Endoscope system and method for operating endoscope system

Abstract

The invention provides an endoscope system and an operation method of the endoscope system. An endoscope system having an oxygen saturation mode and an ischemia evaluation mode, the endoscope system comprising: one or more processors configured to: obtain a plurality of first spectroscopic images; calculating a first measured value of the oxygen saturation of the tissue to be observed based on the plurality of first spectroscopic images; in the oxygen saturation mode, the first measured value is used to generate an observation oxygen saturation image, and the observation oxygen saturation image is displayed on the display. And in the case of the ischemia evaluation mode, calculating a relative value between a first reference value of the oxygen saturation of the tissue to be observed calculated on the basis of the plurality of second spectroscopic images and the first measured value, generating an evaluation oxygen saturation image using the relative value, and displaying the evaluation oxygen saturation image on a display.

Description

[0001] This application is a divisional application of the invention application with an international application date of May 15, 2020 and a national application number of 202080037733.6. The invention name of the invention application is endoscope system, working method of endoscope system, image processing device and computer-readable medium. Technical Field

[0002] The present invention relates to an endoscope system, an operating method of the endoscope system, an image processing device and a computer-readable medium used in a resection operation of a tumor such as a cancer or in postoperative treatment thereof. Background Art

[0003] In recent years, laparoscopic surgery using a laparoscope has attracted attention. For example, in the case of a laparoscopic colorectal cancer resection, a laparoscope and a surgical treatment instrument are inserted into the abdominal cavity via a trocar inserted into the patient's abdomen. Then, the abdominal cavity is inflated with pneumoperitoneum gas composed of carbon dioxide, and the image in the abdominal cavity is displayed on a monitor. Then, the operator observes the image in the abdominal cavity displayed on the monitor while removing the portion of the large intestine where the primary lesion has occurred. The large intestine cut open by the removal of the primary lesion is sutured using an automatic suturing device or the like.

[0004] After surgery, usually, in the normal wound healing process after suturing, activation of fibroblasts in the tissue occurs 2 to 3 days after suturing, and healing is completed in about 7 days. However, if the healing process between the tissues is hindered by some factors, the tissues will not fully heal, and incomplete suturing may occur, with partial or complete dissociation of the sutured part.

[0005] In surgical procedures such as intestinal anastomosis after colorectal cancer resection, it is important to connect the intestines as much as possible in the part with blood flow in order to prevent incomplete suture after surgery. The degree of blood flow is basically judged visually by the color tone of the intestine, but in order to visualize the boundary of ischemia that is difficult to visually identify visually, angiography based on the administration of fluorescent drugs such as ICG (indocyanine green) is also widely performed. In the method based on ICG administration, it is necessary to wait for a few minutes after intravenous injection, and a dedicated light source and camera are required to observe the fluorescent image. In addition, since the drug remains in the blood after one administration, it is difficult to administer it again and observe it again. Therefore, it is expected to visualize or image the oxygen saturation of hemoglobin contained in the observation object using an endoscope, that is, oxygen saturation imaging.

[0006] Patent document 1 discloses an endoscope system having a setting change unit, which changes reference information that specifies the correlation between the pixel value obtained by imaging the observation part and the oxygen saturation according to the properties of the observation part in oxygen saturation imaging using an endoscope, thereby enabling the acquisition of highly reliable oxygen saturation information.

[0007] Previous technical literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2014-76375 Summary of the invention

[0010] Technical issues to be solved by the invention

[0011] In the case of oxygen saturation imaging using a conventional endoscope, for example, information on the level of oxygen saturation can be obtained based on oxygen saturation information visualized by pseudo-color. However, in the case of discriminating an ischemic site based on an oxygen saturation image, in the above-mentioned prior art, since the normal site and the ischemic site are displayed in similar tones, it is sometimes difficult to discern the boundary between the normal site and the ischemic site.

[0012] The object of the present invention is to provide an endoscope system, an operating method of the endoscope system, an image processing device and a program for the image processing device, which can display clearer indicators for determining the boundary between a normal part and an ischemic part, which can serve as judgment materials for determining a resection part or an anastomosis part where incomplete suturing is less likely to occur.

[0013] Means for solving technical problems

[0014] The present invention is an endoscope system, which comprises: a processor that calculates a first measured value of oxygen saturation of a tissue to be observed based on a plurality of first spectral images, calculates a first reference value of oxygen saturation of the tissue to be observed based on a plurality of second spectral images, calculates a relative value of the first measured value based on the first reference value, and generates an oxygen saturation image for evaluation by imaging the relative value of the first measured value based on an evaluation color table; and a display that at least displays the oxygen saturation image for evaluation.

[0015] Preferably, the processor generates an observation oxygen saturation image by imaging the first measured value based on an observation color table, and switches between an oxygen saturation mode for displaying at least the observation oxygen saturation image on the display and an ischemia evaluation mode for displaying at least the evaluation oxygen saturation image on the display.

[0016] Preferably, the processor subtracts the first reference value from the first measured value as a relative value of the first measured value.

[0017] Preferably, the processor generates the observation oxygen saturation image based on an observation color table in which values ​​within a range of 0% to 100% of the oxygen saturation level are associated in advance with color information of the observation oxygen saturation image.

[0018] Preferably, the processor generates an evaluation color table in which relative values ​​of the first measured values ​​and color information of the evaluation oxygen saturation image are associated with each other.

[0019] Preferably, in the evaluation color table, a case where the relative value of the first measured value is 0 corresponds to a specific warm color of the evaluation oxygen saturation image.

[0020] Preferably, the processor sets a lower limit value and / or an upper limit value of a relative value of the first actual measurement value corresponding to color information of the evaluation oxygen saturation image and creates the evaluation color table.

[0021] Preferably, the processor receives an instruction to set a lower limit value and / or an upper limit value, and creates the evaluation color table using the lower limit value and / or the upper limit value based on the instruction.

[0022] Preferably, the processor calculates a second reference value of oxygen saturation of the tissue to be observed based on the plurality of third spectroscopic images, calculates a relative value of the second reference value based on the first reference value, and sets the relative value of the second reference value as a lower limit value.

[0023] Preferably, the processor receives an instruction to calculate the first reference value, and calculates the first reference value based on the instruction.

[0024] Preferably, the processor calculates the first reference value or the second reference value by averaging the second measured values ​​of oxygen saturation calculated for each pixel of the plurality of second spectral images or the third measured values ​​of oxygen saturation calculated for each pixel of the plurality of third spectral images.

[0025] Preferably, the processor calculates a signal ratio that is dependent on both oxygen saturation and blood volume based on a plurality of first spectral images, a plurality of second spectral images, or a plurality of third spectral images, stores a correlation between oxygen saturation and the signal ratio, and calculates a first measured value, a second measured value, or a third measured value of oxygen saturation corresponding to the signal ratio based on the correlation.

[0026] Preferably, the first spectral image is an image obtained by photographing a first observation object including a lesion, and the second spectral image or the third spectral image is an image obtained by photographing a second observation object or a third observation object not including a lesion.

[0027] In addition, the present invention is a working method of an endoscope system, which includes: a measured value calculation step, calculating a first measured value of the oxygen saturation of the tissue to be observed based on a plurality of first spectral images; a reference value calculation step, calculating a first reference value of the oxygen saturation of the tissue to be observed based on a plurality of second spectral images; a relative value calculation step, calculating a relative value of the first measured value based on the first reference value; an image generation step, generating an oxygen saturation image for evaluation by imaging the relative value of the first measured value based on an evaluation color table; and a display step, displaying the oxygen saturation image for evaluation.

[0028] In addition, the present invention is an image processing device possessed by an endoscope system, wherein a first measured value of the oxygen saturation of a tissue to be observed is calculated based on a plurality of first spectral images, a first reference value of the oxygen saturation of the tissue to be observed is calculated based on a plurality of second spectral images, a relative value of the first measured value is calculated based on the first reference value, and an oxygen saturation image for evaluation is generated by imaging the relative value of the first measured value based on an evaluation color table.

[0029] In addition, the present invention is a program for an image processing device, which is installed in an image processing device of an endoscope system, wherein the program is used to enable a computer to implement: a function of calculating a first measured value of the oxygen saturation of a tissue to be observed based on a plurality of first spectral images; a function of calculating a first reference value of the oxygen saturation of the tissue to be observed based on a plurality of second spectral images; a function of calculating a relative value of the first measured value based on the first reference value; and a function of generating an oxygen saturation image for evaluation by imaging the relative value of the first measured value based on an evaluation color table.

[0030] Effects of the Invention

[0031] According to the present invention, it is possible to display a clearer index for determining the boundary between a normal site and an ischemic site, which can serve as a material for determining a resection site or anastomosis site where incomplete suturing is less likely to occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is an external view of the endoscope system.

[0033] Figure 2 This is an illustration of the observation mode.

[0034] Figure 3 This is an external view of a laparoscopic endoscope system.

[0035] Figure 4 This is a block diagram of a lumen endoscope system.

[0036] Figure 5 The diagram is an explanatory diagram of pixels of an image sensor.

[0037] Figure 6 This is an explanatory diagram of a color filter.

[0038] Figure 7 This is an explanatory diagram of the light emission pattern in the normal observation mode.

[0039] Figure 8 This is an explanatory diagram of the light emission pattern and the like in the ischemia evaluation mode or the oxygen saturation mode.

[0040] Fig. 9 This is an explanatory diagram of the light emission pattern and the like in the reference value calculation mode.

[0041] Fig.10 This is a block diagram showing the functions of the image processing unit.

[0042] Fig.11 This is a block diagram showing the functions of the measurement value calculation unit.

[0043] Fig.12 It is a graph showing the correlation between oxygen saturation and signal ratio.

