Color correction device for medical equipment

Abstract

To eliminate a difference in color properties of each device and display images with a uniform color tone even when a medical image display system is constructed by combining devices with various color properties.SOLUTION: In the present invention, to imaging data (Dx-Dz) imaged by each medical imaging device (30X-30Z), a color conversion section for an imaging device (140) carries out conversion for eliminating differences in color properties of each imaging device and generates standard color graphic data (Ds). To this standard color graphic data (Ds), a color conversion section for highlighting a specific tissue (160) carries out color conversion for highlighting a designated specific biological tissue (such as blood vessel) to generate specific tissue highlighted graphic data (De-Dg). To this specific tissue highlighted graphic data (De), a color conversion section for a monitor (170) carries out conversion for eliminating differences in color properties of each monitor to generate display data (Da-Dd). Color monitors (50A-50D) display graphics based on this display data (Da-Dd).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a color correction device for medical equipment, and more particularly to a color correction device that performs color correction suitable for display on a color monitor on image data of biological tissues obtained by imaging with a medical imaging device. [Background technology]

[0002] Medical image display systems that capture images of the patient's affected area and the surrounding area during surgery and display the images on a monitor screen are used in many medical settings. For example, in the case of a typical open abdominal surgery, a medical image display system captures images of the abdominal cavity with a camera installed in the operating room and displays the images on a monitor, allowing the surgeon to monitor the surgical procedure. On the other hand, in laparoscopic surgery, an endoscopic camera is inserted into the patient's abdominal cavity without performing an abdominal incision, and the surgeon must perform the procedure while viewing the images displayed on a monitor, making the use of a medical image display system essential. In addition to surgery, medical image display systems that capture images of sample tissue excised from the human body and display them on a monitor are also sometimes used for the examination and diagnosis of such tissue.

[0003] For example, Patent Document 1 below discloses a medical image display system in which an endoscopic camera is inserted into a patient's body cavity and images of the body cavity are displayed on a monitor. Patent Document 2 discloses a system for supporting remote surgery by transmitting images captured by an endoscopic camera via a public line and displaying them on a monitor installed at a remote location. Meanwhile, systems have also been proposed that perform some kind of image processing on images captured during surgery and display them on a monitor. For example, Patent Document 3 discloses a surgical system that applies image processing to images captured during surgery to match the surgeon's viewing direction, thereby displaying more appropriate images on the monitor. Furthermore, Patent Document 4 discloses a medical image display system that generates three-dimensional volume data from image data of the patient's affected area during surgery and can display intraoperative CT images on a monitor based on this data. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-116425 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-237206 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-046200 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-136132 Summary of the Invention [Problem to be solved by the invention]

[0005] Many of the medical image display systems described above are provided by a single provider as a complete product that includes the entire system, from the camera to the monitor. However, each provider uses different models of cameras and monitors, and the standards for adjusting their characteristics vary. For these reasons, medical image display systems currently provided by multiple providers have different color characteristics. As a result, even if the exact same subject is photographed under the exact same lighting environment and displayed on a color monitor, the color of the subject displayed on the monitor will differ depending on the individual medical image display system.

[0006] Generally, each camera and monitor has its own unique color characteristics. For example, if the exact same subject is photographed using multiple cameras under the exact same lighting conditions, the resulting image data (usually consisting of a collection of pixels with the values ​​of the three primary colors R, G, and B) will be different. This is because the color characteristics of each camera are different. Similarly, if the exact same image data is provided to multiple color monitors and the images are displayed, the color reproduction characteristics of each monitor will differ. This is because the color characteristics of each color monitor are different. For these reasons, the color reproduction characteristics of medical image display systems provided by individual providers will differ from one another. This poses a major problem when practitioners perform various diagnoses based on images displayed on color monitors.

[0007] In the future, as these medical image display systems become more widespread, it is expected that a variety of medical imaging devices (surgical cameras, endoscopic cameras, microscope cameras, etc.) and monitors will be supplied by multiple providers, and there will be an increasing number of cases in which a single medical image display system is constructed by combining various devices supplied by different providers. This will result in an even greater variation in the color reproduction performance of each individual system, which will be a hindrance to practitioners' ability to make accurate diagnoses.

[0008] In addition, there are many cases where surgery requires detailed observation of only specific biological tissue. As mentioned above, Patent Document 3 discloses a technology for applying image processing to a captured image to display an image on a monitor that matches the observation direction of the surgeon, and Patent Document 4 discloses a technology for generating three-dimensional volume data based on a captured image and displaying a CT image on a monitor. However, these technologies are unable to display an image with sufficient visibility suitable for observing specific biological tissue.

[0009] The present invention provides a new technology for solving these problems. The first object of the present invention is to eliminate differences in color characteristics between devices and enable image display with a unified color tone, even when a medical image display system is constructed by combining devices with various color characteristics. The second object of the present invention is to enable image display with visibility suitable for observing specific biological tissues when using a medical image display system. [Means for solving the problem]

[0010] (1) A first aspect of the present invention is a color correction device for a medical device that performs color correction on image data obtained by imaging with a medical imaging device to make the image data suitable for display on a color monitor, comprising: an imaging device individual conversion data storage unit that stores individual conversion data for converting color characteristics of imaging data captured by a specific medical imaging device into standard color characteristics, taking into account color characteristics unique to the medical imaging device; a specific tissue emphasis conversion data storage unit for storing specific tissue emphasis conversion data for performing color conversion to emphasize a specific biological tissue; a monitor-specific conversion data storage unit that stores individual conversion data for performing color conversion so that an image having standard color characteristics is displayed on a specific color monitor, taking into account the color characteristics inherent to that color monitor; a color conversion unit for the imaging device that performs color conversion on imaging data input from a specific medical imaging device using individual conversion data for the specific medical imaging device stored in an individual conversion data storage unit for the imaging device to generate standard color image data; a highlight tissue designation unit that receives a designation input that designates a specific biological tissue to be highlighted; a specific-tissue-emphasizing color conversion unit that performs color conversion on the standard color image data using specific-tissue-emphasizing conversion data stored in a specific-tissue-emphasizing conversion data storage unit for performing color conversion to emphasize a specific biological tissue designated by a designated input, and generates specific-tissue-emphasized image data; and a monitor color conversion unit that performs color conversion on the specific tissue-enhanced image data using individual conversion data for a specific color monitor stored in the monitor individual conversion data storage unit to generate display data, and outputs the generated display data to the specific color monitor.

[0011] (2) A second aspect of the present invention is the color correction device for a medical device according to the first aspect described above, The individual conversion data stored in the individual conversion data storage unit for the imaging device is conversion data that can perform color conversion covering the wide color gamut defined in the specifications of BT.2020, the international standard for ultra-high definition television.

[0012] (3) A third aspect of the present invention is the color correction device for medical equipment according to the first or second aspect, The individual conversion data stored in the individual conversion data storage unit for the imaging device is conversion data that uses the color characteristics of transmitted light through a specified color chart with light from a D65 light source specified by the International Commission on Illumination as background light as standard color characteristics.

[0013] (4) A fourth aspect of the present invention is a color correction device for a medical device according to any one of the first to third aspects, The individual conversion data stored in the individual conversion data storage unit for the imaging device is conversion data for converting the three primary color components Rold, Gold, and Bold of the imaging data into the three primary color components Rnew, Gnew, and Bnew of the standard color image data.

[0014] (5) A fifth aspect of the present invention is a color correction device for a medical device according to any one of the first to fourth aspects, The individual conversion data for each of the plurality of medical imaging devices is stored in an individual conversion data storage unit for the imaging device, The color conversion unit for the imaging device performs color conversion using the i-th individual conversion data on imaging data input from the i-th (1≦i≦I) medical imaging device to generate standard color image data.

[0015] (6) A sixth aspect of the present invention is a color correction device for a medical device according to any one of the first to fifth aspects, The color conversion unit for the imaging device inputs image data captured under a shadowless lamp or an endoscope light source, performs color conversion on the image data, and generates standard color image data.

[0016] (7) A seventh aspect of the present invention is a color correction device for a medical device according to any one of the first to sixth aspects, The individual conversion data stored in the individual conversion data storage unit for the imaging device is configured as a lookup table that converts combinations of color components that make up the imaging data into combinations of color components that make up the standard color image data.

[0017] (8) An eighth aspect of the present invention is a color correction device for a medical device according to any one of the first to sixth aspects, The individual conversion data stored in the individual conversion data storage unit for the imaging device is configured by a function that calculates the combination of each color component that makes up the standard color image data by providing the combination of each color component that makes up the imaging data as a variable value.

[0018] (9) A ninth aspect of the present invention is a color correction device for a medical device according to any one of the first to eighth aspects, a specific tissue emphasis transformation data storage unit stores specific tissue emphasis transformation data for a plurality of J types of biological tissues; When the specific tissue highlighting color conversion unit receives a designation input specifying the jth (1≦j≦J) biological tissue from the highlighting tissue designation unit, it performs color conversion using the jth specific tissue highlighting conversion data to generate specific tissue highlighting image data.

[0019] (10) A tenth aspect of the present invention is the color correction device for a medical device according to the ninth aspect, The emphasis tissue designation unit has a function of receiving designation input for designating a plurality of H (H≦J) biological tissues in overlapping fashion; When the specific tissue emphasis color conversion unit receives a designation input specifying a plurality of H types of biological tissues from the emphasis tissue designation unit, it performs color conversion using a plurality of H types of specific tissue emphasis conversion data corresponding to these plurality of H types of biological tissues in a redundant manner to generate specific tissue emphasis image data.

[0020] (11) An eleventh aspect of the present invention is a color correction device for a medical device according to any one of the first to tenth aspects, the emphasis tissue designation unit has a function of accepting a null designation input indicating that no biological tissue is designated; When the specific tissue emphasizing color conversion unit receives a blank designation input from the emphasis tissue designation unit, it outputs the standard color image data as it is as specific tissue emphasizing image data without performing color conversion.

[0021] (12) A twelfth aspect of the present invention is a color correction device for a medical device according to any one of the first to eleventh aspects, The specific tissue emphasis conversion data stored in the specific tissue emphasis conversion data storage unit is data that performs specific color correction on colors included in a localized color region specific to a specific biological tissue in a specified color space.

[0022] (13) A thirteenth aspect of the present invention is the color correction device for a medical device according to the twelfth aspect, The specific tissue emphasis conversion data stored in the specific tissue emphasis conversion data storage unit is data that performs color correction by increasing or decreasing the abscissa value, the ordinate value, or both of the colors included in the localized color region specific to a specific biological tissue on a predetermined two-dimensional chromaticity diagram.

[0023] (14) A fourteenth aspect of the present invention is the color correction device for a medical device according to the thirteenth aspect, The specific tissue enhancement conversion data stored in the specific tissue enhancement conversion data storage unit is data that performs color correction by increasing or decreasing the u' value, v' value, or both for colors included in the localized color region specific to a specific biological tissue on the u'v' chromaticity diagram.

[0024] (15) A fifteenth aspect of the present invention is the color correction device for a medical device according to the fourteenth aspect, the highlight tissue designation unit has a function of receiving a designation input specifying "blood vessel" as a specific biological tissue to be highlighted; The specific tissue emphasis conversion data storage unit stores conversion data for specific tissue emphasis to perform color conversion to emphasize "blood vessels," which performs color correction to increase the u' value for colors included in the localized color region specific to blood vessels on the u'v' chromaticity diagram.

[0025] (16) A sixteenth aspect of the present invention is the color correction device for a medical device according to the fourteenth or fifteenth aspect described above, the highlight tissue designation unit has a function of receiving a designation input specifying "fat" as a specific biological tissue to be highlighted; The specific tissue emphasis conversion data storage unit stores conversion data for specific tissue emphasis to perform color conversion to emphasize "fat," which performs color correction by decreasing the u' value and increasing the v' value for colors included in the localized color region specific to fat on the u'v' chromaticity diagram.

[0026] (17) A seventeenth aspect of the present invention is a color correction device for a medical device according to any one of the fourteenth to sixteenth aspects, the highlight tissue designation unit has a function of receiving a designation input specifying "surface membrane" as a specific biological tissue to be highlighted; The specific tissue emphasis conversion data storage unit stores conversion data for specific tissue emphasis to perform color conversion to emphasize the ``surface membrane,'' which performs color correction by increasing the u' value and decreasing the v' value for colors included in the localized color region specific to the surface membrane on the u'v' chromaticity diagram.

[0027] (18) An eighteenth aspect of the present invention is a color correction device for a medical device according to any one of the first to seventeenth aspects, The individual conversion data stored in the monitor individual conversion data storage unit is conversion data that can perform color conversion covering the wide color gamut defined in the BT.2020 specifications, an international standard for ultra-high definition televisions.

[0028] (19) A nineteenth aspect of the present invention is a color correction device for a medical device according to any one of the first to eighteenth aspects, A monitor individual conversion data storage unit stores individual conversion data for each of a plurality of K color monitors, When the monitor color conversion unit generates display data to be output to the kth (1≦k≦K) color monitor, it performs color conversion using the kth individual conversion data.

[0029] (20) A twentieth aspect of the present invention is a color correction device for a medical device according to any one of the first to nineteenth aspects, The individual conversion data stored in the monitor individual conversion data storage unit is configured by a lookup table that converts a combination of each color component that constitutes the specific tissue-enhanced image data into a combination of each color component that constitutes the display data.

[0030] (21) A twenty-first aspect of the present invention is a color correction device for a medical device according to any one of the first to nineteenth aspects, The individual conversion data stored in the monitor individual conversion data storage unit is configured by a function that calculates the combination of each color component that makes up the display data by providing the combination of each color component that makes up the specific tissue-enhanced image data as a variable value.

[0031] (22) A 22nd aspect of the present invention is a color correction device for a medical device that performs color conversion to emphasize specific biological tissues on image data of a group of biological tissues, the color correction device comprising: a specific tissue emphasis conversion data storage unit for storing specific tissue emphasis conversion data for performing color conversion to emphasize a specific biological tissue; a highlight tissue designation unit that receives a designation input that designates a specific biological tissue to be highlighted; a specific tissue emphasis color conversion unit that performs color conversion using specific tissue emphasis conversion data stored in a specific tissue emphasis conversion data storage unit for performing color conversion to emphasize a specific biological tissue designated by a designated input on image data obtained based on imaging by the medical imaging device, to generate specific tissue emphasis image data; and The above is provided.

[0032] (23) A twenty-third aspect of the present invention is the color correction device for a medical device according to the twenty-second aspect, The specific tissue emphasis conversion data stored in the specific tissue emphasis conversion data storage unit is data that performs specific color correction on colors included in a specific localized color region unique to a specific biological tissue in a predetermined color space.

[0033] (24) A 24th aspect of the present invention is the color correction device for a medical device according to the 23rd aspect, The specific tissue emphasis conversion data stored in the specific tissue emphasis conversion data storage unit is data that performs color correction by increasing or decreasing the abscissa value, the ordinate value, or both of the colors included in the localized color region specific to a specific biological tissue on a predetermined two-dimensional chromaticity diagram.

[0034] (25) A twenty-fifth aspect of the present invention is the color correction device for a medical device according to the twenty-fourth aspect, The specific tissue enhancement conversion data stored in the specific tissue enhancement conversion data storage unit is data that performs color correction by increasing or decreasing the u' value, v' value, or both for colors included in the localized color region specific to a specific biological tissue on the u'v' chromaticity diagram.

