Color-matching function determination method, color-matching function determination program, and color-matching function determination device

Abstract

Provided are a color-matching function determination method, color-matching function determination program, and color-matching function determination device with which it is possible to easily determine the optimal color-matching function for each individual person. The color-matching function determination method determines a color-matching function for an observer who observes a first display device and a second display device, and includes a first display control step, a first tristimulus value calculation step, a second display control step, a reception step, and a determination step. In the first display control step, a first display color is displayed on the first display device. In the first tristimulus value calculation step, a plurality of first tristimulus values, which are of the first display color displayed on the first display device, are calculated on the basis of each of a plurality of color-matching functions. In the second display control step, a display color range including a plurality of display colors corresponding to the plurality of first tristimulus values is displayed on the second display device. In the reception step, a designation of the display color range is received from the observer. In the determination step, a color-matching function identified, from among the plurality of color-matching functions, on the basis of the designation received from the observer is determined as a color-matching function for the observer.

Description

Color matching function determination method, color matching function determination program, and color matching function determination device

[0001] The present invention relates to a color matching function determination method, a color matching function determination program, and a color matching function determination device.

[0002] When performing multi-monitor color matching (matching the colors of multiple monitors), the monitors are adjusted so that the tristimulus values ​​XYZ calculated using the standard observer CIE 1931 CMF (standard observer defined by the CIE (International Commission on Illumination) in 1931; CMF: Color Matching Function) match. This ensures that the apparent colors between the monitors match when viewed by the standard observer.

[0003] However, if the eye characteristics (color matching functions, CMF) of the standard observer and the actual observer differ, observer metamerism will cause different colors to be perceived by each person, which will cause differences in the appearance of colors between monitors.

[0004] Japanese Patent Application Laid-Open No. 2003-144222 discloses a data processing device that suppresses variations in color appearance due to variations in color matching functions.

[0005] When the eye characteristics of the standard observer and the actual observer differ, in order to achieve better color matching, it is preferable to perform color matching using color matching functions that are tailored to each individual. For this reason, methods have been proposed in which the optimal color matching function is determined and used for each individual, such as performing color matching using a color matching function customized for each individual or using multiple color matching functions that are tailored to each individual.

[0006] However, determining the optimal color matching functions requires the use of special equipment and multiple color matching experiments, making it difficult for anyone other than a color science expert to perform and therefore impractical.

[0007] JP 2014-42119 A

[0008] An object of the present invention is to provide a color matching function determination method, a color matching function determination program, and a color matching function determination device that can easily determine optimal color matching functions for each individual.

[0009] According to the present invention, there is provided a color matching function determination method having the following configuration: [1] A color matching function determination method for determining color matching functions for an observer observing a first display device and a second display device, the color matching function determination method comprising: a first display control step, a first tristimulus value calculation step, a second display control step, a receiving step, and a determining step, wherein the first display control step causes the first display device to display a first display color; the first tristimulus value calculation step calculates a plurality of first tristimulus values ​​that are tristimulus values ​​of the first display color to be displayed on the first display device based on a plurality of color matching functions; the second display control step causes the second display device to display a display color range including a plurality of display colors corresponding to the plurality of first tristimulus values; the receiving step receives a designation for the display color range from the observer; and the determining step determines, from the plurality of color matching functions, a color matching function specified based on the designation received from the observer as the color matching function for the observer.

[0010] According to the present invention, a plurality of first tristimulus values, which are tristimulus values ​​of a first display color displayed on a first display device, are calculated based on each of a plurality of color matching functions, and a display color range including a plurality of display colors corresponding to the plurality of first tristimulus values ​​is displayed on a second display device. When an observer specifies a display color range, one of the plurality of color matching functions identified based on the specification received from the observer is determined as the observer's color matching function. Therefore, the observer's color matching function is automatically determined simply by the observer checking the display color range displayed on the second display device and specifying the display color range. As described above, it is possible to easily determine the optimal color matching function for each individual.

[0011] Various embodiments of the present invention are described below. The embodiments described below can be combined with each other. [2] The color matching function determination method according to [1], further comprising a first spectral distribution acquisition step, in which the spectral distribution of the first display device is acquired as a first spectral distribution, and in the first tristimulus value calculation step, the plurality of first tristimulus values ​​are calculated based on the acquired first spectral distribution and each of the plurality of color matching functions. [3] A color matching function determination method according to [1] or [2], wherein the display color range is a color coordinate system that is displayed based on predetermined color matching functions and includes a plurality of display colors corresponding to the plurality of first tristimulus values, and further includes a candidate coordinate value calculation step and an associating step, wherein the candidate coordinate value calculation step calculates a plurality of candidate coordinate values ​​that correspond to the plurality of first tristimulus values ​​as coordinate values ​​in the color coordinate system, and the associating step associates the plurality of color matching functions with the plurality of candidate coordinate values, and the receiving step receives from the observer designation of designated coordinate values ​​in the color coordinate system, and the determining step determines, as the color matching function for the observer, a color matching function associated with a candidate coordinate value that has a smallest difference from the designated coordinate value whose designation has been received. [4] The color matching function determination method according to [3], wherein in the candidate coordinate value calculation step, a plurality of second tristimulus values ​​corresponding to the plurality of first tristimulus values ​​are calculated based on the predetermined color matching function as tristimulus values ​​of a plurality of display colors included in the color coordinate system displayed on the second display device, and the plurality of candidate coordinate values ​​corresponding to the plurality of second tristimulus values ​​are calculated as coordinate values ​​in the color coordinate system. [5] The color matching function determination method according to [4], further comprising a second spectral distribution acquisition step, wherein in the second spectral distribution acquisition step, the spectral distribution of the second display device is acquired as a second spectral distribution, and in the candidate coordinate value calculation step, the plurality of second tristimulus values ​​corresponding to the plurality of first tristimulus values ​​are calculated based on the acquired second spectral distribution and the predetermined color matching function.[6] The color matching function determination method according to any one of [1] to [5], wherein the display color range is composed of a plurality of second display colors associated with each of the plurality of color matching functions and having the same tristimulus values ​​as the plurality of first tristimulus values, the receiving step receives a designation of a second display color from the observer among the plurality of second display colors, and the determining step determines a color matching function associated with the second display color whose designation has been accepted as the color matching function for the observer. [7] A color matching function determination program that causes a processor to execute the color matching function determination method according to any one of [1] to [6]. [8] A color matching function determination device that determines color matching functions for an observer observing a first display device and a second display device, comprising: a first display control unit, a first tristimulus value calculation unit, a second display control unit, a receiving unit, and a determination unit, wherein the first display control unit causes the first display device to display a first display color; the first tristimulus value calculation unit calculates a plurality of first tristimulus values ​​that are tristimulus values ​​of the first display color to be displayed on the first display device based on each of a plurality of color matching functions; the second display control unit causes the second display device to display a display color range that includes a plurality of display colors corresponding to the plurality of first tristimulus values; the receiving unit receives a designation for the display color range from the observer; and the determination unit determines, from the plurality of color matching functions, a color matching function that is specified based on the designation received from the observer, as the color matching function for the observer.

[0012] According to the present invention, it is possible to easily determine the optimal color matching function for each individual.

[0013] FIG. 1 is a diagram illustrating a hardware configuration of an image display system 1. FIG. 2 is a diagram illustrating differences in spectral characteristics among different display devices. FIG. 3 is a block diagram illustrating a hardware configuration of an image processing device 2. FIG. 4 is a block diagram illustrating an example of the functional configuration of a control unit 11 (image processing device 2). FIG. 5 is a diagram illustrating an example of a reception screen 20 displayed on a second display device 4. FIG. 6 is a flowchart illustrating an example of color matching function determination processing performed by the control unit 11. FIG. 7 is a flowchart illustrating a modified example of color matching function determination processing performed by the control unit 11.

