JP5670399B2 - 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 means for irradiating a specimen with illumination light, and a different absorption wavelength region in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different. First image information acquisition means for acquiring image information in a different absorption wavelength range in which a pixel value of image data obtained by imaging a specimen illuminated with light including the light changes in oxygen saturation of blood hemoglobin; In the illumination light, the second is to obtain image information in an isosbestic wavelength region obtained by imaging a specimen illuminated with light including an equiabsorption wavelength region in which the extinction coefficient of oxygenated hemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same. an image information obtaining unit, together with the changing oxygen saturation adjusting the pixel values of the image information of the image information and the isosbestic wavelength range of the different absorption wavelength region, the image information of the different absorption wavelength range of the pixel value after adjustment In addition, the first color display image information obtained by converting the image information in the isosbestic wavelength region into the first color, the image information in the different absorption wavelength region and the image information in the isosbestic wavelength region after the pixel value adjustment is the second color. Display image information creation means for creating display image information for the second color that has been color-converted into a plurality of pieces of image information including display image information in the first color channel to the third color channel of the display means. A display control means for allocating , and the display image information creating means stores a relationship between the image information in the different absorption wavelength region and the image information in the isoabsorption wavelength region and the display information for the first color. Is used to create the first color display image information and store the relationship between the image information of the different absorption wavelength region and the image information of the equal absorption wavelength region and the display information of the second color. using, characterized in that to create the display image information of the second color To.

Table示制control means, of the first and second colors display image information, to assign one to the first color channel, it is preferable to assign the other to the second color channel and the third color channel.

  In addition to the display information for the first color and the second color, the display image information creating means includes image information in the different absorption wavelength range and image information in the equal absorption wavelength range, and display information for the third color. It is preferable to create display image information of the third color using a third table that stores the relationship of

  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.

It has a standardized information creation means that creates standardized information obtained by standardizing image information in different absorption wavelength regions with image information in equal absorption wavelength regions. it is preferable that. The different absorption wavelength region is preferably a first different absorption wavelength region in which the absorption coefficient of oxyhemoglobin is larger than the absorption coefficient of reduced hemoglobin. The first different absorption wavelength region is preferably 450 to 500 nm. The different absorption wavelength region is preferably a second different absorption wavelength region in which the absorption coefficient of oxyhemoglobin is smaller than the absorption coefficient of reduced hemoglobin. The second different absorption wavelength region is preferably 415 to 450 nm.

The present invention provides image data obtained by irradiating a specimen with illumination light and imaging a specimen illuminated with light including different absorption wavelength ranges in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different. The image value of the different absorption wavelength range where the pixel value of the blood hemoglobin changes due to the change in oxygen saturation of blood hemoglobin is obtained, and the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are approximately the same as the absorption light. In a processor device of an endoscope system used in combination with an endoscope device that acquires image information in an isosbestic wavelength region obtained by imaging a specimen illuminated with light including a wavelength region, from the endoscope device a receiving means for receiving image information of the image information and the isosbestic wavelength range of the different absorption wavelength region, the image information and the image isosbestic wavelength range of the different absorption wavelength region in accordance with the change in oxygen saturation The pixel value of the information is adjusted, the image information in the different absorption wavelength range after the pixel value adjustment and the image information for display in the first color obtained by converting the image information in the equal absorption wavelength range into the first color, and the pixel value adjustment Display image information creating means for creating the second color display image information obtained by converting the image information in the different absorption wavelength region and the image information in the equal absorption wavelength region into the second color, 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 a different absorption wavelength range and the isoabsorption wavelength range. The first color display image information is created using the first table that stores the relationship between the image information of the first color and the display information of the first color, and the image information and the equal absorption of the different absorption wavelength region are created. Image information in the wavelength range, display image information for the second color, and Using a second table for storing a relationship, characterized by creating a displaying image information of the second color.

The operation method of the endoscope system according to the present invention is such that the first image information acquisition unit is configured to detect a specimen illuminated with light including different absorption wavelength ranges in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different from each other in the illumination light. pixel values of the image data obtained by imaging is by a change in oxygen saturation of hemoglobin in blood, comprising the steps of: acquire image information of the different absorption wavelength range that varies, the second image information acquisition unit, of the illumination light comprising the steps of get the image information, such as absorption wavelength range is obtained by imaging the specimen absorption coefficient of reduced hemoglobin and the absorption coefficient of oxyhemoglobin is illuminated substantially with light containing the same isosbestic wavelength range, the display image information creation means, with in accordance with the change in oxygen saturation to adjust the pixel values of the image information of the image information and the isosbestic wavelength range of the different absorption wavelength region, the image information of the different absorption wavelength range of the pixel value after adjustment In addition, the first color display image information obtained by converting the image information in the isosbestic wavelength region into the first color, the image information in the different absorption wavelength region and the image information in the isosbestic wavelength region after the pixel value adjustment is the second color. A second color display image information that has undergone color conversion, and a display control unit that outputs 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. the display control process possess a row cormorants assigning, the display image information generating means in the step of creating a first color display image information of the display image information of the second color, the display image information creating means Uses the first table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region, and the display information for the first color to create the display information for the first color. The display image information creating means is an image in a different absorption wavelength range. By using the image information of the broadcast and isosbestic wavelength region, a 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, in accordance with the change in oxygen saturation, display image information is created by adjusting at least one pixel value of image information in a different absorption wavelength region or image information in an equiabsorption wavelength region, and the created Since a plurality of pieces of image information including display image information are assigned to the first to third color channels of the display means, the difference in the oxygen state of the blood vessel is reliably displayed on the display means as a color difference. .

