Calculation method, calculation device, program, and color correction device

Abstract

The present invention provides a calculation method, calculation apparatus, program, and color correction apparatus capable of calculating a color difference for a specific color between an image and correction parameters used for color correction of the image. [Solution] A calculation method according to one aspect of the present disclosure involves a computer performing the following steps: acquiring an image and a correction coefficient file used for color correction of the image; and calculating the color difference between a first color value of a specific color calculated from the image and a second color value of the specific color included in the correction coefficient file.

Description

[Technical Field]

[0001] This disclosure relates to a calculation method, a calculation apparatus, a program, and a color correction apparatus. [Background technology]

[0002] It is common practice to use an imaging device to photograph a subject and generate an image. Even images of the same subject may appear differently in terms of color when displayed on different display devices.

[0003] Patent Document 1 discloses a technique for performing color correction using color conversion parameters (profiles). Patent Document 2 discloses a technique for automatically selecting parameters to be used for color correction of an image based on the image acquisition conditions and imaging device information. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-19122 [Patent Document 2] Japanese Patent Publication No. 2008-160434 [Overview of the project] [Problems that the invention aims to solve]

[0005] Color conversion parameters vary depending on factors such as the imaging device used to generate the image and the shooting environment. To effectively color-correct an image using these parameters, it is necessary to select the appropriate parameters from among several available options to match the image.

[0006] In the technology disclosed in Patent Document 2, when there are multiple parameters for the same imaging conditions and the same imaging device, it is difficult to determine which parameters are most appropriate.

[0007] This disclosure aims to provide a calculation method, calculation apparatus, program, and color correction apparatus that can calculate a color difference with respect to a specific color between an image and correction parameters used for color correction of the image. [Means for solving the problem]

[0008] A calculation device according to one aspect of the present disclosure includes an acquisition unit that acquires an image and a correction coefficient file used for color correction of the image, and a color difference calculation unit that calculates the color difference between a first color value of a specific color calculated from the image and a second color value of the specific color included in the correction coefficient file.

[0009] A calculation method according to one aspect of the present disclosure involves a computer acquiring an image and a correction coefficient file used for color correction of the image, and calculating the color difference between a first color value of a specific color calculated from the image and a second color value of the specific color included in the correction coefficient file.

[0010] A program according to one aspect of this disclosure causes a computer to perform the following steps: a procedure for obtaining an image and a correction coefficient file used for color correction of the image; and a procedure for calculating the color difference between a first color value of a specific color calculated from the image and a second color value of the specific color included in the correction coefficient file.

[0011] A color correction device according to one aspect of the present disclosure includes an acquisition unit that acquires the color difference between a first color value of a specific color calculated from an image and a second color value of the specific color included in each of the multiple correction coefficient files, from among a plurality of correction coefficient files used for color correction of an image, and a color correction unit that performs color correction of the image using the correction coefficient file from among the plurality of correction coefficient files that has the smallest color difference. [Effects of the Invention]

[0012] According to the present disclosure, the color difference of a specific color can be calculated between an image and a correction parameter used for color correction of the image. According to the present disclosure, a correction parameter suitable for performing color correction on the image can be determined based on the calculated color difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [Figure 1] Figure showing an example configuration of a color correction system according to the first embodiment [Figure 2] Figure showing an example functional configuration of a calculation device in the first embodiment [Figure 3] Figure showing an example functional configuration of a color correction device in the first embodiment [Figure 4] Flowchart explaining an operation example of a calculation device in the first embodiment [Figure 5] Figure showing an example configuration of a color correction system according to the second embodiment [Figure 6] Figure showing an example functional configuration of a calculation device in the second embodiment [Figure 7] Flowchart explaining an operation example of a calculation device in the second embodiment [Figure 8] Figure showing an example hardware configuration of a computer for implementing functions of each component included in a color correction system MODES FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configurations may be omitted. In addition, common configurations in the embodiments are denoted by the same reference numerals, and repeated descriptions thereof may be omitted.

[0015] <First Embodiment> Figure 1 shows an example of the configuration of a color correction system 100 according to the first embodiment. As shown in Figure 1, the color correction system 100 includes a calculation device 10, a color correction device 20, an imaging device 30, a correction coefficient file server 40, an image file server 50, and a display device 60.

[0016] Each component of the color correction system 100 is a type of computer. Computers include PCs (Personal Computers), smartphones, tablet devices, and other computers with various hardware configurations. Furthermore, at least one of the components of the color correction system 100, such as the calculation device 10, the color correction device 20, the correction coefficient file server 40, and the image file server 50, may be implemented by cloud computing or on-premise.

[0017] The imaging device 30 captures an object and generates an image. The imaging device 30 is communicated with the correction coefficient file server 40 and the image file server 50. In this specification, "communicated with" means that various data and files can be sent and received, with or without using a public network such as the Internet. In this disclosure, any known and appropriate communication means can be used for communication between each component.