[0044] Fig.13 It is a graph showing the absorption coefficient of hemoglobin.

[0045] Fig.14 It is explained in Fig.12 The graph shown is an explanatory diagram of a method of obtaining the actual measurement value of oxygen saturation from the signal ratio.

[0046] Fig.15 This is a block diagram showing the functions of the image generating unit.

[0047] Fig.16 This is a block diagram showing the procedure for creating observation images.

[0048] Fig.17 This is an illustration of a color chart for observation.

[0049] Fig.18 It is explained in Fig.12 The graph shown is an explanatory diagram of a method of obtaining the relative value of oxygen saturation from the signal ratio.

[0050] Fig.19 This is a block diagram showing the procedure for creating evaluation images.

[0051] Fig. 20 This is an explanatory diagram of the evaluation color table.

[0052] Fig.21 This is an explanatory diagram for explaining the difference between the color bars of oxygen saturation levels in the observation image and the evaluation image.

[0053] Fig. 22 It is an image diagram of an observation image.

[0054] Fig.23 This is an image diagram of an evaluation image.

[0055] Fig.24 This is an explanatory diagram for explaining the lower limit value and the upper limit value of the evaluation color table.

[0056] Fig.25 This is an explanatory diagram showing the upper limit value and lower limit value setting menu.

[0057] Fig.26 This is an explanatory diagram for explaining the setting of the lower limit value of the evaluation color table.

[0058] Fig. 27 This is a flowchart showing the flow of the ischemia evaluation mode.

[0059] Fig.28 This is an explanatory diagram when the observation image and the evaluation image are compared and displayed in switching order. DETAILED DESCRIPTION

[0060] like Figure 1 As shown, in the present embodiment, the endoscope system 10 is composed of a lumen endoscope system 20 and an abdominal endoscope system 30, and is used to perform resection of a tumor portion generated in the large intestine. The endoscope system 10 includes at least one of the lumen endoscope system 20 and the abdominal endoscope system 30. First, before the tumor portion is resected, the lumen endoscope system 20 is used to detect the tumor portion in the large intestine, and a mark is pre-applied within a certain range (resection range) including the tumor portion. Next, the abdominal endoscope system 30 is used to resect the marked resection range in the large intestine, and the large intestine cut by the resection of the tumor portion is sutured. Finally, the lumen endoscope system 20 is used to confirm whether the sutured portion is healed tissue-wise.

[0061] The lumen endoscope system 20 includes: a lumen light source device 21 that generates light for illuminating the lumen; a lumen endoscope device 22 that irradiates the lumen with light from the lumen light source device 21 and captures its reflected image; and a lumen processor device (lumen image processing device) 23 that performs image processing on an image signal obtained by the imaging of the lumen endoscope device 22. The lumen processor device 23 is connected to a display device 12 (display unit) that displays an endoscopic image obtained by image processing and an input device 14 composed of a keyboard and the like. The display device 12 is, for example, a display.

[0062] The lumen endoscope device 22 photographs the observation object to obtain an image. The lumen endoscope device 22 is a soft endoscope, and includes: a lumen endoscope operation part 24a; a flexible lumen endoscope insertion part 24b; and a scope tip part 25, which is provided at the tip of the lumen endoscope insertion part 24b, irradiates light toward the lumen, and photographs the reflected image in the lumen. The lumen endoscope device 22 has a bending part 27 provided on the tip side of the lumen endoscope insertion part 24b. The lumen endoscope operation part 24a has an angle knob 29 used in the operation for bending the bending part 27. The bending part 27 is bent based on the operation of the angle knob 29, thereby directing the scope tip part 25 to a desired direction. The scope tip part 25 is provided with a spray port (not shown) for spraying a cleaning liquid toward the observation object.

[0063] In addition to the angle knob 29, the lumen endoscope operation unit 24a is provided with a mode switching unit 28a used in the switching operation of the observation mode and a reference value calculation instruction unit 28b for receiving an instruction to calculate a reference value.

[0064] In addition, the lumen endoscope device 22 is provided with a forceps channel 26 for inserting treatment instruments such as a hemostatic probe. The treatment instrument is inserted into the forceps channel 26 from a forceps inlet 26a provided in the lumen endoscope operation portion 24a, and the treatment instrument inserted into the forceps channel 26 protrudes from a forceps outlet 26b of the scope distal end portion 25.

[0065] like Figure 2 As shown, the lumen endoscope system 20 has at least two modes of a normal observation mode and a special observation mode as observation modes. In the normal observation mode, a natural-tone image (hereinafter referred to as a normal image) obtained by photographing the observation area using white light as illumination light is displayed on the monitor. In the special observation mode, the oxygen saturation of the tissue to be observed is visualized and displayed on the monitor.

[0066] The special observation mode has at least two modes. One is the oxygen saturation mode, and the other is the ischemia evaluation mode. In the oxygen saturation mode, an observation oxygen saturation image obtained by visualizing the oxygen saturation (StO2 (tissue oxygensaturation)) of the tissue to be observed is displayed on the monitor. In the ischemia evaluation mode, the relative value of the oxygen saturation of the tissue to be observed is calculated, and the evaluation oxygen saturation image obtained by visualizing the relative value is displayed on the monitor. Hereinafter, the observation oxygen saturation image is referred to as the observation image, and the evaluation oxygen saturation image is referred to as the evaluation image.

[0067] The normal observation mode and the special observation mode, and the oxygen saturation mode and the ischemia evaluation mode are switched, for example, according to an instruction of the mode switching unit 28a of the lumen endoscope device 22. The mode switching unit 28a is an observer button, and the observation mode may be cyclically switched in the order of the normal observation mode, the oxygen saturation mode of the special observation mode, the ischemia evaluation mode of the special observation mode, and the normal observation mode each time the observer button of the mode switching unit 28a is pressed.

[0068] The abdominal endoscope system 30 includes: an abdominal light source device 31 that generates light for illuminating the abdominal cavity; an abdominal endoscope device 32 that irradiates the abdominal cavity with light from the abdominal light source device 31 and captures a reflected image; and an abdominal processor device (abdominal image processing device) 33 that performs image processing on an image signal obtained by the imaging of the abdominal endoscope device 32. The abdominal processor device 33 is connected to the display device 12 and the input device 14. The abdominal endoscope device 32 captures an observation object to obtain an image. The abdominal endoscope device 32 is a rigid endoscope and includes: a rigid abdominal endoscope insertion portion 34; and a abdominal endoscope tip portion 35 that is provided at the tip of the abdominal endoscope insertion portion 34, irradiates light toward the abdominal cavity, and captures a reflected image in the abdominal cavity.

[0069] In addition, the abdominal endoscope system 30 has at least two modes of a normal observation mode and a special observation mode as the observation mode, similarly to the luminal endoscope system 20. The special observation mode has at least two modes, one of which is an oxygen saturation mode and the other is an ischemia evaluation mode. The switching of the oxygen saturation mode can be switched according to the instruction of the foot switch 36 connected to the abdominal processor device 33.

[0070] Furthermore, in addition to the above-mentioned modes, the lumen endoscope system 20 and the abdominal endoscope system 30 may also be provided with a reference value calculation mode. The reference value may be, for example, a reference value calculated by the reference value calculation mode, or a pre-set reference value. In the reference value calculation mode, the oxygen saturation contained in the tissue to be observed is calculated as the reference value of the oxygen saturation. The reference value calculation mode is switched, for example, according to an instruction of a reference value calculation indicating unit 28b or the like provided in the lumen endoscope device 22. The reference value calculation indicating unit 28b is an observer button, and by pressing the observer button of the reference value calculation indicating unit 28b, the reference value is switched to the reference value calculation mode and the reference value is calculated. Therefore, when observing an area to be used as a reference, a reference value calculation instruction is given. After the reference value is calculated in the reference value calculation mode, the mode before switching to the reference value calculation mode is automatically returned.

[0071] like Figure 3As shown, in the abdominal endoscope system 30, in addition to the abdominal light source device 31, the abdominal endoscope device 32, and the abdominal processor device 33, a pneumoperitoneum device 37, a treatment instrument 38, and trocars 39a and 39b are used to perform abdominal observation and tumor removal surgery. In the abdominal endoscope system 30, first, CO2 (carbon dioxide) gas is supplied from the pneumoperitoneum device 37 into the abdominal cavity to make the abdominal cavity pneumoperitoneum. In this way, the visual field / surgical field in the abdominal cavity can be ensured.

[0072] Next, the treatment instrument 38 is inserted into the abdominal cavity via the trocar 39a, and the abdominal endoscope device 32 is inserted into the abdominal cavity via the trocar 39b. These trocars 39a and 39b have a metal hollow tube and a grip portion for the operator, and the operator inserts the hollow tube into the abdominal cavity by piercing the sharp tip of the hollow tube into the abdomen while the operator grips the grip portion. The treatment instrument 38 and the abdominal endoscope device 32 are respectively inserted into the trocars 39a and 39b with the hollow tubes inserted into the abdominal cavity.

[0073] Hereinafter, the lumen endoscope system 20 will be described as an example, but the same is true for the abdominal endoscope system 30. Figure 4 As shown, the lumen light source device 21 includes a light source 41 and a light source control unit 42. The light source 41 includes, for example, a plurality of semiconductor light sources, which are turned on or off respectively. By turning on the light source 41, illumination light for illuminating the observation object can be emitted. In the present embodiment, the light source 41 includes four-color LEDs, namely, BS-LED (Blue Short-wavelength Light Emitting Diode) 41a, BL-LED (Blue Long-wavelength Light Emitting Diode) 41b, G-LED (Green Light Emitting Diode) 41c, and R-LED (Red Light Emitting Diode) 41d.