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 and G filter part of a rotation filter. 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 the image process part of 1st Embodiment. It is a graph which shows the relationship between intensity ratio B / G and the gain for blue images in 1st Embodiment. It is a graph which shows the relationship between intensity ratio B / G and the gain for green images in 1st Embodiment. It is explanatory drawing which shows the content of the 1st thru | or 3rd gain process. It is explanatory drawing which shows the method of calculating the gain GB for blue images from intensity ratio B ^* / G ^* . It is explanatory drawing which shows the method of calculating the gain GG for green images from intensity ratio B ^* / G ^* . It is explanatory drawing for demonstrating the color allocation of blue image data Bx 'and green image data Gy'. It is explanatory drawing which showed the change of the pixel value of the blue image data Bx when not carrying out a gain process, and the green image data Gy. It is explanatory drawing which showed the change of the pixel value of the blue image data Bx 'and green image data Gy' after gain processing in 1st Embodiment. 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 top view which shows the rotation filter of 2nd Embodiment. It is a graph which shows the spectral transmittance of the 2nd narrow-band filter part of a rotation filter, and a G filter part. It is a block diagram which shows the internal structure of the image process part of 2nd Embodiment. It is a graph which shows the relationship between intensity ratio B / G and the gain for blue images in 2nd Embodiment. It is a graph which shows the relationship between intensity ratio B / G and the gain for green images in 2nd Embodiment. It is explanatory drawing which showed the change of the pixel value of blue image data Bx 'and green image data Gy' after gain processing in 2nd Embodiment. It is a block diagram which shows the internal structure of the endoscope system of a semiconductor light source system. It is a top view which shows the rotation filter different from 1st and 2nd embodiment. FIG. 25 is an explanatory diagram showing the operation of the image sensor in the oxygen saturation mode when the rotary filter of FIG. 24 is used. It is explanatory drawing for demonstrating the gain process and color allocation with respect to blue image data Bx, green image data Gx, and red image data Rz. It is explanatory drawing for demonstrating the gain process when there is no difference of intensity ratio B / G 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 / G 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.

  In the second filter region 39, a first narrowband filter portion 39a (described as “first narrowband (450 to 500 nm) in FIG. 3)” and a G filter portion 39b are provided. As shown in FIG. 4B, the first narrowband filter unit 39a has a narrowband light in the first different absorption wavelength range of 450 to 500 nm in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different from the broadband light BB. (See FIG. 5). Further, since the G filter unit 39b has the same transmission characteristics as the G filter unit 38b, the G filter unit 39b also transmits the same G light in the broadband light BB. As described above, the narrow band light and the G light in the first different absorption wavelength region are sequentially emitted by the rotation of the rotary filter 31. These two types of light sequentially enter the ride guides 28 and 29 through the condenser lens 35 and the optical fiber 36.

  Here, the wavelength band of G light (480 to 620 nm), as shown in FIG. 5, the magnitude relationship between the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin is frequently switched. The extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin can be regarded as an isosbestic wavelength region in which they are almost the same.

  The imaging control of the imaging device 60 is different 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, image light of each light is sequentially captured by the image sensor 60 in the irradiation periods Tx and Ty of the narrowband light and G light in the first different absorption wavelength region. Then, charges are accumulated, and a blue signal Bx and a green signal Gy are sequentially output based on the accumulated charges. Such an operation is repeated while the oxygen saturation mode is set. Then, the blue image data Bx and the green image data Gy are obtained by A / D converting the blue signal Bx and the green signal Gy.

  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 obtains an intensity ratio B / G between the blue image data Bx and the green image data Gy. The intensity ratio calculation unit 84 calculates the intensity ratio B / G between the pixels at the same position between the image data, and calculates the intensity ratio B / G for all the pixels of the image data. It should be noted that the intensity ratio B / G may be obtained only for the blood vessel pixel 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, the blue image data Bx used for calculation of the intensity ratio B / G has a wavelength component (450 to 500 nm) in the first different absorption wavelength region in which the absorption coefficient of oxyhemoglobin is larger than the absorption coefficient of reduced hemoglobin. Therefore, when the oxygen saturation is lowered, the pixel value of the blue image data Bx is increased. On the other hand, since the green image data Gy has a wavelength component (480 to 620 nm) in an isosbestic wavelength region in which the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same, the oxygen saturation changes. However, the pixel value of the green image data Gy does not change. Therefore, the intensity ratio B / G obtained by dividing the pixel value of the blue image data Bx by the pixel value of the green image data Gy increases as the oxygen saturation level decreases.

  The gain table 85 correlates and stores the intensity ratio B / G and the blue image gain for multiplying the pixel value of the blue image data Bx, the intensity ratio B / G, and the green image. And a green image table 85b that stores a green image gain to be multiplied with the pixel value of the data Gy in association with each other.

  In the blue image table 85a, as shown in FIG. 8, the first blue color for increasing the pixel value of the blue image data Bx in accordance with the increase in the intensity ratio B / G (that is, the decrease in oxygen saturation). The image gain and the second blue image gain for gradually increasing the pixel value of the blue image data Bx in accordance with the increase in the intensity ratio B / G (that is, the decrease in oxygen saturation) are stored. Yes. When there is a shift, the first blue image gain is set, and when there is no shift, the second blue image gain is set. The first blue image gain range Rb1 is set to be larger than the second blue image gain range Rb2.

  In the green image table 85b, as shown in FIG. 9, the first green color for reducing the pixel value of the green image data Gy in accordance with the increase in the intensity ratio B / G (that is, the decrease in oxygen saturation). The image gain and the second green image gain for gradually decreasing the pixel value of the green image data Gy in accordance with the increase in the intensity ratio B / G (that is, the decrease in oxygen saturation) are stored. Yes. When there is a shift, the first green image gain is set, and when there is no shift, the second green image gain is set. The first green image gain range Rg1 is set to be larger than the second green image gain range Rg2.

  The gain processing unit 86 performs gain processing on the blue image data Bx and the green image data Gy using the intensity ratio B / G obtained by the intensity ratio calculation unit 84 and the gain table 85. As shown in FIG. 10, the gain process includes a first gain process using a first blue image gain (with shift) and a second green image gain (without shift), and a second blue image gain (without shift). And a second gain process using the first green image gain (with shift), and a third gain process using the first blue image gain (with shift) and the first green image gain (with shift). In any of the first to third gain processing, the difference between the pixel value of the blue image data Bx and the pixel value of the green image data Gy is increased. Enlarge. Which of these three gain processes is used can be determined by operating the input device 15.