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently.

[0015] (Hardware Configuration of Image Display System 1) The hardware configuration of the image display system 1 will be described with reference to FIG. 1. As shown in FIG. 1, the image display system 1 includes an image processing device 2, a first display device 3, and a second display device 4. The first display device 3 and the second display device 4 are, for example, liquid crystal display devices (monitors) and display various images. The image display system 1 is installed, for example, in an examination room in a hospital. The image display system 1 may also be installed in a photo studio or a video editing studio.

[0016] The image processing device 2, the first display device 3, and the second display device 4 are configured to be able to communicate with each other via a control signal cable 5 and a video signal cable 6. Image data from the image processing device 2 is transmitted to the first display device 3 and the second display device 4 via the video signal cable 6.

[0017] An image based on the image data transmitted from the image processing device 2 is displayed on the display screen 3a of the first display device 3 and the display screen 4a of the second display device 4. Control signals and data are exchanged between the image processing device 2 and the first display device 3 and second display device 4 via a control signal cable 5.

[0018] Each component of the image processing device 2 may be implemented by software or hardware. When implemented by software, various functions can be realized by a CPU executing a computer program. The program may be stored in an internal memory or in a computer-readable non-transitory recording medium. Alternatively, the program may be read from an external memory and implemented using so-called cloud computing. When implemented by hardware, the functions can be implemented by various circuits such as an ASIC, an FPGA, or a dynamically reconfigurable processor (DRP). This embodiment deals with various pieces of information and concepts that encompass them. These are represented by high or low signal values ​​as a binary bit set consisting of 0 or 1, and communication and calculations can be performed using the software or hardware described above.

[0019] (Spectral Characteristics and Color Matching Functions) Spectral characteristics and color matching functions will be described with reference to Fig. 2. Fig. 2 is a diagram illustrating the difference in spectral characteristics (spectral radiance at each wavelength) between different display devices, specifically the first display device 3 and the second display device 4.

[0020] When comparing the spectral characteristics of the first display device 3 shown in Fig. 2A with the spectral characteristics of the second display device 4 shown in Fig. 2B, a clear difference is observed, particularly in the spectral distribution of R (red). As such, the spectral distribution of each RGB differs for each display device.

[0021] When color matching (matching the colors (e.g., white points) of the first display device 3 and the second display device 4) is performed using a measuring device (e.g., a color sensor) between the first display device 3 and the second display device 4, the first display device 3 and the second display device 4 are adjusted so that the tristimulus values ​​XYZ calculated using the CIE 1931 CMF (a standard observer defined by the CIE (International Commission on Illumination) in 1931; CMF: Color Matching Function), which is a standard observer, match. As a result, the apparent colors of the first display device 3 and the second display device 4 match when viewed by the standard observer.

[0022] However, if the eye characteristics (color matching functions, CMFs) of the standard observer and the actual observer differ, observer metamerism will cause different colors to be perceived by different people, which will cause differences in the apparent colors between the first display device 3 and the second display device 4.

[0023] When the eye characteristics of the standard observer and the actual observer differ, in order to achieve better color matching, it is preferable to perform color matching using color matching functions that are tailored to each individual. For this reason, methods have been proposed in the past in which color matching is performed using color matching functions customized for each individual, or in which a plurality of color matching functions are used to suit each individual, and in which an optimal color matching function is determined and used for each individual.

[0024] However, determining the optimal color matching functions requires the use of special equipment and multiple color matching experiments, making it difficult for anyone other than a color science expert to perform and therefore impractical.

[0025] Therefore, in this embodiment, the image processing device 2 is configured to easily determine the optimal color matching functions for each individual and to make the apparent colors of the second display device 4 (the monitor to be adjusted) match those of the first display device 3 (the reference monitor). Note that the image processing device 2 functions as the "color matching function determination device" of the present invention.

[0026] (Hardware configuration of image processing device 2) Fig. 3 is a block diagram showing the hardware configuration of the image processing device 2 in this embodiment. As shown in Fig. 3, the image processing device 2 is configured to include a control unit 11, a storage unit 12, a communication unit 13, and an operation input unit 14.

[0027] The control unit 11 is, for example, a CPU (Central Processing Unit), a microprocessor, a DSP (Digital Signal Processor), or the like, and controls the overall operation of the image processing device 2 .

[0028] A part of the storage unit 12 is configured with, for example, a RAM (Random Access Memory) or a DRAM (Dynamic Random Access Memory), and is used as a work area when the control unit 11 executes processes based on various programs.

[0029] Furthermore, a part of the storage unit 12 is, for example, a non-volatile memory such as a ROM (Read Only Memory) or an HDD (Hard Disk Drive), and stores various data and programs used in the processing of the control unit 11. The storage unit 12 can hold a database including one or more tables for recording various information, processing results, and the like.

[0030] The programs stored in the memory unit 12 include, for example, an OS (Operating System) for realizing the basic functions of the image processing device 2, drivers for controlling various hardware, programs for realizing various functions, etc., and include a program that functions as the ``color matching function determination program'' of the present invention.

[0031] The communication unit 13 is, for example, a network interface controller (NIC) and has a function of connecting to a communication line (not shown). Note that, instead of or together with the NIC, the communication unit 13 may have a function of connecting to a wireless local area network (LAN), a function of connecting to a wireless wide area network (WAN), a function of enabling short-range wireless communication such as Bluetooth (registered trademark), infrared communication, etc.

[0032] The operation input unit 14 is composed of a keyboard, a mouse, etc., and accepts input of various operations by the user of the image processing device 2.

[0033] The control unit 11, storage unit 12, communication unit 13, operation input unit 14, first display device 3, and second display device 4 are electrically connected to one another via a system bus 16. Therefore, the control unit 11 can access the storage unit 12, display images on the first display device 3 and second display device 4, grasp the operation status of the operation input unit 14 by the user, and access various communication networks via the communication unit 13.

[0034] 4 is a block diagram showing an example of the functional configuration of the control unit 11 included in the image processing device 2 of this embodiment. As shown in Fig. 4, the control unit 11 includes, as its functional configuration, an adjustment unit 11a, an image acquisition unit 11b, a first display control unit 11c, a second display control unit 11d, a first spectral distribution acquisition unit 11e, a first spectral distribution calculation unit 11f, a first tristimulus value calculation unit 11g, a second spectral distribution acquisition unit 11h, a second spectral distribution calculation unit 11i, a second tristimulus value calculation unit 11j, a candidate coordinate value calculation unit 11k, an associating unit 11l, a receiving unit 11m, and a determination unit 11n.

[0035] The adjustment unit 11a adjusts the first display device 3 when performing color matching between the first display device 3 and the second display device 4 (specifically, making the apparent color of the second display device 4 (the monitor to be adjusted) match that of the first display device 3 (the reference monitor)). Here, adjusting the first display device 3 means performing color measurement using a measuring device (e.g., a color sensor) while manipulating circuit parameters set in the first display device 3 to make the state of the first display device 3 match that specified by the adjustment target. The adjustment target of the first display device 3 means the desired final state of the first display device 3 as a result of adjusting the first display device 3. The state of the first display device 3 is set to a white luminance (e.g., 100 cd / m ２ ), chromaticity (for example, color temperature D65), chromaticity (gamut) of primary colors (red, green, and blue), gamma value (for example, 2.2), and luminance of black. Note that the adjustment unit 11a may adjust the second display device 4 in the same way as the first display device 3.