[0035] (26) A 26th aspect of the present invention is the color correction device for a medical device according to the 25th aspect, the highlight tissue designation unit has a function of receiving a designation input specifying "blood vessel" as a specific biological tissue to be highlighted; The specific tissue emphasis conversion data storage unit stores conversion data for specific tissue emphasis to perform color conversion to emphasize "blood vessels," which performs color correction to increase the u' value for colors included in the localized color region specific to blood vessels on the u'v' chromaticity diagram.

[0036] (27) A 27th aspect of the present invention is the color correction device for a medical device according to the 25th or 26th aspect, the highlight tissue designation unit has a function of receiving a designation input specifying "fat" as a specific biological tissue to be highlighted; The specific tissue emphasis conversion data storage unit stores conversion data for specific tissue emphasis to perform color conversion to emphasize "fat," which performs color correction by decreasing the u' value and increasing the v' value for colors included in the localized color region specific to fat on the u'v' chromaticity diagram.

[0037] (28) A 28th aspect of the present invention is a color correction device for a medical device according to any one of the 25th to 27th aspects, the highlight tissue designation unit has a function of receiving a designation input specifying "surface membrane" as a specific biological tissue to be highlighted; The specific tissue emphasis conversion data storage unit stores conversion data for specific tissue emphasis to perform color conversion to emphasize the ``surface membrane,'' which performs color correction by increasing the u' value and decreasing the v' value for colors included in the localized color region specific to the surface membrane on the u'v' chromaticity diagram.

[0038] (29) A 29th aspect of the present invention provides a color correction device for a medical device according to any one of the first to 21st aspects, At least one medical imaging device that provides imaging data to the medical device color correction device; and at least one color monitor that displays an image based on display data output from the medical device color correction device. By adding the above, a medical image display system is constructed.

[0039] (30) A thirtieth aspect of the present invention is a color correction device for a medical device according to any one of the first to twenty-eighth aspects, configured by installing a program in a computer. [Effects of the Invention]

[0040] The color correction devices for medical devices according to the first to twenty-first aspects of the present invention are devices incorporated into a medical image display system including a medical imaging device and a color monitor. In this color correction device, differences in color characteristics between individual medical imaging devices are eliminated by the color conversion unit for the imaging device, and differences in color characteristics between individual color monitors are eliminated by the color conversion unit for the monitor. This achieves the first object of the present invention, which is to "eliminate differences in color characteristics between devices and enable image display with a unified color tone, even when a medical image display system is configured by combining devices with various color characteristics." Furthermore, in this color correction device, standard color image data is generated by conversion by the color conversion unit for the imaging device, and color conversion is performed on this standard color image data to emphasize specific biological tissues. This also achieves the second object of the present invention, which is to "enable image display with visibility suitable for observing specific biological tissues."

[0041] Meanwhile, the color correction devices for medical equipment according to the 22nd to 28th aspects of the present invention are also devices incorporated into a medical image display system including a medical imaging device and a color monitor. In this color correction device, color conversion that emphasizes specific biological tissue is performed on image data obtained based on imaging by the medical imaging device, thereby achieving the second object of the present invention, which is to "enable image display with visibility suitable for observing specific biological tissue." [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a block diagram showing an operating room equipped with a conventional general medical image display system. [Figure 2] FIG. 1 is a block diagram showing the flow of image data in a conventional general medical image display system. [Figure 3] 1 is a block diagram showing the basic configuration of a medical image display system 1000 including a color correction device 100 for a medical instrument according to the present invention. [Figure 4] 4 is a block diagram showing a procedure for creating individual conversion data Cx stored in the individual conversion data storage unit 110 for the imaging device shown in FIG. 3. FIG. [Figure 5] FIG. 5 is a plan view showing a specific example of the color chart 70 shown in FIG. [Figure 6] 4 is a diagram showing specific examples of individual converted data stored in the individual converted data storage section 110 for the imaging device and the individual converted data stored in the individual converted data storage section 130 for the monitor shown in FIG. 3. FIG. [Figure 7] FIG. 1 is a diagram showing the basic procedure for measuring color reproducibility on a color monitor in a medical image display system. [Figure 8] 8 is a u'v' chromaticity diagram showing the color distribution obtained by carrying out the measurement procedure shown in FIG. 7 on the multicolor chart 72 shown in FIG. 5(b). [Figure 9] 8 is a u'v' chromaticity diagram showing the color distribution obtained by carrying out the measurement procedure shown in FIG. 7 on the wide color gamut color chart 73 shown in FIG. 5(c). [Figure 10]This is a u'v' chromaticity diagram (top row) showing a composite color distribution obtained by combining the color distribution shown in Figure 8(b) and the color distribution shown in Figure 9(b), and a diagram (bottom row) showing the color gamut usage rate for that color distribution. [Figure 11] 1 is a graph showing the visible light spectrum of each light source. [Figure 12] This is a u'v' chromaticity diagram showing the color temperatures of each light source. [Figure 13] This is a u'v' chromaticity diagram showing the color distribution of each part of the colon specimen itself measured under a shadowless lamp. [Figure 14] This is a u'v' chromaticity diagram showing the color distribution of each part of the colon specimen itself measured under an endoscopic light source (via fiber) (in reality, the measurement results in Figure 13 were converted to measurement results under an endoscopic light source through simulation). [Figure 15] This is a u'v' chromaticity diagram showing the color distribution of each part of the colon specimen itself measured under a D65 light source (in reality, the measurement results of Figure 13 were converted into measurement results under a D65 light source through simulation). [Figure 16] 14 is a top view showing the colon specimen and sample locations of specific tissues thereof used in the measurements of FIG. 13. FIG. [Figure 17] This is a u'v' chromaticity diagram showing the color distribution obtained by measuring each sample location shown in Figure 16 under a shadowless lamp. [Figure 18] This is a u'v' chromaticity diagram showing the color distribution obtained by measuring each sample location shown in Figure 16 under a D65 light source. [Figure 19] This is a u'v' chromaticity diagram showing the localized color areas Ae, Af, Ag specific to specific biological tissues defined by the specific tissue emphasis conversion data Ce, Cf, Cg in the color correction device 100 for medical equipment shown in Figure 3, and their correction directions Me, Mf, Mg. [Figure 20] 4 is a front view showing an example of an instruction button constituting an emphasis tissue designation unit 150 in the medical instrument color correction device 100 shown in FIG. 3. FIG. [Figure 21]FIG. 11 is a u'v' chromaticity diagram showing the color distribution of image data obtained by performing various enhancement corrections using the specific tissue enhancement color converter 160 on image data having the color distribution shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0043] Hereinafter, the present invention will be described based on the illustrated embodiments.

[0044] <<< §1. Conventional General Medical Image Display Systems >>> First, a brief explanation of a conventional general medical image display system will be provided. Fig. 1 is a block diagram showing an operating room equipped with a conventional general medical image display system. As shown in the figure, an operating table 10 is installed in the operating room, and a subject (patient) P lies on the table. A shadowless lamp 20 is installed above the operating table 10 to illuminate the affected area of ​​the subject P. The example shown in the figure is an example in which laparoscopic surgery is performed on the subject P, and during the surgery, an opening with a diameter of approximately 10 mm is formed in the abdomen of the subject P, and the tip of an endoscopic camera 31 is inserted into the abdominal cavity of the subject P.

[0045] The endoscopic camera 31 is connected by a cable to an endoscope control unit 41. The endoscope control unit 41 is a device for controlling the endoscopic camera 31, and has functions such as supplying power to the endoscopic camera 31, acquiring image data from the endoscopic camera 31, turning on / off the endoscope light source attached to the endoscopic camera 31, and recording the image data. Although only one endoscopic camera 31 is shown in the figure, multiple endoscopic cameras may be used as needed.

[0046] In the illustrated example, four color monitors 51-54 are connected to the endoscope control unit 41, and images captured by the endoscopic camera 31 are sent to each of the color monitors 51-54 via the endoscope control unit 41 and displayed on each screen. The surgeon performs laparoscopic surgery while viewing the images on the screen (surgical instruments are not shown). The color monitors 51-54 do not necessarily have to be installed in the operating room; some or all of them may be installed in another room (for example, a conference room). In the system disclosed in the aforementioned Patent Document 2, the monitors are installed in remote locations, and surgery is performed by remote control.

[0047] In the example shown in Fig. 1, a system including the endoscopic camera 31, the endoscope control unit 41, and the color monitors 51 to 54 constitutes a medical image display system. Of course, such a medical image display system is also introduced in the case of general open surgery as needed. In open surgery, a normal camera that photographs the affected area from above is usually used instead of the endoscopic camera 31, but in special open surgery, an endoscopic camera may also be used in combination. In open surgery, the surgeon usually performs the surgery while observing the affected area with the naked eye, so the image displayed on the monitor is used as information to present to surgical assistants and other relevant parties.

[0048] Fig. 2 is a block diagram showing the flow of image data in a conventional general medical image display system. Fig. 2 shows an example in which an image of an actual organ P1, which is the affected area of ​​a subject P, is captured by a medical imaging device 30, the obtained imaging data is transmitted to a color monitor 50 via an imaging control unit 40, and a display image P2 of the organ is displayed on the screen. In the case of laparoscopic surgery as shown in Fig. 1, an endoscopic camera 31 is used as the medical imaging device 30, and an endoscope control unit 41 is used as the imaging control unit 40. A shadowless lamp 20 is placed above the subject P, and the subject P is illuminated by light from this shadowless lamp 20 (in Fig. 2, the dashed arrow pointing from the shadowless lamp 20 to the actual organ P1 indicates such illumination light). However, in the case of laparoscopic surgery, the illumination light from the shadowless lamp 20 does not reach the actual organ P1 that is the subject, so the organ is illuminated by an endoscopic light source (a light source attached to the endoscopic camera) attached to the endoscopic camera (in Figure 2, the dashed arrow pointing from the medical imaging device 30 to the actual organ P1 indicates the illumination light from this endoscopic light source).

[0049] 2, a medical image display system is constituted by a system including the medical imaging device 30, the imaging control unit 40, and the color monitor 50. Here, the medical imaging device 30 is a component that performs image input by capturing an image of an actual organ P1, the imaging control unit 40 is a component that performs processing to relay image data obtained by this image input, and the color monitor 50 is a component that performs image output by displaying a display image P2 of the organ on a screen based on the provided image data.

[0050] As already mentioned, the medical imaging device 30 and the color monitor 50 each have their own unique color characteristics. Therefore, there is usually a difference in color tone between the display image P2 of the organ displayed on the screen of the color monitor 50 and the actual color tone of the organ P1 (color tone under illumination by the shadowless lamp 20 or the endoscopic light source). Moreover, this difference in color tone differs depending on the device actually used as the medical imaging device 30 and the device actually used as the color monitor 50. Therefore, when multiple types of cameras are used as the medical imaging device 30 or multiple types of devices are used as the color monitor 50, the color tone of the display image P2 of the organ will change depending on the specific aspect, i.e., which camera is used to capture the image and which color monitor is used to display it.

[0051] In the future, it is expected that many endoscopic cameras with various characteristics will be developed and offered by various providers. Similarly, it is expected that many color monitors with various characteristics will be developed and offered by various providers. When a medical image display system is constructed by combining devices with various color characteristics, the color tones of the displayed image P2 of the organ will also vary. This poses a major problem when a practitioner is trying to make various diagnoses based on the image on the color monitor 50.

[0052] In the case of the system described in Patent Document 3, image processing is performed on the captured image in a device corresponding to the imaging control unit 40, and an image that matches the observation direction of the practitioner is displayed on the color monitor 50, but no processing is performed to resolve differences in color characteristics between the devices. Also, in the case of the system described in Patent Document 4, three-dimensional volume data is generated in a device corresponding to the imaging control unit 40, and a CT image is displayed on the color monitor, but again no processing is performed to resolve differences in color characteristics between the devices.

[0053] As described above, conventional medical image display systems have the problem that when a medical image display system is configured by combining devices with various color characteristics, the color tones of images displayed on a color monitor are not consistent due to differences in the color characteristics of each device. In view of this problem, a first object of the present invention is to eliminate the differences in color characteristics of each device and enable image display with consistent color tones, even when a medical image display system is configured by combining devices with various color characteristics.

[0054] Furthermore, from the perspective of a surgeon who actually performs surgery, there are cases where a surgeon wants to observe only specific biological tissues in detail, but the conventional medical image display systems shown in FIGS. 1 and 2 cannot meet such a demand. For example, when the blood vessels of a certain organ are the target of surgery, the surgeon wants to proceed with the surgery while observing the blood vessels in detail. However, in conventional medical image display systems, the blood vessels are displayed in an overall reddish color on the color monitor, making it difficult to grasp the subtle differences in color tone and shading of the blood vessels from the image displayed on the color monitor. In view of these problems, a second object of the present invention is to enable image display with high visibility suitable for observing specific biological tissues.

[0055] Therefore, from Section 2 onwards, a color correction device for medical equipment according to the present invention that can achieve the above two objects will be described in detail.

[0056] <<< §2. Medical image display system according to the present invention >>> Here, the basic configuration and basic functions of a medical image display system according to the present invention and a color correction device for medical equipment that is incorporated into the system and used will be described.

[0057] <2.0 Basic Configuration of Medical Image Display System> Fig. 3 is a block diagram showing the basic configuration of a medical image display system 1000 including a medical equipment color correction device 100 according to the present invention. The medical image display system 1000 shown here is composed of three medical imaging devices 30X-30Z, four color monitors 50A-50D, and one medical equipment color correction device 100. Comparing the medical image display system 1000 shown in Fig. 3 with the conventional medical image display system shown in Fig. 2, the medical imaging devices 30X-30Z correspond to the medical imaging device 30, the color monitors 50A-50D correspond to the color monitor 50, and the medical equipment color correction device 100 corresponds to the imaging control unit 40. However, while the imaging control unit 40 shown in Figure 2 only has a relay function of directly passing on the imaging data obtained from the medical imaging device 30 to the color monitor 50, the color correction device for medical equipment 100 shown in Figure 3 has the function of performing a predetermined color correction process on the imaging data Dx to Dz obtained from the medical imaging devices 30X to 30Z and creating display data Da to Dd suitable for each color monitor 50A to 50D.

[0058] The medical imaging devices 30X-30Z may be any devices capable of capturing medical images. Specifically, they may be, for example, endoscopic cameras used in laparoscopic surgery, or ordinary video cameras installed in operating rooms. Of course, the image data obtained by imaging using the medical imaging devices 30X-30Z may be still image data or video data. Furthermore, the medical image display system 1000 shown here is not limited to use in surgery, but may also be used for imaging sample tissue excised from the human body and displaying the image on a color monitor for examination or diagnosis. When used for such purposes, a microscope camera, for example, may be used as the medical imaging device.

[0059] On the other hand, color monitors 50A-50D can be any device that has the function of displaying color images. Generally, color displays connected to a computer can be used as color monitors 50A-50D. As mentioned in §1, the locations where color monitors 50A-50D are installed can also be arbitrary.

[0060] For ease of explanation, an example is shown in which the medical image display system 1000 is configured by connecting three medical imaging devices 30X-30Z and four color monitors 50A-50D to the medical equipment color correction device 100, but the number of medical imaging devices and the number of color monitors may be arbitrary. To configure the medical image display system 1000 according to the present invention, it is sufficient to connect at least one medical imaging device 30 and at least one color monitor 50 to the medical equipment color correction device 100.