When performing the first gain process, first, as shown in FIG. 11A, the first blue color corresponding to the intensity ratio B ^* / G ^* obtained by the intensity ratio calculation unit 84 with reference to the blue image table 85a. An image gain GB is calculated. Then, by multiplying the first blue image gain GB by the pixel value of the blue image data Bx, the blue image data Bx ′ having been subjected to gain processing is obtained. Next, as shown in FIG. 11B, the second green image gain GG corresponding to the intensity ratio B ^* / G ^* obtained by the intensity ratio calculator 84 is calculated with reference to the green image table 85b. Then, by multiplying the second green image gain GG by the pixel value of the green image data Gy, gain-processed green image data Gy ′ is obtained. The second and third gain processes are performed in the same manner as the first gain process.

  As shown in FIG. 12, the image creating unit 87 uses the blue image data Bx ′ that has undergone gain processing as the B channel of the display device 14 and the green image data Gy ′ 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 Bx and the green image data Gy are assigned to the B, G, and R channels of the display device 14 without performing gain processing, the image is displayed even if the oxygen saturation level is reduced. Since the difference Δ between the pixel values of the data Bx and Gy does not become so large, 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 FIGS. 13B and 22. Further, the image creating unit 87 may assign the gain-processed blue image data Bx ′ to the B channel and the G channel of the display device 14 and the gain-processed green image data Gy ′ to the R channel of the display device 14. .

  On the other hand, in this embodiment, as shown in FIG. 13B, the blue image data Bx ′ and the green image data Gy ′ that have been subjected to gain processing are assigned to the B, G, and R channels of the display device 14, As the degree of saturation decreases (with an increase in intensity ratio B / G), the pixel value difference Δ ′ between the image data Bx ′ and Gy ′ increases. As described above, by increasing the pixel value difference Δ ′ in accordance with the decrease in the oxygen saturation, the change in the color of the blood vessel on the oxygen saturation image can be reliably observed. On the oxygen saturation image, when the oxygen saturation is low, the color of the blood vessel gradually becomes “blue”.

  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 and G light in the first 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 Bx and green image data Gy are obtained.

  Next, the intensity ratio B / G between the blue image data Bx and the green image data Gy is calculated. Then, the blue image gain corresponding to the intensity ratio B / G is calculated with reference to the blue image table 85a, and the green image table corresponding to the intensity ratio B / G is calculated with reference to the green image table 85b. Calculate the gain. Then, by multiplying the calculated blue image gain by the pixel value of the blue image data Bx, gain-processed blue image data Bx ′ is obtained. Further, by multiplying the calculated green image gain by the pixel value of the green image data Gx, the green image data Gy ′ having been subjected to gain processing is obtained. The blue image data Bx ′ after gain processing is assigned to the B channel of the display device 14 and the green image data Gy ′ after gain processing is assigned to the G channel and the R channel of the display device 14, whereby the oxygen saturation image is displayed. 14 is displayed.

  In the first embodiment, a change in blood vessel color associated with a change in oxygen saturation is clarified by performing gain processing on the blue image data Bx and green image data Gy 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. Each 2DLUT outputs a B value, a G value, and an R value corresponding to the input image data Bx and Gy when the blue image data Bx and the green image data Gy are input. The B value, G value, and R value output from the above three 2DLUTs are assigned to the B, G, and R channels of the display device 14.

  In the blue conversion 2DLUT, the blue image data Bx and the green image data Gy and the B value obtained when the 2D-blue conversion program is executed based on the image data Bx and Gy are recorded in association with each other. . The 2D-blue color conversion program executes two processes: an intensity ratio calculation process for calculating the intensity ratio B / G between the blue image data Bx and the green image data Gy, and a B value conversion process for converting to the B value. As a result, B values corresponding to the image data Bx and Gy are output.

  In the B value conversion process, a blue value pixel value adjustment process corresponding to the magnitude of the intensity ratio B / G is performed on the blue image data Bx and the green image data Gy, and then the blue color after the pixel value adjustment process is performed. Image data Bx and green image data Gy are color-converted into B values. Here, the pixel value adjustment process for the B value is a process of increasing the pixel values of the image data Bx and Gy in accordance with the magnitude of the intensity ratio B / G, and as the intensity ratio B / G increases (that is, oxygen As the degree of saturation decreases, the increase rate of the pixel values of the image data Bx and Gy is increased.

  In the green conversion 2DLUT, blue image data Bx and green image data Gy and G values obtained when a 2D-green conversion program is executed based on these image data Bx and Gy are recorded in association with each other. . The 2D-green color conversion program corresponds to the image data Bx and Gy by executing two processes of an intensity ratio calculation process for calculating the intensity ratio B / G and a G value conversion process for converting to the G value. Output G value.

  In the G value conversion process, the blue value data Bx and the green image data Gy are subjected to the G value pixel value adjustment process corresponding to the magnitude of the intensity ratio B / G, and then the blue value after the pixel value adjustment process is performed. Image data Bx and green image data Gy are color-converted to G values. Here, the pixel value adjustment process for the G value is a process of decreasing the pixel values of the image data Bx and Gy in accordance with the magnitude of the intensity ratio B / G, and the greater the intensity ratio B / G (that is, oxygen As the degree of saturation decreases), the decrease rate of the pixel values of the image data Bx and Gy is increased.

  In the red conversion 2DLUT, blue image data Bx and green image data Gy and R values obtained when a 2D-red conversion program is executed based on the image data Bx and Gy are recorded in association with each other. . The 2D-red color conversion program executes two processes: an intensity ratio calculation process for calculating the intensity ratio B / G between the blue image data Bx and the green image data Gy, and an R value conversion process for converting to an R value. As a result, R values corresponding to the image data Bx and Gy are output.

