JP5670400B2 - ENDOSCOPE SYSTEM, PROCESSOR DEVICE THEREOF, AND METHOD FOR OPERATING ENDOSCOPE SYSTEM - Google Patents

Description

The present invention relates to an endoscope system that displays an oxygen saturation image obtained by imaging oxygen saturation of blood hemoglobin, a processor device thereof , and an operation method of the endoscope system .

  In recent medical fields, an endoscope system including a light source device, an endoscope device, and a processor device is widely used. In the diagnosis using this endoscope system, the insertion portion of the endoscope is inserted into the sample, the sample is illuminated from the distal end portion with illumination light of a predetermined wavelength, and the sample is then detected by the imaging device at the distal end portion. By imaging, an endoscopic image reflecting various biological information appearing on the specimen is acquired.

  As an endoscopic image, in addition to a normal image obtained by capturing a visible light image of a specimen illuminated with white light, light in different absorption wavelength ranges where the absorption coefficient of oxidized hemoglobin and the absorption coefficient of reduced hemoglobin are different, and An oxygen saturation image in which the oxygen state of a blood vessel is visualized by narrow band light in an isosbestic wavelength region where the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin are the same is being used.

  For example, in Patent Document 1, narrowband light with a center wavelength of 470 nm and narrowband light with a center wavelength of 430 nm are used as light in the different absorption wavelength region, and narrowband light with a center wavelength of 450 nm is used as light in the equiabsorption wavelength region. Used. Then, the 470 nm image obtained from the irradiation of the narrow band light having the center wavelength of 470 nm is used as the B channel of the monitor, the 450 nm image obtained at the irradiation of the narrow band light having the center wavelength of 450 nm is used as the G channel of the monitor, and the narrow wavelength of 430 nm. The 430 image obtained at the time of irradiation of the band light is assigned to the R channel of the monitor.

  By assigning colors in this way, when the blood vessel is in a high oxygen state, the pixel value of the 430 nm image assigned to the R channel is higher than the pixel value of the 470 nm image, so the color of the blood vessel becomes reddish. On the other hand, when the blood vessel is in a hypoxic state, the pixel value of the 470 nm image assigned to the B channel is higher than the pixel value of the 430 nm image, so the color of the blood vessel becomes bluish. Thereby, the difference in the oxygen state of the blood vessel can be observed by the difference in color. It should be noted that the change in the pixel value of the 430 nm image and the change in the pixel value of the 470 nm image are different depending on the difference in oxygen saturation. The relationship between the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin is different between 430 nm and 470 nm. This is because.

Japanese Patent No. 4270634

  However, in Patent Document 1, when the change in the pixel values of the 430 nm image and the 470 nm image due to the change in the oxygen saturation is small, the difference in the oxygen state of the blood vessel does not appear as a color difference. In such a case, it is difficult to observe the oxygen state of the blood vessel. Therefore, it has been demanded that the difference in the oxygen state of the blood vessel can be reliably displayed on the image as a difference in color.

An object of the present invention is to provide an endoscope system, a processor device thereof , and an operation method of the endoscope system that can reliably display a difference in the oxygen state of a blood vessel as a color difference on an image. .

In order to achieve the above object, an endoscope system according to the present invention includes an illuminating unit that irradiates a specimen with illumination light, and a first different absorption in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin. A first value for acquiring image information of a first different absorption wavelength region in which a pixel value of image data obtained by imaging a specimen illuminated with light including a wavelength region is changed by a change in oxygen saturation of blood hemoglobin. A pixel value of image data obtained by imaging an image information acquisition means and a specimen illuminated with light including a second different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is smaller than the extinction coefficient of reduced hemoglobin among the illumination light but by the change in oxygen saturation of hemoglobin in blood, and the second image information obtaining means for obtaining image information of the second different absorption wavelength range that varies the first and second in accordance with the change in oxygen saturation The display information of the first color obtained by adjusting the pixel value of the image information in the absorption wavelength range and color-converting the image information in the first and second different absorption wavelength ranges after the pixel value adjustment, and the pixel Display image information creating means for creating display image information for the second color obtained by color-converting the image information in the first and second different absorption wavelength ranges after the value adjustment , and display image information Display control means for assigning a plurality of image information including the first color channel to the third color channel of the display means, and the display image information creating means includes image information in the first and second different absorption wavelength ranges, Using the first table storing the relationship with the first color display image information, the first color display image information is created, and the first and second different absorption wavelength region image information and the second color are displayed. For display of the second color using the second table storing the relationship with the display image information of Characterized by creating image information.

  Here, when adjusting the pixel value of the image information in the first different absorption wavelength region or adjusting the pixel value of the image information in the second different absorption wavelength region, the first oxygen saturation having an oxygen saturation level equal to or greater than a certain value. Degree state (for example, the state where the first normalized information obtained by normalizing the image information in the first different absorption wavelength region with the image information including the wavelength information in the equal absorption wavelength region is greater than a certain value) and oxygen saturation It is preferable to change the pixel value adjustment method in a second oxygen saturation state in which the degree is less than a certain value (for example, a state in which the first normalized information is less than a certain value).

  For example, in the first oxygen saturation state, the pixel value of the image information in the first different absorption wavelength region is decreased while the pixel value of the image information in the second different absorption wavelength region is increased according to the oxygen saturation. It is preferable. On the other hand, in the second oxygen saturation state, the pixel value of the image information in the second different absorption wavelength region is increased while the pixel value of the image information in the first different absorption wavelength region is increased according to the oxygen saturation. Is preferably reduced.

  The display image information creation means obtains the relationship between the image information of the first and second different absorption wavelength regions and the display image information of the third color in addition to the display image information of the first color and the second color. It is preferable to create the third color display image information using the third table stored.

  The display control means assigns the first color display image information to the first color channel, assigns the second color display image information to the second color channel, and assigns the third color display image information to the third color channel. It is preferable to assign to. Preferably, the first color channel is a blue channel, the second color channel is a green channel, and the third color channel is a red channel.

A fourth image information acquisition means for acquiring image information in an isosbestic wavelength region in which the extinction coefficient of oxyhemoglobin and the extinction coefficient of deoxyhemoglobin have substantially the same absorption wavelength region, and an image in the first different absorption wavelength region First normalization information obtained by normalizing information with image information in the equiabsorption wavelength region, or second normalization information obtained by normalizing image information in the second different absorption wavelength region with image information in the equiabsorption wavelength region It is preferable that a standardized information creating unit for creating at least one of the above is provided, and the change in oxygen saturation is a change in the value of the first or second standardized information . Image information of the equal absorption wavelength region is preferably obtained by synthesizing the first image information and the image information of the second different absorption wavelength region of the different absorption wavelength region. The first different absorption wavelength region is preferably 450 to 500 nm, and the second different absorption wavelength region is preferably 415 to 450 nm.

The present invention is obtained by irradiating a specimen with illumination light and imaging a specimen illuminated with light including a first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin. The image data of the first different absorption wavelength range in which the pixel value of the obtained image data changes according to the change in oxygen saturation of blood hemoglobin is obtained, and the extinction coefficient of oxyhemoglobin is the extinction coefficient of reduced hemoglobin in the illumination light The pixel value of the image data obtained by imaging the specimen illuminated with light including the second different absorption wavelength range smaller than the second different absorption wavelength range changes due to the change in oxygen saturation of blood hemoglobin. In a processor device of an endoscope system used in combination with an endoscope device that acquires image information, image information in first and second different absorption wavelength ranges is received from the endoscope device. Receiving means, as well as adjusting the first and second pixel value of the image information of the different absorption wavelength range in accordance with the change in oxygen saturation, the image information of the first and second different absorption wavelength range of the pixel value after adjustment First color display image information converted to the first color, and second color display image information obtained by color-converting the image information of the first and second different absorption wavelength ranges after the pixel value adjustment to the second color When, with the display image information generation means for generating a plurality of image information including the display image information, a display control means for assigning to the first color channel to third color channel of the display unit, the display image information The creation means creates display image information for the first color using a first table that stores the relationship between the image information in the first and second different absorption wavelength regions and the display information for the first color. , Image information in the first and second different absorption wavelength regions, and display information for the second color Using a second table for storing a relationship, characterized by creating a displaying image information of the second color.