[0074] BS-LED 41a emits first blue light BS in a wavelength band of 450±10nm. BL-LED 41b emits second blue light BL in a wavelength band of 470±10nm, which is longer than the first blue light BS. G-LED 41c emits green light G in a wavelength band of 500nm to 600nm. R-LED 41d emits red light R in a wavelength band of 620±20nm. In addition, the center wavelength and peak wavelength of each color of light may be the same or different.

[0075] The light source control unit 42 independently controls the lighting or extinguishing of each LED 41a to 41d, the light emission amount when lighting, etc. by independently inputting control signals to each LED 41a to 41d. The lighting and extinguishing control in the light source control unit 42 is different for each observation mode. In the case of the normal observation mode, the light source control unit 42 simultaneously lights up the BS-LED 41a, the G-LED 41c, and the R-LED 41d, so that the first blue light BS, the green light G, and the red light R are emitted simultaneously.

[0076] In the special observation mode, the light source control unit 42 alternately performs a first light emission in which the first blue light BS, green light G and red light R are emitted simultaneously by lighting up the BS-LED41a, G-LED41c and R-LED41d at the same time, and a second light emission in which the second blue light BL, green light G and red light R are emitted simultaneously by lighting up the BL-LED41b, G-LED41c and R-LED41d at the same time.

[0077] Each light emitted from each LED 41a to 41d enters the light guide 43. The light guide 43 is built into the lumen endoscope device 22 and the universal cord. The universal cord is a cord that connects the lumen endoscope device 22, the lumen light source device 21, and the lumen processor device 23. The light guide 43 transmits light to the scope tip 25 of the lumen endoscope device 22.

[0078] The lumen endoscope device 22 is constituted by an electronic endoscope, and includes: an illumination optical system 44a that irradiates the observation object with light guided by the light guide 43; an imaging optical system 44b that captures the observation object; and an imaging control unit 55. In addition, a connector unit (not shown) that detachably connects the lumen endoscope device 22 to the lumen light source device 21 and the lumen processor device 23 is provided.

[0079] The illumination optical system 44a and the imaging optical system 44b are provided at the scope tip portion 25 of the lumen endoscope device 22. The illumination optical system 44a includes an illumination lens 45. The illumination light from the light guide 43 is irradiated to the observation object through the illumination lens 45. The imaging optical system 44b includes an objective lens 46 and an imaging sensor 48. The objective lens 46 allows the return light from the observation object illuminated by the illumination light to enter the imaging sensor 48. As a result, an image of the observation object is formed on the imaging sensor 48.

[0080] The imaging sensor 48 is a color imaging sensor that captures an image of an observation object illuminated by illumination light and outputs an image signal. Figure 5As shown, on the imaging surface 49 of the imaging sensor 48, a plurality of pixels 51 are arranged two-dimensionally in a matrix in the row direction (X direction) and the column direction (Y direction). In one pixel 51, any one of a B (blue) filter 52, a G (green) filter 53, and an R (red) filter 54 is provided. The arrangement of each filter 52 to 54 is a Bayer arrangement, and the G filter 53 is arranged in a checkerboard pattern at every other pixel, and the B filter 52 and the R filter 54 are arranged in a square grid pattern on the remaining pixels.

[0081] like Figure 6 As shown, the B filter 52 transmits light with a wavelength band of 380nm to 560nm. The G filter 53 transmits light with a wavelength band of 450nm to 630nm. The R filter 54 transmits light with a wavelength band of 580nm to 760nm. Therefore, the B pixel is sensitive to the wavelength band of 450±10nm of the first blue light BS and the wavelength band of 470±10nm of the second blue light BL. The G pixel is sensitive to the wavelength band of 500nm to 600nm of the green light G. The R pixel is sensitive to the wavelength band of 640±20nm of the red light R.

[0082] As the imaging sensor 48 (refer to Figure 4 ), you can use CCD (Charge Coupled Device) camera sensor or CMOS (Complementary Metal-Oxide Semiconductor) camera sensor.

[0083] In addition, a complementary color imaging sensor having complementary color filters of C (cyan), M (magenta), Y (yellow), and G (green) may be used instead of the primary color imaging sensor 48. When the complementary color imaging sensor is used, image signals of four colors of CMYG are output, and therefore, the image signals of four colors of CMYG are converted into image signals of three colors of RGB by complementary color-primary color conversion, thereby obtaining image signals of each color of RGB similar to those of the imaging sensor 48.

[0084] The imaging sensor 48 receives light from the objective lens 46 on a light receiving surface (imaging surface), performs photoelectric conversion on the received light, and outputs an imaging signal (analog signal). The imaging control of the imaging sensor 48 is performed by an imaging control unit 55 .

[0085] The camera control unit 55 is electrically connected to the light source control unit 42, and performs camera control according to the light emission control of the light source control unit 42. Figure 7As shown in FIG. 1 , in the case of the normal observation mode, the imaging control unit 55 controls the imaging sensor 48 to capture an image of the illuminated observation object for each frame using the first blue light BS, green light G, and red light R emitted based on the control of the light source control unit 42. As a result, a Bc image signal is output from the B pixel of the imaging sensor 48, a Gc image signal is output from the G pixel, and an Rc image signal is output from the R pixel. In addition, the imaging control unit 55 synchronizes the exposure time of the imaging sensor 48 with the illumination time of the illumination light.

[0086] In the case of the oxygen saturation mode or the ischemia evaluation mode, the imaging control unit 55 makes the imaging control different between the first light emission and the second light emission. Specifically, in the case of the first light emission, Figure 8 As shown, the imaging control unit 55 performs a first imaging for one frame of the first observation object being illuminated by the first blue light BS, green light G, and red light R simultaneously emitted during the first light emission. Thus, during the first imaging, a B1m image signal is output from the B pixel of the imaging sensor 48, a G1m image signal is output from the G pixel, and an R1m image signal is output from the R pixel. In addition, a second imaging for one frame of the first observation object being illuminated by the second blue light BL, green light G, and red light R simultaneously emitted during the second light emission is performed. Thus, during the second imaging, a B2m image signal is output from the B pixel of the imaging sensor 48, a G2m image signal is output from the G pixel, and an R2m image signal is output from the R pixel.

[0087] In addition, the B1m image signal, the G1m image signal, the R1m image signal, and the B2m image signal, the G2m image signal, and the R2m image signal correspond to the first spectroscopic image of the present invention, respectively. Therefore, the plurality of first spectroscopic images include the B1m image signal, the G1m image signal, the R1m image signal, and the B2m image signal, the G2m image signal, and the R2m image signal.

[0088] In the case of the reference value calculation mode, the light source control unit 42 and the imaging control unit 55 function in the same manner as in the oxygen saturation mode or the ischemia evaluation mode. Therefore, in the reference value calculation mode, the light source control unit 42 alternately performs the first light emission of the first blue light BS, the green light G, and the red light R by lighting the BS-LED 41a, the G-LED 41c, and the R-LED 41d at the same time, and the second light emission of the second blue light BL, the green light G, and the red light R by lighting the BL-LED 41b, the G-LED 41c, and the R-LED 41d at the same time.

[0089] In the reference value calculation mode, the imaging control unit 55 makes the imaging control different between the first light emission and the second light emission. Specifically, in the case of the first light emission, Fig. 9As shown, the camera control unit 55 performs a first camera shot of one frame of the second observation object or the third observation object being illuminated by the first blue light BS, green light G, and red light R simultaneously emitted during the first light emission. The first reference value is calculated based on the second observation object, and the second reference value is calculated based on the third observation object. As a result, during the first camera shot, a B1n image signal is output from the B pixel of the camera sensor 48, a G1n image signal is output from the G pixel, and an R1n image signal is output from the R pixel. In addition, a second camera shot of one frame of the second observation object or the third observation object being illuminated by the second blue light BL, green light G, and red light R simultaneously emitted during the second light emission is performed. As a result, during the second camera shot, a B2n image signal is output from the B pixel of the camera sensor 48, a G2n image signal is output from the G pixel, and an R2n image signal is output from the R pixel.

[0090] In addition, the B1n image signal, the G1n image signal, the R1n image signal, and the B2n image signal, the G2n image signal, and the R2n image signal are respectively equivalent to the second spectral image or the third spectral image of the present invention. Therefore, the plurality of second spectral images or the third spectral images include the B1n image signal, the G1n image signal, the R1n image signal, and the B2n image signal, the G2n image signal, and the R2n image signal.

[0091] In addition, in the present embodiment, the first observation object is used as the subject in both the oxygen saturation mode and the ischemia evaluation mode, but the subjects do not need to be the same in the oxygen saturation mode and the ischemia evaluation mode, and different observation objects may be used as the subjects. In addition, the first observation object in the oxygen saturation mode or the ischemia evaluation mode and the second observation object in the reference value calculation mode are different in the subject, but the subjects do not need to be different in these modes, and the same observation object may be used as the subject in several observation modes.

[0092] The imaging signal (analog signal) output from the imaging sensor 48 is input to an A / D converter (not shown) through a viewer cable. The A / D converter converts the imaging signal (analog signal) into an image signal (digital signal) corresponding to its voltage level. The converted image signal is input to the lumen processor device 23 via a connector.

[0093] In the lumen processor device 23, programs related to the process of calculating the first measured value of oxygen saturation, the process of calculating the first reference value of oxygen saturation, the process of calculating the relative value of the first measured value, and the process of generating an oxygen saturation image for evaluation are loaded into a memory (not shown). By operating the program using the control unit 56 composed of a processor, the functions of the central control unit 56a, the image acquisition unit 57, the image processing unit 58, and the display control unit 59 are realized.