  In the R value conversion process, the R value pixel value adjustment process corresponding to the magnitude of the intensity ratio B / G is performed on the blue image data Bx and the green image data Gy, and then the blue color after the pixel value adjustment process is performed. Image data Bx and green image data Gy are color-converted to R values. Here, the pixel value adjustment process for the R value is a process of decreasing the pixel values of the image data Bx and Gy in accordance with the magnitude of the intensity ratio B / G, and the greater the intensity ratio B / G (that is, oxygen As the degree of saturation decreases), the decrease rate of the pixel values of the image data Bx and Gy is increased.

  In the case of using the above 2DLUT, an oxygen saturation image in which the blood vessel becomes “blue” as the oxygen saturation becomes smaller 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 Bx is input, the blue conversion 1DLUT outputs a B value corresponding to the input image data Bx. Further, when the green image data Gy is input, the green conversion 1DLUT outputs a G value corresponding to the input image data Bx. In addition, when the blue image data Bx is input, the red conversion 1DLUT outputs an R value corresponding to the input blue image data Bx. 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, blue image data Bx and a B value obtained when the 1D-blue conversion program is executed based on the image data Bx are recorded in association with each other. The 1D-blue color conversion program outputs a B value corresponding to the blue image data Bx by executing a 1D B value conversion process for converting to a B value.

  In the 1D B-value conversion process, first, a pixel value adjustment process for increasing the pixel value of the blue image data Bx in accordance with the pixel value of the blue image data Bx is performed, and then the blue image after the pixel value adjustment process is performed. Data Bx is color-converted to B value. At this time, in order to increase the difference between the pixel values of the B value, the G value, and the R value when the hypoxia state is reached, the increase rate of the pixel value of the blue image data Bx is blue due to the decrease in the oxygen saturation. The larger the pixel value of the image data Bx, the larger the pixel value is set (the blue image data Bx includes a component in the wavelength range of HbO2> Hb. Therefore, when the oxygen saturation decreases, the pixel of the blue image data Bx The value will increase.)

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

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

  In the 1D B-value conversion process, first, the pixel value adjustment process for increasing the pixel value of the image data Bx in accordance with the pixel value of the blue image data Bx is performed, and then the blue image data Bx after the pixel value adjustment process is performed. Is converted to an R value. At this time, in order to increase the difference between the pixel values of the R value and the B value when the hypoxic state is reached, the decrease rate of the pixel value of the blue image data Bx is reduced by the decrease in the oxygen saturation. The pixel value is set so as to increase as the pixel value increases.

  When the above 1DLUT is used, an oxygen saturation image in which the blood vessel becomes “blue” as the oxygen saturation is reduced is displayed. As shown in FIG. 17, the red DL conversion 1DLUT may convert the green image data Gy into an R value instead of the blue image data Bx.

  In the first embodiment, in the oxygen saturation mode, the sample is irradiated with narrowband light and G light in the first different absorption wavelength range in which the extinction coefficient of oxyhemoglobin is larger than the extinction coefficient of reduced hemoglobin. In the embodiment, instead of the narrow-band light in the first different absorption wavelength region, the narrow-band light and the G light in the second different absorption wavelength region in which the extinction coefficient of reduced hemoglobin is larger than the extinction coefficient of oxyhemoglobin are irradiated into the specimen. . Therefore, in the second embodiment, the rotary filter 100 in FIG. 18 is used instead of the rotary filter 31. The rotary filter 100 is the same as the rotary filter 31 except for the second narrowband filter unit 101 that transmits the narrowband light in the second different absorption wavelength region in the broadband light BB.

  As illustrated in FIG. 19, the second narrowband filter unit 101 transmits narrowband light in the second different absorption wavelength region of 415 to 450 nm in the broadband light BB. This second different absorption wavelength region is a wavelength region in which the extinction coefficient of reduced hemoglobin is larger than the extinction coefficient of oxyhemoglobin (see FIG. 5). Therefore, the amount of reflected light when the blood vessel is irradiated with narrow-band light in the second different absorption wavelength region is reduced due to a decrease in oxygen saturation. Along with this, the pixel value of the blue image data Bx created from the reflected light of the narrow band light in the second different absorption wavelength region also decreases as the oxygen saturation decreases. From the above, the intensity ratio B / G obtained by dividing the pixel value of the blue image data Bx by the pixel value of the green image data Gy decreases as the oxygen saturation level decreases.

  Thus, in 2nd Embodiment, the change of intensity ratio B / G by the change of oxygen saturation differs from 1st Embodiment. The image processing unit 110 according to the second embodiment is the same as the image processing unit 72 according to the first embodiment except for the gain table 115 as shown in FIG. The gain table 115 includes a blue image table 115a that stores the intensity ratio B / G and the blue image gain in association with each other, and a green image table 115b that stores the intensity ratio B / G and the green image gain in association with each other. It has.

  In the blue image table 115a, as shown in FIG. 21, the first blue color for decreasing the pixel value of the blue image data Bx in accordance with the decrease in the intensity ratio B / G (that is, the decrease in oxygen saturation). The image gain and the second blue image gain for gradually decreasing the pixel value of the blue image data Bx according to the decrease in the intensity ratio B / G (that is, the decrease in oxygen saturation) are stored. Yes. When there is a shift, the first blue image gain is set, and when there is no shift, the second blue image gain is set. The first blue image gain range Rb1 is set to be larger than the second blue image gain range Rb2.

  In the green image table 115b, as shown in FIG. 22, the first green color for increasing the pixel value of the green image data Gy in accordance with the decrease in the intensity ratio B / G (that is, the decrease in oxygen saturation). The image gain and the second green image gain for gradually increasing the pixel value of the green image data Gy in accordance with the decrease in the intensity ratio B / G (that is, the decrease in oxygen saturation) are stored. Yes. When there is a shift, the first green image gain is set, and when there is no shift, the second green image gain is set. The first green image gain range Rg1 is set to be larger than the second green image gain range Rg2.