In the operating method of the endoscope system according to the present invention , the first image information acquisition means is illuminated with light including a first different absorption wavelength region in which the absorption coefficient of oxyhemoglobin is larger than the absorption coefficient of deoxyhemoglobin in the illumination light. pixel values of the image data obtained the specimen was imaged, by a change in oxygen saturation of hemoglobin in blood, comprising the steps of: acquire the first image information of the different absorption wavelength range that varies, the second image information acquiring means Among the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the second different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is smaller than the extinction coefficient of reduced hemoglobin is the blood hemoglobin the oxygen saturation changes, the steps acquire image information of the second different absorption wavelength region changes, the display image forming means, first and second different intake to match the change in oxygen saturation Adjusting the pixel value of the image information in the wavelength range, and displaying the first color display image information obtained by color-converting the image information in the first and second different absorption wavelength ranges after the pixel value adjustment, and the pixel value A step of creating display image information of the second color obtained by color-converting the image information of the adjusted first and second different absorption wavelength regions into the second color, and the display control means includes the display image information a plurality of image information, the first color channel to the display control process to assign to the third color channel possess a row cormorants steps, the display image forming means and displaying image information of the first color second color display unit In the step of creating the display image information, the display image information creating means stores a relationship between the image information in the first and second different absorption wavelength regions and the display information of the first color. Using the table, display image information for the first color is created, and the first and first image information is generated. And image information of the different absorption wavelength range, using the second table for storing a relationship between the second-color display image information, characterized by creating a displaying image information of the second color.

  According to the present invention, display image information in which pixel values of image information in the first different absorption wavelength region are adjusted according to the change in the oxygen saturation, or the second different value according to the change in the oxygen saturation. At least one display image information is generated from the display image information in which the pixel value of the image information in the absorption wavelength region is adjusted, and a plurality of pieces of image information including the display image information are displayed in the first color channel through the first color channel. Since it is assigned to the three-color channel, the difference in the oxygen state of the blood vessel is reliably displayed on the display means as a difference in color.

It is the schematic which shows the external appearance of an endoscope system. It is a block diagram which shows the internal structure of the endoscope system of 1st Embodiment. It is a top view which shows the rotary filter of 1st Embodiment. It is a graph which shows the spectral transmittance of the B filter part, G filter part, and R filter part of a rotary filter. It is a graph which shows the spectral transmittance of the 1st narrow-band filter part of a rotation filter, and a 2nd narrow-band filter part. It is a graph which shows the extinction coefficient of oxyhemoglobin HbO2, and the extinction coefficient of reduced hemoglobin Hb. It is explanatory drawing which shows operation | movement of the image pick-up element in normal mode. It is explanatory drawing which shows operation | movement of the image pick-up element in oxygen saturation mode. It is a block diagram which shows the internal structure of an image process part. It is a graph which shows the relationship between intensity ratio B1 / M and a 1st gain. It is a graph which shows the relationship between intensity ratio B2 / M and a 2nd gain. It is explanatory drawing which shows the content of the gain processes A-C. It is explanatory drawing which shows the method of calculating 1st gain GB1 for high ranges from intensity ratio B1 ^* / M ^* . It is explanatory drawing which shows the method of calculating 2nd gain GB2 for normal ranges from intensity ratio B2 ^* / M ^* . It is explanatory drawing for demonstrating the color allocation of blue image data B1 'and blue image data B2'. It is explanatory drawing which showed the change of the pixel value of blue image data B1 when not carrying out a gain process, and blue image data B2. It is explanatory drawing which showed the change of the pixel value of blue image data B1 'and blue image data B2' after gain processing. It is a flowchart showing a series of flows in the oxygen saturation mode. It is a block diagram which shows 2DLUT for blue conversion, 2DLUT for green conversion, and 2DLUT for red conversion. It is a block diagram which shows 1DLUT for blue conversion, 1DLUT for green conversion, and 1DLUT for red conversion. FIG. 17 is a block diagram showing the same blue conversion 1DLUT and green conversion 1DLUT as in FIG. 16, and a red conversion 1DLUT different from FIG. 16; It is a block diagram which shows the internal structure of the endoscope system of 2nd Embodiment. It is a top view which shows the rotation filter different from 1st Embodiment. It is explanatory drawing which shows operation | movement of the image pick-up element at the time of oxygen saturation mode at the time of using the rotation filter of FIG. It is explanatory drawing for demonstrating the gain process and color allocation with respect to blue image data B, green image data G, and red image data R. It is explanatory drawing for demonstrating the gain process when there is no difference of intensity ratio B / M with a predetermined pixel and an adjacent pixel (when there is no difference in oxygen saturation with a predetermined pixel and an adjacent image). It is explanatory drawing for demonstrating the gain process when there exists a difference of intensity ratio B / M between a predetermined pixel and an adjacent pixel (when there is a difference in oxygen saturation between a predetermined pixel and an adjacent image).

  As shown in FIG. 1, an endoscope system 10 according to the first embodiment irradiates light from a light source device 11 that generates light for illuminating the inside of a specimen, and the light from the light source apparatus 11 onto the observation region of the specimen, and reflects the reflected light. An endoscope apparatus 12 that captures an image, a processor apparatus 13 that performs image processing on image data obtained by imaging with the endoscope apparatus 12, and a display apparatus that displays an endoscopic image or the like obtained by image processing 14 and an input device 15 composed of a keyboard or the like.

  The endoscope device 12 is provided with a flexible portion 17, a bending portion 18, and a scope distal end portion 19 in order from the operation portion 16 side. Since the soft part 17 has flexibility, it can be bent freely. The bending portion 18 is configured to be bendable by a turning operation of an angle knob 16 a disposed in the operation portion 16. Since the bending portion 18 can be bent in an arbitrary direction and an arbitrary angle in accordance with the region of the specimen, the scope distal end portion 19 can be directed to a desired observation region.

  The endoscope system 10 includes a normal mode in which a normal image including a specimen image of visible light having a wavelength range from blue to red is displayed on the display device 14, and an oxygen saturation image obtained by imaging oxygen saturation of blood hemoglobin. Is displayed on the display device 14. These two modes can be switched by a changeover switch 21 or an input device 15 provided in the endoscope apparatus.

  As shown in FIG. 2, the light source device 11 is connected to a white light source 30, a rotary filter 31 that separates the broadband light BB from the white light source 30 into light of a predetermined wavelength, and a rotary shaft 31 a of the rotary filter 31. A motor 32 that rotates the rotary filter 31 at a constant rotational speed, a shift unit 34 that shifts the rotary filter 31 in the radial direction, a condenser lens 35 that collects light transmitted through the rotary filter 31, and a condenser lens The optical fiber 36 in which the light from 35 enters, and the branch part 37 which branches the light which injected into the optical fiber 36 into two systems of light.

  The white light source 30 includes a light source body 30a and a diaphragm 30b. The light source body 30a is composed of a broadband light source such as a xenon lamp, a halogen lamp, a metal halide lamp, or a white LED, and emits broadband light BB. The broadband light BB has a wavelength range of visible light from the blue band to the red band, for example, a wavelength range of 400 nm to 700 nm. The diaphragm 30b adjusts the amount of the broadband light BB emitted from the white light source 30 and incident on the rotary filter 31 by adjusting the opening.

  The endoscope device 12 is an electronic endoscope, and light guides 28 and 29 that guide two systems of light branched by the branching portion 37 of the light source device 11, and 2 that are guided by the light guides 28 and 29. An illumination unit 40 that irradiates the observation region with light from the system (two lights), an imaging unit 41 that images the observation region, and the endoscope device 12, the light source device 11, and the processor device 13 are detachably connected. Connector part 42 is provided.

  The illumination unit 40 includes two illumination windows 43 and 44 provided on both sides of the imaging unit 41, and light projecting units 47 and 54 are housed in the back of the illumination windows 43 and 44, respectively. . Each of the light projecting units 47 and 54 irradiates the observation region with the light from the light guides 28 and 29 through the illumination lens 51. The imaging unit 41 includes one observation window 42 that receives reflected light from the observation region at a substantially central position of the scope distal end portion 19.

  An objective lens unit 45 for capturing the image light of the observation region of the specimen is provided in the back of the observation window 42. Further, in the back of the objective lens unit 45, a CCD (Charge Coupled Device) that images the observation region. ) And the like. The imaging device 60 is a monochrome imaging device, and receives light from the objective lens unit 45 on a light receiving surface (imaging surface), photoelectrically converts the received light, and outputs an imaging signal (analog signal). As the image sensor 60, an IT (interline transfer) CCD is used, but a CMOS (Complementary Metal-Oxide Semiconductor) having a global shutter may be used.

  An imaging signal (analog signal) output from the imaging device 60 is input to the A / D converter 68 through the scope cable 67. The A / D converter 68 converts the imaging signal (analog signal) into image data (digital signal) corresponding to the voltage level. The converted image data is input to the processor device 13 via the connector unit 42. The imaging control unit 70 performs imaging control of the image sensor 60. This imaging control is different for each mode.

  The processor device 13 includes a control unit 71, an image processing unit 72, and a storage unit 74, and the display device 14 and the input device 15 are connected to the control unit 71. The control unit 71 controls each unit in the processor device 13 and, based on input information input from the changeover switch 21 or the input device 15 of the endoscope device 12, the imaging control unit 70 and the display of the endoscope device 12. The operation of the device 14 is controlled.