[0036] In this embodiment, after adjustment by the adjustment unit 11a, a process is performed to make the apparent colors of the second display device 4 match those of the first display device 3 to the person actually observing the first display device 3 and the second display device 4 (a user, corresponding to an "observer" in the present invention). During this process, a color matching function (also referred to as a customized CMF) that is optimal for the user is simply determined.

[0037] The image acquisition unit 11b acquires image data (input image data) from an input device (not shown), performs predetermined image processing on the acquired image data to generate first display image data, and outputs the generated first display image data to the first display control unit 11c.

[0038] The image acquisition unit 11b acquires image data from the input device, performs predetermined image processing on the acquired image data to generate second display image data, and outputs the generated second display image data to the second display control unit 11d.

[0039] The input device is, for example, an information processing device such as a personal computer, and is configured to be able to output various data such as image data.

[0040] The first display control unit 11c outputs the first display image data output from the image acquisition unit 11b to the first display device 3 and controls the first display device 3 to display an image corresponding to the first display image data on the first display device 3.

[0041] The second display control unit 11d outputs the second display image data output from the image acquisition unit 11b to the second display device 4 and controls the second display device 4 to display an image corresponding to the second display image data on the second display device 4.

[0042] The first display device 3 includes a display panel including a plurality of pixels arranged on a substrate, and, under the control of the first display control unit 11 c, displays an image corresponding to the first display image data output from the first display control unit 11 c. The images displayed by the first display device 3 include still images and moving images.

[0043] The second display device 4 includes a display panel including a plurality of pixels arranged on a substrate, and, under the control of the second display control unit 11 d, displays an image corresponding to the second display image data output from the second display control unit 11 d. The images displayed by the second display device 4 include still images and moving images.

[0044] The following describes a process for making the apparent colors of the second display device 4 match those of the first display device 3 to a person (user) actually observing the first display device 3 and the second display device 4.

[0045] The first display control unit 11c controls the first display device 3 to display a white image (corresponding to the "first display color" of the present invention) on the first display device 3 as an image corresponding to the first display image data. The first display control unit 11c may also display an image of an achromatic color other than white on the first display device 3. The first display control unit 11c may also allow the user to select the color of the image to be displayed on the first display device 3 from a plurality of achromatic colors including white. The first display control unit 11c may also display a photograph or illustration including the first display color on the first display device 3 as an image corresponding to the first display image data.

[0046] The first spectral distribution acquisition unit 11e references the storage unit 12 and acquires the original spectral distribution of the first display device 3 as the first spectral distribution (original). Note that the spectral distribution of the first display device 3 does not change the characteristics (shape of the spectral distribution) of each RGB light-emitting element, but is determined by the gain values ​​of each RGB and therefore the emission intensity ratio (gain balance). The spectral distribution P1(λ) of the first display device 3 can be expressed by the following formula (1), where the gain values ​​of each RGB (0 to 100%) are (r1, g1, b1), respectively, the spectral distribution when the gain values ​​of each RGB are (100%, 0%, 0%) is R1(λ), ​​the spectral distribution when the gain values ​​of each RGB are (0%, 100%, 0%) is G1(λ), ​​and the spectral distribution when the gain values ​​of each RGB are (0%, 0%, 100%) is B1(λ). In this embodiment, the combination of R1(λ), ​​G1(λ), ​​and B1(λ) is referred to as the original spectral distribution of the first display device 3 or the first spectral distribution (original) of the first display device 3. The first spectral distribution acquisition unit 11e may acquire, as the first spectral distribution (original), the original spectral distribution of the first display device 3 measured at a production factory of the first display device 3, the original spectral distribution of the first display device 3 that is a model representative value of the first display device 3 (a value measured on one individual product), or the original spectral distribution of the first display device 3 measured by a user.

[0047]

[0048] The first spectral distribution calculation unit 11f acquires tristimulus values ​​of white (image) displayed on the first display device 3 by the first display control unit 11c as a result of adjustment of the first display device 3 by the adjustment unit 11a. In this embodiment, the tristimulus values ​​(X, Y, Z) of white displayed on the first display device 3 are values ​​based on a predetermined color matching function (e.g., CIE 1931 CMF, also referred to as "standard CMF") used in the adjustment of the first display device 3 by the adjustment unit 11a, and are measured by a measuring device (e.g., a color sensor).

[0049] The first spectral distribution calculation unit 11f calculates, as the first spectral distribution (current), the current spectral distribution of the first display device 3 that corresponds to the tristimulus values ​​(X, Y, Z) of white to be displayed on the first display device 3, based on the first spectral distribution (original) acquired by the first spectral distribution acquisition unit 11e and a predetermined color matching function (standard CMF).

[0050] Specifically, when the tristimulus value R1 of the first display device 3 where the gain values ​​of each RGB are (100%, 0%, 0%), the tristimulus value G1 of the first display device 3 where the gain values ​​of each RGB are (0%, 100%, 0%), and the tristimulus value B1 of the first display device 3 where the gain values ​​of each RGB are (0%, 0%, 100%) are expressed by the following formula (2), the tristimulus values ​​R1, G1, and B1 can each be calculated based on the first spectral distribution (original) and a predetermined color matching function (standard CMF). When the gain values ​​of each RGB (r1, g1, b1) are expressed by the following formula (3), the tristimulus values ​​(X, Y, Z) of white displayed on the first display device 3 are expressed by the following formula (4). Therefore, by modifying formula (4), the gain values ​​of each RGB can be expressed by the following formula (5). If the spectral distribution when the gain values ​​of each RGB in the first display device 3 are (100%, 0%, 0%) is R1(λ), ​​the spectral distribution when the gain values ​​of each RGB are (0%, 100%, 0%) is G1(λ), ​​and the spectral distribution when the gain values ​​of each RGB are (0%, 0%, 100%) is B1(λ), ​​the current spectral distribution P1(λ) of the first display device 3 can be calculated using the following equation (6).

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] The first tristimulus value calculator 11g calculates a plurality of first tristimulus values ​​(X1, Y1, Z1) that are tristimulus values ​​for white displayed on the first display device 3, based on a plurality of color matching functions (also referred to as candidate CMFs) that are candidates for the optimal color matching function for the person (user) actually observing the first display device 3 and the second display device 4. In this embodiment, the following C1 to C11 can be cited as examples of the multiple color matching functions that are candidates for the optimal color matching function. C1: CIE 1931CMF C2: CIE 1964CMF C3: CIE 2015_2deg_CMF C4: CIE 2015_10deg_CMF C5: Average CMF (standard average of C1, C2, C3, C4) C6: CIE 2006_2deg_20age_CMF C7:CIE 2006_2deg_50age_CMF C8:CIE 2006_2deg_70age_CMF C9:CIE 2006_10deg_20age_CMF C10:CIE 2006_10deg_50age_CMF C11:CIE 2006_10deg_70age_CMF

[0057] Note that C1 is a color matching function that numerically represents the color vision response of the standard observer defined by the CIE in 1931, assuming a viewing angle of 2 degrees. C2 is a color matching function that numerically represents the color vision response of the auxiliary standard observer defined by the CIE in 1964, assuming a viewing angle of 10 degrees. C3 is a color matching function established for practical use based on CIE 2006, assuming a viewing angle of 2 degrees. C3 is defined in CIE 170-2:2015. C4 is a color matching function established for practical use based on CIE 2006, assuming a viewing angle of 10 degrees. C4 is defined in CIE 170-2:2015. C5 is a color matching function determined by averaging the color matching functions C1, C2, C3, and C4. C6 is a color matching function determined from the human cone response characteristics depending on the observer's age (20 years old) and visual field size (2 degrees). C6 is calculated based on CIE 170-1:2006. C7 is a color matching function determined from the human cone response characteristics depending on the observer's age (50 years old) and visual field size (2 degrees). C7 is calculated based on CIE 170-1:2006. C8 is a color matching function determined from the human cone response characteristics depending on the observer's age (70 years old) and visual field size (2 degrees). C8 is calculated based on CIE 170-1:2006. C9 is a color matching function determined from the human cone response characteristics depending on the observer's age (20 years old) and visual field size (10 degrees). C9 is calculated based on CIE 170-1:2006. C10 is a color matching function determined from the human cone response characteristics according to the observer's age (50 years old) and visual field size (10 degrees). C10 is calculated based on CIE 170-1:2006. C11 is a color matching function determined from the human cone response characteristics according to the observer's age (70 years old) and visual field size (10 degrees). C11 is calculated based on CIE 170-1:2006.