[0094] like Figure 4 As shown, the lumen processor device 23 includes a control unit 56, an image acquisition unit 57, an image processing unit 58, and a display control unit 59. The image acquisition unit 57 includes a DSP (Digital Signal Processor) 61, a noise reduction unit 62, and a conversion unit 63. The control unit 56 includes a central control unit 56a. The display control unit 59 includes a display image selection unit 59a.

[0095] DSP61 performs various signal processing such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, de-mosaic processing and YC conversion processing on the received image signal. In the defect correction processing, the signal of the defective pixel of the camera sensor 48 is corrected. In the offset processing, the dark current component is removed from the image signal that has undergone the defect correction processing, and an accurate zero level is set. In the gain correction processing, the signal level of each image signal is adjusted by multiplying the image signal of each color that has undergone the offset processing by a specific gain. In the linear matrix processing, the color reproducibility of the image signal of each color that has undergone the gain correction processing is improved.

[0096] In the gamma conversion process, the brightness or chroma of each image signal subjected to the linear matrix processing is adjusted. In the demosaicing process (also called isotropic processing or synchronization processing), the image signal subjected to the gamma conversion process is interpolated by generating a signal of the color missing in each pixel. Through this demosaicing process, all pixels have signals of each color of RGB. The DSP 61 performs a YC conversion process for converting each demosaiced image signal into a brightness signal Y and a color difference signal Cb and a color difference signal Cr, and outputs them to the noise reduction unit 62.

[0097] The noise reduction unit 62 performs noise reduction processing on the image signal from the DSP 61. The noise reduction processing is, for example, a moving average method or a median filter method. The image signal with noise reduced by the noise reduction processing is input to the conversion unit 63. The conversion unit 63 converts the brightness channel Y, and the color difference channels Cb and Cr after the noise reduction processing into RGB color images again.

[0098] The central control unit 56a executes the normal observation mode, the oxygen saturation mode, the ischemia evaluation mode, and the reference value calculation mode respectively by controlling the light source control unit 42 and the imaging control unit 55. In addition, the central control unit 56a is electrically connected to the image processing unit 58, and notifies the image processing unit 58 which of the normal observation mode, the oxygen saturation mode, the ischemia evaluation mode, and the reference value calculation mode is executed.

[0099] The central control unit 56a performs photography of ordinary images in the ordinary observation mode. In the photography of ordinary images, the light source control unit 42 is controlled to emit illumination light for ordinary images. Thus, in the photography of ordinary images, the observation object illuminated by the first blue light BS, the green light G, and the red light R is photographed to obtain the Bc image signal, the Gc image signal, and the Rc image signal.

[0100] In addition, the central control unit 56a controls the light source control unit 42 in the oxygen saturation mode or the ischemia evaluation mode to alternately perform the first light emission and the second light emission of the illumination light, and controls the imaging control unit 55 in coordination with the first light emission and the second light emission to alternately perform the first imaging and the second imaging. Thus, when the first light emission and the first imaging are performed, the first observation object illuminated by the first blue light BS, the green light G, and the red light R is imaged to obtain the B1m image signal, the G1m image signal, and the R1m image signal. In addition, when the second light emission and the second imaging are performed, the first observation object illuminated by the second blue light BL, the green light G, and the red light R is imaged to obtain the B2m image signal, the G2m image signal, and the R2m image signal. The B1m image signal, the G1m image signal, and the R1m image signal and the B2m image signal, the G2m image signal, and the R2m image signal are two sets of continuous image signals.

[0101] In addition, in the reference value calculation mode, the central control unit 56a controls the light source control unit 42 to alternately perform the first light emission and the second light emission, as in the oxygen saturation mode or the ischemia evaluation mode, and controls the imaging control unit 55 in coordination with the first light emission and the second light emission to alternately perform the first imaging and the second imaging. Thus, when the first light emission and the first imaging are performed, the second observation object or the third observation object illuminated by the first blue light BS, the green light G, and the red light R is imaged to obtain the B1n image signal, the G1n image signal, and the R1n image signal. In addition, when the second light emission and the second imaging are performed, the second observation object or the third observation object illuminated by the second blue light BL, the green light G, and the red light R is imaged to obtain the B2n image signal, the G2n image signal, and the R2n image signal. The B1n image signal, the G1n image signal, and the R1n image signal are two sets of continuous image signals, as are the B2n image signal, the G2n image signal, and the R2n image signal.

[0102] like Fig.10 As shown, the image processing unit 58 includes a normal image processing unit 71 and a special image processing unit 72, and performs predetermined image processing on image signals from the lumen endoscope device 22. The normal image processing unit 71 generates a normal image by performing predetermined image processing on image signals obtained in the normal observation mode.

[0103] The special image processing unit 72 processes images obtained in the oxygen saturation mode, the ischemia evaluation mode, or the reference value calculation mode. The special image processing unit 72 includes a measurement value calculation unit 73, a reference value calculation instruction receiving unit 74, a relative value calculation unit 75, and an image generation unit 76. The special image processing unit 72 performs a series of processing based on the image signal input from the lumen endoscope device 22 to calculate the reference value or calculate the relative value. Then, an observation image or an evaluation image is generated using the relative value.

[0104] The measured value calculation unit 73 has a function of calculating the measured value of the oxygen saturation of the tissue to be observed based on a plurality of spectral images. When the spectral image is a first spectral image, the calculated oxygen saturation is used as the first measured value. When the spectral image is a second spectral image, the calculated oxygen saturation is used as the second measured value. Therefore, the oxygen saturation calculated based on the plurality of first spectral images is the first measured value of the oxygen saturation. In addition, the oxygen saturation calculated based on the plurality of second spectral images is the second measured value of the oxygen saturation. The same is true when the spectral image is a third spectral image, and the oxygen saturation calculated based on the third spectral image is the third measured value of the oxygen saturation.

[0105] In addition, the measurement value calculation unit 73 has a function of calculating a reference value of the oxygen saturation of the tissue to be observed based on the plurality of spectral images. The reference value is calculated using the measured values ​​calculated based on the plurality of spectral images. When the spectral image is the second spectral image, the calculated oxygen saturation is used as the second measured value, and the reference value calculated using the second measured value is used as the first reference value.

[0106] The reference value calculation instruction receiving unit 74 receives an instruction to calculate the reference value. The relative value calculating unit 75 calculates the relative value of the first measured value based on the first measured value of oxygen saturation calculated by the measured value calculating unit 73 and the first reference value of oxygen saturation. The image generating unit 76 generates an evaluation image by imaging the relative value of the first measured value based on the evaluation color table. In addition, the image generating unit 76 generates an observation image by imaging the measured value based on the observation color table.

[0107] like Fig.11As shown, the measured value calculation unit 73 includes a signal ratio calculation unit 81, a correlation storage unit 82, a measured value calculation unit 83, and a reference value calculation unit 84. The signal ratio calculation unit 81, the correlation storage unit 82, and the measured value calculation unit 83 calculate the first measured value of oxygen saturation based on a plurality of first spectral images, calculate the second measured value of oxygen saturation based on a plurality of second spectral images, and calculate the third measured value of oxygen saturation based on a plurality of third spectral images. The reference value calculation unit 84 calculates the reference value based on the second measured value or the third measured value. The first reference value is calculated using the second measured value, and the second reference value is calculated using the third measured value. Therefore, the reference value calculation unit 84 calculates the first reference value of oxygen saturation of the tissue to be observed based on the plurality of second spectral images.

[0108] The signal ratio calculation unit 81 obtains a signal ratio that is dependent on both the blood volume and the oxygen saturation level, using a plurality of first spectral images obtained in the oxygen saturation mode or the ischemia evaluation mode and obtained by imaging the first observation object including the lesion.

[0109] The signal ratio calculation unit 81 calculates the signal ratio between pixels located at the same position in the first spectroscopic image acquired in the oxygen saturation mode or the ischemia assessment mode, that is, the B1m image signal, G1m image signal, and R1m image signal of the first camera and the B2m image signal, G2m image signal, and R2m image signal of the second camera. The signal ratio is calculated for all pixels of the image signal. Therefore, the oxygen saturation is calculated for each pixel. In this embodiment, the signal ratio calculation unit 81 obtains the signal ratio B2m / (B1m+G1m) of the blue signal B1m of the first camera and the green signal G1m of the first camera to the blue signal B2m of the second camera, and the signal ratio R1m / G1m of the green signal G1m of the first camera to the red signal R1m.

[0110] Alternatively, the signal ratio may be calculated only for the pixels of the blood vessel portion in the image signal. In this case, the blood vessel portion is identified based on the difference between the image signal of the blood vessel portion and the image signal of other portions.

[0111] The correlation storage unit 82 stores the correlation between the signal ratio B2m / (B1m+G1m) and the signal ratio R1m / G1m and the oxygen saturation. The correlation between the signal ratio and the oxygen saturation is stored in a two-dimensional table 86. Fig.12 The contour lines of oxygen saturation are defined in the two-dimensional space shown. The position and shape of the contour lines are obtained by physical simulation of light scattering and are defined to change according to the blood volume. For example, when the blood volume changes, the intervals between the contour lines become wider or narrower. In addition, the signal ratio B2m / (B1m+G1m) and the signal ratio R1m / G1m are stored in log scale.