  As shown in FIG. 3, the rotary filter 31 rotates around the rotation shaft 31 a connected to the motor 32. The rotary filter 31 is provided with first and second filter regions 38 and 39 along the radial direction in order from the center of rotation where the rotary shaft 31a is located. The first filter region 38 is set on the optical path of the broadband light BB in the normal mode, and the second filter region 39 is set on the optical path of the broadband light BB in the oxygen saturation mode. The filter regions 38 and 39 are switched by shifting the rotary filter 31 in the radial direction by the shift unit 34.

  In the first filter region 38, a B filter portion 38a, a G filter portion 38b, and an R filter portion 38c are provided in fan-shaped regions having a central angle of 120 °, respectively. As shown in FIG. 4A, the B filter unit 38a transmits B light in the blue band (380 to 520 nm) from the broadband light BB, and the G filter unit 38b transmits G light in the green band (480 to 620 nm) from the broadband light BB. The R filter unit 38c transmits the R light in the red band (580 to 720 nm) from the broadband light BB. Accordingly, the B light, the G light, and the R light are sequentially emitted by the rotation of the rotary filter 31. These B light, G light, and R light are incident on the ride guides 28 and 29 of the endoscope apparatus 12 through the condenser lens 35 and the optical fiber 36.

  The second filter region 39 includes a first narrowband filter portion 39a (described as “first narrowband (450 to 500 nm)” in FIG. 3) and a second narrowband filter portion 39b (“second narrowband” in FIG. 3). Band (415-450 nm) ”). As shown in FIG. 4B, the first narrow band filter unit 39a has a narrow band of 450 to 500 nm (first different absorption wavelength region) in which the absorption coefficient of oxyhemoglobin is larger than the absorption coefficient of deoxyhemoglobin in the broadband light BB. Light is transmitted (see FIG. 5). In addition, the second narrowband filter unit 39b transmits narrowband light of 415 to 450 nm (second different absorption wavelength region) in which the absorption coefficient of oxyhemoglobin is smaller than the absorption coefficient of deoxyhemoglobin in the broadband light BB ( (See FIG. 5). These two types of light sequentially enter the ride guides 28 and 29 through the condenser lens 35 and the optical fiber 36.

  The imaging device 60 performs different imaging for each mode. In the normal mode, as shown in FIG. 6A, in the irradiation periods Tb, Tg, and Tr of B light, G light, and R light, image light of each color is sequentially captured by the image sensor 60 to accumulate charges, and this accumulation is performed. Based on the charge, a blue signal Bc, a green signal Gc, and a red signal Rc are sequentially output. This series of operations is repeated while the normal mode is set. The blue signal data Bc, the green image data Gc, and the red image data Rc are obtained by A / D converting the blue signal Bc, the green signal Gc, and the red signal Rc.

  On the other hand, in the oxygen saturation mode, as shown in FIG. 6B, in the irradiation periods T1 and T2 of the narrow-band light in the first different absorption wavelength region and the narrow-band light in the second different absorption wavelength region, the respective light images. Light is sequentially captured by the image sensor 60 to accumulate charges, and the blue signal B1 and the blue signal B2 are sequentially output based on the accumulated charges. Such an operation is repeated while the oxygen saturation mode is set. The blue signal B1 and the blue image data B2 are obtained by A / D converting the blue signal B1 and the blue signal B2.

  As described above, since different image data is obtained for each mode, image processing performed for each mode is also different. As shown in FIG. 7, the image processing unit 72 performs image processing based on image data acquired in the normal mode and image data acquired in the normal mode and image data acquired in the oxygen saturation mode. And an oxygen saturation mode image processing unit 81.

  The normal mode image processing unit 80 creates a full color normal image including a blue image, a green image, and a red image based on the blue image data Bc, the green image data Gc, and the red image data Rc obtained in the normal mode. Among the created normal images, the blue image is assigned to the B channel of the display device 14, the green image is assigned to the G channel of the display device 14, and the red image is assigned to the R channel of the display device 14.

  The oxygen saturation mode image processing unit 81 includes an intensity ratio calculation unit 84, a gain table 85, a gain processing unit 86, and an image creation unit 87. The intensity ratio calculation unit 84 synthesizes the blue image data B1 and the blue image data B2 to create the composite image data M, and the intensity ratio B1 / M between the blue image data B1 and the composite image data M and the blue image data. An intensity ratio B2 / M between B2 and the composite image data M is obtained. The intensity ratio calculation unit 84 calculates the intensity ratios B1 / M and B2 / M between the pixels at the same position among the image data, and the intensity ratios B1 / M, B2 / M for all the pixels of the image data. M is calculated. Note that the intensity ratios B1 / M and B2 / M may be obtained only for the pixels of the blood vessel portion in the image data. In this case, the blood vessel portion is specified based on the difference between the image data of the blood vessel portion and the image data of the other portion.

  Here, since the blue image data B1 has a wavelength component (450 to 500 nm) in the first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin, the oxygen saturation is decreased. The pixel value of the blue image data B1 increases. On the other hand, the blue image data B2 has a wavelength component (415 to 450 nm) in the second different absorption wavelength range in which the absorption coefficient of oxyhemoglobin is smaller than the absorption coefficient of reduced hemoglobin. When it decreases, the pixel value of the blue image data B2 decreases. On the other hand, since the composite image data M has the wavelength component of the first different absorption wavelength region and the wavelength component of the second different absorption wavelength region, even if the oxygen saturation changes, the pixel value of the composite image data M Hardly changes.

  From the above, the intensity ratio B1 / M obtained by dividing the pixel value of the blue image data B1 by the pixel value of the composite image data M increases as the oxygen saturation decreases. On the other hand, the intensity ratio B2 / M obtained by dividing the pixel value of the blue image data B2 by the pixel value of the composite image data M decreases as the oxidation saturation decreases.

  The gain table 85 associates and stores the intensity ratio B1 / M and the first gain for multiplying the pixel value of the blue image data B1, the intensity ratio B2 / M, and the blue image data. And a second gain table 85b for storing the first gain for multiplying the pixel value of B2 in association with each other.

  In the first gain table 85a, as shown in FIG. 8, the first gain for high range for changing the pixel value of the blue image data B1 in accordance with the change of the intensity ratio B1 / M, and the intensity ratio B1. The first gain for the normal range for gradually changing the pixel value of the blue image data B1 in accordance with the change of / M is stored. When there is a shift, the first gain for the high range is set, and when there is no shift, the first gain for the normal range is set. The first gain range Rh1 for the high range is set larger than the first gain range Rn1 for the normal range.

  Both the first gain for the high range and the first gain for the normal range are gains when the intensity ratio B1 / M is in the range of KL to KM, that is, between the high oxygen state and the intermediate oxygen state. Is smaller than “1”. Therefore, in this range, the pixel value of the blue image data B1 decreases due to the gain reduction. On the other hand, when the intensity ratio B1 / M is in the range of KM to KH, that is, between the intermediate oxygen state and the low oxygen state, the gain is larger than “1”. Therefore, in this range, the pixel value of the blue image data B1 increases due to the gain increase.

  In the second gain table 85b, as shown in FIG. 9, the second gain for the high range for changing the pixel value of the blue image data B2 in accordance with the change of the intensity ratio B2 / M, and the intensity ratio B2 The second gain for the normal range for gradually changing the pixel value of the blue image data B2 in accordance with the change of / M is stored. When there is a shift, the second gain for the high range is set, and when there is no shift, the second gain for the normal range is set. Note that the second gain range Rh2 for the high range is set to be larger than the second gain range Rn2 for the normal range.

  When both the second gain for the high range and the second gain for the normal range are in the range of VH to VM, that is, between the high oxygen state and the intermediate oxygen state, the gain is It is larger than “1”. Therefore, in this range, the pixel value of the blue image data B2 increases due to the gain increase. On the other hand, when the intensity ratio B2 / M is in the range of VM to VL, that is, when the intensity ratio is between the intermediate oxygen state and the low oxygen state, the gain is smaller than “1”. Therefore, in this range, the pixel value of the blue image data B2 increases due to the gain reduction.

  The gain processing unit 86 performs gain processing on the blue image data B1 and the blue image data B2 using the intensity ratios B1 / M and B2 / M obtained by the intensity ratio calculation unit 84 and the gain table 85. As shown in FIG. 10, the gain process includes a gain process A using a first gain for high range (with shift) and a second gain for normal range (without shift), and a first gain for shift (normal shift). None) and gain processing B using the second gain for high range (with shift), and gain processing C using the first gain for high range (with shift) and the second gain for high range (with shift) Consists of. In any of the gain processes A to C, the difference between the pixel value of the blue image data B1 and the pixel value of the blue image data B2 is increased. Among these, the gain process C maximizes the difference between the pixel values. Which of these three gain processes is used can be determined by operating the input device 15.

