Color matching method between display devices, program, and display system

Abstract

Provided are a color matching method, a program, and a display system that enable color matching between a first display device and a second display device. The display system includes: a color gamut matrix calculation unit that calculates a color gamut matrix on the basis of first color information of a display color of an image displayed on the first display device and second color information of a display color of an image displayed on the second display device; a first RGB value calculation unit that calculates a first RGB value corresponding to a gradation value of the image displayed on the first display device on the basis of the first color information; a first lookup table calculation unit that calculates a one-dimensional first lookup table having a gradation level associated with the first RGB value; a second lookup table calculation unit that calculates a one-dimensional second lookup table obtained by correcting the gradation level of the first lookup table on the basis of the color gamut matrix and the first lookup table; and a writing unit that writes the second lookup table to the second display device.

Description

Color matching method, program, and display system between display devices

[0001] This invention relates to a method, program, and display system for color matching between display devices.

[0002] In recent years, the number of users using multiple monitors has increased. In particular, in medical institutions such as university hospitals, public hospitals, and large hospitals, there is an increasing need to display the same image on each monitor when interpreting CR, CT, and PET images. However, the color tones of each monitor differ, making color matching between monitors cumbersome. While there are various factors contributing to these color differences, one is the color shift in the display device's gradation. Ideally, with an ideal display device, each gradation should appear white when each color has the same gradation characteristics. However, in reality, color shifts occur, and LCD panels tend to display white as bluish as the gradation level increases. Some color monitors have circuits to correct this color shift, but not all. Furthermore, monochrome monitors, especially for medical images, sometimes require display with gradation characteristics called GSDF (Grayscale Standard Display Function) according to the DICOM (Digital Imaging and Communication in Medicine) standard. This is a gradation characteristic specifically designed for monochrome images such as radiographic images, and it is well known that the demands for gradation characteristics in medical settings are stringent. In the case of a multi-monitor setup consisting of a monochrome monitor and a color monitor, it is desirable to adjust the gradation characteristics of the color monitor, including the color gamut, chromatic shift, and DICOM standard, on the color monitor.

[0003] Patent Document 1 discloses a method in which the endoscopic image signal input to the color conversion device is input to the first to third color conversion unit without attenuation by amplification in a signal amplifier, the first to third color conversion unit performs color conversion, and the color-converted image signals are supplied to the main monitor, nurse monitor, and patient monitor. The conversion parameters of the first to third color conversion unit are determined and modified in a conversion matrix creation unit based on the endoscopic image signal amplified by the signal amplifier.

[0004] Patent Document 2 discloses a method for correcting the XYZ signal in a color conversion device, in which a first color space conversion unit uses a three-dimensional lookup table in which the correspondence between the RGB color system and the XYZ color system is defined to convert an RGB signal expressed in the RGB color system to an XYZ signal expressed in the XYZ color system, which is an absolute color space; a second color space conversion unit converts the corrected XYZ signal to an R'G'B' signal expressed in the R'G'B' color system; and a second correction unit acquires color space definition data used to rewrite the three-dimensional lookup table as image quality data, and corrects the XYZ signal by rewriting the three-dimensional lookup table using the acquired color space definition data.

[0005] Japanese Patent Publication No. 2001-222709 Japanese Patent Publication No. 2011-024202

[0006] In the technology disclosed in Patent Document 1, in order to display images with the same color characteristics on each monitor, the color conversion parameters are determined and changed in the conversion matrix creation unit to match the color gamut between monitors, but the gradation characteristics are not matched.

[0007] Furthermore, the technology disclosed in Patent Document 2 uses a three-dimensional lookup table (3D-LUT), which requires expensive hardware (color module device), and calibration involves many points of comparison and measurement with a reference color, making it time-consuming. In addition, while a three-dimensional lookup table excels at color matching of mixed colors, it is inferior to a one-dimensional lookup table in matching the gradation characteristics of each color.

[0008] The objective of this invention is to provide a color matching method and program that can easily and quickly match the color gamut and gradation characteristics of monitors. By using this invention, it is possible to eliminate gradation color shifts caused by display devices while accurately matching monochrome gradation characteristics such as GSDF. Furthermore, it can be used not only for monochrome images but also for true-color medical images such as pathology, endoscopy, and dermatology images, as well as images where monochrome and color images are mixed, such as CT images. In addition, it can be used not only for color matching between multiple monitors connected to the same PC, but also for color matching with the master monitor of a medical facility that has an imaging device for primary diagnosis in remote / home diagnosis. Naturally, this technology can also be applied to color matching between monitors other than medical monitors.