  In the second embodiment, since the gain table 115 different from the gain table 85 of the first embodiment is used, the display of the oxygen saturation image is also different. As shown in FIG. 23, the pixel value of the blue image data Bx ′ assigned to the B channel of the display device 14 decreases with a decrease in oxygen saturation (with a decrease in intensity ratio B / G), while the display device 14 The pixel value of the green image data Gy ′ assigned to the G and R channels increases. Therefore, on the oxygen saturation image of the second embodiment, when the oxygen saturation is low, the color of the blood vessel gradually becomes “yellow”.

  In the second embodiment, a 2DLUT or a 1DLUT for converting the blue image data Bx and the green image data Gy into RGB values may be used as in the first embodiment. Also, in the 2DLUT of the second embodiment, the blue image data Bx and the green image data Gy are color-converted to a B value by the blue conversion 2DLUT, and the blue image data Bx and the green image data Gy are converted to the G value by the green conversion 2DLUT. The 2D-blue conversion program used to create these 2DLUTs is the same as that of the first embodiment in that the blue image data Bx and the green image data Gy are converted into R values by the red 2DLUT for red conversion. Among various processes of the 2D-green color conversion program and the 2D-red color conversion program, the processing contents of the B value conversion process, the G value conversion process, and the R value conversion process are different.

  In the B value conversion process of the second embodiment, the pixel values of the blue image data Bx and the green image data Gy are reduced in accordance with the magnitude of the intensity ratio B / G, and the image data Bx after the pixel value is reduced. , Gy is color-converted into B values. At this time, the decrease rate of the pixel value is increased as the intensity ratio B / G is decreased (that is, the oxygen saturation is decreased).

  In contrast, the G value conversion process and the R value conversion process of the second embodiment increase the pixel values of the blue image data Bx and the green image data Gy according to the magnitude of the intensity ratio B / G. Then, the image data Bx, Gy after the pixel value increase is color-converted into G value and R value. At this time, the increase rate of the pixel value is increased as the intensity ratio B / G is decreased (that is, the oxygen saturation is decreased).

  Also for the 1DLUT of the second embodiment, the blue image data Bx is color-converted to a B value by the blue conversion 1DLUT, the green image data Gy is color-converted to the G value by the green conversion 1DLUT, and the blue image data Bx is converted. Although the color conversion to the R value by the 1DLUT for red conversion is the same as that of the first embodiment, the processing contents of the 1D-blue conversion program and the 1D-red conversion program used to create the 1DLUT are different. .

  In the second embodiment, the 1D-blue conversion program and the 1D red conversion program 1D B-value conversion processing and 1D R-value conversion processing are performed in accordance with the pixel value of the blue image data Bx. After the pixel value of Bx is reduced, the image data Bx after the pixel value reduction is color-converted into a B value and an R value. At this time, in order to increase the difference between the pixel values of the B value, the R value, and the G value when the hypoxia state is reached, the pixel value reduction rate is the pixel of the blue image data Bx due to the decrease in oxygen saturation. The smaller the value is set, the larger the value is set (the blue image data Bx includes a component in the wavelength range of HbO> HbO2, so that the pixel value of the blue image data Bx decreases as the oxygen saturation decreases). .

  In the second embodiment, the B value output from the 2DLUT and 1DLUT is assigned to the B channel of the display device 14, and the G value and R value output from the 2DLUT and 1DLUT are assigned to the G channel and R channel of the display device 14. When the oxygen saturation is lowered, an oxygen saturation image in which the color of the blood vessel gradually becomes “yellow” is displayed on the display device 14.

  In the first and second embodiments, in the oxygen saturation mode, the inside of the specimen is illuminated with narrow band light and G light in different absorption wavelength ranges using a rotary filter, but instead, FIG. Narrow band light in a different absorption wavelength range (narrow band light in a first different absorption wavelength range having a center wavelength of 473 nm or narrow band light in a second different absorption wavelength range having a center wavelength of 430 nm) as in the endoscope system 200 shown in FIG. The specimen may be illuminated using the first semiconductor light source 201 that emits G and the second semiconductor light source 202 that emits G light. 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, narrow-band light having a different absorption wavelength from the first semiconductor light source 201 enters the optical fiber 205, and G light from the second semiconductor light source 202 enters the optical fiber 206, and the white light source 203. White light from the light 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. Thereby, narrow-band light and G light in different absorption wavelength regions 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, three-color image data Bx, Gx, and Ry are obtained by imaging the specimen illuminated with the narrow band light in the different absorption wavelength range by the imaging element 215, and illuminated with the G light. By imaging the specimen with the image sensor 215, three-color image data By, Gy, and Ry are obtained. Of these image data, the blue image data Bx and the green image data Gy are used to create an oxygen saturation image.

  In the above embodiment, in the oxygen saturation mode, an oxygen saturation image in which the body cavity is displayed in a pseudo color is created based on two image data of the blue image data Bx and the green image data Gy. In addition to the image data Bx and the green image data Gy, an oxygen saturation image may be created based on three image data of the red image data Rz having a red wavelength component. The oxygen saturation image created based on these three 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. 25 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 an R filter unit 302 in addition to the first narrowband filter unit 39a and the G filter unit 39b similar to the rotary filter 31. Similar to the R filter unit 38c, the R filter unit 302 transmits R light of 580 to 720 nm out of the broadband light BB. From the above, in the oxygen saturation mode, the rotation of the rotary filter 300 sequentially emits narrowband light, G light, and R light in the first different absorption wavelength region. These three types of light are sequentially incident on the ride guides 28 and 29 through the condenser lens 35 and the optical fiber 36.

  The wavelength range of this 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. The amount of reflected light also decreases.

  When the rotary filter 300 is used, imaging control is performed in the procedure shown in FIG. 26 in the oxygen saturation mode. In the oxygen saturation mode, the image sensor 60 sequentially captures the image light of each light in the irradiation periods Tx, Ty, and Tz of the narrowband light, G light, and R light in the first different absorption wavelength region, and charges are obtained. Based on this accumulated charge, a blue signal Bx, a green signal Gy, and a red signal Rz are sequentially output. Such an operation is repeated while the oxygen saturation mode is set. Then, A / D conversion is performed on the blue signal Bx, the green signal Gy, and the red signal Rz to obtain blue image data Bx, green image data Gy, and red image data Rz.