When performing the gain processing A, first, as shown in FIG. 11A, referring to the first gain table 85a, for the high range corresponding to the intensity ratio B1 ^* / M ^* obtained by the intensity ratio calculator 84. The first gain GB1 is calculated. Then, by multiplying the first gain GB1 for high range by the pixel value of the blue image data B1, the blue image data B1 ′ having been subjected to gain processing is obtained. Next, as illustrated in FIG. 11B, the second gain GB2 for the normal range corresponding to the intensity ratio B2 ^* / M ^* obtained by the intensity ratio calculation unit 84 is calculated with reference to the second gain table 85b. Then, by multiplying the second gain GB2 for the normal range by the pixel value of the blue image data B2, the blue image data B2 ′ having been subjected to gain processing is obtained. The gain processes B and C are performed in the same manner as the gain process A.

  As shown in FIG. 12, the image creating unit 87 uses the blue image data B1 ′ that has been subjected to gain processing as the B channel of the display device 14, and the blue image data B2 ′ that has undergone gain processing as the G channel and the R channel of the display device 14. Assign to. As a result, an oxygen saturation image in which the color of the blood vessel changes greatly as the oxygen saturation changes is displayed on the display device. For example, as shown in FIG. 13A, when the blue image data B1 and the blue image data B2 are assigned to the B, G, and R channels of the display device 14 without performing gain processing, between the image data B1 and B2 in the high oxygen state The difference ΔH in pixel value and the difference ΔL in pixel value between the image data B1 and B2 in the low oxygen state are not so large. Therefore, it is difficult to observe the color change of the blood vessel on the oxygen saturation image. In FIG. 13A, high O 2 indicates a “high oxygen state”, middle O 2 indicates a “medium oxygen state”, and low O 2 indicates a “low oxygen state”. The same applies to FIG. 13B. Further, the image creating unit 87 may assign the blue image data B1 ′ after the gain processing to the B channel and the G channel of the display device 14, and the blue image data B2 ′ after the gain processing to the R channel of the display device 14. .

  In contrast, in the present embodiment, as shown in FIG. 13B, blue image data B1 ′ subjected to gain processing (gain processing according to intensity ratios B1 / M and B2 / M) according to the oxygen state of the blood vessel. And the blue image data B2 ′ are assigned to the B, G, and R channels of the display device 14, the pixel value difference ΔH ′ between the image data B1 and B2 in the high oxygen state and the image data B1 in the low oxygen state. , B2 has a large pixel value difference ΔL ′.

  As described above, the reason why the pixel value difference ΔH ′ is large is that the pixel value of the blue image data B2 is gained up while the pixel value of the blue image data B2 is increased in the high oxygen state. It is. The reason why the pixel value difference ΔL ′ is large is that the pixel value of the blue image data B2 is gained down while the pixel value of the blue image data B2 is gained down in the low oxygen state. . From the above, in this embodiment, the difference in the color of the blood vessel due to the difference in the oxygen state of the blood vessel can be reliably observed on the oxygen saturation image. On the oxygen saturation image, the blood vessel is displayed in “yellow tone” in the high oxygen state, and the blood vessel is displayed in “blue” in the low oxygen state.

  Next, a series of flows in the present embodiment, in particular, a series of flows for the oxygen saturation mode will be described with reference to the flowchart of FIG. Under the normal mode, the endoscope apparatus 12 is inserted into the body, for example, the digestive tract. By operating the angle knob 16a, the scope tip 19 is set at a desired observation site and the inside of the body is observed. In the observation in the normal mode, the first filter region 38 of the rotary filter 31 is set on the optical path of the broadband light BB. By rotating the rotary filter 31 in this state, B light, G light, and R light are sequentially irradiated into the specimen. Then, the reflected image in the specimen is picked up by the monochrome image pickup device 60, and a normal image is displayed on the display device 14 based on the blue, green, and red image data Bc, Gc, and Rc obtained by the pick-up.

  And when an observation site | part is estimated to be a lesioned part, it switches to oxygen saturation mode with the changeover switch 21 of an endoscope apparatus. By this mode switching, the rotary filter 31 is shifted outward, and the second filter region 39 of the rotary filter 31 is set on the optical path of the broadband light BB. By rotating the rotary filter 31 in this state, narrowband light in the first different absorption wavelength region and narrowband light in the second different absorption wavelength region are alternately emitted from the rotary filter 31. The emitted light is sequentially irradiated onto the specimen, and the reflected image is sequentially captured by the monochrome image sensor 60. Thereby, blue image data B1 and blue image data B2 are obtained.

  Next, the blue image data B1 and the blue image data B2 are combined to create combined image data M. Then, the intensity ratio B1 / M between the blue image data B1 and the composite image data M is calculated, and the intensity ratio B2 / M between the blue image data B2 and the composite image data M is calculated. Then, the first gain corresponding to the intensity ratio B1 / M is calculated with reference to the first gain table 85a, and the second gain corresponding to the intensity ratio B2 / M is calculated with reference to the second gain table 85b. calculate. Then, the blue image data B1 ′ is obtained by multiplying the calculated first gain by the pixel value of the blue image data B1. Also, the blue image data B2 ′ is obtained by multiplying the calculated second gain by the pixel value of the blue image data B2. The blue image data B1 ′ after the gain processing is assigned to the B channel of the display device 14, and the blue image data B2 ′ after the gain processing is assigned to the G channel and the R channel of the display device 14. Thereby, the oxygen saturation image is displayed on the display device 14.

  In the first embodiment, a change in blood vessel color associated with a change in oxygen saturation is clarified by applying gain processing to the blue image data B1 and blue image data B2 in accordance with the change in oxygen saturation. However, 2DLUT (2 dimension Look Up Table) may be used instead. As shown in FIG. 15, the 2DLUT includes a blue conversion 2DLUT, a green conversion 2DLUT, and a red conversion 2DLUT. When each of the 2DLUTs receives blue image data B1 and B2, the blue image The B value, G value, and R value corresponding to the data B1 and B2 are output. The B value, G value, and R value output from these 2DLUTs are assigned to the B, G, and R channels of the display device 14.

  In the blue conversion 2DLUT, blue image data B1 and B2 and a B value obtained when the blue conversion program is executed based on the blue image data B1 and B2 are recorded in association with each other. The blue color conversion program is composed of a first blue color conversion program and a second blue color conversion program. Which one of the blue color conversion programs is executed depends on the intensity ratio B1 / M (or calculated based on the blue image data B1 and B2). , Intensity ratio B2 / M).

  The first blue conversion program is a program that is executed when the intensity ratio B1 / M is in the range of KL to KM (that is, when the high oxygen state is in the intermediate oxygen state), and the blue image data B1, B2 And the blue image data B1 and B2 after the pixel value reduction is color-converted to a B value. Here, the pixel value reduction rate of the blue image data B1 and B2 is determined based on the intensity ratio B1 / M.

  On the other hand, the second blue color conversion program is a program that is executed when the intensity ratio B1 / M is in the range of KM to KH (that is, from the intermediate oxygen state to the low oxygen state) After the pixel values of the image data B1 and B2 are increased at a predetermined increase rate, the blue image data B1 and B2 after the increase of the pixel values are color-converted into B values. The pixel value increase rate of the blue image data B1 and B2 is determined based on the intensity ratio B1 / M.

  In the 2DLUT for green conversion, the blue image data B1 and B2 and the G value obtained when the green conversion program is executed based on the blue image data B1 and B2 are recorded in association with each other. In the red conversion 2DLUT, blue image data B1 and B2 and an R value obtained when the second red conversion program is executed based on the blue image data B1 and B2 are recorded in association with each other.

  The green color conversion program includes a first green color conversion program and a second green color conversion program. Which green color conversion program is executed is determined by the magnitude of the intensity ratio B1 / M (or the intensity ratio B2 / M). It is done. The red color conversion program includes a first red color conversion program and a second red color conversion program. Which red color conversion program is executed depends on the magnitude of the intensity ratio B1 / M (or the intensity ratio B2 / M). It is decided by.

  The first green color conversion program and the first red color conversion program are programs that are executed when the intensity ratio B1 / M is in the range of KL to KM (that is, when the oxygen state is from a high oxygen state to a medium oxygen state), After the pixel values of the blue image data B1 and B2 are increased at a predetermined increase rate, the blue image data B1 and B2 after the increase in the pixel values are color-converted into G values and R values. Here, the pixel value increase rate of the blue image data B1 and B2 is determined based on the intensity ratio B1 / M.

  On the other hand, the second green color conversion program and the second red color conversion program are executed when the intensity ratio B1 / M is in the range of KM to KH (that is, from the intermediate oxygen state to the low oxygen state). In this program, the pixel values of the blue image data B1 and B2 are reduced at a predetermined reduction rate, and the blue image data B1 and B2 after the pixel value reduction is color-converted into G values and R values. The pixel value reduction rate of the blue image data B1 and B2 is determined based on the intensity ratio B1 / M.