[0058] The first tristimulus value calculator 11g calculates a plurality of first tristimulus values ​​(X1, Y1, Z1) based on each of the plurality of color matching functions (candidate CMFs) based on the first spectral distribution (current) calculated by the first spectral distribution calculator 11f. Specifically, the first tristimulus value calculator 11g calculates a plurality of first tristimulus values ​​(X1, Y1, Z1) based on each of the plurality of color matching functions based on the light intensity at a certain wavelength λ (P1(λ): spectral radiance) and the candidate CMFs (x ｃ (λ), y ｃ (λ), z ｃ The first tristimulus values ​​(X1, Y1, Z1) are calculated by integrating the product of X1, Y1, and Z1 with respect to the wavelength of visible light.

[0059]

[0060] The second spectral distribution acquisition unit 11h references the storage unit 12 and acquires the original spectral distribution of the second display device 4 as the second spectral distribution (original). Note that the spectral distribution of the second display device 4 does not change the characteristics (shape of the spectral distribution) of each RGB light-emitting element, but is determined by the gain values ​​of each RGB and therefore the emission intensity ratio (gain balance). The spectral distribution P2(λ) of the second display device 4 can be expressed by the following equation (8), where the gain values ​​of each RGB (0 to 100%) are (r2, g2, b2), the spectral distribution when the gain values ​​of each RGB are (100%, 0%, 0%) is R2(λ), the spectral distribution when the gain values ​​of each RGB are (0%, 100%, 0%) is G2(λ), and the spectral distribution when the gain values ​​of each RGB are (0%, 0%, 100%) is B2(λ). In this embodiment, the combination of R2(λ), G2(λ), and B2(λ) is referred to as the original spectral distribution of the second display device 4 or the second spectral distribution (original) of the second display device 4. The second spectral distribution acquisition unit 11h may acquire, as the second spectral distribution (original), the original spectral distribution of the second display device 4 measured at a production factory of the second display device 4, the original spectral distribution of the second display device 4 that is a representative value for the model of the second display device 4, or the original spectral distribution of the second display device 4 measured by the user.

[0061]

[0062] The second spectral distribution calculation unit 11i calculates, as the second spectral distribution (current), the current spectral distribution of the second display device 4 that corresponds to the multiple first tristimulus values ​​(X1, Y1, Z1) calculated by the first tristimulus value calculation unit 11g, based on the second spectral distribution (original) acquired by the second spectral distribution acquisition unit 11h and each of the multiple color matching functions (candidate CMFs).

[0063] Specifically, when the tristimulus value R2 of the second display device 4, where the gain values ​​of each RGB are (100%, 0%, 0%), the tristimulus value G2 of the second display device 4, where the gain values ​​of each RGB are (0%, 100%, 0%), and the tristimulus value B2 of the second display device 4, where the gain values ​​of each RGB are (0%, 0%, 100%), are expressed by the following equation (9), R2, G2, and B2 can be calculated based on the second spectral distribution (original) and each of the multiple color matching functions (candidate CMFs). When the gain values ​​of each RGB (r2, g2, b2) are expressed by the following equation (10), the multiple first tristimulus values ​​(X1, Y1, Z1) calculated by the first tristimulus value calculation unit 11g are expressed by the following equation (11). Therefore, by modifying equation (11), the gain values ​​of each RGB are expressed by the following equation (12). If the spectral distribution when the gain values ​​of each RGB in the second display device 4 are (100%, 0%, 0%) is R2(λ), the spectral distribution when the gain values ​​of each RGB are (0%, 100%, 0%) is G2(λ), and the spectral distribution when the gain values ​​of each RGB are (0%, 0%, 100%) is B2(λ), the current spectral distribution P2(λ) of the second display device 4 can be calculated using the following equation (13).

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] The second tristimulus value calculator 11j calculates a plurality of second tristimulus values ​​(X2, Y2, Z2) based on each of the plurality of second spectral distributions (current) calculated by the second spectral distribution calculator 11i for each of the plurality of color matching functions (candidate CMFs) and a predetermined color matching function (standard CMF). Specifically, the second tristimulus value calculator 11j calculates a plurality of second tristimulus values ​​(X2, Y2, Z2) based on each of the plurality of second spectral distributions (current). Specifically, as expressed in the following formula (14), the second tristimulus value calculator 11j calculates a relationship between the intensity of light at a certain wavelength λ (P2(λ): spectral radiance) and the predetermined color matching function (x ｓ (λ), y ｓ (λ), z ｓ The second tristimulus value (X2, Y2, Z2) is calculated by integrating the product of X2, Y2, and Z2 with respect to the wavelength of visible light.

[0070]

[0071] The candidate coordinate value calculation unit 11k calculates a plurality of candidate coordinate values ​​(coordinate points of the candidate CMF) corresponding to the second tristimulus values ​​(X2, Y2, Z2) as coordinate values ​​in a color coordinate system (corresponding to the "display color range" of the present invention) that is displayed on the display screen 4a of the second display device 4 based on a predetermined color-matching function (e.g., a standard CMF) and includes a plurality of display colors corresponding to the second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j. In this embodiment, the color coordinate system including the plurality of display colors corresponding to the second tristimulus values ​​(X2, Y2, Z2) is an XYZ (Yxy) color system, which represents colors based on the mixture of three primary colors. Note that the color coordinate system including the plurality of display colors may represent all or part of the XYZ color system. Furthermore, the color coordinate system including multiple display colors may not be the XYZ color system, but may be the CIELAB color space, which is one of the uniform color spaces established by the CIE (International Commission on Illumination) in 1976. The color coordinate system including multiple display colors may be a two-dimensional xy chromaticity diagram using chromaticity x, y, and luminance Y, or a three-dimensional Yxy color space using chromaticity x, y, and luminance Y. The color coordinate system including multiple display colors may be a two-dimensional a*b* chromaticity diagram using chromaticity a*, b*, and lightness L*, or a three-dimensional L*a*, b* color space using chromaticity a*, b*, and lightness L*. Figure 5 shows the CIE 1931 color space (an example using standard CMF as the predetermined color-matching function).

[0072] The candidate coordinate value calculation unit 11k calculates chromaticity coordinates x, y, z in the XYZ color system corresponding to the second tristimulus values ​​(X2, Y2, Z2) from the second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j, using the following equation (15): The chromaticity coordinates x, y corresponding to the second tristimulus values ​​(X2, Y2, Z2) become candidate coordinate values ​​(coordinate points of the candidate CMF) corresponding to the second tristimulus values ​​(X2, Y2, Z2).

[0073]

[0074] The association unit 11l associates multiple color matching functions (candidate CMFs) with multiple candidate coordinate values ​​(coordinate points of the candidate CMFs) calculated by the candidate coordinate value calculation unit 11k based on each of the multiple color matching functions (candidate CMFs), and stores association information indicating the content of the association in the memory unit 12.