[0112] In addition, the above correlation is similar to Fig.13 The absorption characteristics or light scattering characteristics of the oxidized hemoglobin or reduced hemoglobin shown are closely related. The curve 91 shows the absorption coefficient 91a of the oxidized hemoglobin and the absorption coefficient 91b of the reduced hemoglobin. Fig.13 As shown, for example, at a wavelength such as 470 nm where the difference in the absorption coefficient is large, it is easy to obtain information on the oxygen saturation. However, the blue signal including the signal corresponding to the light of 470 nm is highly dependent not only on the oxygen saturation but also on the amount of blood. Therefore, by using the signal ratio B2m / (B1m+G1m) and the signal ratio R1m / G1m obtained from the red signal R1m corresponding to the light that mainly changes depending on the amount of blood, the blue signal B2m, and the green signal G1m that serves as a reference signal for the red signal R1m in addition to the blue signal B1m, it is possible to accurately obtain the oxygen saturation without depending on the amount of blood.

[0113] In addition, the following three points can be said from the perspective of the wavelength dependence of the absorption coefficient of hemoglobin in observed tissues.

[0114] (1) At a wavelength of around 470 nm (for example, a blue wavelength region with a central wavelength of 470 nm±10 nm), the absorption coefficient changes greatly depending on changes in oxygen saturation.

[0115] (2) If the average is taken within the green wavelength range of 540 to 580 nm, the oxygen saturation level is less likely to be affected.

[0116] (3) In the red wavelength range of 590 to 700 nm, the absorption coefficient appears to change significantly depending on the oxygen saturation at first glance, but since the value of the absorption coefficient itself is very small, it is not easily affected by the oxygen saturation.

[0117] The actual measurement value calculation unit 83 ( Fig.11 ) The oxygen saturation in each pixel is obtained by using the correlation stored in the correlation storage unit 82 and the signal ratio B2m / (B1m+G1m) and the signal ratio R1m / G1m obtained by the signal ratio calculation unit 81. Regarding the oxygen saturation, first, Fig.14 As shown, in the two-dimensional space, the signal ratio B2m obtained by the signal ratio calculation unit 81 is specified. / (B1m +G1m ) and signal ratio R1m / G1m The corresponding point P.

[0118] Then, if Fig.14As shown in FIG. 1 , when the corresponding point P is located between the lower limit line 92a of "oxygen saturation = 0% limit" and the upper limit line 92b of "oxygen saturation = 100% limit", the percentage value represented by the contour line where the corresponding point P is located becomes the oxygen saturation. Fig.14 In the case of , since the contour line where the corresponding point P is located indicates 60%, this 60% becomes the oxygen saturation. In addition, when the corresponding point P deviates from between the lower limit line 92a and the upper limit line 92b, when the corresponding point P is located above the lower limit line 92a, the oxygen saturation is set to 0%, and when the corresponding point P is located below the upper limit line 92b, the oxygen saturation is set to 100%. In addition, when the corresponding point P deviates from between the lower limit line 92a and the upper limit line 92b, it is also possible to reduce the reliability of the oxygen saturation in the pixel and not display it.

[0119] In the oxygen saturation mode, the image generating unit 76 generates an observation image by imaging the first actual measurement value of the oxygen saturation calculated as described above based on the observation color table.

[0120] like Fig.15 As shown in FIG. 1 , the image generation unit 76 includes a color table storage unit 93, a color table creation unit 94, and a setting acceptance unit 95. The image generation unit 76 generates an observation image by imaging the first measured value obtained by the measured value calculation unit 83 based on the observation color table. The observation color table is a color table for the observation image in which the oxygen saturation and the color information of the observation image are associated. The observation color table is stored in the color table storage unit 93.

[0121] like Fig.16 As shown, when the observation image is a video signal output to the monitor, it is composed of an image signal composed of a brightness signal Y and a color difference signal Cb and a color difference signal Cr. The observation image is generated by assigning the pixel value of the G1m image signal of the first camera to the brightness signal Y and assigning the calculated first measured value of the oxygen saturation to the color difference signals Cb and Cr. The pixel value of the G1m image signal of the first camera corresponds to the reflected light of the wavelength band in which the absorption of hemoglobin is slightly stronger, so the unevenness of the mucosa, blood vessels, etc. can be visually recognized from the image based on the pixel value. Therefore, by assigning the pixel value g1 of the G1m image signal to the brightness signal Y, the overall brightness of the observation image can be defined.

[0122] The color difference signals Cb and Cr are, for example, Fig.17The observation color table 96 shown is assigned a signal value corresponding to the first measured value of oxygen saturation. The observation color table 96 is defined as a region with high oxygen saturation, where the signal value of the color difference signal Cr98a is positive, and the signal value of the color difference signal Cb98b is negative, and is defined as a region with low oxygen saturation, where the signal value of the color difference signal Cr98a is negative, and the signal value of the color difference signal Cb98b is positive. Furthermore, it is defined that when the oxygen saturation is 50%, the magnitude relationship between the signal value of the color difference signal Cr98a and the signal value of the color difference signal Cb98b is reversed. Therefore, as the oxygen saturation changes from low to high, the color tone changes from blue → light blue → green → yellow → orange → red.

[0123] Next, the calculation of the reference value is described. The calculation of the reference value is started, for example, by the reference value calculation instruction receiving unit 74 receiving the operator's instruction to switch the mode to the reference value calculation mode. The operator's instruction specifically refers to, for example, pressing the observer button that serves as the reference value calculation instruction unit 28b. During the examination, the operator includes the area in which the value of the oxygen saturation of the tissue to be observed is desired to be used as the reference value in the observation object, and presses the observer button that serves as the reference value calculation instruction unit 28b. As a result, the observation mode is switched to the reference value calculation mode, and a plurality of second spectral images that photograph the observation object are acquired. The second measured value is calculated based on the plurality of second spectral images, and the first reference value is calculated based on the second measured value.

[0124] The second measured value is obtained by processing the second measured value of oxygen saturation in each pixel in the same manner as the calculation of the first measured value, using the plurality of second spectral images obtained by the operation of the reference value calculation indication unit 28b. More specifically, the signal ratio calculation unit 81 uses the plurality of second spectral images obtained based on the operation of the reference value calculation indication unit 28b to obtain a signal ratio that is dependent on both the blood volume and the oxygen saturation. The signal ratio based on the second spectral image becomes the second measured value of oxygen saturation of the second observation object. Specifically, with the plurality of second spectral images as the object, the signal ratio B2n / (B1n+G1n) and the signal ratio R1n / G1n calculated by the signal ratio calculation unit 81, and the correlation stored in the correlation storage unit 82 and the two-dimensional space (refer to Fig.14 ), and the second measured value is obtained. The oxygen saturation is calculated for each pixel of the second spectral image. Therefore, in the plurality of second spectral images, the oxygen saturation is calculated for each pixel at the same location by calculating each pixel.

[0125] The reference value calculation unit 84 averages the second measured values ​​of the oxygen saturation at the locations of the pixels calculated by the measured value calculation unit 83, for example, within the range of one spectral image. The average calculated value is used as the first reference value of the oxygen saturation. When the first reference value is calculated, the calculated first reference value is sent to the relative value calculation unit 75, and the relative value calculation unit 75 calculates the relative value using the calculated first reference value.

[0126] In addition, the reference value calculation unit 84 may also use a plurality of groups of a plurality of second spectral images to calculate the first reference value. In this case, for example, a group of spectral images may be set as one frame, and the average value of the oxygen saturation of each frame may be calculated in the plurality of frames, and then the calculated average values ​​may be added and divided by the number of frames to calculate the first reference value of the oxygen saturation of the plurality of frames as a whole. In addition, the average value may be calculated for pixels at the same position and averaged within the range of the spectral image. In addition, regarding the first measured value of the oxygen saturation based on the first spectral image, the average value may be calculated for pixels at the same position with a plurality of frames as the object, as the first measured value of the hemoglobin concentration and the oxygen saturation.

[0127] In addition, the reference value may also use a value obtained by a method other than each calculation. Specifically, for example, at the beginning of the operation, a typical value of the oxygen saturation represented by the normal mucosa of the digestive tract from the mouth to the anus may be set as a default first reference value. In addition, the first reference value up to the last time may be stored in advance, and the first reference value may be used before the operator instructs the calculation of the first reference value, and the first reference value may be updated by the operator's instruction to calculate the first reference value. In addition, the switching to the reference value calculation mode or the calculation of the first reference value may be performed by a method other than starting according to the operator's instruction. Specifically, for example, when the ischemia evaluation mode is set by the mode switching unit 28a, it may be automatically temporarily switched to the reference value calculation mode, the first reference value is calculated, and after the first reference value is set, it may be automatically switched to the ischemia evaluation mode.

[0128] Next, the calculation of the relative value of the first measured value based on the first reference value is described. The relative value calculation unit 75 calculates the relative value of the first measured value based on the first spectral image, based on the first measured values ​​of the oxygen saturation based on the first spectral image and the first reference value of the oxygen saturation. For example, the relative value of the first measured value can be set to a value obtained by subtracting the first reference value from the first measured value. Therefore, the relative value calculation unit 75 calculates the relative value of the first measured value based on the first reference value. Specifically, if the first measured value of the oxygen saturation based on the first spectral image is set to StO2 (MV), and the first reference value of the oxygen saturation is set to StO2 (STD), then the relative value ΔStO2 of the first measured value is a value obtained by subtracting the first reference value StO2 (STD) of the oxygen saturation from the first measured value StO2 (MV). Therefore, as Fig.18 As shown, the relative value ΔStO2 of the first measured value is the difference PD when the first reference value PS of oxygen saturation and the first measured value PM of oxygen saturation are set. If expressed in an equation, it is as shown in the following equation (1). In addition, since the relative value ΔStO2 of the first measured value is a relative value calculated based on the first reference value, it has the same unit (%) as the oxygen saturation.