  When the above 2DLUT is used, an oxygen saturation image is displayed on the display device 14 in which the blood vessel is represented by “yellow tone” in the high oxygen state and is represented in “blue” in the hypoxic state. Is displayed. The R value converted by the red conversion 2DLUT may not be assigned to the R channel of the display device 14, but instead, the G value converted by the green conversion 2DLUT may be assigned to the G channel and the R channel of the display device 14. .

  Further, a 1DLUT (1 dimension Look Up Table) may be used instead of the 2DLUT. As shown in FIG. 16, the 1DLUT includes a blue conversion 1DLUT, a green conversion 1DLUT, and a red conversion 1DLUT. When the blue image data B1 is input, the blue conversion 1DLUT A B value corresponding to the data B1 is output. When the blue image data B2 is input, the green conversion 1DLUT outputs a G value corresponding to the blue image data B2. When the blue image data B1 is input, the red conversion 1DLUT outputs an R value corresponding to the blue image data B1. The B value, G value, and R value output from the three 1DLUTs are assigned to the B, G, and R channels of the display device 14.

  In the blue conversion 1DLUT, the blue image data B1 and the B value obtained when the 1D-blue conversion program is executed based on the image data B1 are recorded in association with each other. The 1D-blue color conversion program obtains a B value corresponding to the image data B1 by executing a 1D B value conversion process for converting to a B value.

  The 1D B-value conversion process is performed by applying a B-value pixel value adjustment process corresponding to the size of the pixel value of the blue image data B1 to the blue image data B1, and then performing a blue image after the pixel value adjustment process. Data B1 is color-converted to B value. Here, the pixel value adjustment processing for the B value is performed in order to increase the difference between the B value and the G value pixel values in the high oxygen state and the low oxygen state. In the present embodiment, when the pixel value (Pv1) of the blue image data B1 is in a high oxygen state with a threshold value Th or less (Pv1 ≦ Th), the pixel value of the image data B1 is decreased at a predetermined decrease rate, and the pixel value In a hypoxic state where Pv1 exceeds the threshold Th (Pv1> Th), the pixel value of the image data B1 is increased at a predetermined increase rate. At the threshold Th, the pixel value of the blood vessel portion of the blue image data B1 and the pixel value of the blood vessel portion of the blue image data B2 are substantially the same (however, the amount of illumination light does not change due to AE or the like). Limited).

  In the 1DLUT for green conversion, blue image data B2 and a G value obtained when a 1D-green conversion program is executed based on the blue image data B2 are recorded in association with each other. The 1D-green color conversion program obtains a G value corresponding to the image data B2 by executing a 1D G value conversion process for converting to a G value.

  In the 1D G value conversion process, the blue image data B2 is subjected to a G value pixel value adjustment process corresponding to the size of the pixel value of the blue image data B2, and then the blue image after the pixel value adjustment process is performed. Data B2 is color-converted to G value. Here, the G value pixel value adjustment processing is performed in order to increase the difference between the G value and the B value in the high oxygen state and the low oxygen state. In the present embodiment, when the pixel value (Pv2) of the blue image data B2 is in a high oxygen state that is equal to or higher than the threshold Th (Pv2 ≧ Th), the pixel value of the image data B2 is increased at a predetermined increase rate, In a hypoxic state where Pv2 is lower than the threshold Th (Pv2 <Th), the pixel value of the image data B2 is decreased at a predetermined decrease rate. The threshold value Th is the same as described above.

  In the red conversion 1DLUT, the blue image data B1 and the R value obtained when the 1D-red conversion program is executed based on the blue image data B1 are recorded in association with each other. The 1D-red color conversion program obtains an R value corresponding to the image data B1 by executing a 1D R value conversion process for converting to an R value.

  The R value conversion process for 1D is performed by applying the pixel value adjustment process for R value corresponding to the size of the pixel value of the blue image data B1 to the blue image data Bx, and then the blue image after the pixel value adjustment process Data Bx is color-converted to an R value. Here, the pixel value adjustment process for the R value is performed in order to increase the difference between the pixel values of the R value and the G value in the high oxygen state and the low oxygen state. In the present embodiment, when the pixel value Pv1 is in a high oxygen state where the threshold value Th is equal to or less than the threshold Th (Pv1 ≦ Th), the pixel value of the image data B1 is decreased at a predetermined decrease rate, and the pixel value Pv1 is lower than the threshold Th. In the oxygen state (Pv2> Th), the pixel value of the image data B1 is increased at a predetermined increase rate.

  When the above 1DLUT is used, an oxygen saturation image in which the blood vessel is represented by “green tone” in the high oxygen state and the blood vessel is represented by “magenta” in the low oxygen state is displayed on the display device 14. Is displayed.

  As shown in FIG. 17, the red conversion 1DLUT may output an R value corresponding to the blue image data B2 when the blue image data B2 is input instead of the blue image data B1. . In this case, the content of the pixel value adjustment process is different from the above. When the pixel value Pv2 of the blue image data B2 is in a high oxygen state equal to or higher than the threshold Th (Pv2 ≧ Th), the pixel value of the blue image data B2 is increased at a predetermined increase rate and then converted to an R value. On the other hand, in a hypoxic state where the pixel value Pv2 is lower than the threshold Th (Pv2 <Th), the pixel value of the blue image data B2 is reduced at a predetermined reduction rate and converted to an R value.

  In the first embodiment, in the oxygen saturation mode, the sample is alternately irradiated with the narrowband light in the first different absorption wavelength region and the narrowband light in the second different absorption wavelength region using the rotary filter. Instead, as in the endoscope system 200 shown in FIG. 18, the first semiconductor light source 201 that emits narrow-band light in the first different absorption wavelength region having a center wavelength of 473 nm and the second different light source having a center wavelength of 430 nm are used. Illumination within the specimen may be performed using the second semiconductor light source 202 that emits narrow-band light in the absorption wavelength range. In this endoscope system 200, in addition to the first and second semiconductor light sources 201 and 202, excitation light having a central wavelength of 445 nm and green to red fluorescence obtained by wavelength conversion of the excitation light with a phosphor are mixed. A white light source 203 that emits white light is provided. Hereinafter, only parts of the endoscope system 200 that are different from the endoscope system 10 will be described. In addition, as the first and second semiconductor light sources, LEDs or the like are used in addition to the laser light sources.

  In this endoscope system 200, the narrowband light having the first different absorption wavelength from the first semiconductor light source 201 enters the optical fiber 205, and the narrowband light having the second different absorption wavelength from the second semiconductor light source 202 is light. The white light from the white light source 203 enters the fiber 206 and enters the optical fiber 207. The light from each of the optical fibers 205, 206, and 207 is branched into two systems of light at the branching unit 208 and enters the light guides 28 and 29.

  The first and second semiconductor light sources 201 and 202 and the white light source 203 are driven and controlled by the light source control unit 210. When the normal mode is set, the first and second semiconductor light sources 201 and 202 are turned off, and the white light source 203 is turned on. Thereby, white light is irradiated into the specimen. On the other hand, when the oxygen saturation mode is set, the white light source 203 is turned off, and the first and second semiconductor light sources 201 and 202 are alternately turned on and off. As a result, narrow band light in the first different absorption wavelength region and narrow band light in the second different absorption wavelength region are alternately irradiated into the specimen.

  Further, in the endoscope system 200, the inside of the specimen is imaged by the color imaging element 215 provided with the RGB color filters. In the normal mode, by imaging the specimen illuminated with white light with the image sensor 215, the blue image data Bc, the green image data Gc, and the red image data Rc for creating a normal image can be obtained simultaneously. On the other hand, in the oxygen saturation mode, image data B1, G1, and R1 of three colors are obtained by imaging the specimen illuminated with the narrowband light in the first different absorption wavelength range by the imaging device 215, and the second different absorption. Three-color image data B2, G2, and R2 are obtained by imaging the specimen illuminated with the narrow-band light in the wavelength range by the imaging device 215. Of these image data, the blue image data B1 and the blue image data B2 are used to create an oxygen saturation image.

  In the first embodiment, the oxygen saturation image in which the body cavity is displayed in a pseudo color is created based on the two image data of the blue image data B1 and the blue image data B2 in the oxygen saturation mode. In addition to the blue image data B1 and the blue image data B2, the oxygen saturation image is created based on the four image data of the green image data G having the green wavelength component and the red image data R having the red wavelength component. May be performed. The oxygen saturation image created based on these four image data is displayed in a pseudo color only in the low oxygen region where the oxygen saturation is below a certain value, and the other images are displayed in the same color as the normal image + It is an oxygen saturation image. For creating the normal image + oxygen saturation image, a rotation filter 300 shown in FIG. 19 is used instead of the rotation filter 31.