[0075] The second display control unit 11d references the association information stored in the storage unit 12 by the association unit 11l and causes the display screen 4a of the second display device 4 to display a color coordinate system (XYZ color system) including multiple display colors corresponding to multiple second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j. In this embodiment, the second display control unit 11d displays a reception screen 20 (see FIG. 5) for optionally receiving designation of designated coordinate values ​​in the color coordinate system including multiple display colors corresponding to multiple second tristimulus values ​​(X2, Y2, Z2). Here, the designated coordinate values ​​in the color coordinate system are coordinate points designated by a user actually observing the first display device 3 and the second display device 4 when matching the apparent color of the second display device 4 to the apparent color of the first display device 3.

[0076] Fig. 5 is a diagram showing an example of a reception screen 20 displayed on the display screen 4a of the second display device 4. As shown in Fig. 5, the reception screen 20 displays a color coordinate system 30 including a plurality of display colors corresponding to a plurality of second tristimulus values ​​(X2, Y2, Z2), a designation button 32, and the like. The second display control unit 11d may adjust the saturation of the display color and display it on the display screen 4a of the second display device 4, so that the user can easily designate the display color.

[0077] In the color coordinate system 30, the position indicated by reference numeral 30A is a position where a display color corresponding to second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j based on color matching function C6 (CIE 2006_2deg_20age_CMF) among the plurality of color matching functions C1 to C11 (candidate CMFs) is displayed, and the position is a candidate coordinate value (coordinate point of the candidate CMF) calculated by the candidate coordinate value calculation unit 11k based on color matching function C6. The position indicated by reference numeral 30B is a position where a display color corresponding to second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j based on color matching function C9 (CIE 2006_10deg_20age_CMF) among the plurality of color matching functions C1 to C11 is displayed, and the candidate coordinate value is calculated by the candidate coordinate value calculation unit 11k based on color matching function C9. The position indicated by reference symbol 30C is a position where a display color corresponding to the second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j based on the color matching function C1 (CIE 1931 CMF) among the multiple color matching functions C1 to C11 is displayed, and the position is a candidate coordinate value calculated by the candidate coordinate value calculation unit 11k based on the color matching function C1. The position indicated by reference symbol 30D is a position where a display color corresponding to the second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j based on the color matching function C7 (CIE 2006 2deg 50age CMF) among the multiple color matching functions C1 to C11 is displayed, and the candidate coordinate value is calculated by the candidate coordinate value calculation unit 11k based on the color matching function C7. The position indicated by the symbol 30E is a position where a display color corresponding to the second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j based on the color matching function C10 (CIE 2006_10deg_50age_CMF) among the multiple color matching functions C1 to C11 is displayed, and is a candidate coordinate value calculated by the candidate coordinate value calculation unit 11k based on the color matching function C10.

[0078] The user specifies a display color in the color coordinate system 30 that matches the appearance of the image (white) displayed on the first display device 3. For example, as shown in FIG. 5 , the user specifies the display color at the position indicated by reference numeral 34 and then presses the designation button 32 to complete the display color designation. For user reference, the color coordinate system 30 may display the position of the display color corresponding to the second tristimulus values ​​(X2, Y2, Z2) calculated based on each of multiple color-matching functions C1 to C11 (candidate CMFs) and the values ​​of the tristimulus values ​​(X2, Y2, Z2). In this case, the user may select a display color that matches the appearance of the second display device 4 to the appearance of the first display device 3 (white) from among the display colors corresponding to the candidate coordinate values ​​30A to 30E. Furthermore, the display color that matches the appearance of the second display device 4 to the appearance of the first display device 3 (white) may be specified in response to a user's text input or voice input via the operation input unit 14.

[0079] When the reception screen 20 is displayed on the display screen 4a of the second display device 4, the reception unit 11m receives, via a user's operation on the operation input unit 14, a designation of a display color that matches the appearance color of the second display device 4 with the designated coordinate value in the color coordinate system 30, i.e., the appearance color (white) of the first display device 3. Note that the second display control unit 11d may display the entire display screen 4a of the second display device 4 in the display color corresponding to the designated coordinate value, the designation of which is accepted by the reception unit 11m, for user confirmation. Furthermore, when the second display control unit 11d causes the first display device 3 to display a photograph or illustration including the first display color, the second display control unit 11d may also display, on the display screen 4a of the second display device 4, a photograph or illustration including the display color corresponding to the designated coordinate value, the designation of which is accepted by the reception unit 11m.

[0080] The determination unit 11n determines, as the user's color matching function, a color matching function identified based on a user's designation received by the reception unit 11m from among the plurality of color matching functions C1 to C11 (candidate CMFs). In this embodiment, the determination unit 11n determines, as the user's color matching function, a color matching function associated with a candidate coordinate value (any of the candidate coordinate values ​​30A to 30E) that has the smallest difference from the designated coordinate value designated by the reception unit 11m from among the plurality of candidate coordinate values ​​30A to 30E. The determination unit 11n stores color matching function information indicating the color matching function determined as the user's color matching function in the storage unit 12. The color matching function information stored in the storage unit 12 is referenced by the second display control unit 11d and used to control the display of images on the second display device 4. Here, the difference between the designated coordinate value and the candidate coordinate value is a difference calculated using, for example, Euclidean distance, the CIE 1976 color difference formula, the CIE 1994 color difference formula, the CIE 2000 color difference formula, or the like.

[0081] 5, when the position indicated by reference numeral 34 is the designated coordinate value, the determination unit 11n determines, as the user's color matching function, the color matching function C9 (CIE 2006_10deg_20age_CMF) associated with the candidate coordinate value 30B, of the plurality of candidate coordinate values ​​30A to 30E, which has the smallest difference from the designated coordinate value 34, the designation of which is accepted by the reception unit 11m. Note that the determination unit 11n may determine, as the user's color matching function, a weighted average of the color matching functions associated with the plurality of candidate coordinate values ​​30A to 30E, depending on the difference between the designated coordinate value 34, the designation of which is accepted by the reception unit 11m, and the plurality of candidate coordinate values ​​30A to 30E.

[0082] 6 is a flowchart showing an example of the color matching function determination process (corresponding to the "color matching function determination method" of the present invention) performed by the control unit 11 (image processing device 2) in this embodiment. Note that before step S100 is performed, the adjustment unit 11a has already adjusted the first display device 3, and the first spectral distribution calculation unit 11f has already acquired tristimulus values ​​based on predetermined color matching functions (standard CMFs) for white (image) displayed on the first display device 3 by the first display control unit 11c as a result of the adjustment of the first display device 3 by the adjustment unit 11a.

[0083] First, the first display control unit 11c controls the first display device 3 to display an image of white (first display color) as an image corresponding to the first display image data on the first display device 3 (step S100).

[0084] Next, the first spectral distribution acquisition unit 11e refers to the storage unit 12 and acquires the original spectral distribution of the first display device 3 as the first spectral distribution (original) (step S110).

[0085] Next, the first spectral distribution calculation unit 11f calculates, as the first spectral distribution (current), a spectral distribution of the first display device 3 that corresponds to the tristimulus values ​​(X, Y, Z) of white (image) displayed on the first display device 3, based on the first spectral distribution (original) acquired by the first spectral distribution acquisition unit 11e and a predetermined color matching function (standard CMF) (step S120). Note that the first spectral distribution calculation unit 11f may calculate the first spectral distribution (current) using a gain value acquired from the first display device 3. The calculated first spectral distribution (current) may be stored in the storage unit 12. Alternatively, the first spectral distribution (current) measured by a spectroscopic measuring instrument may be stored in the storage unit 12. The first spectral distribution acquisition unit 11e may acquire the spectral distribution of the first display device 3 as the first spectral distribution (current) by referring to the storage unit 12.