[0129] StO2(MV)-StO2(STD)=ΔStO2 (1)

[0130] Next, the generation of an evaluation image based on the imaging of the relative value ΔStO2 of the first measured value will be described. The image generation unit 76 images the relative value ΔStO2 of the first measured value obtained by the relative value calculation unit 75 based on the evaluation color table, thereby generating an evaluation image. The evaluation color table 97 is a color table for the evaluation image that stores pseudo-color information that changes according to the relative value ΔStO2 of the first measured value. The color table creation unit 94 creates the evaluation color table 97 that corresponds the relative value ΔStO2 of the first measured value to the color information of the evaluation image. In addition, the evaluation color table 97 is a general term, including the evaluation color table 97a and the evaluation color table 97b.

[0131] like Fig.19As shown, when the evaluation image is a video signal output to the monitor, it is composed of an image signal composed of a brightness signal Y and a color difference signal Cb and a color difference signal Cr. The evaluation image is generated by assigning the pixel value of the G1m image signal of the first camera to the brightness signal Y and assigning the calculated relative value ΔStO2 of the first measured value to the color difference signals Cb and Cr. The pixel value of the G1m image signal of the first camera corresponds to the reflected light of the wavelength band where the absorption of hemoglobin is slightly stronger, so the unevenness of the mucosa, blood vessels, etc. can be visually recognized from the image based on the pixel value. Therefore, by assigning the pixel value g1 of the G1m image signal to the brightness signal Y, the overall brightness of the evaluation image can be defined.

[0132] The color difference signals Cb and Cr are, for example, Fig. 20 The evaluation color table 97a shown is assigned a signal value corresponding to the relative value ΔStO2 of the first measured value. The evaluation color table 97a is defined as a region where the relative value ΔStO2 of the first measured value is large, where the signal value of the color difference signal Cr98a is positive, and the signal value of the color difference signal Cb98b is negative, and is defined as a region where the relative value ΔStO2 of the first measured value is small, where the signal value of the color difference signal Cr98a is negative, and the signal value of the color difference signal Cb98b is positive. Therefore, as the relative value ΔStO2 of the first measured value increases from low to high, the color tone changes from blue to light blue to green to yellow to orange to red. In addition, for example, when the relative value ΔStO2 of the first measured value is between -10% and 0%, the magnitude relationship between the signal value of the color difference signal Cr98a and the signal value of the color difference signal Cb98b is reversed.

[0133] In addition, the evaluation color table 97a is prepared so that, for example, the range from the lower limit value of the relative value ΔStO2 of the first actual value displayed in blue to the upper limit value of the relative value ΔStO2 of the first actual value displayed in red corresponds to the range of the relative value ΔStO2 of the first actual value. The relative value ΔStO2 of the first actual value is a relative value based on the first reference value. Therefore, the evaluation color table 97 is a color table in which the color changes within a narrow range corresponding to the relative value ΔStO2 of the first actual value. According to the evaluation color table 97, in the ischemia evaluation mode, for example, on the basis of the oxygen saturation of the region not including any lesion etc. as the first reference value, by photographing the region including the lesion etc. whose subtle change of oxygen saturation is desired to be known, it is possible to prepare an evaluation image in which a slight change of oxygen saturation from the first reference value in the region including the lesion etc. is represented as a color difference and displayed on the monitor.

[0134] In addition, the evaluation color table 97a is prepared by setting the lower limit value of the relative value ΔStO2 of the first measured value displayed in blue to -30%, and the upper limit value of the relative value ΔStO2 of the first measured value displayed in red to +10%. Furthermore, the evaluation color table 97a is prepared so that the case where the relative value ΔStO2 of the first measured value is 0 (zero) corresponds to the yellow color of the evaluation image. The case where the relative value ΔStO2 of the first measured value is 0 (zero) means that the oxygen saturation is the same value as the first reference value StO2 (STD) in the first measured value StO2 (MV).

[0135] In addition, the case where the relative value ΔStO2 of the first measured value is 0 (zero) may be made to correspond to a color other than yellow of the evaluation image, preferably to a specific warm color. Therefore, in the evaluation image using the first spectroscopic image in which the first observation object is photographed, the evaluation color table is prepared based on the relative value ΔStO2 of the first measured value in such a manner that the case where the oxygen saturation is high and the case where the oxygen saturation is low are displayed with warm and cold color tones, respectively, across the case where the relative value ΔStO2 of the first measured value is 0 (zero). As a result, an evaluation image can be prepared in which the low oxygen side of the low oxygen saturation caused by ischemia can be visually recognized with high contrast and color tone.

[0136] The observation image and / or evaluation image produced as described above is displayed on the monitor. As described above, in the oxygen saturation mode, the observation image is displayed on the monitor, and in the ischemia evaluation mode, the evaluation image is displayed on the monitor. The oxygen saturation mode and the ischemia evaluation mode are switched according to the instructions of the mode switching unit 28a and the like. Therefore, the operator switches the mode by pressing the observer button of the mode switching unit 28a of the lumen endoscope device 22, and can display the observation image and the evaluation image on the monitor in sequence and compare them.

[0137] In the case where the oxygen saturation is expressed in pseudo color in the observation image using the observation color table 96 and the evaluation image using the evaluation color table 97, for example, the observation image expressing the first measured value based on the observation color table 96 becomes the observation image using pseudo color. Fig.21 The color bar 100a shown on the left side of the diagram shows an observation image of the first measured value, and the evaluation image showing the relative value ΔStO2 of the first measured value based on the evaluation color table 97 becomes the evaluation image using the method of ... Fig.21 The color bar 100 b shown on the right side of is an evaluation image of the relative value ΔStO2 of the first measured value.

[0138] Color bar 100a is based on oxygen saturation (in Fig.21The color bar 100a is blue at the bottom and oxygen saturation is 0%, the color bar 100a is red at the top and oxygen saturation is 100%, and the center of the color bar 100a is green and oxygen saturation is 50%. Fig.21 The color bar 100b shown on the right side of the figure is colored according to the relative value ΔStO2 of the first measured value. The lower direction of the color bar 100b is blue, and the lower limit corresponds to the relative value ΔStO2 of the first measured value of -30%. The upper direction of the color bar 100b is red, and the upper limit corresponds to the relative value ΔStO2 of the first measured value of +10%. The yellow color of the color bar 100b corresponds to the relative value ΔStO2 of the first measured value of 0%, that is, the first reference value StO2 (STD). In addition, according to Fig.21 The relative value ΔStO2 of the first measured value shown on the right side of ΔStO2 makes the relative value ΔStO2 of the first measured value and the upper and lower limits of the color bar 100b in the color bar 100b corresponding to the color correspond to the upper and lower limits of the evaluation color table 97 .

[0139] Therefore, in the case where the display grayscale of the colors in the observation color table 96 and the evaluation color table 97 is the same, a pseudo color image, i.e., an evaluation image, is created in the evaluation color table 97 with a high display grayscale relative to the change in oxygen saturation. The evaluation image is obtained by calculating the relative value of the oxygen saturation of the tissue to be observed and displaying the evaluation image in which the relative value is visualized on the monitor, so that the subtle change in oxygen saturation can be clearly visually recognized. Therefore, the evaluation image becomes a clearer indicator for determining the boundary between the normal part and the ischemic part.

[0140] Next, the display of the observation image and / or the evaluation image will be described. The display control unit 59 (see Figure 4 ) controls the image displayed on the monitor (display device 12). Fig. 22 As shown in FIG. 1 , in the oxygen saturation mode, when the observation image 101 is generated, the display control unit 59 performs control to display at least the observation image 101 on the monitor. Fig.23As shown, in the ischemia evaluation mode, when the evaluation image 102 is generated, the display control unit 59 controls to display at least the evaluation image 102 on the monitor. The monitor displays at least the observation image 101 in the oxygen saturation mode, and displays at least the evaluation image 102 in the ischemia evaluation mode. In addition, the monitor may display the observation image 101 and the evaluation image 102 generated just before side by side in the oxygen saturation mode, for example. In addition, similarly, in the ischemia evaluation mode, the evaluation image 102 and the observation image 101 generated just before may be displayed side by side. In the observation image 101 and the evaluation image 102, even if there is no color change in the region with low oxygen saturation in the observation image 101, the color in the evaluation image 102 is displayed with a change.

[0141] As described above, in the evaluation image, in addition to observing the oxygen saturation in a large numerical range based on the observation image, it is also possible to emphasize the observation of the subtle oxygen saturation difference based on the oxygen saturation of a specific observation area. Based on the evaluation image, for example, in the abdominal endoscope system 30, it is possible to distinguish the ischemic area of ​​the organ during surgery. Therefore, for example, it can serve as a judgment material for the resection site or anastomosis site where incomplete suturing is unlikely to occur. In addition, for example, in the luminal endoscope system 20, it is easy to visually recognize the subtle difference in oxygen saturation between the lesion site and the normal site, or the subtle oxygen saturation unevenness of a large lesion site.

[0142] Next, the preparation of the evaluation color table 97 is described. The evaluation color table 97 can also be prepared as follows. Fig.24 As shown, the color table generating unit 94 may also pre-set the lower limit 99a and upper limit 99b of the relative value ΔStO2 of the first measured value corresponding to the color information of the evaluation image, and prepare the evaluation color table 97. For example, in the evaluation color table 97b, the lower limit 99a of the relative value ΔStO2 of the first measured value is set to -30%, and the upper limit 99b is set to +10%. In the evaluation color table 97b, the lower limit 99a and the upper limit 99b are set to fixed values, but in the case where it is desired to visually recognize a more subtle difference in oxygen saturation according to the observation area, the range of the lower limit 99a and the upper limit 99b may be set to a narrower value, and the fixed value may be changed. Thus, an evaluation image in which a more subtle difference in oxygen saturation can be visually recognized can be prepared. On the other hand, the range of the lower limit 99a and the upper limit 99b may be set to a wider value, and the fixed value may be changed. Thus, when the observed area is an area where the difference in oxygen saturation is large and the area with the same hue is large in the evaluation image, the evaluation image with the hue adjusted can be obtained.