  The rotary filter 300 is provided on the optical path of the broadband light BB in the normal mode, and provided outside the first filter area 38, and is set on the optical path of the broadband light BB in the oxygen saturation mode. The second filter region 301 is provided. The first filter region 38 includes a B filter unit 38 a, a G filter unit 38 b, and an R filter unit 38 c that are the same as the rotary filter 31. The second filter region 301 includes a G filter unit 302 and an R filter unit 303 in addition to the first narrowband filter unit 39a and the second narrowband filter unit 39b similar to the rotary filter 31.

  Similarly to the G filter unit 38b, the G filter unit 302 transmits G light of 480 to 620 nm in the broadband light BB. The R filter unit 302 transmits R light of 580 to 720 nm in the broadband light BB, similarly to the R filter unit 38c. From the above, in the oxygen saturation mode, when the rotary filter 300 rotates, narrowband light in the first different absorption wavelength region, narrowband light in the second different absorption wavelength region, G light, and R light are sequentially emitted. These four types of light sequentially enter the ride guides 28 and 29 through the condenser lens 35 and the optical fiber 36.

  The wavelength range of G light (480 to 620 nm) is a wavelength range in which the magnitude relationship between the absorption coefficients of oxyhemoglobin and reduced hemoglobin is frequently switched. Therefore, even if the oxygen saturation changes, the reflected light of G light The amount of light hardly changes. Further, the wavelength range of R light (580 to 720 nm) is mostly the wavelength range in which the extinction coefficient of reduced hemoglobin is larger than the extinction coefficient of oxyhemoglobin. Therefore, as the oxygen saturation decreases, the R light The amount of reflected light also decreases.

  When the rotary filter 300 is used, imaging control is performed in the procedure shown in FIG. 20 in the oxygen saturation mode. As shown in FIG. 20, in the irradiation periods T1, T2, T3, and T4 of the narrow band light in the first different absorption wavelength region, the narrow band light in the second different absorption wavelength region, the G light, and the R light, The image light of the light is sequentially picked up by the image pickup device 60 and charges are accumulated. Based on the accumulated charges, the blue signal B1, the blue signal B2, the green signal G, and the red signal R are sequentially output. Such an operation is repeated while the oxygen saturation mode is set. The blue signal B1, blue signal B2, green signal G, and red signal R are A / D converted to obtain blue image data B1, blue image data B2, green image data G, and red image data R.

  Here, as described above, for the blue image data B1, the pixel value increases with a decrease in oxygen saturation, while for the blue image data B2, the pixel value decreases with a decrease in oxygen saturation. For the green image data Gy, the amount of R reflected light from the blood vessel does not change with the oxygen saturation, and therefore the pixel value hardly changes with the change in oxygen saturation. On the other hand, for the red image data Rz, the amount of R reflected light from the blood vessel decreases with a decrease in oxygen saturation, so that the pixel value also decreases with a decrease in oxygen saturation.

  When the above four image data are obtained in the oxygen saturation mode, first, the blue image data B1 and the blue image data B2 are synthesized to obtain the blue image data B as shown in FIG. The synthesized blue image data B is obtained by synthesizing two blue image data B1 and B2 having different pixel value changes due to a change in oxygen saturation. The pixel value of the image data B hardly changes.

  Then, gain processing is performed on the blue image data B, the green image data G, and the red image data R that have been combined. In the gain processing, the pixel value of each image data is adjusted according to the intensity ratio B / G between the blue image data B1 and the green image data G. The blue image data B is subjected to gain processing for increasing the pixel value as the intensity ratio B / G increases. On the other hand, the green image data G and red image data R are subjected to gain processing for decreasing the pixel value as the intensity ratio B / G increases. The blue image data B ′, the green image data G ′, and the red image data R ′ after the gain processing are assigned to the B, G, and R channels of the display device 14. As a result, the normal image + oxygen saturation image is displayed on the display device 14.

  In the first and second embodiments, the pixel value of the image data is adjusted (increased or decreased) in accordance with the change in oxygen saturation, but instead, between pixels (spatially), If there is a difference in the degree of oxygen saturation, the pixel value of the image data may be adjusted in accordance with the difference in oxygen saturation between the pixels. For example, as a value indicating a difference in oxygen saturation between pixels, a first difference value obtained by subtracting an intensity ratio B1 / M of an adjacent pixel from an intensity ratio B1 / M of a predetermined pixel (intensity ratio B1 / M of an adjacent pixel−adjacent) Pixel intensity ratio B1 / M) and a second difference value obtained by subtracting the predetermined pixel intensity ratio B1 / M from the adjacent pixel intensity ratio B1 / M (adjacent pixel intensity ratio B1 / M−predetermined pixel B1 / M) is calculated.

  Then, gain processing is performed on the blue image data B1 and B2 of the predetermined pixel using the gain coefficient corresponding to the first difference value, and the blue image data of the adjacent pixel is used using the gain coefficient corresponding to the second difference value. Gain processing is performed on B1 and B2. Then, the blue image data B1 ′ of the predetermined pixel after the gain processing and the blue image data B1 ′ of the adjacent pixel are assigned to the B channel of the display device 14, and the blue image data B2 ′ of the predetermined pixel and the adjacent pixel after the gain processing are assigned. Blue image data B2 ′ is assigned to the G channel and R channel of the display device. In addition, when adjusting the pixel value according to the difference in oxygen saturation between pixels, in addition to the gain processing, the pixel value may be adjusted by 2DLUT or 1DLUT as in the above embodiment. .

  For example, as shown in FIG. 22A, when the intensity ratio B1 / M of a predetermined pixel is “1” and the intensity ratio B1 / M of an adjacent pixel adjacent to the predetermined pixel is “1”, the first Both the second difference values are “0”. In the case of the difference value “0”, there is no difference in oxygen saturation between the predetermined pixel and the adjacent pixel, so there is no need to adjust the pixel values of the predetermined pixel and the adjacent pixel. Therefore, the gain coefficient corresponding to the difference value “0” is set to “1”. Then, the gain processing of the gain coefficient “1” is performed on the blue image data B1 and B2 of the predetermined pixel and the blue image data B1 and B2 of the adjacent pixels. Even after this gain processing, there is no difference in pixel value between the predetermined pixel and the adjacent pixel, and thus no difference in color between the predetermined pixel and the adjacent pixel occurs on the display device 14.

  On the other hand, as shown in FIG. 22B, when the intensity ratio B1 / M of the predetermined pixel is “0.5” and the intensity ratio B1 / M of the adjacent pixels is “2”, the first difference value is “ −1.5 ”, and the second difference value is“ 1.5 ”. Thus, when the difference value is other than “0”, there is a difference in oxygen saturation between the predetermined pixel and the adjacent pixel. In order to increase the pixel value difference between the pixels due to the difference in oxygen saturation, the gain coefficient corresponding to the negative difference value is “1” or less, and the gain coefficient corresponding to the positive difference value is “1” or more. It is stipulated in. Therefore, the gain coefficient corresponding to “−1.5” of the first difference value is “1” or less, and the gain coefficient corresponding to “1.5” of the second difference value is “1” or more. .

  Then, the blue image data B1 ′ and B2 ′ whose pixel values are reduced according to the gain coefficient are obtained by performing the gain processing of the gain coefficient “1 or less” on the blue image data B1 and B2 of the predetermined pixel. . On the other hand, by performing gain processing with a gain coefficient “1 or more” on the blue image data B1 and B2 of adjacent pixels, blue image data B1 ′ and B2 ′ having pixel values increased according to the gain coefficient are obtained. . As described above, the gain process for decreasing the pixel value is performed on the image data of the predetermined pixel, while the gain process for increasing the pixel value is performed on the image data of the adjacent pixel. The difference in pixel value between adjacent pixels increases. By increasing the difference in pixel value in this way, the difference in color between the predetermined pixel and the adjacent pixel in the display device 14 becomes clearer.

  In the first and second embodiments, the image for two wavelengths, the blue image data B1 having the wavelength component in the first different absorption wavelength region and the blue image data B2 having the wavelength component in the second different absorption wavelength region. Although the oxygen saturation is created and displayed using the data, three or more pieces of image data having different wavelength components may be used. In this case, only image data having a wavelength component in the different absorption wavelength region may be combined. In addition to the image data having a wavelength component in the different absorption wavelength region, the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin. May be combined with image data having wavelength components in substantially the same isosbestic wavelength region.

  In the above embodiment, the intensity ratio B1 / M between the blue image data B1 and the composite image data M is used as the information indicating the change in the oxygen saturation on the blue image data B1, but instead of this, The pixel value itself of the blue image data B1 may be used as information indicating a change in oxygen saturation. Similarly, as information indicating the change in oxygen saturation on the blue image data B2, the pixel value itself of the blue image data B2 is used as information indicating the change in oxygen saturation instead of the intensity ratio B2 / M. May be.