[0061] The medical device color correction device 100 shown in Figure 3 includes an imaging device individual conversion data storage unit 110, a specific tissue enhancement conversion data storage unit 120, a monitor individual conversion data storage unit 130, an imaging device color conversion unit 140, an enhancement tissue designation unit 150, a specific tissue enhancement color conversion unit 160, and a monitor color conversion unit 170, as shown enclosed by dashed lines in the figure. In practice, each of these components can be implemented by installing a dedicated program in a computer. Therefore, in practice, the medical device color correction device 100 shown in Figure 3 is configured by a computer with a dedicated program installed, and the medical imaging devices 30X-30Z and color monitors 50A-50D are connected to this computer. Note that in Figure 3, each component is depicted as a rectangular block, and the digital data exchanged between these rectangular blocks is depicted as an oval block.

[0062] This medical device color correction device 100 has a function of performing color correction suitable for display on color monitors 50A-50D on image data (actually, multiple image data arranged in time series to form a moving image) obtained by imaging using medical imaging devices 30X-30Z. In the block diagram of FIG. 3, the image data obtained by imaging using each medical imaging device 30X-30Z (image data input to medical device color correction device 100) are referred to as imaging data Dx, Dy, and Dz, respectively, and the image data provided to each color monitor 50A-50D (image data output from medical device color correction device 100) are referred to as display data Da, Db, Dc, and Dd, respectively. Therefore, the medical device color correction device 100 performs a predetermined color correction process on the input imaging data Dx, Dy, and Dz, and outputs the processed image data as display data Da, Db, Dc, and Dd.

[0063] This color correction process is performed as a three-stage conversion process. The first conversion process is performed on the input imaging data Dx, Dy, Dz, and is executed by the imaging device color converter 140 using the individual conversion data Cx, Cy, Cz stored in the imaging device individual conversion data storage unit 110. The purpose of this first conversion process is to eliminate differences in color characteristics between the medical imaging devices 30X, 30Y, 30Z, and the standard color image data Ds output from the imaging device color converter 140 becomes image data with standard color hues that eliminate differences in color characteristics between the devices.

[0064] The subsequent second conversion process is performed on the standard color image data Ds output from the imaging device color converter 140, and is executed by the specific tissue enhancement color converter 160 using the specific tissue enhancement conversion data (in the illustrated example, blood vessel enhancement data Ce, fat enhancement data Cf, and superficial membrane enhancement data Cg) stored in the specific tissue enhancement conversion data storage unit 120. The purpose of this second conversion process is to perform color conversion that emphasizes a specific biological tissue designated by the operator in order to display an image with visibility suitable for observing the specific biological tissue. The specific tissue enhancement image data (in the figure, data De, Df, and Dg are shown according to the designated biological tissue) output from the specific tissue enhancement color converter 160 becomes image data corresponding to an image with visibility suitable for observing the specific biological tissue.

[0065] The final third conversion process is performed on the specific-tissue-enhanced image data De, Df, and Dg output from the specific-tissue-enhancing color conversion section 160, and is executed by the monitor color conversion section 170 using the individual conversion data Ca, Cb, Cc, and Cd stored in the monitor individual conversion data storage section 130. The purpose of this third conversion process is to eliminate differences in color characteristics between the individual color monitors 50A-50D, and the display data Da, Db, Dc, and Dd output from the monitor color conversion section 170 are image data that have been corrected to eliminate differences in color characteristics between the individual devices.

[0066] 3, the downward arrows do not indicate the flow of individual image data themselves, but rather the flow of a conversion process related to color hues. For example, three downward arrows are drawn at the input stage of the image capture device color converter 140, while only one downward arrow is drawn at the output stage. This indicates that the three sets of input image data Dx, Dy, and Dz each have their own unique color hues, while the standard color image data Ds at the output side have a common standard color. In other words, the three downward arrows at the input stage indicate that even when the same subject is captured under the same conditions, the image capture data Dx, Dy, and Dz will be different data (data with different color hues) due to the unique color characteristics of each image capture device. The single downward arrow at the output stage indicates that the conversion process by the image capture device color converter 140 eliminates the difference in color hues among the image capture data Dx, Dy, and Dz, resulting in standard color image data Ds with a common color hue.

[0067] The specific-tissue-enhancing color converter 160 converts the color of this standard color image data Ds according to the specific biological tissue to be enhanced and outputs specific-tissue-enhancing image data (any of image data De, Df, or Dg). Therefore, the specific-tissue-enhancing image data depicted as a single downward arrow is provided to the input stage of the monitor color converter 170. The four downward arrows at the output stage of the monitor color converter 170 indicate that the color of the display data Da-Dd provided to each of the color monitors 50A-50D will differ depending on the color characteristics unique to each of the color monitors 50A-50D. In other words, even if the same specific-tissue-enhancing image data is provided to the input stage of the monitor color converter 170, different display data Da-Dd will be obtained at the output stage.

[0068] <2.1 Basic operations related to the first conversion process> Next, we will explain the basic functions of the individual components shown as rectangular blocks in the medical equipment color correction device 100. First, we will explain the basic functions of the individual conversion data storage unit for imaging device 110 and the color conversion unit for imaging device 140 related to the first conversion process (processing performed on the input imaging data Dx, Dy, Dz).

[0069] First, the imaging device individual conversion data storage unit 110 is a component that stores individual conversion data for converting the color characteristics of imaging data captured by a particular medical imaging device into standard color characteristics, taking into account the color characteristics unique to that device. In the embodiment shown in FIG. 3, three medical imaging devices 30X, 30Y, and 30Z are connected to the medical equipment color correction device 100, and the imaging device individual conversion data storage unit 110 provides individual conversion data Cx, Cy, and Cz corresponding to each of the three medical imaging devices 30X, 30Y, and 30Z. For example, the individual conversion data Cx is conversion data for converting the color characteristics of imaging data Dx captured by the medical imaging device 30X into standard color characteristics, taking into account the color characteristics unique to the medical imaging device 30X. The substance of such conversion data will be described in detail in Section 3.

[0070] The color converter for imaging devices 140 is a component that generates standard color image data by performing color conversion on imaging data input from a specific medical imaging device using individual conversion data for the specific medical imaging device stored in the individual conversion data storage unit for imaging devices 110. For example, when imaging data Dx is provided from a medical imaging device 30X, the color converter for imaging devices 140 performs color conversion on the imaging data Dx using the individual conversion data Cx for the medical imaging device 30X stored in the individual conversion data storage unit for imaging devices 110, thereby generating standard color image data Ds.

[0071] In the illustrated example, three medical imaging devices 30X, 30Y, and 30Z are connected to the medical equipment color correction device 100, and therefore three sets of individual conversion data Cx, Cy, and Cz are prepared in the individual conversion data storage unit for imaging devices 110. However, in general, if it is expected that a plurality of I medical imaging devices will be used, it is sufficient to store the individual conversion data for these I medical imaging devices in the individual conversion data storage unit for imaging devices 110. In this case, the color conversion unit for imaging devices 140 performs color conversion using the ith individual conversion data Ci (the individual conversion data for the ith medical imaging device 30i) on the imaging data Di input from the ith (1≦i≦I) medical imaging device 30i, and generates standard color image data Ds.

[0072] In this way, the standard color image data Ds obtained by the color conversion process by the imaging device color converter 140 converts the color characteristics specific to each medical imaging device into standard color characteristics, resulting in image data with a unified color tone that eliminates differences in color characteristics between devices. Therefore, when the same subject is photographed using three medical imaging devices 30X, 30Y, and 30Z under the same imaging conditions, the contents of the resulting imaging data Dx, Dy, and Dz will be different from one another, but the three standard color image data (here, referred to as Dsx, Dsy, and Dsz) obtained by color conversion process for these imaging data Dx, Dy, and Dz will theoretically be the same image data. In other words, the color hues of the images represented by the individual imaging data Dx, Dy, and Dz will differ from one another depending on the color characteristics specific to each imaging device, but the color hues of the images represented by the standard color image data Dsx, Dsy, and Dsz obtained after color conversion by the imaging device color converter 140 will theoretically be the same.

[0073] <2.2 Basic operations for the second conversion process> Next, we will describe the basic functions of the specific tissue emphasis conversion data storage unit 120, the emphasis tissue designation unit 150, and the specific tissue emphasis color conversion unit 160 regarding the second conversion process (processing performed on the standard color image data Ds output from the color conversion unit 140 for the imaging device).

[0074] One of the important features of the medical equipment color correction device 100 shown in Figure 3 is that the imaging data Dx, Dy, Dz obtained from each medical imaging device 30X, 30Y, 30Z is first converted into standard color image data Ds by color conversion processing by the imaging device color conversion unit 140 (first conversion processing), this standard color image data Ds is then subjected to color conversion processing by the specific tissue emphasis color conversion unit 160 to generate specific tissue emphasis image data De, Df, Dg in which specific biological tissues are emphasised (second conversion processing), and this is further subjected to color conversion processing by the monitor color conversion unit 170 to generate display data Da to Dd corresponding to each color monitor 50A to 50D (third conversion processing). Since the target of color conversion processing by the specific tissue enhancement color conversion unit 160 is standard color image data Ds with standard color shades, color characteristics specific to each medical imaging device 30X, 30Y, 30Z do not need to be taken into consideration when performing color conversion processing by the specific tissue enhancement color conversion unit 160.

[0075] Therefore, the specific tissue enhancement conversion data storage unit 120 may store specific tissue enhancement conversion data for performing color conversion on standard color image data Ds having standard color shades to enhance specific biological tissues. In the embodiment shown in FIG. 3, the specific tissue enhancement conversion data storage unit 120 stores three types of specific tissue enhancement conversion data. Specifically, the three types of specific tissue enhancement conversion data are: blood vessel enhancement data Ce for performing color conversion to enhance blood vessels; fat enhancement data Cf for performing color conversion to enhance fat; and superficial membrane enhancement data Cg for performing color conversion to enhance superficial membranes (membranes that constitute the surface layers of organs, etc.). The substance of these specific tissue enhancement conversion data Ce, Cf, and Cg, as well as examples of "highlighting" specific biological tissues, will be described in detail in §6.

[0076] The emphasis tissue designation unit 150 is a component that receives a designation input that designates a specific biological tissue to be highlighted. This designation input is made by the operator of the medical instrument color correction device 100 (for example, the practitioner during surgery). The operator performs an input that designates the biological tissue to be highlighted in the image to be displayed on the color monitors 50A to 50D. In short, the operator can designate a specific biological tissue from the perspective of which biological tissue he or she wants to display an image with improved visibility, or in other words, which biological tissue he or she wants to display an image suitable for observing. The emphasis tissue designation unit 150 plays a role in transmitting the designation input from the operator to the specific tissue emphasis color conversion unit 160.

[0077] The specific-tissue-enhancing color converter 160 generates specific-tissue-enhancing image data by performing color conversion on the standard color image data Ds using specific-tissue-enhancing conversion data stored in the specific-tissue-enhancing conversion data storage unit 120. The specific-tissue-enhancing conversion data is used for color conversion to enhance a specific biological tissue designated by a designated input. For example, if the operator designates "blood vessels" as the specific biological tissue to be highlighted, the highlighted-tissue designation unit 150 notifies the specific-tissue-enhancing color converter 160 that the target of highlighting is "blood vessels." The specific-tissue-enhancing color converter 160 then selects blood vessel enhancement data Ce from the three sets of specific-tissue-enhancing conversion data stored in the specific-tissue-enhancing conversion data storage unit 120, performs color conversion processing on the standard color image data Ds using the blood vessel enhancement data Ce, and outputs specific-tissue-enhancing image data De for the blood vessels as the processed image data. Similarly, if "fat" or "surface membrane" is specified as the target for highlighting, color conversion processing using fat-enhanced data Cf and surface membrane-enhanced data Cg will output specific tissue-enhanced image data Df for fat and specific tissue-enhanced image data Dg for the surface membrane.

[0078] In the illustrated example, three types of biological tissues, "blood vessels," "fat," and "surface membrane," are prepared as targets for highlighting, but it is of course possible to specify various other biological tissues, such as "bone," "cartilage," and "muscle," as targets for highlighting. In other words, when multiple types of biological tissues are to be targeted for highlighting, specific-tissue-enhancing conversion data for multiple J types of biological tissues are stored in the specific-tissue-enhancing conversion data storage unit 120, and when the specific-tissue-enhancing color conversion unit 160 receives a designation input specifying the jth (1≦j≦J) biological tissue from the emphasis-tissue designation unit 150, it performs color conversion using the jth specific-tissue-enhancing conversion data Cj (conversion data for emphasizing the jth biological tissue) to generate specific-tissue-enhancing image data.

[0079] The input to the emphasis tissue designation unit 150 does not necessarily have to designate a single biological tissue, but may designate multiple biological tissues. For example, if the operator wishes to highlight both “blood vessels” and “fat,” the operator simply inputs both of these designations to the emphasis tissue designation unit 150. In this case, the emphasis tissue designation unit 150 transmits to the specific tissue enhancement color conversion unit 160 the designation of both “blood vessels” and “fat.” The specific tissue enhancement color conversion unit 160 then performs color conversion using the blood vessel enhancement data Ce and color conversion using the fat enhancement data Cf on the standard color image data Ds, outputting the specific tissue enhancement image data Def. The display on the color monitor using this specific tissue enhancement image data Def highlights both “blood vessels” and “fat.”

[0080] In short, to enable multiple biological tissues to be specified as targets for highlighting, the highlighting tissue designation unit 150 is provided with a function for accepting a designation input that designates multiple H (H≦J) biological tissues in duplicate (J is the total number of specific tissue emphasis conversion data stored in the specific tissue emphasis conversion data storage unit 120), and when the specific tissue emphasis color conversion unit 160 receives a designation input from the highlighting tissue designation unit 150 that designates multiple H biological tissues, it performs redundant color conversion using the multiple H specific tissue emphasis conversion data corresponding to these multiple H biological tissues to generate specific tissue emphasis image data.

[0081] The emphasis tissue designation unit 150 can also accept a designation input of "not designating any biological tissue" (hereinafter referred to as "empty designation input"). When this "empty designation input" is received, the specific tissue emphasis color conversion unit 160 outputs the input standard color image data Ds as is without performing any substantial color conversion processing. In this case, the standard color image data Ds is output as is as the specific tissue emphasis image data Ds. Naturally, the display on the color monitor using this specific tissue emphasis image data Ds will be an image in which no biological tissue is emphasized.

[0082] In short, in the embodiment described here, the emphasis tissue designation unit 150 has the function of accepting an empty designation input indicating that no biological tissue is designated, and when the color conversion unit 160 for specific tissue emphasis accepts an empty designation input from the emphasis tissue designation unit 150, it will output the standard color image data Ds as is as specific tissue emphasis image data without performing color conversion.

[0083] Of course, it is also possible to provide a dedicated color correction device 100 that always targets only specific biological tissues for highlighting. For example, in an embodiment where only "blood vessels" need to be targeted for highlighting and other biological tissues do not need to be highlighted, it is sufficient to store only blood vessel highlighting data Ce in the specific tissue highlighting conversion data storage unit 120. In this case, when the specific tissue highlighting color conversion unit 160 performs color conversion, it always uses blood vessel highlighting data Ce, and specific tissue highlighting image data De is always output. Of course, even in this case, the highlighting tissue designation unit 150 can be equipped with a function to accept a null designation input. In this case, the designation input to the highlighting tissue designation unit 150 is an input that selects whether to highlight (input specifying blood vessels) or not to highlight (blank designation input).