[0018] The objects photographed by the imaging device 30 are various specimens and color charts that have been set as observation targets by the administrator or user of the color correction system 100.

[0019] The administrator of the color correction system 100 is the person who provides users with the right to use the color correction system 100, and who manages and maintains the color correction system 100. Specifically, the administrator of the color correction system 100 is the person in charge of the company that provides the calculation device 10, which is one of the components of the color correction system 100. The user of the color correction system 100 is the person who uses the color correction system 100.

[0020] In this disclosure, the specimen to be photographed by the imaging device may be of any kind, but as an example, the specimen is a tissue sample taken from a patient receiving treatment at a medical institution such as a hospital. In this example, the image produced by the imaging device 30 when it photographs the specimen is a medical image, more specifically a pathological image. In this example, the imaging device 30 is installed in a medical institution to which the user belongs. In this example, the user is a physician or a medical technician, etc.

[0021] The specimen to be photographed by the imaging device 30 may be prepared in advance by the user, for example. The specimen may have undergone various staining treatments. Specifically, the specimen may have been stained with hematoxylin-eosin (HE) staining or immunohistochemical staining. However, the staining method of the specimen is not limited to these in this disclosure, and specimens that have undergone other types of staining treatments may be used as the target object.

[0022] In the following description, the image generated by the imaging device 30 after capturing the sample will be referred to as the target image. The target image is the image that will be color corrected by the color correction device 20.

[0023] The imaging device 30, after capturing a sample through user operation, transmits the generated target image to the image file server 50. The imaging device 30 generates related information for the target image when capturing it. This related information includes at least the date and time the target image was generated, identification information of the device (imaging device 30), and information regarding the type of target image. Information regarding the type of target image may, for example, indicate the staining method of the target image. In this specification, the related information for the target image is referred to as image metadata. The imaging device 30 transmits the target image and its image metadata to the image file server 50, associating them with each other.

[0024] The image file server 50 stores the target image transmitted from the imaging device 30 and the image metadata of that target image, associating them with each other. The image file server 50 transmits the target image and image metadata to be color corrected by the color correction device 20 to the calculation device 10, which has started the extraction process described later.

[0025] The color chart captured by the imaging device 30 is a color sample that includes at least the colors contained in the target image. In the following description, the image generated by the imaging device 30 capturing the color chart will be referred to as the color chart image. The color chart may be prepared in advance by the administrator or user of the color correction system 100.

[0026] In particular, when HE-stained images are assumed as the target image, the color chart preferably comprises a substrate and color patches formed on the substrate. Here, it is preferable that the color patches include a second specific color other than the specific color (white). The coordinate points of the second specific color are preferably located within the region enclosed by the three points (0.200, 0.070), (0.450, 0.280), and (0.310, 0.340) on the xy chromaticity diagram. Such a color chart includes a second specific color that is likely to appear in HE-stained images.

[0027] The imaging device 30 captures a color chart based on user input and then transmits the generated color chart image to the correction coefficient file server 40. The imaging device 30 also generates related information about the color chart image when capturing it. This related information includes at least the date and time the color chart image was generated, identification information of the device (imaging device 30), and information about the type of color chart image. In this specification, the related information about the color chart image is referred to as correction coefficient metadata.

[0028] It should be noted that the correction coefficient metadata does not necessarily have to be generated by the imaging device 30. For example, the user may input the correction coefficient metadata using an input device included in the color correction system 100. The input device that accepts the input of the correction coefficient metadata can, for example, be installed alongside the imaging device 30.

[0029] The identification information of the imaging device 30 included in the correction coefficient metadata may be, for example, a serial number unique to the imaging device 30. Alternatively, the identification information of the imaging device 30 may be, for example, information indicating the installation location of the imaging device 30. Preferably, the identification information of the imaging device 30 is information that enables identification of imaging devices from the same manufacturer and of the same model number.

[0030] Information regarding the type of color chart image includes, for example, information about the types of colors of the color patches included in the color chart, such as a standard color chart containing red, green, and blue color patches, a grayscale chart containing gray color patches, and an HE chart containing color patches for HE staining. The imaging device 30 associates the color chart image with the correction coefficient metadata of the color chart image and transmits it to the correction coefficient file server 40.

[0031] The correction coefficient file server 40 creates a correction coefficient file used for color correction processing of the target image in the color correction device 20, based on the color chart image generated by the imaging device 30. The correction coefficient file contains correction parameters for color correction of the target image. An example of a correction coefficient file is an ICC (International Color Consortium) profile.

[0032] Known techniques can be appropriately adopted for the method of creating the correction coefficient file in the correction coefficient file server 40. For example, the correction coefficient file server 40 may be created based on a color chart image and the colorimetric values ​​of the color chart.

[0033] Furthermore, the correction coefficient file server 40 stores multiple correction coefficient files created using multiple color chart images. Each of the multiple correction coefficient files has different correction parameters. As a result, the way color correction is performed differs depending on which of the multiple correction coefficient files is used for color correction.