  In the above-described embodiment, both the pixel value of the blue image data B1 and the pixel value of the blue image data B2 are matched with changes in oxygen saturation (for example, matched with changes in intensity ratios B1 / M and B2 / M). However, the present invention is not limited to this, and the pixel value of one of the blue image data B1 and the blue image data B2 is adjusted according to the change in oxygen saturation, and the pixel value of the other image data is adjusted. Need not be adjusted in accordance with changes in oxygen saturation. In this case, among the B, G, and R channels of the display device, image data whose pixel value is adjusted is assigned to a predetermined color channel, and image data whose pixel value is not adjusted is assigned to the remaining color channels. It is done.

  In the above embodiment, the oxygen saturation image is generated using the oxygen saturation, which is the proportion of oxyhemoglobin in the blood volume (the sum of oxyhemoglobin and deoxyhemoglobin), but instead or in addition, An oxygenated hemoglobin index obtained from “blood volume × oxygen saturation (%)” or a reduced hemoglobin index obtained from “blood volume × (100−oxygen saturation) (%)” may be used.

The problems of the present invention can also be solved by the following technical idea.
[Additional Item 1]
Illumination means for illuminating the specimen with illumination light;
Of the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin is the blood hemoglobin First image information acquisition means for acquiring image information of a first different absorption wavelength region that changes due to a change in oxygen saturation;
Among the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the second different absorption wavelength range in which the extinction coefficient of oxyhemoglobin is smaller than the extinction coefficient of reduced hemoglobin is blood hemoglobin. Second image information acquisition means for acquiring image information of a second different absorption wavelength region that changes due to a change in oxygen saturation of
Normalized information acquisition means for acquiring standardized information by normalizing the image information in the different absorption wavelength region with specific image information having a specific wavelength component;
Difference value information calculating means for obtaining a difference value between a value of a predetermined pixel in the normalization information and a value of an adjacent pixel adjacent to the predetermined pixel;
Display image information in the first different absorption wavelength range obtained by adjusting the pixel value of the image information in the first different absorption wavelength range according to the difference value, or an image in the second different absorption wavelength range according to the difference value. Display image information creating means for creating at least one display image information of the display image information in the second different absorption wavelength range in which the pixel value of the information is adjusted;
An endoscope system comprising: display control means for assigning a plurality of pieces of image information including the display image information to the first color channel to the third color channel of the display means.

[Additional Item 2]
The display image information creating means includes:
Display image information for the first different absorption wavelength region is generated by a gain process for the first different absorption wavelength region for adjusting a pixel value of the image information of the first different absorption wavelength region according to the difference value. ,
Display image information for the second different absorption wavelength region is created by a gain process for the second different absorption wavelength region that adjusts a pixel value of the image information of the second different absorption wavelength region according to the difference value. The endoscope system according to Additional Item 1, wherein

[Additional Item 3]
The gain processing for the first different absorption wavelength region is performed by calculating a pixel value within a range of either the first pixel value adjustment range or the second pixel value adjustment range narrower than the first pixel value adjustment range. Adjust
In the gain processing for the second different absorption wavelength region, the pixel value is set within either the third pixel value adjustment range or the fourth pixel value adjustment range narrower than the third pixel value adjustment range. The endoscope system according to Additional Item 2, wherein the endoscope system is adjusted.

[Additional Item 4]
The display control means includes
Item 2. The image information for display in the different absorption wavelength region and the equal absorption wavelength region is assigned one to the first color channel and the other is assigned to the second color channel and the third color channel. Or the endoscope system of 3.

[Additional Item 5]
The display image information creating means includes:
Instead of the display image information in the first or second different absorption wavelength region,
A first color display image obtained by adjusting the pixel value of the image information in the first and second different absorption wavelength regions according to the difference value and color-converting the image information after the pixel value adjustment to the first color. information,
A display image of the second color obtained by adjusting the pixel value of the image information in the first and second different absorption wavelength regions according to the difference value and color-converting the image information after the pixel value adjustment to the second color. The pixel value of the image information in the first and second different absorption wavelength ranges is adjusted according to the information or the difference value, and the image information after the pixel value adjustment is converted into the third color. The endoscope system according to Additional Item 1, wherein display image information of at least one color is generated from the display image information.

[Additional Item 6]
The display image information creating means includes:
Using the first table that stores the relationship between the image information of the first and second different absorption wavelength ranges and the display information of the first color, the display information of the first color is created,
The second color display image information is created using a second table that stores the relationship between the image information of the first and second different absorption wavelength ranges and the display information of the second color. The endoscope system according to appendix 5, characterized by:

[Additional Item 7]
The display control means includes
One of the display information of the first color and the second color is assigned to the first color channel, and the other is assigned to the second color channel and the third color channel. The endoscope system according to appendix 6.

[Appendix 8]
In the endoscope system according to appendix 6,
In addition to the first color and second color display image information, the display image information creation means includes:
Creating the third color display image information using a third table storing the relationship between the image information of the first and second different absorption wavelength regions and the display information of the third color. It is characterized by.

[Additional Item 9]
The display image information creating means includes:
Instead of the display image information in the first or second different absorption wavelength region,
A first color display image obtained by adjusting the pixel value of the image information in the first different absorption wavelength region in accordance with the change in the oxygen saturation and color-converting the image information after the pixel value adjustment to the first color. information,
A second color display image obtained by adjusting the pixel value of the image information in the second different absorption wavelength region according to the change in the oxygen saturation and color-converting the image information after the pixel value adjustment to the second color. Information or
In accordance with the change in the oxygen saturation, either the pixel value of the image information in the first different absorption wavelength region or the pixel value of the image information in the second different absorption wavelength region is adjusted, and after the pixel value adjustment The endoscope system according to claim 1, wherein the display image information of at least one color is generated from the display information of the third color obtained by converting the image information into the third color.

[Additional Item 10]
The display image information creating means includes:
Using the fourth table storing the relationship between the image information of the first different absorption wavelength region and the display information of the first color, the display image information of the first color is created,
Using the fifth table that stores the relationship between the image information of the second different absorption wavelength region and the display information of the second color, the display information of the second color is created,
The third color display image information is created by using a sixth table that stores the relationship between the image information in the first different absorption wavelength region and the third color display image information. The endoscope system according to appendix 9.

[Additional Item 11]
The display image information creating means includes:
Instead of the sixth table, a seventh table for storing the relationship between the image information in the second different absorption wavelength region and the display information for the third color is used, and the display information for the third color is used. The endoscope system according to item 10, wherein the endoscope system is created.

[Additional Item 12]
The display control means includes
The first color display image information is assigned to the first color channel, the second color display image information is assigned to the second color channel, and the third color display image information is assigned to the third color channel. The endoscope system according to any one of appendices 8 to 11, wherein the endoscope system is assigned to a channel.

[Additional Item 13]
The internal vision according to any one of claims 1 to 12, wherein the first color channel is a blue channel, the second color channel is a green channel, and the third color channel is a red channel. Mirror system.

[Additional Item 14]
Third image information acquisition means for acquiring image information of a specific wavelength range obtained by imaging a specimen illuminated with light including a specific wavelength range other than the first and second different absorption wavelength ranges among the illumination light. When,
A normal image creating means for creating a normal image having a wavelength component of visible light based on the image information of the first and second different absorption wavelength regions and the image information of the specific wavelength region;
The display image information creating means includes:
The display image information in which the pixel value of the normal image is adjusted according to the difference value is created instead of the display image information in the first or second different absorption wavelength region. Endoscope system.

[Appendix 15]
The specific image information is image information in an isosbestic wavelength region having a wavelength component in the equiabsorbing wavelength region in which the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same.
The standardized information includes first normalized information obtained by normalizing image information in the first different absorption wavelength region with image information in the equal absorption wavelength region, or image information in the second different absorption wavelength region. The endoscope system according to any one of additional items 1 to 14, wherein the endoscope system is any one of second standardized information obtained by normalizing with image information in an equiabsorption wavelength region.

[Additional Item 16]
16. The endoscope system according to claim 15, wherein the image information in the equiabsorption wavelength region is obtained by combining image information in the first different absorption wavelength region and image information in the second different absorption wavelength region. .

[Additional Item 17]
The endoscope system according to any one of appendices 1 to 16, wherein the first different absorption wavelength region is 450 to 500 nm, and the second different absorption wavelength region is 415 to 450 nm.