[0143] In addition, the setting receiving unit 95 may also receive an instruction to set the lower limit value 99a and / or the upper limit value 99b of the evaluation color table 97b. The setting instruction is given by the operator. When the setting operation of the lower limit value 99a of the relative value ΔStO2 of the first measured value and / or the upper limit value 99b of the relative value ΔStO2 of the first measured value is received through the operation of the input device 14, the setting receiving unit 95 displays a display on the monitor as shown in FIG. Fig.25 The upper limit value and lower limit value setting menu are shown. The upper limit value 99b can be changed between -100% and +100%, for example. The upper limit value 99b is allocated to the slide bar 103a.

[0144] When changing the upper limit value 99b, operate the cursor 106 with a mouse or the like, or operate the foot switch 36 to click the minus button 107a or the plus button 107b. Each time the minus button 107a or the plus button 107b is clicked once with the cursor 106, a change of 10% is made. In addition, when the monitor is a touch panel, the operation can also be performed by directly pressing the minus button 107a or the plus button 107b of the monitor. When changing the lower limit value 99a, click the minus button 107c or the plus button 107d in the same manner as in the case of the upper limit value 99b. Each time the minus button 107c or the plus button 107d is clicked once with the cursor 106, a change of 10%.

[0145] On the slide bar 103a of the upper limit value 99b, the current setting of the upper limit value 99b is displayed by the slider 104a. Regarding the lower limit value 99a, the current setting of the lower limit value 99a is also displayed by the slider 104b on the slide bar 103b of the lower limit value 99a. In the case where you want to significantly change the upper limit value 99b and / or the lower limit value 99a, you can also change the setting by directly moving the slider 104a or the slider 104b. In addition, the upper limit value 99b of the current relative value ΔStO2 of the first measured value is numerically indicated in the upper limit value display unit 105a. Similarly, the lower limit value 99a of the current relative value ΔStO2 of the first measured value is numerically indicated in the lower limit value display unit 105b. In addition, the range of the current lower limit value 99a and the upper limit value 99b is numerically indicated in the range display unit 105c. The lower limit value 99a and / or the upper limit value 99b set in this way are set as the lower limit value 99a and / or the upper limit value 99b of the relative value ΔStO2 of the first actual measurement value as the horizontal axis in the evaluation color table 97b.

[0146] In addition, when the lower limit value 99a and / or the upper limit value 99b are changed, the curves of the color difference signal Cr98a and the color difference signal Cb98b are not changed. Therefore, even if the upper limit value 99b and / or the lower limit value 99a of the relative value ΔStO2 of the first measured value are changed, in the evaluation image, the lower limit value 99a of the relative value ΔStO2 of the first measured value corresponds to blue, and as the relative value ΔStO2 of the first measured value increases and approaches red, the upper limit value 99b of the relative value ΔStO2 of the first measured value displays a pseudo-color evaluation image corresponding to red.

[0147] Furthermore, even when the lower limit value 99a and / or the upper limit value 99b of the relative value ΔStO2 of the first measured value is changed, the color table creating unit 94 creates the evaluation color table 97b so that the relative value ΔStO2 of the first measured value is 0 (zero) and the yellow color of the evaluation image is associated with it. Thus, when the oxygen saturation is the first reference value, the yellow color tone is kept constant, and even when the oxygen saturation of the tissue to be observed changes, the difference in the oxygen saturation of the tissue to be observed can be visually recognized with the same reference.

[0148] In addition, the color table creation unit 94 may calculate the lower limit value 99a of the relative value ΔStO2 of the first measured value based on a second reference value different from the first reference value. In this case, the lower limit value 99a of the relative value ΔStO2 of the first measured value is set as a relative value of the second reference value based on the first reference value. The second reference value is, for example, a third observation object, i.e., an area including an ischemic site, as a subject, and the second reference value is calculated based on the obtained third spectral image. Regarding the image signal in the second reference value (refer to Fig. 9 ) and calculation method are the same as those of the first reference value. Therefore, the second reference value is the average value of the oxygen saturation in the region including the ischemic site.

[0149] The second reference value is obtained in accordance with the operator's instruction in the same manner as the first reference value. For example, the operator can calculate the first reference value and the second reference value according to the instruction of the reference value calculation instruction unit 28b by making the timing of pressing the viewer button of the reference value calculation instruction unit 28b different from the timing of obtaining the first reference value. Specifically, the operator observes the area to be set as the first reference value, such as a normal part, and takes the area where the viewer button of the reference value calculation instruction unit 28b was pressed once as the first observation area, obtains the second spectral image, and calculates the first reference value. Next, the operator observes the area to be set as the second reference value, such as an ischemic part, and presses the viewer button of the reference value calculation instruction unit 28b. The area pressed for the second time is taken as the second observation area, and the third spectral image is obtained, and the third measured value and the second reference value are calculated.

[0150] Specifically, the third measured value is calculated by the measured value calculation unit 83 in the same manner as the first measured value and the second measured value. The reference value calculation unit 84 averages the third measured values ​​of the oxygen saturation at the locations of the pixels calculated by the measured value calculation unit 83, for example, within the range of one spectral image, and the average calculated value is used as the second reference value of the oxygen saturation.

[0151] The relative value calculation unit 75 calculates the relative value of the second reference value based on the first reference value. If the second reference value is StO2 (STD2) and the relative value of the second reference value StO2 (STD2) is ΔStO2 (LL), the relative value ΔStO2 (LL) of the second reference value StO2 (STD2) is the value obtained by subtracting the second reference value StO2 (STD2) from the first reference value StO2 (STD). Therefore, if expressed in an equation, it becomes the following equation (2). In addition, since the relative value is a relative value calculated based on the first reference value, it has the same unit (%) as the oxygen saturation.

[0152] StO2(STD)-StO2(STD2)=ΔStO2(LL) (2)

[0153] like Fig.26 As shown, the lower limit value 99c of the relative value ΔStO2 of the first measured value of the evaluation color table 97c is set to the relative value ΔStO2 (LL) of the second reference value StO2 (STD2) calculated as above. Thus, by a simple instruction of the operator based on pressing the viewer button, an evaluation image based on an appropriate evaluation color table 97c with two references of the ischemic part and the normal part of the tissue to be observed can be displayed. Therefore, it is possible to visually recognize the part such as the normal part with more blood flow than the ischemic part easily and more clearly. In addition, the upper limit value 99d of the evaluation color table 97c can also be set using the reference value.

[0154] Next, follow Fig. 27 Flowchart and Fig.28 The effects of the present invention are explained using observation images and evaluation images. For example, when a large intestine resection is performed using a luminal endoscope system 20 and an abdominal endoscope system 30, the operator uses the luminal endoscope device 22 set to the normal observation mode to find the site where the tumor has occurred in the large intestine. Then, the clamp device is inserted into the tumor site through the forceps channel, and the clamp device is operated to compress the relatively thick blood vessels located near the tumor site with the clamp. The tissue around the blood vessels compressed by the clamp becomes ischemic, and becomes a hypoxic area where the oxygen saturation of the observed tissue is reduced. The hypoxic area serves as a mark for the location of a specific tumor site in the subsequent operation. After the mark is affixed with the clamp, the luminal endoscope device 22 is pulled out of the large intestine.

[0155] In the next operation, the abdominal endoscope device 32 is inserted into the abdomen of the patient. The part marked by the clamp is observed in the oxygen saturation mode of the abdominal endoscope device 32 by the endoscopic device 22. The observation image 101 is created using the observation color table 96. The observation image 101 is displayed on the monitor, and for example, the part whose oxygen saturation is reduced by the clamp can be confirmed as a tumor part. Next, in order to determine the resection site or the anastomosis site, the same area as the area where the observation image 101 was obtained is observed in the ischemia evaluation mode (step ST100). Here, the first measured value is calculated (step ST110). In order to obtain the first reference value, the area to be set as the reference value is observed, and the observer button as the reference value calculation instruction unit 28b is pressed (YES in step ST120). Here, the operator observes the same area as the area observed in the oxygen saturation mode and gives a reference value calculation instruction. The reference value calculation instruction is given, the reference value calculation mode is switched, and the first reference value is calculated (step ST130). When the first reference value is calculated, the mode returns to the ischemia assessment mode. When the value used last time is used again as the reference value (NO in step ST120 ), the last reference value is set as the first reference value (step ST140 ).

[0156] In the ischemia evaluation mode, the relative value ΔStO2 of the first measured value as the relative value of the oxygen saturation of the tissue to be observed is calculated (step ST150), and the evaluation image 102 is created using the evaluation color table 97. The evaluation image 102 is displayed on the monitor (step ST160), and the difference in oxygen saturation is visually confirmed in more detail than the observation image 101. The operator confirms the specific location of the tumor part, the oxygen saturation near the tumor part, and the ischemic state. In the case of creating the evaluation image 102 again, the actual value calculation is returned (NO in step ST170), and in the case of terminating the creation of the evaluation image 102, the ischemia evaluation mode is terminated (YES in step ST170). For example, the part with the most blood flow can be selected by the evaluation image 102 to determine the resection part or the anastomosis part. In addition, even if there is a part with low oxygen saturation, it is possible to select the boundary between the ischemic area and the normal area, avoid the ischemic area, avoid the part where congestion and ischemia are mixed, or select a uniform part, so as to determine the resection part or the anastomosis part that is less likely to cause incomplete suture. After the treatment is completed, the abdominal endoscope device 32 is removed from the patient's body to end the operation.