[0034] Here, the correction coefficient file server 40 stores the correction coefficient metadata associated with a specific color chart image and the correction coefficient file created using that specific color chart image, in relation to each other.

[0035] The correction coefficient file server 40 then transmits multiple correction coefficient files and correction coefficient metadata associated with each correction coefficient file to the calculation device 10, which has started the extraction process described later.

[0036] The calculation device 10 performs an extraction process to extract a correction coefficient file suitable for color correcting the target image from among multiple correction coefficient files received from the correction coefficient file server 40. Details of the extraction process by the calculation device 10 will be described later. The calculation device 10 transmits the correction coefficient file suitable for color correcting the target image, which was extracted through the extraction process, to the color correction device 20.

[0037] The color correction device 20 performs color correction processing on the target image using the correction coefficient file received from the calculation device 10. The color correction device 20 transmits the color-corrected image to the display device 60. In this specification, the color-corrected image is referred to as the corrected image.

[0038] The display device 60 is a device that displays corrected images. By displaying the corrected images on the display device 60, users can perform diagnoses and image interpretation using the corrected images.

[0039] If the target image is a medical image such as a pathological image, the display device 60 will be installed at the medical institution to which the user belongs. The imaging device 30 and the display device 60 may be installed at the same medical institution, or they may be installed at different medical institutions.

[0040] The display device 60 may accept an operation to select a specific target image from among the target images stored in the image file server 50, and an operation to start color correction of the selected target image. When the display device 60 receives such an operation from the user, it sends a processing start instruction to the calculation device 10 to start the extraction process. In this case, the calculation device 10 executes the extraction process upon receiving the processing start instruction from the display device 60, and the color correction device 20 starts executing the color correction process based on the correction coefficient file extracted in the extraction process. In this disclosure, the trigger for the calculation device 10 to start the extraction process is not limited to receiving the processing start instruction from the display device 60. For example, the image file server 50 may send the new target image to the calculation device 10 when it receives and stores a new target image, and the calculation device 10 may start the extraction process on the received target image.

[0041] As described above, in the color correction system 100 according to this first embodiment, the calculation device 10 extracts a correction coefficient file suitable for color correction of the target image from among a plurality of correction coefficient files that have been created in advance, and the color correction device 20 performs color correction of the target image using the extracted correction coefficient file. This makes it possible to extract an appropriate correction coefficient file from among a plurality of correction coefficient files according to the target image and perform appropriate color correction.

[0042] (Calculation device 10) Figure 2 is a block diagram showing an example of the functional configuration of the calculation device 10. The calculation device 10 comprises an acquisition unit 11, a color value calculation unit 12, a classification unit 13, a selection unit 14, a color difference calculation unit 15, an extraction unit 16, and an output unit 17. With these components, the calculation device 10 performs an extraction process to extract a correction coefficient file suitable for the target image from among multiple correction coefficient files.

[0043] In the following description, the calculation device 10 will be described in an manner in which it extracts a correction coefficient file for use in color correction of a single target image during the extraction process. However, the disclosure is not limited thereto, and for example, the calculation device 10 may extract correction coefficient files suitable for each of multiple target images in parallel with each other.

[0044] The acquisition unit 11 acquires the target image and the image metadata associated with the target image from the image file server 50. The acquisition unit 11 also acquires from the correction coefficient file server 40 multiple correction coefficient files as candidates for correction coefficient files to be used for color correction of the target image, and multiple correction coefficient metadata associated with each of the multiple correction coefficient files.

[0045] The color value calculation unit 12 calculates a first color value, which is the color value of a specific color pixel in the target image. The specific color is a color used for comparing the colors of the target image with a color chart used to create a correction coefficient file. More specifically, the specific color is a color that is included in both the target image and the color chart used to create the correction coefficient file. The specific color may be a color set by the administrator of the color correction system 100, or it may be a color set by a user of the color correction system 100 while viewing the target image displayed on an appropriate display device.

[0046] Common images and color charts almost certainly contain white or a color close to white. Therefore, it is preferable that specific colors be set to white or a color close to white.

[0047] Furthermore, if the target image is an HE-stained image and the color chart for creating the correction coefficient file is prepared to match the colors contained in the HE-stained image, then it is expected that colors close to red, blue, or purple will definitely be included in the target image and the correction coefficient file. In such cases, the specific color may be set to a color close to red, blue, or purple.

[0048] The following explanation describes the case where white is set as the specific color, and the color value calculation unit 12 calculates the color value of the white pixels (white points) in the target image as the first color value.

[0049] The color value calculation unit 12 may calculate the first color value of the white point in the target image by, for example, using the color value of the pixel in the target image whose sum of R, G, and B values ​​is the maximum value as the first color value. Alternatively, the color value calculation unit 12 may calculate the first color value using the color values ​​of multiple pixels in the target image whose sum of R, G, and B values ​​is greater than a threshold. In this case, the color value calculation unit 12 may, for example, use the average value of the color values ​​of each of the multiple pixels as the first color value.

