-07-11 2016-02-04 オリンパス株式会社 Image processing device, image processing method, image processing program, and endoscope system
JP2016022043A (en) * 2014-07-17 2016-02-08 Hoya株式会社 Method for creating image showing concentration distribution of biological substances in biological tissue
WO2016132940A1 (en) * 2015-02-20 2016-08-25 Hoya株式会社 Light source device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011188929A (en) * 2010-03-12 2011-09-29 Olympus Corp Fluorescent endoscope apparatus
WO2014192781A1 (en) * 2013-05-30 2014-12-04 Hoya株式会社 Method and device for generating image showing concentration distribution of biological substances in biological tissue
JP2016019569A (en) * 2014-07-11 2016-02-04 オリンパス株式会社 Image processing device, image processing method, image processing program, and endoscope system
JP2016022043A (en) * 2014-07-17 2016-02-08 Hoya株式会社 Method for creating image showing concentration distribution of biological substances in biological tissue
WO2016132940A1 (en) * 2015-02-20 2016-08-25 Hoya株式会社 Light source device

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