[0086] Next, the first tristimulus value calculation unit 11g calculates a plurality of first tristimulus values ​​(X1, Y1, Z1) that are the tristimulus values ​​of white to be displayed on the first display device 3 in step S100, based on the first spectral distribution (current) calculated by the first spectral distribution calculation unit 11f and each of a plurality of color matching functions (candidate CMFs) that are candidates for the color matching function that is optimal for the user who is actually observing the first display device 3 and the second display device 4 (step S130).

[0087] Next, the second spectral distribution acquisition unit 11h refers to the storage unit 12 and acquires the original spectral distribution of the second display device 4 as the second spectral distribution (original) (step S140).

[0088] Next, the second spectral distribution calculation unit 11i calculates, as the second spectral distribution (current), a current spectral distribution of the second display device 4 that satisfies the multiple first tristimulus values ​​(X1, Y1, Z1) calculated by the first tristimulus value calculation unit 11g in step S130, based on the second spectral distribution (original) acquired by the second spectral distribution acquisition unit 11h and each of the multiple color matching functions (candidate CMFs) (step S150). The calculated second spectral distribution (current) may be stored in the storage unit 12. Alternatively, the second spectral distribution acquisition unit 11h may refer to the storage unit 12 and acquire the spectral distribution of the second display device 4 as the second spectral distribution (current).

[0089] Next, the second tristimulus value calculation unit 11j calculates a plurality of second tristimulus values ​​(X2, Y2, Z2) based on each of the plurality of second spectral distributions (current) calculated by the second spectral distribution calculation unit 11i for each of the plurality of color matching functions (candidate CMFs) and a predetermined color matching function (standard CMF) (step S160).

[0090] Next, the candidate coordinate value calculation unit 11k calculates a plurality of candidate coordinate values ​​(coordinate points of the candidate CMF) corresponding to the plurality of second tristimulus values ​​(X2, Y2, Z2) as coordinate values ​​in a color coordinate system that includes a plurality of display colors corresponding to the plurality of second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j in step S160 and that is displayed on the display screen 4a of the second display device 4 based on a predetermined color matching function (e.g., a standard CMF) (step S170).

[0091] Next, the association unit 11l associates multiple color matching functions (candidate CMFs) with multiple candidate coordinate values ​​(coordinate points of the candidate CMFs) calculated by the candidate coordinate value calculation unit 11k based on each of the multiple color matching functions (candidate CMFs), and stores association information indicating the content of the association in the memory unit 12 (step S180).

[0092] Next, the second display control unit 11d displays a reception screen 20 (see FIG. 5) for optionally receiving the designation of designated coordinate values ​​in a color coordinate system including a plurality of display colors corresponding to a plurality of second tristimulus values ​​(X2, Y2, Z2) (step S190).

[0093] Next, when the reception screen 20 is displayed on the display screen 4a of the second display device 4, the reception unit 11m receives, via user operation of the operation input unit 14, the specification of a specified coordinate value in the color coordinate system 30, i.e., a display color that matches the apparent color (white) of the first display device 3 with the apparent color of the second display device 4 (step S200).

[0094] Finally, the determination unit 11n determines as the user's color matching function the color matching function associated with the candidate coordinate value (any of the candidate coordinate values ​​30A to 30E) that has the smallest difference from the specified coordinate value accepted by the acceptance unit 11m in step S200, among the multiple candidate coordinate values ​​30A to 30E (step S210).

[0095] As described above in detail, in this embodiment, the image processing device 2 (color matching function determination device) determines color matching functions for a user (observer) observing the first display device 3 and the second display device 4. The image processing device 2 includes a first display control unit 11c, a first tristimulus value calculation unit 11g, a second display control unit 11d, a reception unit 11m, and a determination unit 11n. The first display control unit 11c causes the first display device 3 to display a first display color (an achromatic color such as white). The first tristimulus value calculation unit 11g calculates multiple first tristimulus values ​​(X1, Y1, Z1) that are tristimulus values ​​of the first display color displayed on the first display device 3 based on multiple color matching functions (candidate CMFs). The second display control unit 11d causes the second display device 4 to display a color coordinate system 30 (display color range) that includes multiple display colors corresponding to the multiple first tristimulus values ​​(X1, Y1, Z1). The reception unit 11m receives a user specification for the color coordinate system 30. The determining unit 11n determines, from among a plurality of color matching functions (candidate CMFs), a color matching function specified based on a specification received from a user as the color matching function of that user.

[0096] According to this embodiment configured as described above, a plurality of first tristimulus values ​​(X1, Y1, Z1) that are the tristimulus values ​​of the first display color displayed on the first display device 3 are calculated based on each of a plurality of color matching functions (candidate CMFs), and a color coordinate system 30 including a plurality of display colors corresponding to the plurality of first tristimulus values ​​(X1, Y1, Z1) is displayed on the second display device 4. When a user specifies a color coordinate system 30, one of the plurality of color matching functions identified based on the specification received from the user is determined as the user's color matching function. Therefore, the user's color matching function can be automatically determined simply by the user checking the color coordinate system 30 displayed on the second display device 4 and specifying the color coordinate system 30. As described above, the optimal color matching function for each individual can be determined easily.

[0097] In this embodiment, the image processing device 2 further includes a first spectral distribution acquisition unit 11e. The first spectral distribution acquisition unit 11e references the storage unit 12 and acquires the spectral distribution of the first display device 3 as the first spectral distribution. The first tristimulus value calculation unit 11g calculates multiple first tristimulus values ​​(X1, Y1, Z1) based on the acquired first spectral distribution and each of multiple color matching functions (candidate CMFs).

[0098] In this embodiment, the image processing device 2 further includes a candidate coordinate value calculation unit 11k and an associating unit 11l. The candidate coordinate value calculation unit 11k calculates, as coordinate values ​​in the color coordinate system 30, a plurality of candidate coordinate values ​​(coordinate points of candidate CMFs) corresponding to a plurality of first tristimulus values ​​(X1, Y1, Z1). Specifically, the candidate coordinate value calculation unit 11k calculates, as tristimulus values ​​of a plurality of display colors included in the color coordinate system 30 displayed on the second display device 4, a plurality of second tristimulus values ​​(X2, Y2, Z2) corresponding to the plurality of first tristimulus values ​​(X1, Y1, Z1) based on a predetermined color matching function (standard CMF). The candidate coordinate value calculation unit 11k then calculates, as coordinate values ​​in the color coordinate system 30, a plurality of candidate coordinate values ​​corresponding to the plurality of second tristimulus values ​​(X2, Y2, Z2). The associating unit 11l associates the plurality of color matching functions (candidate CMFs) with the plurality of candidate coordinate values. The receiving unit 11m receives from the user a designated coordinate value in the color coordinate system 30 (a coordinate point designated by the user when matching visual colors). The determining unit 11n determines, as the user's color matching function, a color matching function associated with a candidate coordinate value that is the smallest difference from the designated coordinate value, among multiple candidate coordinate values. According to this embodiment configured as described above, by determining, as the user's color matching function, a color matching function associated with the candidate coordinate value that is closest to the designated coordinate value, there is no need to generate a new color matching function, and it is possible to determine a color matching function suitable for the user with less cost (e.g., computational cost).

[0099] In this embodiment, the image processing device 2 further includes a second spectral distribution acquisition unit 11h. The second spectral distribution acquisition unit 11h references the storage unit 12 and acquires the spectral distribution of the second display device 4 as the second spectral distribution. The candidate coordinate value calculation unit 11k calculates a plurality of second tristimulus values ​​(X2, Y2, Z2) corresponding to a plurality of first tristimulus values ​​(X1, Y1, Z1) based on the acquired second spectral distribution and a predetermined color matching function (standard CMF).