[0050] The color value calculation unit 12 may present the calculated first color value to the user via an appropriate display device (for example, a display device 60 or a display device attached to the imaging device 30) and accept the user's confirmation. If the user inputs a color value more appropriate than the first color value calculated by the color value calculation unit 12, the color value calculation unit 12 may use the value input by the user as the first color value.

[0051] The classification unit 13 classifies the multiple correction coefficient files into multiple file groups based on the correction coefficient metadata associated with each of the multiple correction coefficient files.

[0052] As described above, the correction coefficient metadata includes the date and time the color chart image was generated, identification information of the imaging device 30, and information regarding the type of color chart image.

[0053] The classification unit 13 may perform the classification using one of the classification methods described below, or a combination of several methods.

[0054] The classification unit 13, for example, classifies multiple correction coefficient files created based on color chart images generated by the same imaging device 30 into the same file group.

[0055] Alternatively, the classification unit 13 may classify multiple correction coefficient files created based on color chart images generated at similar times (e.g., the same day, or the same time of day) into the same file group.

[0056] Alternatively, the classification unit 13 may classify, for example, multiple correction coefficient files created by the imaging device 30 capturing the same type of color chart into the same file group.

[0057] In this embodiment, the classification unit 13 of the calculation device 10 classifies multiple correction coefficient files into multiple file groups. However, for example, the classification of multiple correction coefficient files into multiple file groups may be performed by the correction coefficient file server 40. In this case, the calculation device 10 does not need to have the classification unit 13 as a function.

[0058] The selection unit 14 selects a file group from among multiple file groups to be used for color difference calculation by the color difference calculation unit 15 (described later), based on the comparison result between the image metadata of the target image and the correction coefficient metadata of multiple file groups classified by the classification unit 13 or the correction coefficient file server 40. The selection unit 14 may select only one file group from among multiple file groups as the target for color difference calculation, or it may select two or more file groups.

[0059] The selection unit 14 selects a file group for color difference calculation, for example, using the imaging device 30 that generated the target image and the color chart image as a selection criterion. Specifically, the selection unit 14 selects a file group containing multiple correction coefficient files created based on a color chart image generated by the same imaging device 30 that generated the target image as the file group for color difference calculation.

[0060] Alternatively, the selection unit 14 may, for example, use the date and time the target image and color chart image were generated as selection criteria to select a file group for color difference calculation. Specifically, the selection unit 14 selects a file group containing multiple correction coefficient files created based on a color chart image generated at the same date and time as the target image (for example, the same day or the same time slot on the same day) as the date and time the target image was generated, as the file group for color difference calculation.

[0061] Alternatively, the selection unit 14 may, for example, use the type of target image and color chart image (e.g., dyeing method) as a selection criterion to select a file group for which color difference calculation is to be performed. Specifically, the selection unit 14 selects a file group containing multiple correction coefficient files created based on a color chart image corresponding to the dyeing method of the target image as the file group for which color difference calculation is to be performed.

[0062] The selection unit 14 may select a file group for which color difference calculations are to be performed by using a combination of multiple selection criteria (imaging device, date and time, image type).

[0063] In this way, the classification unit 13 or the correction coefficient file server 40 classifies multiple correction coefficient files into multiple file groups, and the selection unit 14 selects the file group to be used for color difference calculation from among the multiple file groups based on the comparison result of the metadata of the target image and each correction coefficient file. This makes it possible to narrow down the candidates for correction coefficient files suitable for color correcting the target image from among the multiple correction coefficient files to some extent, before the color difference calculation process by the color difference calculation unit 15. This reduces the processing load of the extraction process in the calculation device 10 and shortens the processing time.

[0064] If the minimum value among the multiple color differences calculated by the color difference calculation unit 15 for multiple correction coefficient files included in a previously selected file group is greater than a predetermined threshold, in other words, if the selected file group is deemed not to contain a correction coefficient file suitable for color correcting the target image, the selection unit 14 may re-select the file group to be used for color difference calculation based on the comparison result between the image metadata of the target image and the correction coefficient metadata of the multiple file groups classified by the classification unit 13. In this case, the selection unit 14 may re-select a second file group, selected using different selection criteria than those used for the first file group initially selected, as the target for color difference calculation.

[0065] The color difference calculation unit 15 calculates the color difference between the first color value of the white point in the target image and the second color value of the white point in each of the multiple correction coefficient files. Here, the multiple correction coefficient files for which the color difference calculation unit 15 is performed are the correction coefficient files included in the first file group or the second file group selected by the selection unit 14.

[0066] The color difference calculation unit 15 calculates the color difference, for example, using the following method. In the following explanation, the first color value is assumed to be represented by an RGB value.

[0067] According to formula (1), the primary color value of the RGB values ​​is converted to the XYZ value.

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[0068] [Table 1]

[0069] Next, based on the XYZ values ​​of the first color value calculated by equation (1), the L of the first color value is calculated using the following equations (2) to (5). * a * b* Calculate the value.

[0070] [[Mathematical Expression]] L * is a lightness index.