[0084] Furthermore, if the emphasis tissue designation unit 150 is provided with a function for receiving different designation inputs for each of the color monitors 50A to 50D, it is possible to display images in which different biological tissues are emphasized on each of the color monitors 50A to 50D. For example, if the emphasis tissue designation unit 150 receives a designation input of "blank" for color monitor 50A, a designation input of "blood vessel" for color monitor 50B, a designation input of "fat" for color monitor 50C, and a designation input of "superficial membrane" for color monitor 50D, the specific tissue emphasis color conversion unit 160 will output four types of specific tissue emphasis image data Ds, De, Df, and Dg.

[0085] In this case, monitor color conversion unit 170 performs color conversion on image data Ds using individual conversion data Ca to generate display data Da, performs color conversion on image data De using individual conversion data Cb to generate display data Db, performs color conversion on image data Df using individual conversion data Cc to generate display data Dc, and performs color conversion on image data Dg using individual conversion data Cd to generate display data Dd. In this way, a standard color image is displayed on color monitor 50A, an image with "blood vessels" emphasized is displayed on color monitor 50B, an image with "fat" emphasized is displayed on color monitor 50C, and an image with "surface membrane" emphasized is displayed on color monitor 50D.

[0086] <2.3 Basic operations related to the third conversion process> Finally, we will describe the basic functions of the monitor individual conversion data storage unit 130 and the monitor color conversion unit 170 regarding the third conversion process (processing performed on the specific tissue-enhanced image data De, Df, Dg, etc. output from the specific tissue-enhancing color conversion unit 160).

[0087] First, the monitor individual conversion data storage unit 130 is a component that stores individual conversion data Ca through Cd corresponding to each of the color monitors 50A through 50D. These individual conversion data Ca through Cd are conversion data for performing color conversion that takes into account the color characteristics unique to each corresponding specific color monitor 50A through 50D, so that an image with standard color characteristics is displayed on that color monitor 50A through 50D.

[0088] On the other hand, the monitor color converter 170 is a component that performs color conversion on the specific-tissue-emphasized image data provided by the specific-tissue-emphasized color converter 160 using individual conversion data for a specific color monitor stored in the monitor individual conversion data storage unit 130, to generate display data, and outputs the generated display data to the specific color monitor. For example, in the case where specific-tissue-emphasized image data De that emphasizes "blood vessels" is provided to the monitor color converter 170 from the specific-tissue-emphasized color converter 160 and an image based on this image data De is displayed on the first color monitor 50A, the monitor color converter 170 performs color conversion on the specific-tissue-emphasized image data De using the individual conversion data Ca for the first color monitor 50A stored in the monitor individual conversion data storage unit 130, to generate display data Da, and outputs the generated display data Da to the first color monitor 50A.

[0089] As described above, the individual conversion data Cx-Cz stored in the imaging device individual conversion data storage unit 110 is data that performs conversion to eliminate differences in the inherent color characteristics of the medical imaging devices 30X-30Z, and the imaging device color converter 140 performs processing to generate standard color image data Ds that eliminates these differences in inherent color characteristics.In contrast, the individual conversion data Ca-Cd stored in the monitor individual conversion data storage unit 130 is data that performs conversion to eliminate differences in the inherent color characteristics of the color monitors 50A-50D, and the monitor color converter 170 performs processing to eliminate these differences in inherent color characteristics and generate display data Da-Dd that is suitable for each of the color monitors 50A-50D so that the same color shades are displayed on the screens of all the color monitors.

[0090] In the illustrated example, four color monitors 50A-50D are connected to medical equipment color correction device 100, and therefore four sets of individual conversion data Ca-Cd are prepared in monitor individual conversion data storage unit 130. However, in general, if it is expected that a plurality of K color monitors will be used, it is sufficient to store the individual conversion data for these K medical imaging devices in monitor individual conversion data storage unit 130. In this case, when generating display data Dk to be output to the kth (1≦k≦K) color monitor 50k, monitor color conversion unit 170 simply performs color conversion using the kth individual conversion data Ck (the individual conversion data for the kth color monitor 50k).

[0091] Note that when the same image data is provided to and displayed on multiple color monitors with different color characteristics, the technology itself of color converting image data using individual conversion data prepared for each color monitor in order to uniformly display the color tones of the images displayed on the screens of the individual color monitors is already known. In particular, in the case of color monitors used by professionals such as printers, individual conversion data (generally referred to as color profile data) that takes into account the color characteristics unique to that color monitor is often prepared in advance. In this way, if color profile data is attached to a color monitor, that color profile data can be used as the individual conversion data to be stored in the monitor individual conversion data storage unit 130. Since the method of creating color profile data unique to each color monitor is also already known, a detailed description thereof will be omitted here.

[0092] <2.4 Characteristics of the color correction device for medical equipment according to the present invention> As described above, the color correction device 100 for medical equipment according to the present invention performs three stages of color conversion processing: a first conversion processing by the color conversion unit 140 for the imaging device, a second conversion processing by the color conversion unit 160 for highlighting specific tissue, and a third conversion processing by the color conversion unit 170 for the monitor.

[0093] The first and third conversion processes serve to eliminate differences in color characteristics between devices, and these processes achieve the first object of the present invention, which is to "eliminate differences in color characteristics between devices and enable image display with a unified color tone, even when a medical image display system is constructed by combining devices with various color characteristics."

[0094] The second conversion process also serves to highlight specific biological tissues designated by the operator, thereby achieving the second object of the present invention, which is to "enable image display with visibility suitable for observing specific biological tissues when using a medical image display system." For example, as will be described in detail later, if the operator designates specific biological tissues such as "blood vessels," "fat," or "surface membrane" as targets for highlighting, a display with improved visibility of the designated biological tissues can be obtained. For example, the color of blood, which would otherwise be saturated during imaging in conventional systems, can now be accurately read on a color monitor.

[0095] Furthermore, because the second conversion process is performed between the first and third conversion processes, it can be performed on the standard color image data Ds obtained by the first conversion process. Therefore, when performing the second conversion process, it is not necessary to consider the "device-specific color characteristics" of each medical imaging device; it is sufficient to always perform uniform color correction on the standard color image data Ds having standard color characteristics. Furthermore, because the third conversion process is performed after the second conversion process, it is not necessary to consider the "device-specific color characteristics" of the color monitor on which the image will ultimately be displayed. In other words, it is sufficient to always prepare uniform specific-tissue-enhancing conversion data in the specific-tissue-enhancing conversion data storage unit 120, regardless of the model of medical imaging device or color monitor actually used.

[0096] In this way, the medical equipment color correction device 100 according to the present invention can be used with any model of medical imaging device connected to the input side and any model of color monitor connected to the output side, regardless of the manufacturer's model, without considering differences in color characteristics between models. Therefore, any facility that has introduced the medical image display system 1000 according to the present invention, whether it is a hospital or a research facility, can make color judgments based on the same standards.

[0097] <<< §3. Entity of Individual Conversion Data for Imaging Devices >>> Here, we will provide a more detailed explanation of the substance of the individual conversion data Cx, Cy, and Cz for imaging devices stored in the individual conversion data storage unit 110 for imaging devices, which is a component of the medical equipment color correction device 100 shown in Fig. 3. As already explained in Section 2, the individual conversion data Cx, Cy, and Cz are conversion data for converting the color characteristics of each piece of imaging data Dx, Dy, and Dz into standard color characteristics, taking into account the unique color characteristics of the corresponding medical imaging devices 30X, 30Y, and 30Z. Here, we will describe the specific procedure for creating the individual conversion data Cx for the medical imaging device 30X, with reference to the block diagram in Fig. 4.

[0098] Generally, image data handled by imaging devices and color monitors is composed of a collection of numerous pixels. Each pixel typically has a pixel value for each of the three primary color components R, G, and B. For example, if one color component is represented by 8-bit data, the pixel value of one pixel is represented by 24-bit data. If the pixel values ​​of each pixel constituting the imaging data Dx obtained from the medical imaging device 30X are represented by the three primary color components Rold, Gold, and Bold, and the pixel values ​​of each pixel constituting the standard color image data Ds obtained by color conversion by the imaging device color converter 140 are represented by the three primary color components Rnew, Gnew, and Bnew, the individual conversion data Cx stored in the imaging device individual conversion data storage unit 110 is conversion data for converting the three primary color components Rold, Gold, and Bold of the imaging data Dx into the three primary color components Rnew, Gnew, and Bnew of the standard color image data Ds. That is, any information that can uniquely determine another value (Rnew, Gnew, Bnew) based on any value (Rold, Gold, Bold) can be used as the individual conversion data Cx.

[0099] To create such individual conversion data Cx, actual measurements can be performed using a color chart that displays color samples. As shown in Figure 4, a white light source 60 and a color chart 70 are prepared. In this example, a light source conforming to the CIE standard illuminant D65 (hereinafter simply referred to as the "D65 illuminant") is used as the white light source 60. This D65 illuminant is a standard illuminant defined by the International Commission on Illumination (CIE). It is considered a hypothetical light source with a spectrum equivalent to the average noonday light in Europe / Northern Europe, and its correlated color temperature is approximately 6500 K. Note that the "D65 illuminant" itself is not actually available commercially. Therefore, in practice, a commercially available device (e.g., an LED light source) that emits light similar to the standard illuminant D65 can be used as the light source 60 shown in Figure 4. The reason for using the D65 illuminant as a light source will be discussed in Section 5.

[0100] On the other hand, a color chart 70 is a plate-like object on which color samples are arranged, and is used for checking the color reproduction of various imaging devices and for color calibration. Plan views of several specific examples of this color chart 70 are shown in Figures 5(a), (b), and (c). The three-primary color chart 71 shown in Figure 5(a) is the simplest color chart, with red, blue, and green primary color samples arranged on it. The three hatched areas in the figure represent the primary color sample areas, and each area is translucent, allowing the red, blue, and green color components to pass through. Therefore, when a white light source 60 is placed behind the three-primary color chart 71 and the three-primary color chart 71 is observed from the front, each area appears as a red, blue, or green window.

[0101] The multi-color chart 72 shown in Figure 5(b) is a two-dimensional array of numerous square color samples. It is typically used to verify the color reproducibility of cameras and monitors in the low- to medium-saturation range. While the primary color chart 71 shown in Figure 5(a) contains only the three primary colors of red, blue, and green, the multi-color chart 72 shown in Figure 5(b) contains 153 color samples, allowing for more detailed color calibration. On the other hand, the wide color gamut color chart 73 shown in Figure 5(c) does not contain as many color samples, but it does cover the wide color gamut defined by the BT.2020 international standard for ultra-high-definition televisions. This wide color gamut color chart 73 is suitable for verifying the color reproducibility of highly saturated colors and primary colors. A specific color calibration method using this chart will be described in Section 4.

[0102] Although Fig. 5 shows three types of color charts 71, 72, and 73, there are, of course, a variety of color charts available on the market, and the color charts used in the present invention are not limited to the three types shown in Fig. 5. For example, to compensate for mid-saturation colors, a color chart generally known as a Macbeth chart may also be used.

[0103] As shown in FIG. 4, a light source 60 is placed behind a color chart 70, and a medical imaging device 30X (e.g., an endoscopic camera) is placed in front of the color chart 70, and an image of the front of the color chart 70 is captured by the medical imaging device 30X. Transmitted light within each color sample area of ​​the color chart 70 is incident on the light receiving surface of the medical imaging device 30X. The dashed arrows in FIG. 4 indicate the path of light from the light source 60. Of the imaging data obtained in this manner, the three primary color (R, G, B) color components for each color sample area of ​​the color chart 70 will be referred to as imaging color data Dt(Rt, Gt, Bt).

[0104] For example, if the three-primary color chart 71 shown in Fig. 5(a) is used as the color chart 70, captured color data Dt1 (Rt1, Gt1, Bt1) for the red region, captured color data Dt2 (Rt2, Gt2, Bt2) for the green region, and captured color data Dt3 (Rt3, Gt3, Bt3) for the red region will be obtained. Similarly, if the multi-color chart 72 shown in Fig. 5(b) is used as the color chart 70, captured color data Dt1 (Rt1, Gt1, Bt1) for the first color sample through captured color data Dt153 (Rt153, Gt153, Bt153) for the 153rd color sample will be obtained.

[0105] Meanwhile, the original color data DT (RT, GT, BT) is measured for each color sample of the color chart 70. The dashed-dotted arrows in FIG. 4 indicate that the color data DT is obtained using this measurement process. For example, if the three-primary color chart 71 shown in FIG. 5(a) is used as the color chart 70, original color data DT1 (RT1, GT1, BT1) for the red region, original color data DT2 (RT2, GT2, BT2) for the green region, and original color data DT3 (RT3, GT3, BT3) for the blue region will be obtained. Similarly, if the multi-color chart 72 shown in FIG. 5(b) is used as the color chart 70, original color data DT1 (RT1, GT1, BT1) for the first color sample through original color data DT153 (RT153, GT153, BT153) for the 153rd color sample will be obtained.

[0106] The original color data DT can be measured, for example, by placing a spectrophotometer (colorimeter) at the position of the medical imaging device 30X shown in Figure 4, measuring the spectrum of each area of ​​the individual color sample (a measurement system similar to that shown in Figure 7(a) described below can be used), and calculating the values ​​of the three primary color components (RT, GT, BT) based on this spectral data. However, commercially available color charts 70 may come with original color data DT (RT, GT, BT) obtained by measurement at the supplier, and in such cases, the measurement process can be omitted and the original color data DT (RT, GT, BT) that was included can be used as is.

[0107] Once the captured color data Dt (Rt, Gt, Bt) and original color data DT (RT, GT, BT) for the same color chart 70 are obtained in this way, these data can be provided to the individual conversion data creation unit 80 to obtain the individual conversion data Cx. The individual conversion data creation unit 80 is actually a device configured by installing a dedicated program in a computer, and performs processing to recognize the color characteristics unique to the medical imaging device 30X based on the difference between the captured color data Dt (Rt, Gt, Bt) for each color sample and the original color data DT (RT, GT, BT), and to create the individual conversion data Cx for matching the captured color data Dt (Rt, Gt, Bt) to the original color data DT (RT, GT, BT).

[0108] When the three-primary-color chart 71 shown in FIG. 5( a) is used, the individual conversion data Cx (data enabling conversion of any color) must be created based on the results of comparing the data Dt (Rt, Gt, Bt) with the data DT (RT, GT, BT) for each of the three color samples. This results in a relatively low level of accuracy for the resulting individual conversion data Cx. In contrast, when the multi-color chart 72 shown in FIG. 5( b) is used, the individual conversion data Cx can be created based on the results of comparing the data Dt (Rt, Gt, Bt) with the data DT (RT, GT, BT) for each of the 153 color samples. This results in more accurate individual conversion data Cx. The process of creating the individual conversion data Cx based on the results of comparing the data Dt (Rt, Gt, Bt) with the data DT (RT, GT, BT) for several color samples is a well-known color calibration method. Therefore, a detailed description of the processing algorithm used in the individual conversion data creation unit 80 will be omitted here.