[0009] The inventors have succeeded in developing an emulation technology that enables color matching between display devices, which is simpler and faster than conventional technology, by calculating a one-dimensional first lookup table and a color gamut matrix for matching the display colors of the first and second display devices based on first color information relating to the display color of an image displayed on the first display device and second color information relating to the display color of an image displayed on the second display device, recalculating a one-dimensional second lookup table that takes into account the color gamut and gradation characteristics based on the color gamut matrix and the first lookup table, writing the second lookup table to the second display device, and having the second display device refer to the second lookup table to perform the display.

[0010] The present invention provides a display system with the following configuration: [1] A display system that enables matching the display color of an image displayed on a first display device to the display color of an image displayed on a second display device, comprising: a color gamut matrix calculation unit that calculates a color gamut matrix for matching the display color of the second display device to the display color of the first display device based on first color information relating to the display color of an image displayed on the first display device and second color information relating to the display color of an image displayed on the second display device; a first RGB value calculation unit that calculates a first RGB value corresponding to the gradation value of an image displayed on the first display device based on the first color information; a first lookup table calculation unit that calculates a one-dimensional first lookup table having gradation levels associated with the first RGB value; a second lookup table calculation unit that calculates a one-dimensional second lookup table with the gradation levels of the first lookup table modified based on the color gamut matrix and the first lookup table; and a writing unit that writes the second lookup table to the second display device.

[0011] According to the present invention, a one-dimensional first lookup table and a color gamut matrix for matching the display color of the second display device to the display color of the first display device are calculated based on first color information relating to the display color of an image displayed on the first display device and second color information relating to the display color of an image displayed on the second display device. Based on the color gamut matrix and the first lookup table, a one-dimensional second lookup table that takes into account the color gamut and gradation characteristics is recalculated. The second lookup table is written to the second display device, and the second display device displays by referring to the second lookup table. This makes it possible to match the color gamut and gradation characteristics of display devices more easily and quickly than in the prior art.

[0012] Various embodiments of the present invention are illustrated below. The embodiments shown below can be combined with each other. [2] The display system according to [1], further comprising: a determination unit that determines whether the range of the first color gamut is included in the range of the second color gamut, the first color information includes a first color gamut relating to the first color information, the second color information includes a second color gamut relating to the second color information, and, if the range of the first color gamut is not included in the range of the second color gamut, a modification unit that modifies the first color information so that the range of the first color gamut is included in the range of the second color gamut.

[0013] [3] The display system according to [1] or [2], wherein the second lookup table is calculated in the second lookup table calculation unit by modifying the gradation levels of the first lookup table based on the inverse matrix of the color gamut matrix.

[0014] [4] The display system according to [3], wherein the first lookup table includes a red first lookup table, a green first lookup table, and a blue first lookup table, and the second lookup table includes a red second lookup table, a green second lookup table, and a blue second lookup table, and the second lookup table is calculated based on the following formula (16). (In the formula, M represents the color gamut matrix, LUT_Rn represents the tonal level of the first red lookup table, LUT_Gn represents the tonal level of the first green lookup table, LUT_Bn represents the tonal level of the first blue lookup table, LUT_Rn' represents the tonal level of the second red lookup table, LUT_Gn' represents the tonal level of the second green lookup table, and LUT_Bn' represents the tonal level of the second blue lookup table.)

[0015] [5] The display system according to any one of [1] to [4], further comprising a confirmation and adjustment unit that confirms whether the display color of the image displayed on the first display device matches the display color of the image displayed on the second display device on which the second lookup table is written.

[0016] [6] The display system according to any one of [1] to [5], wherein the first color information includes the first chromaticity of an image displayed on the first display device, and the second color information includes the second chromaticity of an image displayed on the second display device.