[0071] [[Mathematical Expression]] [[Mathematical Expression]] a * and b * are chromaticness indices.

[0072] However, X / Xn, Y / Yn, and Z / Zn satisfy the condition of the following formula (5) (in the case of JIS Z8781-4). [[Mathematical Expression]]

[0073] The color difference calculation unit 15 thus calculates L of the first color value * a * b * value.

[0074] On the other hand, the color difference calculation unit 15 acquires second color values in each of the plurality of correction coefficient files. For the color difference calculation unit 15, for example, a color value of a color closest to white among the color charts that are sources of the correction coefficient file may be set as the second color value in the correction coefficient file. The "color value of a color closest to white" is, for example, a color value of a white color patch image. In the following description, it is assumed that the second color value of each correction coefficient file is represented by L * a * b * value, respectively.

[0075] The color difference calculation unit 15 calculates a color difference ΔE between the first color value and the second color value, for example, using the following formula (6) defined in CIE1976.

[0076]

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[0077] In equation (6), L * 1,a * 1,b * 1 is, for example, the first color value L * a * b * It is a value, L * 2,a * 2,b * 2 is, for example, the second color value L * a * b * It is a value.

[0078] Note that the first color value L * a * b * Value and second color value L * a * b * The method for calculating the color value from the value is not limited to the method using formula (6); for example, formula (7) defined in the CIE2000 DE standard may also be used.

[0079]

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[0080]

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[0081] In the following explanation, for simplicity, the color difference between the first color value of the target image and the second color value of the correction coefficient file, calculated by the color difference calculation unit 15, may be referred to as the color difference related to the correction coefficient file.

[0082] Returning to the explanation of Figure 2, the extraction unit 16 extracts the correction coefficient file that minimizes the color difference from among multiple correction coefficient files. In the following explanation, the file extracted by the extraction unit 16 will be referred to as the extracted file. The extracted file is a correction coefficient file used by the color correction device 20, described later, when it performs color correction processing on the target image.

[0083] The extracted file with the smallest color difference is the correction coefficient file among multiple correction coefficient files that contains the specific color (white) closest to the specific color (white) in the target image. The fact that the white values ​​of the target image and the correction coefficient file are similar means that the light source conditions when the target image and the correction coefficient file were captured were similar. Therefore, by setting the specific color to white and having the color correction device 20 perform color correction processing on the target image using the extracted file extracted by the extraction unit 16, more suitable color correction can be performed on the target image.

[0084] The output unit 17 outputs the extracted file extracted by the extraction unit 16 to the color correction device 20. This allows the color correction device 20 to perform appropriate color correction processing on the target image using the extracted file.

[0085] Furthermore, the output unit 17 outputs the minimum color difference for the extracted file, in other words, the minimum color difference in the first file group, to the color correction device 20, in association with the extracted file. The color difference for the extracted file is used by the color correction device 20 to indicate the accuracy of the color correction.

[0086] (Color correction device 20) Figure 3 is a block diagram showing an example of the functional configuration of the color correction device 20. The color correction device 20 comprises an acquisition unit 21, a color correction unit 22, an accuracy calculation unit 23, and an output unit 24. With these configurations, the color correction device 20 can perform color correction on a target image using the correction coefficient file that is most suitable for the target image from among multiple correction coefficient files.

[0087] The acquisition unit 21 acquires the target image from the image file server 50, and also acquires an extraction file suitable for the target image and the color difference related to the extraction file from the calculation device 10.

[0088] The color correction unit 22 performs color correction on the target image by applying color correction parameters contained in the extracted file to each pixel of the target image. In the following description, the target image that has been color corrected by the color correction unit 22 will be referred to as the corrected image. A known method can be appropriately adopted for the color correction performed by the color correction unit 22.

[0089] The accuracy calculation unit 23 calculates the accuracy of the color correction performed by the color correction unit 22 based on the color difference of the extracted files. The accuracy calculation unit 23 may determine the accuracy of the color correction by, for example, ranking the color difference values ​​of the extracted files.

[0090] Table 2 shows examples of accuracy ranked based on color difference in extracted files. Table 2 is quoted from the newly revised Handbook of Color Science (3rd edition) published by the Color Science Association of Japan. [Table 2]

[0091] The method for calculating the accuracy of color correction by the accuracy calculation unit 23 is not limited to the example described above, and any method can be adopted.

[0092] The output unit 24 outputs the corrected image and the accuracy of the color correction to the display device 60. This allows users of the color correction system 100 to refer to the corrected image, which has been color corrected using the correction coefficient file (extracted file) that is most suitable for the target image from among multiple correction coefficient files, via the display device 60. Consequently, users can refer to the correction accuracy when making a diagnosis.

[0093] (Example of operation in the first embodiment) Figure 4 is a flowchart illustrating an example of the operation of the calculation device 10 in the first embodiment. The operation example shown in Figure 4 provides a detailed explanation of the extraction process performed by the calculation device 10. As described above, the extraction process is initiated, for example, when a user of the color correction system 100 selects a desired target image via the display device 60 and initiates the extraction process on the calculation device 10.