  Here, as described above, the pixel value of the blue image data Bx increases as the oxygen saturation decreases, while the pixel value of the green image data Gy hardly changes due to the change of the 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 three pieces of image data are obtained in the oxygen saturation mode, gain processing is performed on the blue image data Bx, the green image data Gy, and the red image data Rz as shown in FIG. The blue image data Bx is subjected to gain processing for increasing the pixel value as the intensity ratio B / G is increased, and the green image data Gy is subjected to gain processing for decreasing the pixel value as the intensity ratio B / G is increased. Is given.

  On the other hand, the red image data Rz is subjected to gain processing for decreasing the pixel value as the intensity ratio B / G is increased in consideration of the decrease in the pixel value as the oxygen saturation is decreased. The blue image data Bx ′, the green image data Gy ′, and the red image data Rz ′ 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 above embodiment, the pixel value of the image data is adjusted (increased or decreased) in accordance with the change in the oxygen saturation, but instead, the oxygen saturation is large between pixels (spatially). If there is a difference, the pixel value of the image data may be adjusted according to the difference in oxygen saturation between the pixels. For example, as a characteristic value indicating a difference in oxygen saturation between pixels, a first difference value obtained by subtracting B / G of an adjacent pixel from B / G of a predetermined pixel (B / G of the predetermined pixel−B / G of the adjacent pixel) ) And a second difference value obtained by subtracting the B / G of the predetermined pixel from the B / G of the adjacent pixel (B / G of the adjacent pixel−B / G of the predetermined pixel) is calculated.

  Then, gain processing is performed on the blue image data Bx and the green image data Gy of the predetermined pixel using the gain coefficient corresponding to the first difference value, and at the same time, using the gain coefficient corresponding to the second difference value, Gain processing is performed on the blue image data Bx and the green image data Gy. Then, the blue image data Bx ′ of the predetermined pixel after the gain processing and the blue image data Bx ′ of the adjacent pixel are assigned to the B channel of the display device 14, and the green image data Gy ′ of the predetermined pixel and the green of the adjacent pixel after the gain processing are assigned. The image data Gy ′ is assigned to the G channel and R channel of the display device 14. In addition to gain processing, pixel values may be adjusted using 2DLUTs and 1DLUTs as in the above embodiment.

  For example, as shown in FIG. 28A, when the intensity ratio B / G of a predetermined pixel is “1” and the intensity ratio B / G 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 Bx and green image data Gy of the predetermined pixel and the blue image data Bx and green image data Gy of the adjacent pixel. Therefore, even if the gain processing is performed, the difference in pixel value between the predetermined pixel and the adjacent pixel does not change, so that the color difference between the predetermined pixel and the adjacent pixel does not change even on the display device 14.

  On the other hand, as shown in FIG. 28B, when the intensity ratio B / G of the predetermined pixel is “0.5” and the intensity ratio B / G 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 Bx ′ and the green image whose pixel values are reduced according to the gain coefficient by performing gain processing of the gain coefficient “1 or less” on the blue image data Bx and the green image data Gy of the predetermined pixel. Data Gy ′ is obtained. On the other hand, the blue image data Bx ′ and the green image whose pixel values are increased according to the gain coefficient by performing the gain processing of the gain coefficient “1 or more” on the blue image data Bx and the green image data Gy of the adjacent pixels. Data Gy ′ is 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, two image data, that is, the blue image data Bx having a wavelength component in the different absorption wavelength region and the green image data Gy having a wavelength component in the equal absorption wavelength region, are used. Although the degree of saturation is created and displayed, three or more image data may be used. In this case, when multiple image data having wavelength components in different absorption wavelength regions are used, each image data has a wavelength component in the wavelength region in which the magnitude relationship between the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin is the same. It is necessary to do.

  In the above embodiment, the intensity ratio B / G between the blue image data Bx and the green image data is used as the information indicating the change in the oxygen saturation. Instead, the pixel value of the blue image data Bx is used as the information. Alternatively, it may be used as information indicating a change in oxygen saturation.

  In the above embodiment, both the pixel value of the blue image data Bx and the pixel value of the green image data Gx are adjusted according to the change in the oxygen saturation (for example, according to the change in the intensity ratio B / G). However, the present invention is not limited to this, and the pixel value of one of the blue image data Bx and the green image data Gx is adjusted in accordance with the change in oxygen saturation, and the pixel value of the other image data is oxygen saturated. It is not necessary to adjust to the change of the degree. 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;
Among the illumination light, the pixel value of the image data obtained by imaging a specimen illuminated with light having different absorption wavelength ranges in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different is the oxygen saturation of blood hemoglobin A first image information acquisition means for acquiring image information in a different absorption wavelength range that changes due to a change in
A second image acquisition unit obtains image information in an isosbestic wavelength region obtained by imaging a specimen illuminated with light including an equiabsorption wavelength region in which the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same among the illumination lights. Image information acquisition means;
Normalized information acquisition means for acquiring standardized information by normalizing the image information of the different absorption wavelength range with the image information of the isoabsorption wavelength range,
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;
In accordance with the difference value, a display image in a different absorption wavelength range obtained by adjusting a pixel value of the image information in the different absorption wavelength range, or in accordance with the difference value, a pixel value of the image information in the isoabsorption wavelength range. Display image information creating means for creating at least one display image information among the adjusted display image information in the isosbestic wavelength region;
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:
According to the difference value, the image processing for display of the different absorption wavelength region is created by the gain processing for the different absorption wavelength region that adjusts the pixel value of the image information of the different absorption wavelength region,
The display image information in the isoabsorption wavelength region is created by gain processing for the isoabsorption wavelength region that adjusts the pixel value of the image information in the isoabsorption wavelength region according to the difference value. The endoscope system according to Item 1.