[0109] As described above, the individual conversion data Cx is conversion data for converting the three primary color components Rold, Gold, and Bold of each pixel constituting the imaging data Dx obtained by the medical imaging device 30X into the three primary color components Rnew, Gnew, and Bnew of each pixel constituting the standard color image data Ds. Such individual conversion data Cx can be prepared, for example, in the form of a lookup table LUT as shown in FIG. 6(a). The left half of the table in FIG. 6(a) shows the three primary color components Rold, Gold, and Bold of each pixel constituting the image data before conversion (imaging data Dx), and the right half shows the three primary color components Rnew, Gnew, and Bnew of each pixel constituting the image data after conversion (standard color image data Ds). In this example, each color component is represented by an 8-bit (0 to 255) numerical value. The left half of the table has 256 x 256 x 256 possible columns ranging from (0,0,0) to (255,255,255), and the right half of the table lists the new color component values ​​corresponding to each of these columns.

[0110] Therefore, by using the individual conversion data consisting of this lookup table LUT, when an arbitrary combination of pixel values ​​(l, m, n) indicating the three primary color components is given, it can be converted into a predetermined combination of pixel values ​​(l', m', n'). In this way, the individual conversion data Cx stored in the individual conversion data storage unit 110 for the imaging device can be composed of a lookup table LUT that converts combinations of color components of pixels that make up the imaging data Dx into combinations of color components of pixels that make up the standard color image data Ds.

[0111] The individual conversion data Cx can also be prepared in the form of a function as shown in Fig. 6(b). In this case, a function is prepared that calculates the combination of each color component of the pixels that make up the standard color image data Ds by providing the combination of each color component of the pixels that make up the imaging data Dx as variable values, and this function is stored as the individual conversion data Cx in the individual conversion data storage unit 110 for the imaging device.

[0112] For example, the relationship between the three primary color components (Rold, Gold, Bold) and (Rnew, Gnew, Bnew) in the lookup table LUT shown in FIG. 6(a) can be expressed as follows: Rnew = f1(Rold,Gold,Bold ) Gnew = f2(Rold,Gold,Bold ) Bnew = f3(Rold,Gold,Bold ) If the above functions f1, f2, and f3 can be expressed as the individual conversion data Cx, then the above functions f1, f2, and f3 can be used as the individual conversion data Cx instead of the lookup table LUT. In general, it is difficult to find a function that can perform exactly the same conversion as that performed by the lookup table LUT, but in practice, there is no problem in using a function that can approximate the conversion performed by the lookup table LUT to a certain extent as the individual conversion data Cx.

[0113] As described above, a lookup table LUT for 8-bit pixel values ​​requires 256 x 256 x 256 sets of conversion data. Therefore, when a lookup table LUT is used as the individual conversion data Cx, a fairly large storage capacity must be secured in the individual conversion data storage unit 110 for the imaging device. In contrast, when a function is used as the individual conversion data Cx, the storage capacity required for the individual conversion data storage unit 110 for the imaging device can be significantly reduced.

[0114] While the lookup table LUT shown in Fig. 6(a) and the function shown in Fig. 6(b) have been exemplified above as the entity of the individual conversion data stored in the imaging device individual conversion data storage unit 110, similar forms can also be adopted for the individual conversion data stored in the monitor individual conversion data storage unit 130. That is, the individual conversion data (e.g., data Ca) stored in the monitor individual conversion data storage unit 130 can be a lookup table that converts combinations of color components of pixels that make up specific tissue-enhanced image data (e.g., data De) into combinations of color components of pixels that make up display data (e.g., data Da), or a function that calculates combinations of color components of pixels that make up display data (e.g., data Da) by providing combinations of color components of pixels that make up specific tissue-enhanced image data (e.g., data De) as variable values.

[0115] <<< §4. Expansion to 4K / 8K Image Systems >>> In recent years, 4K / 8K satellite broadcasting has begun, and 4K and 8K televisions capable of displaying high-resolution images are beginning to become commonplace in ordinary homes. However, currently available medical image display systems do not employ color management platforms designed for such 4K / 8K images, making it difficult to display high-resolution biological tissue images on color monitors. Therefore, the inventors of the present application investigated the degree of color reproducibility achieved on color monitors for conventional, general medical image display systems, such as those shown in Figures 1 and 2. The results of these measurements are described below.

[0116] FIG. 7 shows the basic steps in a measurement to check the color reproducibility on a color monitor of a medical image display system (the dashed lines in the figure indicate the path of light). The measurement described here uses a color chart 70 on which multiple color samples are arranged. In the first step shown in FIG. 7(a), the original color of each color sample on the color chart 70 is measured. Meanwhile, in the second step shown in FIG. 7(b), each color sample on the color chart 70 is imaged by the medical image display system and displayed on a color monitor, and the colors displayed on the color monitor are measured. Specifically, the measurement is performed in the following manner.

[0117] First, in the first step, as shown in Fig. 7(a), a light source 60 is placed behind a color chart 70, a spectroscopic analyzer 90 is placed in front of the color chart 70, and the spectrum of transmitted light from each color sample placed on the color chart 70 is measured to obtain spectral data Dsp1. For example, if the multi-color chart 72 shown in Fig. 5(b) is used as the color chart 70, spectral data Dsp1 of transmitted light will be obtained for each of the 153 sets of color samples.

[0118] On the other hand, in the second procedure, as shown in FIG. 7(b), a light source 60 is placed behind the color chart 70, and a medical imaging device 30 (e.g., an endoscopic camera) is placed in front of the color chart 70 to capture an image of the color chart 70 and obtain image data Dp. This image data Dp is sent to a color monitor 50 via an imaging control unit 40, and the captured image of the color chart 70 is displayed on the screen of the color monitor 50. Here, the medical imaging device 30, imaging control unit 40, and color monitor 50 are components of a medical image display system, as shown in FIG. 2. Furthermore, a spectroscopic analyzer 90 is placed in front of the color monitor 50 to measure the spectrum of each color sample of the color chart 70 displayed on the color monitor 50 and obtain spectral data Dsp2. For example, if the multi-color chart 72 shown in FIG. 5(b) is used as the color chart 70, spectral data Dsp2 of transmitted light can be obtained for each of the 153 sets of color samples.

[0119] The same D65 light source is used as the light source 60 in both Figures 7(a) and (b), and the same multi-color chart 72 is used as the color chart 70. Therefore, the first procedure shown in Figure 7(a) and the second procedure shown in Figure 7(b) share the commonality of illuminating the same subject (multi-color chart 72) under the same lighting environment (D65 light source). However, the spectral data Dsp1 obtained in the former procedure is a spectrum obtained by directly measuring the transmitted light through the color sample, whereas the spectral data Dsp2 obtained in the latter procedure is a spectrum obtained when the color sample is observed through a medical image display system (medical imaging device 30, imaging control unit 40, color monitor 50). Note that an endoscopic camera is used as the medical imaging device 30, but the measurement was performed with the endoscopic light source built into the endoscopic camera turned off. That is, in the second procedure shown in Figure 7(b), the only light source illuminating the color chart 70 is the light source 60 (D65 light source).

[0120] Therefore, by comparing the spectral data Dsp1 and Dsp2, it is possible to evaluate the color reproducibility when observed through a medical image display system. Generally, a two-dimensional chromaticity diagram is used to evaluate color reproducibility. Here, we show the results of evaluating color reproducibility using a u'v' chromaticity diagram as a two-dimensional chromaticity diagram. Figure 8 shows an example of such an evaluation result, a u'v' chromaticity diagram showing the color distribution obtained by performing the measurement procedure shown in Figure 7 on the multi-color chart 72 shown in Figure 5(b).

[0121] Specifically, Figure 8(a) plots the colors corresponding to the spectral data Dsp1 obtained by the first procedure shown in Figure 7(a) on a u'v' chromaticity diagram. This shows the original color distribution (measured under a D65 light source) of the multi-color chart 72 itself shown in Figure 5(b). As mentioned above, a total of 135 sets of color samples are arranged on the multi-color chart 72, and the first procedure shown in Figure 7(a) obtains spectral data Dsp1 for each of these 135 sets of color samples. Then, by calculating the u'v' values ​​for each color sample based on the spectral data Dsp1 and plotting them on a u'v' chromaticity diagram, the color distribution shown in Figure 8(a) is obtained. The tiny white squares on the plot represent the colors of each individual color sample. Note that the method of calculating predetermined color values ​​(RGB values, tristimulus values, u'v' values, etc.) based on arbitrary spectral data is a well-known method that has been known for a long time, and therefore a detailed description thereof will be omitted here.

[0122] Similarly, Figure 8(b) plots the colors corresponding to the spectral data Dsp2 obtained by the second procedure shown in Figure 7(b) on a u'v' chromaticity diagram. This shows the color distribution (photographed under a D65 light source) obtained by observing the multi-color chart 72 shown in Figure 5(b) through a conventional medical image display system (observing the screen of the color monitor 50). The second procedure shown in Figure 7(b) also obtains spectral data Dsp2 for each of the 135 color samples. Therefore, by calculating the u'v' values ​​for each color sample based on the spectral data Dsp2 and plotting them on the u'v' chromaticity diagram, the color distribution shown in Figure 8(b) is obtained. The tiny black squares on the plot represent the colors of the individual color samples.

[0123] Next, let's take a closer look at the u'v' chromaticity diagram shown in Figure 8(a). The horizontal axis of this diagram is the u' axis, and the vertical axis is the v' axis. Any coordinate point (u', v') corresponds to a specific color. Therefore, each tiny white square plotted on the diagram represents a specific color sample. Points R, G, and B (shown as white circles) on the u'v' chromaticity diagram correspond to ideal red, green, and blue, respectively. The area near the triangle enclosed by the solid lines passing through these points R, G, and B represents the actual color region E, where actual colors are distributed. While it would be desirable for an imaging system to cover the entire actual color region E, achieving such an imaging system is extremely difficult. The boundary of this actual color region E represents the most saturated colors. Tracing this boundary from R to G to B reveals a shift in hue from wavelength 660 nm to 440 nm while maintaining high saturation. In FIG. 8(a), the points marked with the symbol W (points marked with an x) correspond to white.

[0124] In this way, the distribution of hue and saturation can be shown on a two-dimensional u'v' chromaticity diagram. To show lightness, it is necessary to add a lightness axis perpendicular to the plane of the u'v' chromaticity diagram (the plane of the diagram) and define a three-dimensional color space. However, for the sake of convenience, we will use the two-dimensional u'v' chromaticity diagram to explain the color distribution of hue and saturation.

[0125] The u'v' chromaticity diagram used in this application features dashed triangles labeled "BT.709" and "BT.2020." The BT.709 triangle represents the color gamut defined by the BT.709 international standard for high-definition televisions. A color monitor compatible with high-definition televisions (equivalent to 2K) can display any color within this color gamut. The BT.2020 triangle represents the color gamut defined by the BT.2020 international standard for ultra-high-definition televisions. A color monitor compatible with 4K / 8K televisions can display any color within this color gamut. As shown in the figure, the BT.2020 triangle is wider than the BT.709 triangle, indicating that a color monitor compatible with 4K / 8K televisions can display a wider color gamut.

[0126] As mentioned above, Figure 8(a) shows the original color distribution of the multi-color chart 72 itself, as shown in Figure 5(b). Therefore, the color distribution of the 135 color samples arranged on this multi-color chart 72 fully covers the area of ​​triangle BT.709 and also covers the area of ​​triangle BT.2020 to some extent. However, when this multi-color chart 72 is viewed through a conventional medical image display system, the color distribution is significantly narrowed, as shown in Figure 8(b). In other words, the color monitor 50 of the conventional medical image display system does not fully reproduce the original color distribution of the subject (biological tissue), resulting in significantly reduced color reproducibility compared to viewing the subject directly with the naked eye. In particular, with this conventional system, orange is split into yellow and red on the color monitor, and intermediate colors are reduced to emphasize the yellow and red.

[0127] The inventors of the present application also performed measurements using a different color chart, following the basic procedure shown in FIG. 7 . While the results shown in FIG. 8 are for an example using the multi-color chart 72 shown in FIG. 5( b) as the subject, similar measurements were performed using the wide color gamut color chart 73 shown in FIG. 5( c) as the subject instead. The wide color gamut color chart 73 was developed by the applicant of the present application for color management of 4K8K images, and is a color chart on which the color samples necessary to cover the area of ​​the BT.2020 triangle are arranged. The configuration of a wide color gamut color chart compatible with color management for 4K8K images is described in detail in International Publication WO2017 / 170910 and International Application PCT / JP2018 / 038780, and therefore will not be described in detail here.

[0128] FIG. 9 is a u'v' chromaticity diagram showing the color distribution obtained by performing the measurement procedure shown in FIG. 7 on the wide color gamut color chart 73 shown in FIG. 5(c). Specifically, FIG. 9(a) plots the colors corresponding to the spectral data Dsp1 obtained by the first procedure shown in FIG. 7(a) on the u'v' chromaticity diagram, showing the original color distribution of the wide color gamut color chart 73 itself (measurements under a D65 light source). A total of 18 sets of color samples are arranged on the wide color gamut color chart 73, and the plotted white squares represent the colors of these color samples. Meanwhile, FIG. 9(b) plots the colors corresponding to the spectral data Dsp2 obtained by the second procedure shown in FIG. 7(b) on the u'v' chromaticity diagram, showing the color distribution (photographed under a D65 light source) obtained by observing the wide color gamut color chart 73 through a conventional medical image display system (observing the screen of the color monitor 50). The plotted black squares represent the colors of each color sample.

[0129] Points RR, GG, and BB (shown as white squares) in Figure 9(a) represent the colors of the red, green, and blue samples, respectively, arranged on the wide color gamut color chart 73. Thus, the color distribution of the 18 color samples arranged on the wide color gamut color chart 73 adequately covers the area of ​​triangle BT.2020. However, when this wide color gamut color chart 73 is viewed through a conventional medical image display system, the color distribution is significantly narrowed, as shown in Figure 9(b), and it is clear that it does not even adequately cover the area of ​​triangle BT.709. Specifically, with this conventional system, the saturation of reddish colors is significantly reduced, yellowish colors are shifted toward green, and blueish colors are shifted toward cyan while also losing saturation.

[0130] The diagram in the upper part of Figure 10 is a u'v' chromaticity diagram showing a composite color distribution obtained by combining the color distributions shown in Figures 8(b) and 9(b). In other words, it is a color distribution diagram obtained by viewing a color chart including both the color samples on the multi-color chart 72 shown in Figure 5(b) and the color samples on the wide-gamut color chart 73 shown in Figure 5(c) through a conventional medical image display system. In this color distribution diagram, the black dots represent the colors of each color sample. The polygon M shown by the dashed line in the diagram is the circumscribed polygon of these points and represents the color distribution area on the monitor screen.

[0131] We then calculated the ratio of the area Area(M) of this color distribution area M to the area Area(BT.709) of the triangle BT.709, and obtained the result Area(M) / Area(BT.709) = 63%, as shown in the bottom of Figure 10. This indicates that the display screen on the color monitor of a conventional medical image display system uses only 63% of the color gamut of the high-definition monitor. Similarly, we calculated the ratio of the area Area(M) of this color distribution area M to the area Area(BT.2020) of the triangle BT.2020, and obtained the result Area(M) / Area(BT.2020) = 37%, as shown in the bottom of Figure 10. This indicates that the display screen on the color monitor of a conventional medical image display system uses only 37% of the color gamut of the 4K / 8K monitor.