[0094] In step S11, the calculation device 10 obtains the target image to be color corrected, selected by the user, from the image file server 50.

[0095] In step S12, the calculation device 10 calculates the first color value, which is the color value of a specific color (white) in the target image. In step S12, the calculation device 10 may have an appropriate display device display the first color value and allow the user to confirm the calculated first color value. If the user who has confirmed the first color value inputs that they may use the first color value, the calculation device 10 proceeds to step S13; otherwise, it adopts the value input by the user as the first color value and proceeds to step S13.

[0096] In step S13, the calculation device 10 obtains multiple correction coefficient files from the correction coefficient file server 40.

[0097] In step S14, the calculation device 10 classifies the multiple correction coefficient files obtained in step S13 into multiple file groups.

[0098] In step S15, the calculation device 10 selects a file group from a plurality of file groups to be used for calculating the color difference, based on the image metadata and the correction coefficient metadata.

[0099] In step S16, the calculation device 10 calculates the color difference for each of the multiple correction coefficient files included in the file group for which the color difference is to be calculated.

[0100] In step S17, the calculation device 10 determines whether the minimum value of the color differences among the multiple correction coefficient files included in the file group for which color difference calculation was performed in step S16 is less than or equal to a predetermined threshold. If the minimum value of the color difference is less than or equal to the predetermined threshold, the file group for which color difference calculation is performed can be considered to contain correction coefficient files suitable for color correction of the target image. If the minimum value of the color difference is not less than or equal to the predetermined threshold (i.e., the minimum value of the color difference is greater than the predetermined threshold), the file group for which color difference calculation is performed can be considered not to contain correction coefficient files suitable for color correction of the target image.

[0101] If it is determined in step S17 that the minimum value of the color difference is less than or equal to a predetermined threshold (step S17:Y), the calculation device 10 proceeds to step S19; otherwise (step S17:N), it proceeds to step S18.

[0102] If the minimum value of the color difference is determined to be greater than a predetermined threshold, in step S18, the calculation device 10 re-selects another file group as the target for color difference calculation. Then, the calculation device 10 returns to step S16 and calculates the color difference for the re-selected file group.

[0103] If it is determined that the minimum color difference is less than or equal to a predetermined threshold, in step S19, the calculation device 10 extracts the correction coefficient file that has the minimum color difference from the file group to be calculated for color difference.

[0104] In step S110, the calculation device 10 outputs the extracted correction coefficient file (extracted file) and the minimum color difference value to the color correction device 20. In this case, the minimum color difference value output by the calculation device 10 is a value that indicates the color difference between a specific color in the extracted file and a specific color in the image. This allows the color correction device 20 to suitably perform color correction of the target image using a correction coefficient file suitable for the target image.

[0105] Note that the processes in steps S12 to S14 do not necessarily have to be performed in the order shown in Figure 4, and the order may be changed. Also, in the example shown in Figure 4, the calculation device performs the process of classifying multiple correction coefficient files into multiple file groups in step S14, but for example, the calculation device 10 may obtain the results of a prior classification by the correction coefficient file server 40.

[0106] (Operation and effects in the first embodiment) As described above, according to the color correction system 100 of the first embodiment, the calculation device 10 calculates the color difference between the color value (first color value) of a specific color (white) included in the target image to be color corrected and the color value (second color value) of the specific color (white) included in the correction coefficient file. Based on the color difference calculated in this way, the calculation device 10 can extract a correction coefficient file suitable for color correcting the target image from among a plurality of correction coefficient files. By performing color correction of the target image using the correction coefficient file extracted by the calculation device 10, the color correction device 20 can perform color correction of the target image with higher accuracy.

[0107] Furthermore, in the color correction system 100 according to the first embodiment, the calculation device 10 selects a file group from among a plurality of file groups, which include a plurality of correction coefficient files classified based on the correction coefficient metadata, to be used for calculating the color difference, based on the comparison result between the correction coefficient metadata and the image metadata of the target image. This reduces the number of correction coefficient files to be used for calculating the color difference, thereby reducing the processing load related to the color difference calculation process and shortening the processing time.

[0108] Furthermore, in the color correction system 100 according to the first embodiment, if the minimum value of the color difference for the correction coefficient files of a previously selected file group is greater than a predetermined threshold, the calculation device 10 re-selects another file group as the target for color difference calculation based on the above comparison result. This allows the calculation device to extract a correction coefficient file suitable for color correction of the target image from another file group if the correction coefficient file included in the previously selected file group is not suitable for color correction of the target image. This improves the accuracy of the color correction processing performed by the color correction device 20.

[0109] <Second Embodiment> A second embodiment of the present disclosure is described below. In the second embodiment, the calculation device 10A is shown to include the functions of the color correction device 20 in the first embodiment.