[Additional Item 3]
The gain processing for the different absorption wavelength region adjusts the 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. ,
The gain processing for the equal absorption wavelength range adjusts the pixel value 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

[Additional Item 4]
The display control means includes
Of the display image information in the different absorption wavelength region and the display image information in the equiabsorption wavelength region, one is assigned to the first color channel and the other is assigned to the second color channel and the third color channel. Item 5. The endoscope system according to item 2 or 3,

[Additional Item 5]
The display image information creating means includes:
In place of the image information for display in the different absorption wavelength region and the image information in the isoabsorption wavelength region,
A first color display image obtained by adjusting the pixel value of the image information in the different absorption wavelength region and the equal absorption wavelength region according to the difference value, 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 different absorption wavelength region and the equal absorption wavelength region according to the difference value, and color-converting the image information after the pixel value adjustment to the second color. Information or
A third color display image obtained by adjusting the pixel value of the image information in the different absorption wavelength region and the equal absorption wavelength region according to the difference value, and color-converting the image information after the pixel value adjustment to the third color. The endoscope system according to Additional Item 1, wherein display image information of at least one color among the information is created.

[Additional Item 6]
The display image information creating means includes:
The display information of the first color using the first table that stores the relationship between the image information of the different absorption wavelength region and the image information of the equiabsorption wavelength region, and the display image information of the first color. Create
Using the second table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region and the display information for the second color, the display information for the second color The endoscope system according to appendix 5, wherein the endoscope system is created.

[Additional Item 7]
The display control means includes
Item 7. The additional item 6, wherein one of the first color and second color display image information is assigned to the first color channel, and the other is assigned to the second color channel and the third color channel. Endoscope system.

[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:
Using the third table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region and the display information for the third color, the display information for the third color It is characterized by creating.

[Additional Item 9]
The display image information creating means includes:
Instead of the image information for display in the different absorption wavelength region and the equal absorption wavelength region,
Adjusting the pixel value of the image information in the different absorption wavelength region in accordance with the change in the oxygen saturation, and the display information of the first color obtained by color-converting the image information after the pixel value adjustment,
Adjusting the pixel value of the image information in the isosbestic wavelength region in accordance with the change in the oxygen saturation, and the second color display image information obtained by color-converting the image information after the pixel value adjustment, Or
In accordance with the change in the oxygen saturation, the pixel value of either the image information in the different absorption wavelength region or the image information in the isoabsorption wavelength region is adjusted, and the image information after the pixel value adjustment is adjusted to the third color. The endoscope system according to claim 1, wherein display image information of at least one color among the display image information of the third color that has been color-converted to is generated.

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

[Additional Item 11]
The display image information creating means includes:
In place of the sixth table, the third color display image information is created by using a seventh table that stores the relationship between the image information in the isosbestic wavelength region and the third color display image information. The endoscope system according to appendix 10, wherein:

[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 different absorption wavelength range and the equal absorption wavelength range among the illumination light When,
Normal image creating means for creating a normal image having a wavelength component of visible light based on the image information of the different absorption wavelength region, the image information of the isoabsorption wavelength region, and the image information of the specific wavelength region. ,
The display image information creating means includes:
Instead of the display image information in the different absorption wavelength region or the display image information in the equiabsorption wavelength region, creating display image information in which the pixel value of the normal image is adjusted according to the difference value. The endoscope system according to item 1, wherein the endoscope system is characterized.

[Appendix 15]
The endoscope system according to any one of appendices 1 to 14, wherein the different absorption wavelength region is a first different absorption wavelength region in which an absorption coefficient of oxyhemoglobin is larger than an absorption coefficient of reduced hemoglobin.

[Additional Item 16]
The endoscope system according to Additional Item 15, wherein the first different absorption wavelength region is 450 to 500 nm.

[Additional Item 17]
The endoscope system according to any one of appendices 1 to 14, wherein the different absorption wavelength region is a second different absorption wavelength region in which an absorption coefficient of oxyhemoglobin is smaller than an absorption coefficient of reduced hemoglobin.

[Additional Item 18]
The endoscope system according to item 17, wherein the second different absorption wavelength region is 415 to 450 nm.

[Appendix 19]
Pixel value of image data obtained by irradiating the specimen with illumination light and imaging the specimen illuminated with light including different absorption wavelength regions in which the absorption coefficient of oxyhemoglobin and that of deoxyhemoglobin differ in the illumination light However, the image information of the different absorption wavelength region that changes due to the change of oxygen saturation of blood hemoglobin is acquired, and among the illumination light, the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are substantially the same isosbestic wavelength region In a processor device of an endoscope system used in combination with an endoscope device that acquires image information in an isosbestic wavelength range obtained by imaging a specimen illuminated with light including:
Receiving means for receiving the image information in the different absorption wavelength region and the image information in the equal absorption wavelength region from the endoscope device;
Normalized information acquisition means for acquiring standardized information by normalizing the image information of the different absorption wavelength range with the image information of the isoabsorption wavelength range,
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;
In accordance with the difference value, a display image in a different absorption wavelength range obtained by adjusting a pixel value of the image information in the different absorption wavelength range, or in accordance with the difference value, a pixel value of the image information in the isoabsorption wavelength range. Display image information creating means for creating at least one display image information among the adjusted display image information in the isosbestic wavelength region;
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 20]
Irradiating illumination light from the illumination means toward the specimen;
Among the illumination light, the pixel value of the image data obtained by imaging a specimen illuminated with light having different absorption wavelength ranges in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different is the oxygen saturation of blood hemoglobin Acquiring the image information of the different absorption wavelength region that changes due to the change by the first image information acquisition means;
Of the illumination light, the second image is image information in an isosbestic wavelength region obtained by imaging a specimen illuminated with light including an isosbestic wavelength region in which the extinction coefficient of oxygenated hemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same. Obtaining by an information obtaining means;
Normalizing the image information of the different absorption wavelength region with the image information of the isoabsorption wavelength region and acquiring the normalized information by a 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;
In accordance with the difference value, a display image in a different absorption wavelength range obtained by adjusting a pixel value of the image information in the different absorption wavelength range, or in accordance with the difference value, a pixel value of the image information in the isoabsorption wavelength range. Creating at least one display image information of the adjusted image information for display in the isosbestic wavelength region by display image information 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 means.