[0017] Furthermore, the present invention provides a color matching method with the following configuration: [7] A method for matching the display color of an image displayed on a second display device to the display color of an image displayed on a first display device, comprising: a color gamut matrix calculation step of calculating a color gamut matrix for matching the display color of the second display device to the display color of the first display device based on first color information relating to the display color of an image displayed on the first display device and second color information relating to the display color of an image displayed on the second display device; a first RGB value calculation step of calculating a first RGB value corresponding to the gradation value of an image displayed on the first display device based on the first color information; a first lookup table calculation step of calculating a one-dimensional first lookup table having gradation levels associated with the first RGB value; a second lookup table calculation step of calculating a one-dimensional second lookup table with the gradation levels of the first lookup table modified based on the color gamut matrix and the first lookup table; and a writing step of writing the second lookup table to the second display device.

[0018] [8] The method according to [7], wherein the first color information includes a first color gamut relating to the first color information, the second color information includes a second color gamut relating to the second color information, and further comprises: a determination step of determining whether the range of the first color gamut is included in the range of the second color gamut; and, if the range of the first color gamut is not included in the range of the second color gamut, a modification step of modifying the first color information so that the range of the first color gamut is included in the range of the second color gamut.

[0019] [9] The method according to [7] or [8], wherein in the second lookup table calculation step, the second lookup table is calculated by modifying the gradation levels of the first lookup table based on the inverse matrix of the color gamut matrix.

[0020]

[10] The method according to [9], wherein the first lookup table includes a red first lookup table, a green first lookup table, and a blue first lookup table, and the second lookup table includes a red second lookup table, a green second lookup table, and a blue second lookup table, and the second lookup table is calculated based on the following formula (16). (In the formula, M represents the color gamut matrix, LUT_Rn represents the tonal level of the first red lookup table, LUT_Gn represents the tonal level of the first green lookup table, LUT_Bn represents the tonal level of the first blue lookup table, LUT_Rn' represents the tonal level of the second red lookup table, LUT_Gn' represents the tonal level of the second green lookup table, and LUT_Bn' represents the tonal level of the second blue lookup table.)

[0021]

[11] The method according to any one of [7] to

[10] , further comprising a verification step of verifying whether the display color of the image displayed on the first display device matches the display color of the image displayed on the second display device on which the second lookup table is written.

[0022]

[12] The method according to any one of [7] to

[11] , wherein the first color information includes the first chromaticity of an image displayed on the first display device, and the second color information includes the second chromaticity of an image displayed on the second display device.

[0023]

[13] A color matching program that causes the processor to execute one of the color matching methods described in [7] to

[12] .

[0024] Figure 1 shows the hardware configuration of the display system 1 according to this embodiment. Figure 2 is a block diagram showing an example configuration of the display device 10 according to this embodiment. Figure 3 is a conceptual diagram showing an example of the contents of the LUT. Figure 4 is a diagram showing the input / output characteristics of the source driver. Figure 5 is a block diagram showing the hardware configuration of the PC 20 in this embodiment. Figure 6a is a block diagram showing an example of the functional configuration of the control unit 110 provided in the PC 20 in this embodiment. Figure 6b is a block diagram showing a functional configuration example different from Figure 6a. Figure 7 is a flowchart showing an example of a color matching method between monitors according to this embodiment. Figure 8 is a flowchart showing an example of the LUT calculation process for calculating the LUT. Figure 9 is a flowchart showing an example of the LUT generation / storage process.

[0025] The embodiments of the present invention will now be described. The following embodiments are illustrative, and the scope of the present invention is not limited to those shown in the following embodiments. In order to avoid repetition and complexity, explanations of similar content will be omitted as appropriate.

[0026] (Image Display System 1) Figure 1 shows the hardware configuration of the display system 1 according to this embodiment. The image display system 1 consists of a display device 10 (reference monitor 10A, adjustment target monitor 10B), a personal computer (PC) 20 (PC 20A and PC 20B), and a communication cable 30. The reference monitor 10A and adjustment target monitor 10B are, for example, liquid crystal display devices (monitors) that display various images. Control signals and data are exchanged between PC 20A and PC 20B via the communication cable 30. If PC 20B is located at a distance from PC 20A (remote location), control signals and data may be exchanged between PC 20A and PC 20B via wireless communication. Video signals, control signals, and data are exchanged between the reference monitor 10A and PC 20A, and between the adjustment target monitor 10B and PC 20B via the signal cable 40.