[0110] In the following, the differences between the color correction system 100A according to the second embodiment and the color correction system 100 according to the first embodiment will be mainly described. In the second embodiment, components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions may be omitted. In the second embodiment, components that differ from those in the first embodiment are denoted by the reference numeral "A" to distinguish them from the components in the first embodiment.

[0111] Figure 5 shows an example configuration of the color correction system 100A according to the second embodiment. As shown in Figure 5, the color correction system 100A does not include the color correction device 20 described in the first embodiment. Instead, the calculation device 10A of the color correction system 100A includes the function of a color correction device. The calculation device 10A in the second embodiment is an example of a color correction device of the present disclosure.

[0112] Figure 6 shows an example of the functional configuration of the calculation device 10A in the second embodiment. The calculation device 10A includes an acquisition unit 11, a color value calculation unit 12, a classification unit 13, a selection unit 14, a color difference calculation unit 15, an extraction unit 16, an output unit 17A, a color correction unit 18, and an accuracy calculation unit 19.

[0113] The color correction unit 18 performs color correction on the target image by applying color correction parameters contained in the extracted file extracted by the extraction unit 16 to each pixel of the target image. The method of color correction by the color correction unit 18 can be any known method, similar to that of the color correction unit 22 in the first embodiment.

[0114] The accuracy calculation unit 19 calculates the accuracy of the color correction performed by the color correction unit 18 based on the color difference of the extracted files. The accuracy calculation unit 19 may determine the accuracy of the color correction by ranking the color difference values ​​of the extracted files, for example, similar to the accuracy calculation unit 23 in the first embodiment.

[0115] The output unit 17A outputs the corrected image and the accuracy of the color correction to the display device 60. This allows users of the color correction system 100A to refer to the corrected image, which has been color-corrected using the correction coefficient file (extracted file) that is most suitable for the target image from among multiple correction coefficient files, via the display device 60.

[0116] Figure 7 is a flowchart illustrating an example of the operation of the calculation device 10A in the second embodiment.

[0117] In step S21, the calculation device 10A performs the extraction process of a correction coefficient file suitable for the target image. The extraction process in step S21 includes the processes from step S11 to step S19 of the extraction process by the calculation device 10 in the first embodiment, as described in Figure 4.

[0118] In step S22, the calculation device 10A performs color correction on the target image using the correction coefficient file (extracted file) extracted by the extraction process in step S21, and generates a corrected image.

[0119] In step S23, the calculation device 10A calculates the color correction accuracy based on the color difference used to extract the extracted files in the extraction process of step S21.

[0120] In step S24, the calculation device 10A outputs the corrected image and color correction accuracy to the display device 60.

[0121] Through this operation, the calculation device 10A can extract a correction coefficient file suitable for the target image and perform appropriate color correction of the target image using the extracted correction coefficient file.

[0122] (Operation and effects in the second embodiment) According to the second embodiment of the color correction system 100A, the calculation device 10A extracts an appropriate correction coefficient file for color correction of the target image and performs color correction of the target image using the extracted file. As a result, the calculation device 10A can suitably perform color correction of the target image by selecting a correction coefficient file suitable for color correction of the target image from among a plurality of correction coefficient files.

[0123] <Example of variation> The embodiments described above are examples of implementation of the Disclosure, and the Disclosure is not limited to the matters described in the embodiments described above, but can take various forms.

[0124] <Example hardware configuration> In the embodiments described above, each component included in the color correction systems 100 and 100A, namely the calculation devices 10 and 10A, the color correction device 20, the imaging device 30, the correction coefficient file server 40, the image file server 50, and the display device 60, was described as a computer. Below, an example of the computer hardware configuration for realizing the functions of each component included in the color correction systems 100 and 100A will be described.

[0125] Figure 8 shows an example of a computer hardware configuration for realizing the functions of each component included in the color correction systems 100 and 100A.

[0126] Computer 1000 includes an input device 1001, an output device 1002, a CPU 1003, a ROM (Read Only Memory) 1004, a RAM (Random Access Memory) 1005, a storage device 1006, a reader 1007 for reading information from various storage media, and a transceiver 1008, with each part connected by a bus 1009.

[0127] The reading device 1007 reads a program from a recording medium that contains a program for realizing the functions of each component of the color conversion system, and stores it in the storage device 1006. Alternatively, the transmitting / receiving device 1008 communicates with a system device connected to the network and stores a program downloaded from the system device in the storage device 1006.

[0128] Then, the CPU 1003 copies the program stored in the memory device 1006 to the RAM 1005, and sequentially reads and executes the instructions contained in that program from the RAM 1005, thereby realizing the functions of each component included in the color correction system 100, 100A. [Industrial applicability]

[0129] This disclosure is useful for a color correction system that extracts a correction coefficient file suitable for color correction of a target image from among multiple correction coefficient files. [Explanation of symbols]

[0130] 100,100A Color Correction System 10,10A Calculation Device 11 Acquisition Department 12. Color Value Calculation Unit 13 Classification section 14 Selection Department 15 Color difference calculation section 16 Extraction part 17,17A Output Section 18. Color Correction Section 19. Accuracy Calculation Unit 20 Color Correction Device 21 Acquisition Department 22 Color Correction Section 23. Accuracy Calculation Unit 24 Output section 30 Imaging device 40 Correction Factor File Server 50 Image File Servers 60 Display device

Claims

1. An acquisition unit that acquires an image and a correction coefficient file used for color correction of the image, A color difference calculation unit calculates the color difference between a first color value of a specific color calculated from the aforementioned image and a second color value of the same specific color included in the correction coefficient file. A calculation device equipped with the following features.