[0132] These results show that the color gamut utilization rate in conventional medical image display systems is quite low. Therefore, in the future, it will be preferable to introduce equipment that can handle 4K / 8K images into medical image display systems as well, and display high-resolution biological tissue images captured by high-resolution cameras on color monitors that support 4K / 8K.

[0133] From this perspective, when constructing the medical image display system 1000 according to the present invention shown in Fig. 3, it is preferable to use devices compatible with capturing 4K8K images as the medical imaging devices 30X, 30Y, and 30Z, and devices compatible with displaying 4K8K images as the color monitors 50A-50D. Furthermore, it is preferable that the medical device color correction device 100 according to the present invention performs color management compatible with the wide color gamut of 4K8K images, assuming that devices compatible with 4K8K images are connected and used. This allows practitioners to make more precise color judgments than with conventional medical image display systems.

[0134] Specifically, the individual conversion data stored in the imaging device individual conversion data storage unit 110 may be conversion data capable of color conversion that covers the wide color gamut defined in the BT.2020 international standard for ultra-high definition televisions (color conversion that obtains standard color image data Ds that covers the wide color gamut). To create such conversion data, a wide color gamut color chart 73 such as that shown in FIG. 5(c) may be used as the color chart 70 in the block diagram shown in FIG. 4. Similarly, the individual conversion data stored in the monitor individual conversion data storage unit 130 may be conversion data that enables color conversion that covers the wide color gamut defined in the BT.2020 international standard for ultra-high definition televisions (color conversion that enables colors that cover the wide color gamut to be displayed on a color monitor).

[0135] <<< §5. Benefits of using D65 light source >>> In Section 3 above, a specific procedure for creating the individual conversion data Cx for the medical imaging device 30X was explained with reference to the block diagram in Fig. 4. In this procedure, a "D65 light source" is used as the light source 60. Here, we will explain why it is preferable to use a "D65 light source" as the light source 60 when creating the individual conversion data stored in the imaging device individual conversion data storage unit 110.

[0136] First, let's compare the spectra of various light sources. Figure 11 shows a graph of the visible light spectrum of each light source (the vertical axis is normalized so that the spectral intensity at 560 nm is 1.0). Here, graph G1 represents the spectrum of a shadowless lamp, graph G2 represents the spectrum of an endoscope light source (observing light transmitted through a fiber optic cable), graph G3 represents the spectrum of an endoscope light source (observing light directly), and graph G4 represents the spectrum of a D65 light source. Figure 12 shows the u'v' chromaticity diagram, which shows the color temperature of each light source. Here, point G1 represents the color temperature of a shadowless lamp, point G3 represents the color temperature of an endoscope light source (observing light directly), point G4 represents the color temperature of a D65 light source, and point G5 represents the color temperature of a D50 light source. As mentioned above, triangles BT.709 and BT.2020 represent the color regions defined by the international standards BT.709 and BT.2020, respectively (the same applies to the u'v' chromaticity diagrams below).

[0137] Figures 11 and 12 show that these light sources differ significantly in terms of both spectral waveform and color temperature. The results shown here were obtained by measurements using a specific operating light and a specific endoscope light source. However, the spectra and color temperatures of operating lights and endoscope light sources vary from product to product. Operating lights typically use halogen lamps, which produce reddish illumination light with a color temperature of approximately 3400 K. Endoscope light sources typically use xenon lamps, which produce white illumination light with a color temperature of approximately 4700 K. In contrast, the light from a D65 light source produces bluish illumination light with a color temperature of 6504 K. The D65 and D50 light sources are standard light sources defined by the International Commission on Illumination (CIE), and their spectra and color temperatures are determined by clear standards.

[0138] In general, the light source used to illuminate a subject is an important factor that determines the color tone of the subject when observed, and even if the subject is the same, the color tone of the observed subject will differ if the light source is different. Therefore, in the case of the medical image display system shown in Figure 3, the color tone of the obtained imaging data Dx to Dz will differ depending on which light source is used to illuminate the subject (biological tissue) to be imaged by the medical imaging devices 30X to 30Z.

[0139] Therefore, the inventors of the present invention conducted an experiment in which the same colon specimen was prepared as a subject and the color shades of the colon specimen were compared when illuminated with various light sources. Figures 13 to 15 show the results in u'v' chromaticity diagrams. First, Figure 13 is a u'v' chromaticity diagram showing the color distribution of each part of the colon specimen itself under illumination by a shadowless lamp. It shows the actual measurement results obtained by directly measuring the colors of multiple sample locations using a spectrometer while the colon specimen was illuminated by a shadowless lamp. The group of plots consisting of many black dots in the color distribution diagram of Figure 13 represents the colors of individual sample locations. All of the plots show highly saturated colors ranging from red to orange.

[0140] On the other hand, Figure 14 is a u'v' chromaticity diagram showing the color distribution of various parts of a colon specimen under illumination by an endoscopic light source (via fiber optics). It shows the results of measuring the color of multiple sample locations while the colon specimen was illuminated by an endoscopic light source via fiber optics. However, instead of actually measuring under an endoscopic light source, the results of Figure 14 were obtained by performing a simulation to convert the measurement results of Figure 13 to those under an endoscopic light source based on the spectral differences shown in Figure 11. For ease of comparison, Figure 14 also includes the color distribution shown in Figure 13. Specifically, the group of plots marked "original color distribution" (consisting of many black dots) represents the measurement results under the shadowless lamp shown in Figure 13, while the group of plots marked "converted color distribution" (consisting of many crosses) represents the measurement results under an endoscopic light source (results after conversion by simulation). As shown in the figure, the "converted color distribution" is broader than the "original color distribution."

[0141] Figure 15 is a u'v' chromaticity diagram showing the color distribution of various parts of a colon specimen under illumination by a D65 illuminant. It shows the results of measuring the color of multiple sample locations while the colon specimen was illuminated by a D65 illuminant. However, here too, instead of actually measuring under a D65 illuminant, the results of Figure 15 were obtained by performing a simulation to convert the measurement results of Figure 13 to those under a D65 illuminant based on the spectral differences shown in Figure 11. For ease of comparison, Figure 15 also includes the color distribution shown in Figure 13. Specifically, the group of plots marked "original color distribution" (consisting of many black dots) represents the measurement results under a shadowless lamp shown in Figure 13, while the group of plots marked "converted color distribution" (consisting of many crosses) represents the measurement results under a D65 illuminant (results after the simulation). As shown in the figure, the "converted color distribution" is broader than the "original color distribution."

[0142] The results shown in Figures 13 to 15 demonstrate that, even when the exact same colon specimen is used as the subject, the measured color distribution varies significantly depending on the light source used. Focusing on the breadth of the color distribution range, the following relationship is observed: "under shadowless light illumination" < "under endoscopic light source illumination" < "under D65 light source illumination." In particular, the results shown in Figure 15 reveal that the group of black dots labeled "original color distribution" (measurement results under shadowless light illumination) is distributed near the upper edge of the triangle BT.2020, while the group of cross-marked plots labeled "transformed color distribution" (measurement results under D65 light source illumination) is widely distributed in the upper half of the triangle BT.2020. While the example shown here is the measurement result of a specific colon specimen, this tendency is not limited to colon specimens, but is observed in a variety of biological tissues.

[0143] Generally, when displaying a captured image of a subject on a color monitor, the wider the color distribution range, the more colors can be used to display the image, thereby improving visibility (the ease with which one part can be visually distinguished from another). For example, in the example shown in Figure 15, under illumination with a shadowless lamp, only relatively saturated colors within the range marked "original color distribution" (colors near the upper edge of the triangle BT.2020) can be displayed. However, under illumination with a D65 light source, a display can be made using less saturated colors within the wider range marked "transformed color distribution" (colors in the upper half of the triangle BT.2020). Therefore, at least for the purpose of improving visibility of biological tissue, illumination with a D65 light source is preferable to illumination with a shadowless lamp or illumination with an endoscopic light source.

[0144] However, the results shown in Figures 13 to 15 do not necessarily indicate that illumination using a D65 light source is superior to illumination using a shadowless lamp or an endoscopic light source as illumination used during surgery. They merely indicate that illumination using a D65 light source is preferable from the perspective of improving visibility (ease of distinguishing and recognizing one tissue from another during surgery). In fact, shadowless lamps have traditionally been used as light sources to illuminate operating tables, and endoscopic light sources have traditionally been used as light sources to illuminate the abdominal cavity during laparoscopic surgery. Therefore, if these light sources were suddenly replaced with a D65 light source, many surgeons would likely experience discomfort based on their past experience.

[0145] The medical image display system 1000 according to the present invention described in Section 2 and the medical equipment color correction device 100 used therein are assumed to continue using a shadowless lamp or an endoscopic light source as a light source for illuminating the subject (biological tissue), and do not require replacing these with a D65 light source. That is, the imaging device color conversion unit 140 shown in Fig. 3 may be configured to perform color conversion on the imaging data Dx-Dz captured under a shadowless lamp or an endoscopic light source and generate standard color image data Ds, assuming that the imaging data Dx-Dz is input.

[0146] However, it is preferable that the standard color image data Ds obtained by the conversion process of the imaging device color converter 140 be image data whose standard color characteristics are those that would be obtained under illumination with a D65 light source. For example, in the system shown in Fig. 3, assume that the medical imaging device 30X is a medical video camera manufactured by Company X installed in an operating room, the medical imaging device 30Y is an endoscopic camera manufactured by Company Y, and the medical imaging device 30Z is an endoscopic camera manufactured by Company Z. Assume that the medical imaging device 30X provides imaging data Dx captured under illumination with a shadowless lamp manufactured by Company X, the medical imaging device 30Y provides imaging data Dy captured under illumination with an endoscopic light source manufactured by Company Y, and the medical imaging device 30Z provides imaging data Dz captured under illumination with an endoscopic light source manufactured by Company Z.

[0147] As described above, the spectra of shadowless lamps and endoscope light sources vary from product to product. Shadowless lamps manufactured by Company X, endoscope light sources manufactured by Company Y, and endoscope light sources manufactured by Company Z each have unique color characteristics based on the design specifications of their respective product providers. As previously mentioned, the imaging device color converter 140 is a component that performs color conversion to eliminate differences in the unique color characteristics of each piece of imaging data Dx to Dz and generate standard color image data Ds with common color characteristics. Therefore, the color characteristics under illumination with a D65 light source are included as one of the conditions for these common color characteristics. In this way, even though the imaging data Dx is image data obtained under illumination with a shadowless lamp manufactured by Company X, the imaging data Dy is image data obtained under illumination with an endoscope light source manufactured by Company Y, and the imaging data Dz is image data obtained under illumination with an endoscope light source manufactured by Company Z, the conversion process of the imaging device color converter 140 performs color conversion on all imaging data to produce images obtained under illumination with a D65 light source. By performing such color conversion, the image finally displayed on the screen of each of the color monitors 50A to 50D will have a wider color distribution range, improving the visibility of the living tissue.

[0148] In this way, to generate standard color image data Ds by performing conversion using the color characteristics under illumination by a D65 light source as the standard color characteristics, conversion data that uses the color characteristics of transmitted light through a predetermined color chart with light from a D65 light source specified by the International Commission on Illumination as the background light as the standard color characteristics can be used as the individual conversion data Cx, Cy, and Cz stored in the individual conversion data storage unit for imaging device 110. Specifically, as described in §3, the D65 light source can be used as light source 60 in the procedure shown in Figure 4.

[0149] Of course, if a conversion is performed in this way using the color characteristics under illumination with a D65 illuminant as the standard color characteristics, the color of the biological tissue will differ from the color of the tissue when observed directly with the naked eye. For example, in an open abdominal surgery, the surgeon can directly observe the biological tissue of the open abdominal area under the illumination of a shadowless lamp with the naked eye. In this case, the color of the biological tissue observed with the naked eye will differ from the color of the biological tissue displayed on a color monitor. In other words, the color of the biological tissue displayed on a color monitor will differ from the actual color of the biological tissue under shadowless lamp illumination. Therefore, from the perspective of faithfully reproducing the color of actual biological tissue under shadowless lamp illumination and displaying it on a color monitor, a conversion that "uses the color characteristics under illumination with a D65 illuminant as the standard color characteristics" is counterproductive.

[0150] However, there is no absolute standard for the "color of actual biological tissue." In other words, the color of biological tissue observed with the naked eye during surgery is merely the color under the illumination of a specific shadowless lamp provided by a specific manufacturer, and the color will change if the shadowless lamp is replaced with a different product. Furthermore, in the case of laparoscopic surgery, since it is not possible to observe actual biological tissue with the naked eye, there is no way to confirm the "color of actual biological tissue." Considering these points, it is clear that there is little point in faithfully reproducing on a color monitor the color obtained under the illumination of a specific shadowless lamp or a specific endoscopic light source.

[0151] Therefore, in practice, it is preferable to perform conversion so that the color characteristics under illumination with a D65 light source become the standard color characteristics, and generate standard color image data Ds. The color tone of an image displayed on a color monitor based on such standard color image data Ds will be slightly different from the color tone of an image observed under illumination from a shadowless lamp or an endoscopic light source, but this will not cause any particular sense of incongruity. For example, in the example shown in Figure 15, the "original color distribution" occupies a highly saturated range from red to orange, while the "converted color distribution" occupies a range from high to low saturation for red to orange, with no significant change in hue.

[0152] The first reason why it is preferable to use a D65 light source as a light source that provides standard color characteristics when implementing the present invention (i.e., to use a D65 light source as light source 60 shown in FIG. 4) is that, whereas the color shades (emission spectra) of shadowless lamps and endoscope light sources vary depending on the manufacturer and product, the color shades (emission spectra) of D65 light sources are standardized and defined by the International Commission on Illumination (CIE). Therefore, if the color shades of the standard color image data Ds are determined based on the D65 light source, then regardless of the manufacturer and product of the shadowless lamp or endoscope light source used as the light source when obtaining the individual pieces of imaging data Dx, Dy, and Dz, the displayed images on color monitors 50A-50D will always match the color shades of the standardized D65 light source.

[0153] The second reason is that using a D65 light source as a light source that provides standard color characteristics can widen the color distribution range and improve visibility. As already explained with reference to the measurement results in Figures 13 to 15, the following relationship is obtained regarding the breadth of the color distribution range: "under illumination by a shadowless lamp" < "under illumination by an endoscopic light source" < "under illumination by a D65 light source." Therefore, if the color characteristics under illumination by a D65 light source are set as the standard color characteristics, the color distribution range in the image obtained on the color monitor can be widened, thereby improving visibility. For example, even if biological tissue has the same orange hue, parts with high saturation and parts with low saturation will be displayed distinctly on the color monitor, making it easier to visually distinguish each part from the other.

[0154] <<< §6. Example of color transformation for specific tissue emphasis >>> In Section 2.2 above, the basic operation of the specific-tissue-enhancing color conversion unit 160 in the medical device color correction device 100 shown in Fig. 3 was described as "basic operation related to the second conversion process." In this basic operation, three types of specific-tissue-enhancing conversion data are stored in the specific-tissue-enhancing conversion data storage unit 120: blood vessel enhancement data Ce for performing color conversion to enhance blood vessels, fat enhancement data Cf for performing color conversion to enhance fat, and epidermal membrane enhancement data Cg for performing color conversion to enhance epidermal membranes. The specific-tissue-enhancing color conversion unit 160 then uses these conversion data to perform color conversion to enhance specific biological tissues on the standard color image data Ds, thereby generating specific-tissue-enhancing image data De, Df, and Dg. Here, the substance of these specific-tissue-enhancing conversion data Ce, Cf, and Cg, as well as examples of "highlighting" specific biological tissues, will be described in more detail.