[0157] In the above-mentioned embodiment, the hardware structure of the processing unit (processing unit) that performs various processes, such as the central control unit 56a, the image acquisition unit 57, the image processing unit 58, and the display control unit 59, is various processors (processors) as shown below. The various processors include a general-purpose processor that executes software (programs) and functions as various processing units, namely a CPU (Central Processing Unit), a processor whose circuit structure can be changed after manufacturing, such as a FPGA (Field Programmable Gate Array), namely a programmable logic device (PLD), and a processor having a circuit structure specially designed to perform various processes, namely a dedicated circuit (Graphical Processing Unit: GPU).

[0158] A processing unit can be composed of one of these various processors, or a combination of two or more processors of the same or different types (for example, multiple FPGAs, or a combination of a CPU and FPGA, a combination of a GPU and a CPU). In addition, multiple processing units can also be composed of one processor. As an example of a plurality of processing units composed of one processor, first, there is a form such as a computer such as a client or server, which uses a combination of one or more CPUs and software to constitute a processor, and the processor functions as multiple processing units. Secondly, there is a form such as a system on chip (System OnChip: SoC) and the like, which uses a processor that implements the functions of the entire system including multiple processing units with one IC (Integrated Circuit) chip. In this way, various processing units are composed of one or more of the above-mentioned various processors as a hardware structure.

[0159] Furthermore, more specifically, the hardware structure of these various processors is a circuit in the form of a combination of circuit elements such as semiconductor elements.

[0160] Explanation of symbols

[0161] 10 Endoscopic system

[0162] 12 Display device

[0163] 14 Input Devices

[0164] 20 Lumen endoscope system

[0165] 21. Lumen light source device

[0166] 22 Endoscopic device for lumen

[0167] 23 Lumen Processor Device

[0168] 24a Lumen endoscope operation unit

[0169] 24b Endoscope insertion portion for lumen

[0170] 25 Observer top

[0171] 26 forceps channel

[0172] 26a Clamp inlet

[0173] 26b Pliers outlet

[0174] 27 Bend

[0175] 28a Mode switching unit

[0176] 28b Reference value calculation instruction unit

[0177] 29 Corner Button

[0178] 30 Laparoscopic endoscope system

[0179] 31 Abdominal cavity light source device

[0180] 32. Laparoscopic endoscope

[0181] 33 Abdominal processor device

[0182] 34 Laparoscopic endoscope insertion section

[0183] 35 Laparoscopic endoscope

[0184] 36 Foot switch

[0185] 37 Pneumoperitoneum device

[0186] 38 Disposal equipment

[0187] 39a, 39b Trocar

[0188] 41 Light Source

[0189] 41a BS-LED

[0190] 41b BL-LED

[0191] 41c G-LED

[0192] 41d R-LED

[0193] 42 Light source control unit

[0194] 43 Light guide

[0195] 44a Illumination optical system

[0196] 44b Camera optical system

[0197] 45 Lighting lens

[0198] 46 Objective lens

[0199] 48 Camera Sensor

[0200] 49 Camera surface

[0201] 51 pixels

[0202] 52 B color filter

[0203] 53 G Color Filter

[0204] 54 R Color Filter

[0205] 55 Camera Control Unit

[0206] 56 Control Department

[0207] 56a Central Control Department

[0208] 57 Image acquisition unit

[0209] 58 Image Processing Unit

[0210] 59 Display control unit

[0211] 59a Display image selection section

[0212] 61 DSP

[0213] 62 Noise Reduction Unit

[0214] 63 Conversion Department

[0215] 71 General Image Processing Unit

[0216] 72 Special image processing unit

[0217] 73 Measurement value calculation unit

[0218] 74 Reference value calculation instruction receiving unit

[0219] 75 Relative value calculation unit

[0220] 76 Image Generation Unit

[0221] 81 Signal ratio calculation unit

[0222] 82 Correlation storage unit

[0223] 83 Measured value calculation unit

[0224] 84 Reference value calculation unit

[0225] 86 Two-dimensional table

[0226] 91 Graph

[0227] 91a Absorption coefficient of oxygenated hemoglobin

[0228] 91b Absorption coefficient of reduced hemoglobin

[0229] 92a Lower limit

[0230] 92b Upper limit

[0231] 93 Color table storage unit

[0232] 94 Color Table Production Department

[0233] 95 Setting acceptance unit

[0234] 96 Observation Color Chart

[0235] 97a, 97b, 97c Evaluation color chart

[0236] 98a Color difference signal Cr

[0237] 98b color difference signal Cb

[0238] 99a, 99c lower limit

[0239] 99b, 99d upper limit

[0240] 100a, 100b color bars

[0241] 101 Observation images

[0242] 102 Evaluation images

[0243] 103a, 103b Slide bar

[0244] 104a, 104b Slider

[0245] 105a Upper limit value display unit

[0246] 105b Lower limit value display unit

[0247] 105c Range display unit

[0248] 106 Cursor

[0249] 107a, 107c Negative button

[0250] 107b, 107d positive button

[0251] X row direction

[0252] Y column direction

[0253] Steps ST100 to ST170.

Claims

1. An endoscope system having an oxygen saturation mode and an ischemia evaluation mode, The endoscope system comprises: One or more processors configured to: obtaining a plurality of first spectroscopic images; Calculating a first measured value of oxygen saturation of the tissue to be observed based on the plurality of first spectroscopic images; In the case of the oxygen saturation mode, generating an observation oxygen saturation image using the first measured value, and displaying the observation oxygen saturation image on a display; as well as In the ischemia evaluation mode, a relative value between a first reference value of the oxygen saturation of the tissue to be observed calculated based on a plurality of second spectral images and the first measured value is calculated, an evaluation oxygen saturation image is generated using the relative value, and the evaluation oxygen saturation image is displayed on the display.

2. The endoscope system according to claim 1, wherein: The endoscope system further comprises: An endoscope that captures an image of the tissue to be observed, the endoscope including a switch that receives an instruction to switch between the oxygen saturation mode and the ischemia assessment mode.

3. The endoscope system according to claim 1, wherein: The one or more processors are configured to generate the evaluation oxygen saturation image by assigning a green image signal to a brightness channel and assigning a relative value of the first measured value of oxygen saturation to two color difference channels.

4. The endoscope system according to claim 1, wherein: The one or more processors are configured to generate the evaluation oxygen saturation image using an observation color table different from an observation color table used to generate the observation oxygen saturation image.

5. The endoscope system according to claim 4, wherein: The evaluation color table generates an image having a higher display gradation relative to a change in oxygen saturation level than the observation color table.

6. The endoscope system according to claim 1, wherein: The endoscope system can also switch to a reference value calculation mode, and the one or more processors are configured to: in the reference value calculation mode, Obtaining the plurality of second spectroscopic images; as well as The first reference value is calculated based on the oxygen saturation calculated from the plurality of second spectroscopic images.

7. The endoscope system according to claim 6, wherein: The previously used first reference value is used as the first reference value until the first reference value is calculated in the reference value calculation mode.

8. The endoscope system according to claim 6, wherein: The one or more processors are configured to automatically switch to the reference value calculation mode and perform calculation of the first reference value upon receiving an instruction to switch to the ischemia assessment mode.

9. The endoscope system according to claim 8, wherein: The one or more processors are configured to automatically switch to the ischemia assessment mode after setting the first reference value in the reference value calculation mode.

10. The endoscope system according to claim 1, wherein: The endoscope system can also be switched to a reference value calculation mode, and The one or more processors are configured to: in the reference value calculation mode, Calculating the oxygen saturation of the ischemic part or the normal part of the tissue to be observed; as well as The oxygen saturation level of the ischemic site or the normal site is set as the first reference value.

11. The endoscope system according to claim 1, wherein: The endoscope system further comprises: an abdominal cavity light source device that generates light for illuminating the interior of the abdominal cavity; and An abdominal endoscope device irradiates the interior of the abdominal cavity with light from the abdominal light source device and captures an image of the tissue to be observed.

12. The endoscope system according to claim 11, wherein: The plurality of first spectroscopic images include: images captured when a first blue light with a wavelength range of 450±10 nm enters the abdominal cavity; and images captured when a second blue light with a wavelength range of 470±10 nm enters the abdominal cavity.

13. The endoscope system according to claim 1, wherein: The one or more processors are configured to display the evaluation oxygen saturation image and the observation oxygen saturation image in parallel in the case of the ischemia evaluation mode.

14. The endoscope system according to claim 4, wherein: The one or more processors are configured to create the evaluation color table in which a relative value of the first measured value and color information of the evaluation oxygen saturation image are associated with each other.

15. The endoscope system according to claim 14, wherein: The one or more processors are configured to set a lower limit value and / or an upper limit value of a relative value of the first measured value corresponding to color information of the oxygen saturation image for evaluation and to create the color table for evaluation.

16. The endoscope system according to claim 15, wherein: The one or more processors are configured to: calculating a second reference value of the oxygen saturation level of the tissue to be observed based on the plurality of third spectroscopic images; and A relative value of the second reference value is set as the lower limit value.

17. A method for operating an endoscope system, the endoscope system having an oxygen saturation mode and an ischemia assessment mode, the method comprising the following steps: obtaining a plurality of first spectroscopic images; Calculating a first measured value of oxygen saturation of the tissue to be observed based on the plurality of first spectroscopic images; In the case of the oxygen saturation mode, generating an observation oxygen saturation image using the first measured value, and displaying the observation oxygen saturation image on a display; as well as In the ischemia evaluation mode, a relative value between a first reference value of the oxygen saturation of the tissue to be observed calculated based on a plurality of second spectral images and the first measured value is calculated, an evaluation oxygen saturation image is generated using the relative value, and the evaluation oxygen saturation image is displayed on the display.

Images