[0027] (Display Device 10) Figure 2 is a block diagram showing an example configuration of the display device 10 according to this embodiment. The display device 10 according to this embodiment includes a display control unit 2, ROM 3, RAM 4, display operation unit 5, display storage unit 6, signal input / output unit 7, liquid crystal drive circuit 8, liquid crystal panel 9, backlight 11, light sensor 12, ADC (A / D converter) 13, backlight power supply circuit 14, etc. The display device 10 has the function of displaying an image on the display screen of the liquid crystal panel 9 based on an image signal input to the signal input / output unit 7. The image signal may be in analog format, but in the following description it will be described as being in digital format.

[0028] The display control unit 2 is specifically composed of a CPU and is connected to the hardware components described above via the bus 15. It controls these components and executes various software functions according to the control program stored in the ROM 3. The ROM 3 pre-stores various software programs necessary for the operation of the display device 10, as described above. The RAM 4 is composed of SRAM and stores temporary data generated during software execution. The display control unit 2, ROM 3, and RAM 4 may each be implemented using electronic circuits 16 such as a microcontroller, and various processes may be executed in hardware.

[0029] The display operation unit 5 is equipped with various function keys for operating the display device 10. The function keys include a brightness adjustment execution key 5a for setting whether or not to perform brightness adjustment processing, and a brightness setting key 5b for setting the brightness of the display device 10. Alternatively, an on-screen display (OSD) may be displayed on the liquid crystal panel 9 to operate various settings of the display device 10, or the liquid crystal panel 9 may be made a touch panel, thereby substituting some or all of the various function keys on the display operation unit 5.

[0030] The display memory unit 6 is a device that can be rewritten via software, and it stores the brightness L of the approximate center of the display surface of the liquid crystal panel 9 when the brightness is at its maximum (100%). ＭＨ , ADC13 output value AD Ｈand the luminance LM at the substantially central portion of the display surface of the liquid crystal panel when the brightness is minimum (0%) Ｌ , the output value AD of the ADC13 Ｌ , AD Ｌ and the first color luminance R for each of the three primary colors at the substantially central portion of the display surface when the source driver described later outputs the output voltage for each input level (for example, 10 bits: 0 to 1023) to the liquid crystal panel ０ , R １ ,..., R １０２３ The second color luminance G ０ , G １ ,..., G １０２３ The third color luminance B ０ , B １ ,..., B １０２３ The normalized first color luminance R ０ / R １０２３ , R １ / R １０２３ ,..., R １０２３ / R １０２３ The second color luminance G ０ / G １０２３ , G １ / G １０２３ ,..., G １０２３ / G １０２３ The third color luminance B ０ / B １０２３ , B １ / B １０２３ ,..., B １０２３ / B １０２３ are stored. Further, the display memory unit 6 has a function of appropriately updating and storing the LUTs 6a, 6b, 6c of each color in which the gradation level (index) and the input level (value) to the liquid crystal panel corresponding to the gradation level are associated (for the contents of each of the LUTs 6a, 6b, 6c, refer to FIG. 3).

[0031] The signal input / output unit 7 is connected to an external PC 20 (PC20A, PC20B) via a video signal line L. The display control unit 2 receives the video signal output from the PC 20 and corrects the received video signal based on the LUTs 6a, 6b, and 6c stored in the display storage unit 6 before outputting it to the liquid crystal drive circuit 8. The liquid crystal drive circuit 8 mainly consists of a gate driver 8a and a source driver 8b, and drives the display device (liquid crystal panel) 10 based on the video signal (correction signal) input from the display control unit 2. As a result, the display control unit 2 can adjust the transmittance of the display device (liquid crystal panel) 10 at a gradation level associated with the input level of the video signal output from the PC 20.

[0032] The source driver 8b has input / output characteristics as shown in Figure 4. The source driver 8b is supplied with a reference voltage (10-bit: VREF1, VREF2, ..., VREF10) and has the function of generating output voltages corresponding to the input level input from the display control unit 2 and outputting them to each output stage. In other words, the source driver 8b supplies data voltages to the source lines of the liquid crystal panel by outputting output voltages (data voltages) V0, V1, ..., V1023 corresponding to the input levels 0, 1, ..., 1023 to each output stage.

[0033] The liquid crystal panel 9 has a configuration in which a pair of glass substrates are arranged opposite each other, with a liquid crystal layer formed in the gap between them. One glass substrate has multiple pixel electrodes and TFTs with drains connected to each pixel electrode, while the other glass substrate has a common electrode. The gates and sources of the TFTs are sequentially connected to the output stages of the gate driver 8a and source driver 8b, respectively. The liquid crystal panel 9 is sandwiched between a pair of polarizing plates, and a backlight 11 is positioned behind it.