10,200 Endoscope system 11 Light source device 12 Endoscope device 13 Processor unit 31, 100, 300 Rotary filter 85 Gain table

Claims (12)

Illumination means for illuminating the specimen with illumination light;
Among the illumination light, the pixel value of the image data obtained by imaging a specimen illuminated with light having different absorption wavelength ranges in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different is the oxygen saturation of blood hemoglobin A first image information acquisition means for acquiring image information in a different absorption wavelength range that changes due to a change in
A second image acquisition unit obtains image information in an isosbestic wavelength region obtained by imaging a specimen illuminated with light including an equiabsorption wavelength region in which the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same among the illumination lights. Image information acquisition means;
While adjusting the pixel value of the image information of the different absorption wavelength region and the image information of the equiabsorption wavelength region according to the change in the oxygen saturation, the image information of the different absorption wavelength region after the pixel value adjustment and the like The first color display image information obtained by converting the image information in the absorption wavelength region into the first color, the image information in the different absorption wavelength region after the pixel value adjustment, and the image information in the isoabsorption wavelength region in the second color Display image information creating means for creating display image information of the second color that has been color-converted into ,
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:
The display information of the first color using the first table that stores the relationship between the image information of the different absorption wavelength region and the image information of the equiabsorption wavelength region, and the display image information of the first color. Create
Using the second table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region and the display information for the second color, the display information for the second color An endoscope system characterized by creating an endoscope. The display control means includes
One of the first and second colors display image information, the one assigned to the first color channel, and the other according to claim 1, characterized in that allocated to the second color channel and the third color channel Endoscope system. 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:
Using the third table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region, and the third color display image information, the third color display image information is It is characterized by creating. 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. Having normalized information creating means for creating normalized information obtained by normalizing image information in the different absorption wavelength region with image information in the isoabsorption wavelength region;
The endoscope system according to any one of claims 1 to 3 , wherein the change in the oxygen saturation is a change in a value of the normalized information. The endoscope system according to any one of claims 1 to 6, wherein the different absorption wavelength region is a first different absorption wavelength region in which an absorption coefficient of oxyhemoglobin is larger than an absorption coefficient of reduced hemoglobin. The endoscope system according to claim 7, wherein the first different absorption wavelength region is 450 to 500 nm. The endoscope system according to any one of claims 1 to 6, wherein the different absorption wavelength range is a second different absorption wavelength range in which an absorption coefficient of oxyhemoglobin is smaller than an absorption coefficient of reduced hemoglobin. The endoscope system according to claim 9, wherein the second different absorption wavelength region is 415 to 450 nm. Pixel value of image data obtained by irradiating the specimen with illumination light and imaging the specimen illuminated with light including different absorption wavelength regions in which the absorption coefficient of oxyhemoglobin and that of deoxyhemoglobin differ in the illumination light However, the image information of the different absorption wavelength region that changes due to the change of oxygen saturation of blood hemoglobin is acquired, and among the illumination light, the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are substantially the same isosbestic wavelength region In a processor device of an endoscope system used in combination with an endoscope device that acquires image information in an isosbestic wavelength range obtained by imaging a specimen illuminated with light including:
Receiving means for receiving the image information in the different absorption wavelength region and the image information in the equal absorption wavelength region from the endoscope device;
While adjusting the pixel value of the image information of the different absorption wavelength region and the image information of the equiabsorption wavelength region according to the change in the oxygen saturation, the image information of the different absorption wavelength region after the pixel value adjustment and the like The first color display image information obtained by converting the image information in the absorption wavelength region into the first color, the image information in the different absorption wavelength region after the pixel value adjustment, and the image information in the isoabsorption wavelength region in the second color Display image information creating means for creating display image information of the second color that has been color-converted into ,
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:
The display information of the first color using the first table that stores the relationship between the image information of the different absorption wavelength region and the image information of the equiabsorption wavelength region, and the display image information of the first color. Create
Using the second table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region and the display information for the second color, the display information for the second color processor unit of the endoscope system, characterized in that to create. The pixel value of the image data obtained by the first image information acquisition unit imaging the specimen illuminated with light including different absorption wavelength ranges in which the absorption coefficient of oxyhemoglobin and the absorption coefficient of reduced hemoglobin are different from each other in illumination light, by a change in oxygen saturation of hemoglobin in blood, comprising the steps of: acquire image information of the different absorption wavelength range that varies,
The second image information acquisition means obtains an isosbestic wavelength region obtained by imaging a specimen illuminated with light including the equiabsorption wavelength region in which the extinction coefficient of oxygenated hemoglobin and the extinction coefficient of reduced hemoglobin are substantially the same among the illumination light comprising the steps of: get the image information,
The display image information creating means adjusts the pixel value of the image information in the different absorption wavelength region and the image information in the equal absorption wavelength region according to the change in the oxygen saturation, and the different absorption after the pixel value adjustment. Image information for the wavelength range and image information for the first color obtained by color-converting the image information for the isoabsorption wavelength range to the first color, the image information for the different absorption wavelength range after the pixel value adjustment, and the isosbestic wavelength Creating image information for display of the second color obtained by color-converting the image information of the area into the second color ;
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 information creating means creating the first color display image information and the second color display image information,
The display image information creating means uses a first table that stores the relationship between the image information in the different absorption wavelength region and the image information in the equiabsorption wavelength region, and the display image information for the first color, Creating the first color display image information;
The display image information creation means uses a second table that stores the relationship between the image information in the different absorption wavelength region and the image information in the isoabsorption wavelength region, and the display image information of the second color, A method of operating an endoscope system, wherein the display image information for the second color is created .

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