[Additional Item 18]
Image data obtained by irradiating the specimen with illumination light and imaging the specimen illuminated with light including a first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin in the illumination light The image value of the first different absorption wavelength region where the pixel value of the blood hemoglobin changes due to the change in oxygen saturation of blood hemoglobin is obtained, and the extinction coefficient of oxyhemoglobin is greater than the extinction coefficient of reduced hemoglobin in the illumination light. Image information of the second different absorption wavelength region in which the pixel value of the image data obtained by imaging a specimen illuminated with light including a small second different absorption wavelength region changes due to a change in the oxygen saturation of blood hemoglobin In a processor device of an endoscope system used in combination with an endoscope device that acquires
Receiving means for receiving image information in the first and second different absorption wavelength regions from the endoscope apparatus;
Normalized information acquisition means for acquiring standardized information by normalizing the image information in the different absorption wavelength region with specific image information having a specific wavelength component;
Difference value information calculating means for obtaining a difference value between a value of a predetermined pixel in the normalization information and a value of an adjacent pixel adjacent to the predetermined pixel;
Display image information in which the pixel value of the image information in the first different absorption wavelength range is adjusted according to the difference value, or the pixel value of the image information in the second different absorption wavelength range is adjusted in accordance with the difference value. Display image information creating means for creating at least one display image information of the display image information;
A processor device for an endoscope system, comprising: display control means for assigning a plurality of pieces of image information including the display image information to a first color channel to a third color channel of a display means.

[Appendix 19]
Irradiating illumination light from the illumination means toward the specimen;
Of the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin is the blood hemoglobin Acquiring image information of a first different absorption wavelength region that changes due to a change in oxygen saturation by a first image information acquisition unit;
Among the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the second different absorption wavelength range in which the extinction coefficient of oxyhemoglobin is smaller than the extinction coefficient of reduced hemoglobin is blood hemoglobin. Acquiring the image information of the second different absorption wavelength region that changes due to the change in the oxygen saturation of the second image information acquisition means,
Normalizing the image information of the different absorption wavelength region with the specific image information having a specific wavelength component, and acquiring the normalized information by the normalized information acquisition unit;
Obtaining a difference value between a value of a predetermined pixel in the normalized information and a value of an adjacent pixel adjacent to the predetermined pixel by a difference value information calculating unit;
Display image information in which the pixel value of the image information in the first different absorption wavelength range is adjusted according to the difference value, or the pixel value of the image information in the second different absorption wavelength range is adjusted in accordance with the difference value. Creating at least one display image information of the display image information by a display image creating means;
An endoscopic image comprising: a display control unit performing display control processing for assigning a plurality of pieces of image information including the display image information to the first color channel to the third color channel of the display unit. Display control method.

10,200 Endoscope system 11 Light source device 12 Endoscope device 13 Processor device 31 Rotary filter 85 Gain table

Claims (10)

Illumination means for illuminating the specimen with illumination light;
Of the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin is the blood hemoglobin First image information acquisition means for acquiring image information of a first different absorption wavelength region that changes due to a change in oxygen saturation;
Among the illumination light, the pixel value of the image data obtained by imaging the specimen illuminated with light including the second different absorption wavelength range in which the extinction coefficient of oxyhemoglobin is smaller than the extinction coefficient of reduced hemoglobin is blood hemoglobin. Second image information acquisition means for acquiring image information of a second different absorption wavelength region that changes due to a change in oxygen saturation of
The pixel values of the image information in the first and second different absorption wavelength ranges are adjusted according to the change in the oxygen saturation, and the image information in the first and second different absorption wavelength ranges after the pixel value adjustment is changed to the first. First color display image information converted to one color, and second color display image information obtained by color-converting the image information of the first and second different absorption wavelength ranges after pixel value adjustment to the second color And display image information creating means for creating
Display control means for assigning a plurality of pieces of image information including the display image information to the first color channel to the third color channel of the display means ;
The display image information creating means includes:
Using the first table that stores the relationship between the image information of the first and second different absorption wavelength ranges and the display information of the first color, the display information of the first color is created,
Creating the second color display image information by using a second table that stores the relationship between the image information of the first and second different absorption wavelength regions and the display information of the second color. Endoscope system characterized by. The display control means includes
One of the display information of the first color and the second color is assigned to the first color channel, and the other is assigned to the second color channel and the third color channel. The endoscope system according to claim 1 . The endoscope system according to claim 1 , wherein
In addition to the first color and second color display image information, the display image information creation means includes:
Creating the third color display image information using a third table storing the relationship between the image information of the first and second different absorption wavelength regions and the display information of the third color. It is characterized by. The display control means includes
The first color display image information is assigned to the first color channel, the second color display image information is assigned to the second color channel, and the third color display image information is assigned to the third color channel. 4. The endoscope system according to claim 3 , wherein the endoscope system is assigned to a channel. The first color channel is a blue channel, the second color channel is green channel, the endoscope of claims 1, wherein any of the preceding Claims in that the third color channel is red channel Mirror system. A fourth image information acquisition means for acquiring image information in an isosbestic wavelength region having a wavelength component in the equiabsorbing wavelength region where the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same;
The first normalized information obtained by normalizing the image information of the first different absorption wavelength region with the image information of the isoabsorption wavelength region, or the image information of the second different absorption wavelength region is the image of the isoabsorption wavelength region. Having standardized information creating means for creating at least one of the second standardized information obtained by standardizing with information;
The endoscope system according to any one of claims 1 to 3 , wherein the change in the oxygen saturation is a change in the value of the first or second normalized information. The endoscope system according to claim 6 , wherein the image information in the equiabsorption wavelength region is obtained by combining image information in the first different absorption wavelength region and image information in the second different absorption wavelength region. . The endoscope system according to any one of claims 1 to 7, wherein the first different absorption wavelength region is 450 to 500 nm, and the second different absorption wavelength region is 415 to 450 nm. Image data obtained by irradiating the specimen with illumination light and imaging the specimen illuminated with light including a first different absorption wavelength region in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin in the illumination light The image value of the first different absorption wavelength region where the pixel value of the blood hemoglobin changes due to the change in oxygen saturation of blood hemoglobin is obtained, and the extinction coefficient of oxyhemoglobin is greater than the extinction coefficient of reduced hemoglobin in the illumination light. Image information of the second different absorption wavelength region in which the pixel value of the image data obtained by imaging a specimen illuminated with light including a small second different absorption wavelength region changes due to a change in the oxygen saturation of blood hemoglobin In a processor device of an endoscope system used in combination with an endoscope device that acquires
Receiving means for receiving image information in the first and second different absorption wavelength regions from the endoscope apparatus;
The pixel values of the image information in the first and second different absorption wavelength ranges are adjusted according to the change in the oxygen saturation, and the image information in the first and second different absorption wavelength ranges after the pixel value adjustment is changed to the first. First color display image information converted to one color, and second color display image information obtained by color-converting the image information of the first and second different absorption wavelength ranges after pixel value adjustment to the second color And display image information creating means for creating
Display control means for assigning a plurality of pieces of image information including the display image information to the first color channel to the third color channel of the display means ;
The display image information creating means includes:
Using the first table that stores the relationship between the image information of the first and second different absorption wavelength ranges and the display information of the first color, the display information of the first color is created,
Creating the second color display image information by using a second table that stores the relationship between the image information of the first and second different absorption wavelength regions and the display information of the second color. A processor device of an endoscope system characterized by the above. First image information acquiring means, the pixels of the image data obtained by imaging the specimen absorption coefficient of oxyhemoglobin is illuminated with light comprising a first different absorption wavelength region greater than the absorption coefficient of reduced hemoglobin of the irradiation Meiko value, by a change in oxygen saturation of hemoglobin in blood, comprising the steps of: acquire the first image information of the different absorption wavelength range that varies,
Image data obtained by the second image information acquisition unit imaging the specimen illuminated with light including a second different absorption wavelength region in which the absorption coefficient of oxyhemoglobin is smaller than the absorption coefficient of reduced hemoglobin among the illumination light the pixel values, the change in oxygen saturation of hemoglobin in blood, comprising the steps of: acquire image information of the second different absorption wavelength range that varies,
The display image creating means adjusts the pixel value of the image information in the first and second different absorption wavelength regions in accordance with the change in the oxygen saturation, and the first and second different absorption after the pixel value adjustment. The first color display image information obtained by converting the image information in the wavelength range into the first color and the first and second different absorption wavelength range image information after the pixel value adjustment are converted into the second color. Creating two-color display image information; and
Display control means, a plurality of image information including the display image information, a display control process to assign to the first color channel to third color channel of the display unit possess a row cormorants step,
In the step of the display image creating means creating the first color display image information and the second color display image information,
The display image information creating means includes:
Using the first table that stores the relationship between the image information of the first and second different absorption wavelength ranges and the display information of the first color, the display information of the first color is created,
Creating the second color display image information by using a second table that stores the relationship between the image information of the first and second different absorption wavelength regions and the display information of the second color. An operation method of an endoscope system characterized by the above.

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