[0155] Generally, the various biological tissues that make up the human body each have their own unique color shades, and practitioners can distinguish and recognize many biological tissues with the naked eye. For example, when visually inspecting a human large intestine, multiple biological tissues, such as blood vessels, fat, and surface membranes, can be observed. Figures 13 to 15 show the color distribution of each part of a colon specimen, and the individual plotted points represent the colors of the various biological tissues that make up the large intestine.

[0156] FIG. 16 is a top view showing a colon specimen and sample locations of specific tissues used in measuring the color distribution maps shown in FIGS. 13 to 15. As shown in the figure, this colon specimen contains biological tissues such as vascular regions V1, V2, and V3 and fatty regions F1 and F2 in addition to the main portion constituting the colon proper. Therefore, the inventors determined multiple sample locations on this colon specimen and directly measured the color of each sample location using a spectrophotometer. The regions indicated by circled numbers 1 to 8 in FIG. 16 (hatched circular regions) represent the respective sample locations. Specifically, the regions indicated by circled numbers 1 to 3 represent sample locations for vascular regions, the regions indicated by circled numbers 4 and 5 represent sample locations for fatty regions, and the regions indicated by circled numbers 6 to 8 represent sample locations for superficial membrane regions.

[0157] FIG. 17 is a u′v′ chromaticity diagram showing the color distribution obtained by measuring each sample location shown in FIG. 16 under a shadowless lamp, and FIG. 18 is a u′v′ chromaticity diagram showing the color distribution obtained by measuring each sample location shown in FIG. 16 under a D65 light source. Circled numbers 1 to 8 on these u′v′ chromaticity diagrams correspond to the sample locations indicated by circled numbers 1 to 8 in FIG. 16. Looking at FIGS. 17 and 18, it can be seen that each sample location has its own unique hue. Specifically, the sample locations in the vascular area indicated by circled numbers 1 to 3 exhibit a highly saturated red color, the sample locations in the fatty area indicated by circled numbers 4 and 5 exhibit a highly saturated orange color, and the sample locations in the superficial area indicated by circled numbers 6 to 8 exhibit a slightly less saturated orange color.

[0158] As mentioned in §5, even for the same colon specimen, the observed color tone varies depending on the light source used for illumination, and the color distribution range is wider when illuminated with a D65 light source (Figure 18) than when illuminated with a shadowless lamp (Figure 17). Comparing the color distribution ranges for the same sample area in Figures 17 and 18, it can be seen that the latter is wider than the former. As already explained in §5, when the color distribution range is wider, it becomes possible to represent the same biological tissue using a greater number of colors, which has the advantage of improving visibility. Therefore, we will continue our explanation below using the results illuminated with a D65 light source (Figure 18).

[0159] Figure 19(a) is a u'v' chromaticity diagram showing the points plotted to represent individual colors in Figure 18 grouped by region. That is, in Figure 19(a), the distribution region of the blood vessel plots indicated by circled numbers 1 to 3 in Figure 18 is shown as region Ae, the distribution region of the fat plots indicated by circled numbers 4 and 5 in Figure 18 is shown as region Af, and the distribution region of the superficial membrane plots indicated by circled numbers 6 to 8 in Figure 18 is shown as region Ag. Here, these regions Ae, Af, and Ag are referred to as "localized color regions specific to specific biological tissues." That is, color region Ae is the localized color region specific to blood vessels (blood vessel color region Ae), color region Af is the localized color region specific to fat (fat color region Af), and color region Ag is the localized color region specific to the superficial membrane (surface membrane color region Ag).

[0160] Considering that the localized color regions on the u'v' chromaticity diagram are arranged differently for each biological tissue, it is possible to estimate which biological tissue any point on the u'v' chromaticity diagram corresponds to. For example, if a point is plotted within the blood vessel color region Ae in Figure 19(a), it can be estimated that the measurement point corresponds to a sample location belonging to a blood vessel. Of course, there are other biological tissues on a colon sample besides blood vessels, fat, and the surface membrane, and even blood vessels may exhibit colors outside the blood vessel color region Ae. Therefore, the above estimation cannot be said to be 100% accurate, but this method allows for estimation with a certain degree of accuracy.

[0161] As already described in Section 2, the specific-tissue-enhancing color converter 160 shown in FIG. 3 is a component that performs color conversion on the standard color image data Ds provided by the imaging device color converter 140 to emphasize a specific biological tissue designated by a designation input to the emphasis tissue designator 150. The color distribution diagram shown in FIG. 19(a) can be used as a diagram showing the color distribution of the specific tissue on this standard color image data Ds. For example, if the specific biological tissue to be emphasized is designated as "blood vessels," the specific-tissue-enhancing color converter 160 simply selects the color within the blood vessel color region Ae shown in FIG. 19(a) in the standard color image data Ds as the color to be converted. As described above, the color within the blood vessel color region Ae can be estimated to be the color exhibited by blood vessels. Therefore, by selecting the color within the blood vessel color region Ae (pixels having that color) and performing emphasis conversion processing, the blood vessels can be emphasized.

[0162] Next, a method of highlighting will be described using specific examples. The purpose of highlighting in the present invention is to display an image with visibility suitable for observing specific biological tissue. For example, when the treatment target is a blood vessel, the practitioner will likely want to perform image processing that highlights only the blood vessels, thereby displaying an image with visibility suitable for observing the blood vessels. In this way, the visibility of blood vessels can be improved by simply changing the color of the blood vessels to a more distinctive color so that the blood vessels can be clearly distinguished from other biological tissues. Generally speaking, the visibility of a specific biological tissue can be improved by simply changing the color of the specific biological tissue to a more distinctive color so that the specific biological tissue can be clearly distinguished from other biological tissues.

[0163] Based on this concept, in the embodiment described herein, a color conversion method for emphasizing specific biological tissues is performed by shifting the colors included in the localized color regions on the color distribution map corresponding to the specific biological tissues in a predetermined correction direction on the color distribution map. Figure 19(b) is a u'v' chromaticity diagram showing the correction directions Me, Mf, and Mg for the localized color regions Ae, Af, and Ag shown in Figure 19(a). Specifically, color conversion processing is performed to shift the colors included in the blood vessel color region Ae in the correction direction Me, the colors included in the fat color region Af in the correction direction Mf, and the colors included in the superficial membrane color region Ag in the correction direction Mg.

[0164] The correction direction Me for the blood vessel color region Ae shown in FIG. 19(b) is the rightward direction on the u'v' chromaticity diagram, i.e., the direction that increases the u' value. This means that the color contained in the blood vessel color region Ae (the color estimated to be exhibited by blood vessels) is corrected to be more reddish. Experiments conducted by the inventors of the present application have shown that such color correction can improve the visibility of blood vessels. This is thought to be because color correction to increase the reddish color of blood vessels allows them to be differentiated from other biological tissues.

[0165] Ultimately, in the case of the color correction device 100 for medical equipment shown in Figure 3, the specific tissue emphasis conversion data storage unit 120 simply stores conversion data for specific tissue emphasis (vascular emphasis data) Ce for performing color conversion to emphasize "blood vessels," which is conversion data that performs color correction to increase the u' value for colors included in the localized color region specific to blood vessels on the u'v' chromaticity diagram.

[0166] Specifically, the blood vessel enhancement data Ce may include data representing a localized color region (blood vessel color region) Ae of the blood vessels in FIG. 19(b) and data representing a correction direction Me and a correction amount for the blood vessel color region Ae. The data representing the blood vessel color region Ae may, for example, be data representing the boundary of the region Ae. The data representing the correction direction Me and the correction amount may, for example, be data representing a correction calculation for adding a correction value Δu′e. In practice, it is preferable to set an upper limit on the correction value after addition so that it does not extend beyond the actual color region E indicated by the solid line on the u′v′ chromaticity diagram.

[0167] Here, if the emphasis tissue designation unit 150 receives a designation input specifying "blood vessels" as the specific biological tissue to be highlighted, the specific tissue emphasis color conversion unit 160 reads out the blood vessel emphasis data Ce from the specific tissue emphasis conversion data storage unit 120 and recognizes the blood vessel color region Ae defined by this blood vessel emphasis data Ce. Next, the specific tissue emphasis color conversion unit 160 extracts pixels of colors included in the recognized blood vessel color region Ae from the standard color image data Ds provided by the imaging device color conversion unit 140, performs a correction operation to add a correction value Δu'e to the color data of the pixel (in practice, a correction is performed to increase or decrease the RGB values), and outputs the data after the correction operation as specific tissue emphasis image data De in which the blood vessels are highlighted.

[0168] In the above-described embodiment, a predetermined correction value Δu′e is uniformly added to the u′ values ​​of the colors included in the blood vessel color region Ae for correction, but corrections may be made to vary the correction value Δu′e depending on the original u′ value. For example, if the original u′ value is small (for colors located to the left of the blood vessel color region Ae shown in FIG. 19(b)), the correction value Δu′e may be set to a large value, and if the original u′ value is large (for colors located to the right of the blood vessel color region Ae shown in FIG. 19(b)), the correction value Δu′e may be set to a small value. Furthermore, in the above-described embodiment, only the u′ value is corrected, but if necessary, the v′ value may also be corrected.

[0169] On the other hand, the correction direction Mf for the fat color region Af shown in FIG. 19(b) is the upper left direction on the u'v' chromaticity diagram, i.e., the direction in which the u' value decreases and the v' value increases. This means that the color contained in the fat color region Af (the color estimated to be exhibited by fat) is corrected to be more yellowish while maintaining saturation. Experiments conducted by the inventors of the present application have shown that such color correction can improve the visibility of fat. This is thought to be because color correction of fat to be more yellowish while maintaining saturation allows it to be differentiated from other biological tissues.

[0170] Therefore, in the case of the color correction device 100 for medical equipment shown in Figure 3, the specific tissue emphasis conversion data storage unit 120 should store conversion data for specific tissue emphasis (fat emphasis data) Cf for performing color conversion to emphasize "fat," which is conversion data that performs color correction to decrease the u' value and increase the v' value for colors included in the localized color region specific to fat on the u'v' chromaticity diagram.

[0171] Specifically, the fat-enhanced data Cf may include data indicating a localized color region (fat color region) Af of fat in FIG. 19(b) and data indicating a correction direction Mf and a correction amount for this fat color region Af. The data indicating the fat color region Af may, for example, be data indicating the boundary of the region Af. Furthermore, the data indicating the correction direction Mf and the correction amount may, for example, be data indicating a correction calculation that subtracts a correction value Δu′f and adds a correction value Δv′f. Again, in practice, it is preferable to set upper and lower limits on the correction value after addition and subtraction so that it does not extend beyond the actual color region E indicated by the solid line on the u′v′ chromaticity diagram.

[0172] Here, if the emphasis tissue designation unit 150 receives a designation input specifying "fat" as the specific biological tissue to be highlighted, the specific tissue emphasis color conversion unit 160 reads the fat emphasis data Cf from the specific tissue emphasis conversion data storage unit 120 and recognizes the fat color region Af defined by this fat emphasis data Cf. Next, the specific tissue emphasis color conversion unit 160 extracts pixels of colors included in the recognized fat color region Af from the standard color image data Ds provided by the imaging device color conversion unit 140, performs a correction operation on the color data of the pixel by subtracting a correction value Δu'f and adding a correction value Δv'f (in practice, a correction is performed by increasing or decreasing the RGB values), and outputs the data after the correction operation as specific tissue emphasis image data Df in which fat is highlighted.

[0173] In this embodiment, instead of uniformly subtracting a predetermined correction value Δu′f or adding a correction value Δv′f to the u′ and v′ values ​​of the colors included in the fatty color area Af, the correction values ​​Δu′f and Δv′f may be changed depending on the original u′ and v′ values.

[0174] Similarly, the correction direction Mg for the superficial membrane color region Ag shown in Figure 19(b) is the downward right direction on the u'v' chromaticity diagram, i.e., the direction in which the u' value increases and the v' value decreases. This means that the color contained in the superficial membrane color region Ag (the color estimated to be exhibited by the superficial membrane portion) is corrected to a redder color while decreasing saturation. Experiments conducted by the inventors of the present application have shown that such color correction can improve the visibility of the superficial membrane. This is thought to be because color correction of the superficial membrane portion, which decreases saturation and increases redness, allows it to be differentiated from other biological tissues.

[0175] Therefore, in the case of the color correction device 100 for medical equipment shown in Figure 3, the specific tissue emphasis conversion data storage unit 120 simply stores conversion data for specific tissue emphasis (superficial membrane emphasis data) Cg for performing color conversion to emphasize the ``superficial membrane,'' which is conversion data that performs color correction to increase the u' value and decrease the v' value for colors included in the localized color region specific to the superficial membrane on the u'v' chromaticity diagram.

[0176] Specifically, the surface film enhancement data Cg may include data representing the localized color region (surface film color region) Ag of the surface film in FIG. 19(b) and data representing the correction direction Mg and correction amount for this surface film color region Ag. The data representing the surface film color region Ag may, for example, be data representing the boundary of the region Ag. Furthermore, the data representing the correction direction Mg and correction amount may, for example, be data representing a correction calculation in which a correction value Δu′g is added and a correction value Δv′g is subtracted. Again, in practice, it is preferable to set upper and lower limits on the correction value after addition and subtraction so that it does not extend beyond the actual color region E indicated by the solid line on the u′v′ chromaticity diagram.

[0177] If the emphasis tissue designation unit 150 receives a designation input specifying "superficial membrane" as the specific biological tissue to be highlighted, the specific tissue emphasis color conversion unit 160 reads the superficial membrane emphasis data Cg from the specific tissue emphasis conversion data storage unit 120 and recognizes the superficial membrane color region Ag defined by the superficial membrane emphasis data Cg. Next, the specific tissue emphasis color conversion unit 160 extracts pixels of colors included in the recognized superficial membrane color region Ag from the standard color image data Ds provided by the imaging device color conversion unit 140, performs a correction operation on the color data of the pixel by adding a correction value Δu'g and subtracting a correction value Δv'g (in practice, a correction is performed by increasing or decreasing the RGB value), and outputs the data after the correction operation as specific tissue emphasis image data Dg in which the superficial membrane is emphasized.

[0178] In this embodiment, instead of uniformly adding a predetermined correction value Δu′g or subtracting a correction value Δv′g to the u′ and v′ values ​​of the colors contained in the surface film color region Ag, it is also possible to change the correction values ​​Δu′g and Δv′g depending on the original u′ and v′ values.

[0179] 3 has a function of performing color conversion to emphasize specific biological tissues on image data (standard color image data Ds) having a group of biological tissues as its subject, and the specific-tissue-enhancing conversion data storage unit 120 stores specific-tissue-enhancing conversion data Ce, Cf, and Cg for performing color conversion to emphasize specific biological tissues. When the emphasis-tissue designation unit 150 receives a designation input specifying the specific biological tissue to be highlighted, the specific-tissue-enhancing color conversion unit 160 performs color conversion on the image data obtained based on imaging by the medical imaging device (i.e., the standard color image data Ds obtained based on the imaging data Dx, Dy, and Dz) using the specific-tissue-enhancing conversion data Ce, Cf, and Cg for performing color conversion to emphasize the specific biological tissue designated by the designation input, which is stored in the specific-tissue-enhancing conversion data storage unit 120, thereby generating specific-tissue-enhancing image data De, Df, and Dg.