[0100] In the above embodiment, from the viewpoint of reducing the cost of calculating the first tristimulus values ​​(X1, Y1, Z1), the first tristimulus value calculation unit 11g may store in advance in the storage unit 12 a first transformation matrix for converting the tristimulus values ​​(X, Y, Z) of white displayed on the first display device 3 from tristimulus values ​​based on a predetermined color matching function (standard CMF) to tristimulus values ​​based on color matching functions (candidate CMFs) that are candidates for the optimal color matching function for the user, and may use the first transformation matrix to calculate multiple first tristimulus values ​​(X1, Y1, Z1) based on each of the multiple color matching functions (candidate CMFs). In this case, there is no need to store the first spectral distribution (original) and the first spectral distribution (current) in the storage unit 12, thereby reducing the capacity of the storage unit 12.

[0101] Furthermore, from the viewpoint of reducing the cost of calculating the second tristimulus values ​​(X2, Y2, Z2), the second tristimulus value calculation unit 11j may calculate the second tristimulus values ​​(X2, Y2, Z2) using a second transformation matrix that is used to convert the first tristimulus values ​​(X1, Y1, Z1) calculated by the first tristimulus value calculation unit 11g from tristimulus values ​​based on multiple color matching functions (candidate CMFs) to tristimulus values ​​based on a predetermined color matching function (standard CMF), by storing the second transformation matrix in advance in the storage unit 12. In this case, there is no need to store the second spectral distribution (original) and the second spectral distribution (current) in the storage unit 12, and the capacity of the storage unit 12 can be reduced.

[0102] Here, a method for creating a transformation matrix for converting tristimulus values ​​based on the first color matching function into tristimulus values ​​based on the second color matching function will be described. Assuming additive color mixing of the display device, the tristimulus values ​​(X, Y, Z) based on the first color matching function for each color specified by RGB values ​​(R, G, B) can be expressed by the following equation (17) using the matrix expressed by the following equation (16). The matrix expressed by the following equation (16) is obtained by converting the tristimulus values ​​(X, Y, Z) of each RGB color based on the original spectral distribution of the display device (a combination of a spectral distribution with gain values ​​of each RGB of (100%, 0%, 0%), a spectral distribution with gain values ​​of each RGB of (0%, 100%, 0%), and a spectral distribution with gain values ​​of each RGB of (0%, 0%, 100%)) and the first color matching function. Ｒ / Ｇ / Ｂ , Y Ｒ / Ｇ / Ｂ , ZＲ / Ｇ / Ｂ ) can be obtained by calculating the tristimulus values ​​(X', Y', Z') of each color specified by the RGB values ​​(R, G, B) based on the second color matching function, using the matrix expressed by the following formula (18), as shown in the following formula (19). The matrix expressed by the following formula (18) is obtained by calculating the tristimulus values ​​(X') of each RGB color based on the original spectral distribution of the display device (a combination of a spectral distribution with RGB gain values ​​of (100%, 0%, 0%), a spectral distribution with RGB gain values ​​of (0%, 100%, 0%), and a spectral distribution with RGB gain values ​​of (0%, 0%, 100%)) and the second color matching function. Ｒ / Ｇ / Ｂ , Y' Ｒ / Ｇ / Ｂ , Z' Ｒ / Ｇ / Ｂ ) can be obtained by calculating

[0103] By transforming the following equation (17) into the following equation (20) and substituting the result into the following equation (19), the following equation (21) can be obtained. As shown in the following equation (21), the transformation matrix for converting tristimulus values ​​(X, Y, Z) based on the first color matching function into tristimulus values ​​(X', Y', Z') based on the second color matching function is the product of the inverse matrix of the matrix expressed by the following equation (16) and the matrix expressed by the following equation (18).

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] 7 is a flowchart showing a modified example of the color-matching function determination process performed by the control unit 11 (image processing device 2). This flowchart differs from the flowchart shown in FIG. 6 in that the first tristimulus value calculation unit 11g calculates a plurality of first tristimulus values ​​(X1, Y1, Z1) using a first transformation matrix, and the second tristimulus value calculation unit 11j calculates a plurality of second tristimulus values ​​(X2, Y2, Z2) using a second transformation matrix. Note that, before step S300, the adjustment unit 11a adjusts the first display device 3, and the first tristimulus value calculation unit 11g acquires tristimulus values ​​based on a predetermined color-matching function (standard CMF) for white (image) displayed on the first display device 3 by the first display control unit 11c as a result of the adjustment of the first display device 3 by the adjustment unit 11a.

[0111] First, the first display control unit 11c controls the first display device 3 to display an image of white (first display color) as an image corresponding to the first display image data on the first display device 3 (step S300).

[0112] Next, the first tristimulus value calculation unit 11g acquires from the storage unit 12 a first transformation matrix for converting the tristimulus values ​​(X, Y, Z) of white displayed on the first display device 3 from tristimulus values ​​based on a predetermined color matching function (standard CMF) to tristimulus values ​​based on a color matching function (candidate CMF) that is a candidate for the optimal color matching function for the user (step S310).

[0113] Next, the first tristimulus value calculation unit 11g calculates a plurality of first tristimulus values ​​(X1, Y1, Z1) based on each of the plurality of color matching functions (candidate CMFs) using the first transformation matrix obtained in step S310 (step S320).

[0114] Next, the second tristimulus value calculation unit 11j obtains from the storage unit 12 a second transformation matrix for converting the first tristimulus values ​​(X1, Y1, Z1) calculated by the first tristimulus value calculation unit 11g in step S320 from tristimulus values ​​based on multiple color matching functions (candidate CMFs) to tristimulus values ​​based on a predetermined color matching function (standard CMF) (step S330).

[0115] Next, the second tristimulus value calculation unit 11j calculates a plurality of second tristimulus values ​​(X2, Y2, Z2) using the second transformation matrix acquired in step S330 (step S340).

[0116] Next, the candidate coordinate value calculation unit 11k calculates a plurality of candidate coordinate values ​​(coordinate points of the candidate CMF) corresponding to the plurality of second tristimulus values ​​(X2, Y2, Z2) as coordinate values ​​in a color coordinate system that includes a plurality of display colors corresponding to the plurality of second tristimulus values ​​(X2, Y2, Z2) calculated by the second tristimulus value calculation unit 11j in step S340 and that is displayed on the display screen 4a of the second display device 4 based on a predetermined color matching function (e.g., a standard CMF) (step S350).

[0117] Next, the association unit 11l associates multiple color matching functions (candidate CMFs) with multiple candidate coordinate values ​​(coordinate points of the candidate CMFs) calculated by the candidate coordinate value calculation unit 11k based on each of the multiple color matching functions (candidate CMFs), and stores association information indicating the content of the association in the memory unit 12 (step S360).

[0118] Next, the second display control unit 11d displays a reception screen 20 (see FIG. 5) for optionally receiving the designation of designated coordinate values ​​in a color coordinate system including a plurality of display colors corresponding to a plurality of second tristimulus values ​​(X2, Y2, Z2) (step S370).

[0119] Next, when the reception screen 20 is displayed on the display screen 4a of the second display device 4, the reception unit 11m receives, via user operation of the operation input unit 14, the specification of a specified coordinate value in the color coordinate system 30, i.e., a display color that matches the apparent color (white) of the first display device 3 with the apparent color of the second display device 4 (step S380).

[0120] Finally, the determination unit 11n determines as the user's color matching function the color matching function associated with the candidate coordinate value (any of the candidate coordinate values ​​30A to 30E) that has the smallest difference from the specified coordinate value accepted by the acceptance unit 11m in step S380, among the multiple candidate coordinate values ​​30A to 30E (step S390).