2. The aforementioned specific color is white. The calculation apparatus according to claim 1.

3. The color difference calculation unit calculates the color difference between the first color value and the multiple second color values ​​in each of the multiple correction coefficient files. The calculation apparatus according to claim 1.

4. The system further includes an extraction unit that extracts the correction coefficient file from the plurality of correction coefficient files that has the minimum color difference. The calculation apparatus according to claim 3.

5. The system further includes a classification unit that classifies the plurality of correction coefficient files into a plurality of file groups based on the correction coefficient metadata associated with each of the plurality of correction coefficient files. The calculation apparatus according to claim 4.

6. The system further includes a selection unit that selects a first file group to be used for calculating the color difference from among the plurality of file groups, based on the result of comparing the correction coefficient metadata of the correction coefficient files included in each of the file groups with the image metadata associated with the image. The color difference calculation unit calculates the color difference with respect to the correction coefficient file included in the first file group. The calculation apparatus according to claim 5.

7. In the process of selecting the first file group, if the minimum value of the color difference among the correction coefficient files included in the first file group is greater than a predetermined threshold, the selection unit selects a second file group other than the first file group from among the plurality of file groups as the target for calculating the color difference based on the comparison result. The color difference calculation unit calculates the color difference with respect to the correction coefficient file included in the second file group. The calculation apparatus according to claim 6.

8. The correction coefficient file is created based on a color chart image taken of a color chart and the colorimetric values ​​of the color chart. The calculation apparatus according to claim 6.

9. The aforementioned image metadata is information indicating the date and time the image was taken. The correction coefficient metadata is information indicating the date and time the color chart was photographed. The calculation apparatus according to claim 8.

10. The aforementioned image metadata is information about the imaging device that captured the image, The correction coefficient metadata is information about the imaging device that captured the color chart. The calculation apparatus according to claim 8.

11. The aforementioned image metadata is information relating to the type of the image, The correction coefficient metadata is information relating to the type of color chart. The calculation apparatus according to claim 8.

12. The aforementioned image is a medical color image. The calculation apparatus according to claim 1.

13. The aforementioned image is a pathological image. The calculation device according to claim 12.

14. The aforementioned image is a pathological image obtained by imaging a specimen that has been stained with hematoxylin and eosin. The calculation apparatus according to claim 13.

15. The aforementioned correction coefficient file is created based on a color chart image taken from a color chart and the colorimetric values ​​of the color chart. The color chart comprises a substrate and color patches formed on the substrate. The aforementioned color patch includes a second specific color, The coordinate points of the second specific color are located within the region enclosed by the three points (0.200, 0.070), (0.450, 0.280), and (0.310, 0.340) on the xy chromaticity diagram. The calculation apparatus according to claim 14.

16. The aforementioned image is a pathological image obtained by imaging a specimen that has undergone immunohistochemical staining. The calculation apparatus according to claim 13.

17. The first color value is the RGB value of the pixel in the image whose sum of R, G, and B values ​​is the maximum value. The calculation apparatus according to claim 1.

18. The color correction unit further comprises a color correction unit that performs color correction on the image using the correction coefficient file that yields the minimum color difference from among the plurality of correction coefficient files. The calculation apparatus according to claim 4.

19. The color correction unit, when the minimum value is less than or equal to a predetermined threshold, performs color correction of the image using the correction coefficient file that results in the minimum color difference. The calculation apparatus according to claim 18.

20. The system further includes an accuracy calculation unit for calculating the color correction accuracy related to the aforementioned color correction. The calculation apparatus according to claim 18 or 19.

21. Computers Obtain an image and a correction coefficient file used for color correction of the said image. The color difference between the first color value of a specific color calculated from the aforementioned image and the second color value of the same specific color included in the correction coefficient file is calculated. Calculation method.

22. A procedure for obtaining an image and a correction coefficient file used for color correction of the said image, A procedure for calculating the color difference between the first color value of a specific color calculated from the aforementioned image and the second color value of the same specific color included in the correction coefficient file, A program that causes a computer to execute something.

23. An acquisition unit that acquires the color difference between the first color value of a specific color calculated from the image and the second color value of the specific color included in each of the multiple correction coefficient files, from among multiple correction coefficient files used for color correction of the image. A color correction unit performs color correction on the image using the correction coefficient file that minimizes the color difference from among the plurality of correction coefficient files. A color correction device equipped with the following features.

Images