[0180] Generally speaking, the specific tissue enhancement conversion data Ce, Cf, and Cg stored in the specific tissue enhancement conversion data storage unit 120 are data that perform specific color correction on colors contained in a localized color region specific to a specific biological tissue in a predetermined color space. Here, a three-dimensional color space may be used as the predetermined color space. In this case, a three-dimensional region in the three-dimensional color space is set as the localized color region specific to the specific biological tissue, and a predetermined direction in the three-dimensional space is set as the color correction direction.

[0181] In the embodiments described so far, a two-dimensional color space is used as the predetermined color space for the specific-tissue-enhancing color converter 160 to perform color conversion of hue and saturation. That is, the specific-tissue-enhancing transformation data Ce, Cf, and Cg are data for performing color correction by increasing or decreasing the abscissa value, the ordinate value, or both of the colors included in the localized color region specific to the specific biological tissue on a predetermined two-dimensional chromaticity diagram. In particular, in the embodiment shown in FIG. 19 , a u′v′ chromaticity diagram is used as the two-dimensional chromaticity diagram, and the specific-tissue-enhancing transformation data Ce, Cf, and Cg are data for performing color correction by increasing or decreasing the u′ value, the v′ value, or both of the colors included in the localized color region specific to the specific biological tissue on the u′v′ chromaticity diagram. Of course, chromaticity diagrams other than the u′v′ chromaticity diagram (e.g., an xy chromaticity diagram) may also be used as the two-dimensional chromaticity diagram.

[0182] On the other hand, when a three-dimensional color space is used as the color space for color conversion by the specific tissue enhancement color conversion unit 160, color correction can be performed by increasing or decreasing some or all of the three-dimensional coordinate values ​​of the colors contained in the localized color region (three-dimensional region) specific to each biological tissue. For example, while a two-dimensional u'v' chromaticity diagram can only show the distribution of hue and saturation, if an Lu'v' space (three-dimensional color space) is defined by adding a lightness axis L orthogonal to the u'v' chromaticity diagram, a single point (u', v', L) in this three-dimensional color space can show the color distribution of the three elements: hue, saturation, and lightness. Therefore, by performing color correction by increasing or decreasing not only the u' and v' values ​​but also the L value for the colors contained in the localized color region (three-dimensional region) specific to a specific biological tissue, it is possible to highlight the specific biological tissue. In other words, not only color differences in hue and saturation but also differences in lightness can be emphasized. In this way, the specific biological tissue can be visually differentiated from other biological tissues in terms of brightness as well, so that the visibility of the specific biological tissue can be further improved.

[0183] If such color conversion is to be performed in the Lu′v′ space, as each of the local color regions Ae, Af, Ag shown in Fig. 19(b), a three-dimensional region is defined, and as each correction direction Me, Mf, Mg, a three-dimensional direction with an L-axis direction component added is set. For each biological tissue, correction may be performed so that the brightness difference from another tissue is emphasized. Specifically, for the colors included in the blood vessel color region Ae, correction may be performed to increase at least the u′ value (correction to increase or decrease the v′ value or the L value may also be performed). For the colors included in the fat color region Af, correction may be performed to decrease at least the u′ value and increase the v′ value (correction to increase or decrease the L value may also be performed). For the colors included in the surface membrane color region Ag, correction may be performed to increase at least the u′ value and decrease the v′ value (correction to increase or decrease the L value may also be performed).

[0184] Of course, the three-dimensional color space for performing color conversion by the specific tissue emphasis color conversion unit 160 is not limited to the above-described Lu′v′ space. For example, it is also possible to use the HLS space in the HLS color model, the HSV space in the HSV color model, etc. In this case, each correction direction Me, Mf, Mg will be set in an appropriate direction according to the three-dimensional color space to be used.

[0185] In Fig. 19, an example in which specific conversion data for three types of biological tissues, namely blood vessels, fat, and surface membranes, is used as the specific tissue emphasis conversion data is illustrated. In this example, the emphasis tissue designation unit 150 has a function of receiving a designation input for designating "blood vessels" as a specific biological tissue to be emphasized, and in the specific tissue emphasis conversion data storage unit 120, as the specific tissue emphasis conversion data Ce for performing color conversion to emphasize "blood vessels", conversion data for performing a color correction to increase at least the u′ value for the colors included in the local color region Ae unique to blood vessels on the u′v′ chromaticity diagram (or the Lu′v′ space may also be used) is stored.

[0186] In addition, in this embodiment, the highlighting tissue designation unit 150 has a function of accepting a designation input specifying "fat" as the specific biological tissue to be highlighted, and the specific tissue highlighting conversion data storage unit 120 stores conversion data Cf for highlighting specific tissue to perform color conversion to highlight "fat," which performs color correction to reduce at least the u' value and increase the v' value for colors included in the localized color region Af specific to fat on the u'v' chromaticity diagram (or Lu'v' space).

[0187] Furthermore, in this embodiment, the highlighting tissue designation unit 150 has the function of accepting a designation input specifying the "surface membrane" as the specific biological tissue to be highlighted, and the specific tissue highlighting conversion data storage unit 120 stores conversion data Cg for highlighting specific tissue to perform color conversion to highlight the "surface membrane," which performs color correction to increase at least the u' value and decrease the v' value for colors included in the localized color region Ag specific to the surface membrane on the u'v' chromaticity diagram (or alternatively, Lu'v' space).

[0188] FIG. 20 is a front view showing an example of instruction buttons constituting the emphasis tissue designation unit 150 in the medical device color correction device 100 shown in FIG. 3. In this example, the emphasis tissue designation unit 150 has an input function for designating “blood vessels,” “fat,” and “surface membrane” as specific biological tissues to be highlighted. As shown in the figure, the emphasis tissue designation unit 150 is provided with a blood vessel emphasis instruction button Q1, a fat emphasis instruction button Q2, a surface membrane emphasis instruction button Q3, and a cancel emphasis button Q4. The emphasis tissue designation unit 150 defaults to a blank state in which no biological tissues are designated as targets for highlighting. Therefore, if the operator does not perform any operation, it is treated as if a “blank designation input” has been made, and the specific tissue emphasis color conversion unit 160 outputs the input standard color image data Ds as is without performing any substantial color conversion processing.

[0189] The operator presses the blood vessel emphasis command button Q1 if he / she wants to highlight "blood vessels," the fat emphasis command button Q2 if he / she wants to highlight "fat," and the superficial membrane emphasis command button Q3 if he / she wants to highlight "superficial membrane." Pressing the highlight cancel button Q4 cancels the emphasis designation for all biological tissues. The emphasis tissue designation unit 150 also allows multiple biological tissues to be designated simultaneously. For example, if the operator wants to highlight both "blood vessels" and "fat," he / she can simultaneously press the blood vessel emphasis command button Q1 and the fat emphasis command button Q2. In this case, the specific tissue emphasis color conversion unit 160 performs color conversion using the blood vessel emphasis data Ce and color conversion using the fat emphasis data Cf on the standard color image data Ds, simultaneously outputting the specific tissue emphasis image data Def. 19(b), the colors included in the blood vessel color region Ae are corrected in the correction direction Me, and the colors included in the blood vessel color region Af are corrected in the correction direction Mf. Note that if there is an overlapping portion among the localized color regions of multiple biological tissues that are specified in an overlapping manner, the colors within the overlapping portion will be subjected to overlapping color correction, but this does not cause any particular problems.

[0190] When the medical device color correction device 100 is configured using a computer, the emphasis tissue designation unit 150 shown in Fig. 20 can be realized by utilizing a display for operating the computer. That is, the input screen shown in Fig. 20 can be displayed on the display for operating the computer, and instructions to press each of the buttons Q1 to Q4 can be recognized by input operations using a touch panel or a pointing device such as a mouse. Furthermore, in the case of a system in which multiple color monitors 50A to 50D are connected as in the example shown in Fig. 3, it is possible to display images in which different biological tissues are emphasized for each individual color monitor. In this case, the designation input shown in Fig. 20 can be performed for each individual color monitor (for example, a monitor designation button for designating the color monitor to be displayed can be provided).

[0191] The above describes an embodiment in which three types of biological tissues, "blood vessels," "fat," and "surface membrane," can be highlighted. However, various other biological tissues, such as "bone," "cartilage," and "muscle," can also be highlighted.

[0192] FIG. 21 is a u′v′ chromaticity diagram showing the color distribution of image data obtained by performing various enhancement corrections (enhancement color conversions for “blood vessels,” “fat,” and “surface membrane” shown in FIG. 19 , plus enhancement color conversions for several other biological tissues) using the specific tissue enhancement color conversion unit 160 on image data having the color distribution shown in FIG. 10 (image data including color samples of various color charts 70). The black dots in FIG. 21 indicate the color distribution before correction, and the white squares indicate the color distribution after correction. Because the example shown in FIG. 21 uses the color chart 70 as the subject, rather than actual biological tissue, the colors before correction (black dots) are distributed over a fairly wide range. However, by performing color conversion corrections using the specific tissue enhancement color conversion unit 160, the distribution range of the corrected colors (white squares) is further expanded.

[0193] In this way, when displaying on a color monitor, if correction is made to expand the color distribution range, individual biological tissues can be represented using more colors, which has the effect of improving overall visibility. [Explanation of symbols]

[0194] 10:Operating table 20: Shadowless light 30: Medical imaging device (e.g., endoscopic camera) 30X, 30Y, 30Z: medical imaging devices (e.g., endoscopic cameras) 31: Endoscope camera 40: Imaging control unit 41: Endoscope control unit 50: Color monitor 50A, 50B, 50C, 50D: Color monitor 51~54: Color monitor 60: Light source (D65 light source) 70: Color chart 71: Primary color chart 72: Multicolor chart 73: Wide color gamut color chart 80: Individual conversion data creation unit 90: Spectroscopic analyzer 100: Color correction device for medical equipment 110: Individual conversion data storage unit for imaging device 120: Specific tissue emphasis conversion data storage unit 130: Individual conversion data storage unit for monitor 140: Color conversion unit for imaging device 150: Emphasized tissue designation section 160: Color conversion unit for specific tissue emphasis 170: Color conversion unit for monitor 1000: Medical image display system Ae: Blood vessel color area (localized color area specific to blood vessels) Af: Fat color area (localized color area specific to fat) Ag: Surface film color area (localized color area specific to surface film) B, BB: blue point on the u′v′ chromaticity diagram Bnew: Blue component of the converted color data Bold: Blue component of the color data before conversion BT: Blue component of the original color data Bt: Blue component of the image color data BT.709: A triangle showing the color range defined by the international standard BT.709. BT.2020: A triangle indicating the color range defined by the international standard BT.2020. Ca, Cb, Cc, Cd: Individual conversion data for monitor Ce: Transformation data for specific tissue emphasis (vascular emphasis data) Cf: Transformation data for specific tissue emphasis (fat emphasis data) Cg: Transformation data for specific tissue emphasis (surface membrane emphasis data) Cx, Cy, Cz: Individual conversion data for imaging devices Da, Db, Dc, Dd: Display data De, Df, Dg: specific tissue weighted image data Dp: Imaging data Ds: Standard color image data Dsp1, Dsp2: Spectral data DT: Original color data Dt: Image color data Dx, Dy, Dz: Imaging data E: Existing color area F1,F2: Fat area f1, f2, f3: Conversion functions G,GG: Green point on the u′v′ chromaticity diagram G1: Color temperature points on the visible light spectrum / u'v' chromaticity diagram of shadowless lamps G2: Visible light spectrum of the endoscope light source (via fiber) G3: Color temperature point on the visible light spectrum / u'v' chromaticity diagram of the endoscope light source (direct) G4: Color temperature points on the visible light spectrum / u′v′ chromaticity diagram of the D65 light source G5: Color temperature points on the visible light spectrum / u′v′ chromaticity diagram of the D50 light source Gnew: Green component of the converted color data Gold: Green component of the color data before conversion GT: Green component of the original color data Gt: Green component of the image color data l, l': red component of color data LUT: Look-up table M: Color distribution area on the monitor screen Me: Correction direction for blood vessel color area Ae Mf: Correction direction for the fat color area Af Mg: Correction direction for surface film color area Ag m, m': green component of color data n, n': blue component of color data P: Subject (patient) P1: Actual organ P2: Display image of organ Q1: Blood vessel emphasis command button Q2: Fat enhancement instruction button Q3: Surface membrane emphasis button Q4: Unhighlight button R,RR: Red point on the u′v′ chromaticity diagram RT: Red component of the original color data Rt: Red component of the image color data Rold: Red component of the color data before conversion Rnew: Red component of the converted color data Horizontal axis on the u′:u′v′ chromaticity diagram V1, V2, V3: Blood vessel area Vertical axis on the v′:u′v′ chromaticity diagram W: White point on the u′v′ chromaticity diagram

Claims

1. A color correction device for a medical device, comprising a display and connected to a plurality of color monitors, The medical device color correction device has a function of performing a first conversion process for performing color conversion using individual conversion data for a specific medical imaging device on imaging data from the medical imaging device to generate standard color image data, and a function of performing a second conversion process for performing color conversion on the standard color image data to emphasize specific biological tissues to generate specific tissue-enhanced image data, the display has a function of displaying an instruction button for receiving a designation input for designating a specific biological tissue to be highlighted, and receiving the designation input for designating the specific biological tissue by an input operation on the instruction button; When a designation input specifying the specific biological tissue is received, display data obtained based on the specific tissue-enhanced image data in which the specific biological tissue is enhanced is output to the color monitor; the display has a function of further displaying a highlight cancel button for accepting cancellation of the highlight designation of the specific biological tissue, and accepting cancellation of the highlight designation of the specific biological tissue by an input operation on the highlight cancel button; When cancellation of the emphasis designation of the specific biological tissue is accepted, display data obtained based on the standard color image data is output to the color monitor. the medical device color correction device further has a function of performing a third conversion process of performing color conversion on the specific tissue-enhanced image data using individual conversion data for a specific color monitor to generate display data; the display has a function of further displaying a monitor designation button for receiving a designation input for designating the color monitor to be displayed, and receiving a designation input for designating the color monitor by an input operation on the monitor designation button; A color correction device for medical equipment that, when it receives a designation input specifying the color monitor, outputs display data generated from specific tissue-enhanced image data in which the specific biological tissue is emphasized to the designated color monitor.

2. the specific biological tissue is plural, the instruction button is plural, 2. The color correction device for medical equipment according to claim 1, wherein, when a designation input specifying a plurality of the specific biological tissues in an overlapping manner is received, display data obtained based on specific tissue-enhanced image data in which the plurality of specific biological tissues are overlappingly emphasized is output to the color monitor.

3. the specific biological tissue is plural, the instruction button is plural, performing an input operation on the instruction button for each of the color monitors; 3. The color correction device for medical equipment according to claim 1, wherein, when a designation input specifying a different specific biological tissue for each of the plurality of color monitors is received, display data generated from specific tissue-enhanced image data in which the different specific biological tissue is emphasized is output to each of the specified plurality of color monitors.

4. 4. A medical image display system comprising: a color correction device for a medical device according to claim 1; and at least one color monitor that displays images based on display data output from the color correction device for a medical device.

5. A program that causes a computer to function as the color correction device for medical equipment according to any one of claims 1 to 3.

Images