[0121] In the above embodiment, the second display control unit 11d displays, on the second display device 4, a display color range (color coordinate system 30) including multiple display colors corresponding to multiple first tristimulus values ​​(X1, Y1, Z1). However, the present invention is not limited to this. For example, the second display control unit 11d may display, as the display color range, an image (e.g., a patch image) associated with each of multiple color matching functions (candidate CMFs) and composed of multiple second display colors (e.g., achromatic colors such as white) whose tristimulus values ​​are the same as the multiple first tristimulus values ​​(X1, Y1, Z1) on the second display device 4. In this case, the accepting unit 11m accepts a second display color from the user (observer) that is designated from among the multiple second display colors. The determining unit 11n then determines the color matching function associated with the designated second display color as the user's color matching function. By having the second display control unit 11d display an image (e.g., a patch image) composed of the second display color (e.g., an achromatic color such as white), the user's options are limited, making it easier for the user to specify the second display color.

[0122] In the above embodiment, an example in which color matching is performed between two display devices (the first display device 3 and the second display device 4) has been described, but the present invention is not limited to this. For example, color matching may be performed between three or more display devices. Furthermore, the user may be allowed to select multiple display devices to be subjected to color matching from among the three or more display devices.

[0123] Furthermore, in the above embodiment, an example of color matching between two display devices (the first display device 3 and the second display device 4) has been described. However, the present invention is not limited to this. For example, the first display device 3 may be replaced with a light-reflecting object, such as paper or plastic, having a first display color. In this case, the first spectral distribution calculation unit 11f acquires, as the first spectral distribution, a spectral distribution obtained by measuring reflected light from the object illuminated by a light source. The first spectral distribution calculation unit 11f may also acquire, as the first spectral distribution, a spectral distribution of reflected light calculated from the spectral reflectance of the object and the spectral characteristics of the light source. The first tristimulus value calculation unit 11g calculates multiple first tristimulus values ​​(X1, Y1, Z1) that are tristimulus values ​​of the first display color of the object, based on the first spectral distribution acquired by the first spectral distribution calculation unit 11f and each of multiple color matching functions (candidate CMFs).

[0124] That is, there is provided a color matching function determination method having the following configuration: A color matching function determination method for determining color matching functions for an observer observing an object having a first display color and a second display device, the color matching function determination method having a first tristimulus value calculation step, a second display control step, a receiving step, and a determination step, in which the first tristimulus value calculation step calculates a plurality of first tristimulus values ​​that are tristimulus values ​​of the first display color based on each of a plurality of color matching functions, the second display control step causes the second display device to display a display color range including a plurality of display colors corresponding to the plurality of first tristimulus values, the receiving step receives a designation for the display color range from the observing observer, and the determination step determines, from the plurality of color matching functions, a color matching function specified based on the designation received from the observing observer as the color matching function for the observing observer.

[0125] Various embodiments of the present invention have been described above, but these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0126] 1: image display system, 2: image processing device, 3: first display device, 3a: display screen, 4: second display device, 4a: display screen, 5: video signal cable, 6: control signal cable, 11: control unit, 11a: adjustment unit, 11b: image acquisition unit, 11c: first display control unit, 11d: second display control unit, 11e: first spectral distribution acquisition unit, 11f: first spectral distribution calculation unit, 11g: first tristimulus value calculation unit, 11h: second spectral distribution acquisition unit, 11i: second spectral distribution calculation unit, 11j: second tristimulus value calculation unit, 11k: candidate coordinate value calculation unit, 11l: association unit, 11m: reception unit, 11n: determination unit, 12: storage unit, 13: communication unit, 14: operation input unit, 20: reception screen, 30: color coordinate system, 30A, 30B, 30C, 30D, 30E: candidate coordinate values, 32: designation button

Claims

1. A color matching function determination method for determining color matching functions for an observer observing a first display device and a second display device, the method comprising: a first display control step, a first tristimulus value calculation step, a second display control step, a receiving step, and a determination step; in the first display control step, a first display color is displayed on the first display device; in the first tristimulus value calculation step, a plurality of first tristimulus values ​​that are tristimulus values ​​of the first display color to be displayed on the first display device are calculated based on each of a plurality of color matching functions; in the second display control step, a display color range including a plurality of display colors corresponding to the plurality of first tristimulus values ​​is displayed on the second display device; in the receiving step, a designation for the display color range is received from the observer; and in the determination step, a color matching function from the plurality of color matching functions that is specified based on the designation received from the observer is determined as the color matching function for the observer.

2. A color matching function determination method according to claim 1, further comprising a first spectral distribution acquisition step, wherein the first spectral distribution acquisition step acquires the spectral distribution of the first display device as a first spectral distribution, and wherein the first tristimulus value calculation step calculates the plurality of first tristimulus values ​​based on the acquired first spectral distribution and each of the plurality of color matching functions.

3. A color matching function determination method according to claim 1, wherein the display color range is a color coordinate system displayed based on predetermined color matching functions and including a plurality of display colors corresponding to the plurality of first tristimulus values, and further comprising a candidate coordinate value calculation step and an associating step, wherein the candidate coordinate value calculation step calculates a plurality of candidate coordinate values ​​corresponding to the plurality of first tristimulus values ​​as coordinate values ​​in the color coordinate system, and the associating step associates the plurality of color matching functions with the plurality of candidate coordinate values, and the receiving step receives from the observer designation of designated coordinate values ​​in the color coordinate system, and the determining step determines as the observer's color matching function the color matching function associated with the candidate coordinate value whose designation has been received and whose difference from the designated coordinate value is the smallest.

4. A color-matching function determination method according to claim 3, wherein in the candidate coordinate value calculation step, a plurality of second tristimulus values ​​corresponding to the plurality of first tristimulus values ​​are calculated based on the predetermined color-matching function as tristimulus values ​​of a plurality of display colors included in the color coordinate system displayed on the second display device, and the plurality of candidate coordinate values ​​corresponding to the plurality of second tristimulus values ​​are calculated as coordinate values ​​in the color coordinate system.

5. A color matching function determination method according to claim 4, further comprising a second spectral distribution acquisition step, wherein the second spectral distribution acquisition step acquires the spectral distribution of the second display device as a second spectral distribution, and wherein the candidate coordinate value calculation step calculates the plurality of second tristimulus values ​​corresponding to the plurality of first tristimulus values ​​based on the acquired second spectral distribution and the predetermined color matching function.

6. A color matching function determination method according to claim 1, wherein the display color range is associated with each of the plurality of color matching functions and is composed of a plurality of second display colors whose tristimulus values ​​are the same as the plurality of first tristimulus values; the receiving step receives from the observer a designation of a second display color from among the plurality of second display colors; and the determining step determines, as the color matching function for the observer, the color matching function associated with the second display color whose designation has been accepted.

7. A color-matching function determination program that causes a processor to execute the color-matching function determination method according to claim 1.

8. A color matching function determination device that determines color matching functions for an observer observing a first display device and a second display device, comprising: a first display control unit, a first tristimulus value calculation unit, a second display control unit, a reception unit, and a determination unit, wherein the first display control unit causes the first display device to display a first display color, the first tristimulus value calculation unit calculates a plurality of first tristimulus values ​​that are tristimulus values ​​of the first display color to be displayed on the first display device based on each of a plurality of color matching functions, the second display control unit causes the second display device to display a display color range including a plurality of display colors corresponding to the plurality of first tristimulus values, the reception unit receives specifications for the display color range from the observer, and the determination unit determines, from the plurality of color matching functions, a color matching function specified based on the specifications received from the observer as the color matching function for the observer.

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