[0034] The backlight power supply circuit 14 has a function to adjust its output voltage, and by outputting the adjusted voltage to the backlight 11, it functions as a brightness adjustment means to adjust the brightness of the light emitted from the backlight 11. The liquid crystal panel 9 controls the on / off state of each pixel by the gate signal input from the gate driver 8a, and displays an image by controlling the light transmittance determined by the electro-optical properties of the liquid crystal material by applying the output voltage (data voltage) input from the source driver 8b to each pixel during the on period.

[0035] (PC20) Figure 5 is a block diagram showing the hardware configuration of PC20 in this embodiment. The hardware configuration of PC20B is the same as that of PC20A. As shown in Figure 5, PC20 is configured to include a control unit 110, a storage unit 120, a communication unit 130, and an operation input unit 140.

[0036] The control unit 110 is, for example, a CPU (Central Processing Unit), a microprocessor, a DSP (Digital Signal Processor), etc., and controls the overall operation of the PC 20.

[0037] A portion of the memory unit 120 is composed of, for example, RAM (Random Access Memory) or DRAM (Dynamic Random Access Memory), and is used as a work area when the control unit 110 executes various programs.

[0038] Furthermore, a portion of the storage unit 120 is, for example, a non-volatile memory such as ROM (Read Only Memory) or an HDD (Hard Disk Drive), which stores various data and programs used for processing by the control unit 110. The storage unit 120 can also hold a database including one or more tables for recording various information and processing results.

[0039] The programs stored in the memory unit 120 include, for example, an OS (Operating System) for realizing the basic functions of the PC 20, drivers for controlling various hardware, and programs for realizing various functions. These programs include a program that functions as the "color matching program" of the present invention. Note that the "color matching program" of the present invention may be stored only in the memory unit 120 of the PC 20 (PC 20A or PC 20B) that executes the program.

[0040] The communication unit 130 is, for example, a NIC (Network Interface Controller) and has the function of connecting to a communication line (not shown). Alternatively, the communication unit 130 may have functions to connect to a wireless LAN (Local Area Network), a wireless WAN (Wide Area Network), short-range wireless communication such as Bluetooth®, and infrared communication, either in place of or in conjunction with the NIC.

[0041] The operation input unit 140 consists of a keyboard and mouse, and accepts input of various operations from the user using the PC 20.

[0042] The control unit 110, storage unit 120, communication unit 130, operation input unit 140, and display device 10 are electrically connected to each other via the system bus 150. Therefore, the control unit 110 can access the storage unit 120, display images on the display device 10, understand the user's operation status on the operation input unit 140, and access various communication networks via the communication unit 130.

[0043] (Functional Configuration of Control Unit 110) Figures 6a and 6b are block diagrams showing an example of the functional configuration of the control unit 110 provided in the PC 20 in this embodiment. As shown in Figure 6a, the control unit 110 has a functional configuration that includes a color gamut matrix calculation unit 110a, a first RGB value calculation unit 110b, a first lookup table calculation unit 110c, and a second lookup table calculation unit 110d. The control unit 110 may further include a determination unit 111a, a correction unit 112a, a writing unit 110e, and a confirmation and adjustment unit 110f (Figure 6b).

[0044] The color gamut matrix calculation unit 110a calculates the color gamut matrix of the second display device based on first color information relating to the display color of the image displayed on the first display device (reference monitor 10A) and second color information relating to the display color of the image displayed on the second display device (adjustment target monitor 10B).

[0045] The first and second color information may include, for example, chromaticity (e.g., RGBW chromaticity), color gamut (panel color gamut), XYZ coordinates for each gradation, matrix data, color balance data, and self-corrected gradation data. The first color information may include the first chromaticity and / or first color gamut relating to the first color information of the image displayed on the first display device. The second color information may include the second chromaticity and / or second color gamut relating to the second color information of the image displayed on the second display device.

[0046] The color gamut matrix is ​​used to modify the gradation levels in a lookup table that associates gradation levels with the corresponding input levels to the display device, and is temporarily stored in the calculated storage unit 120.

[0047] The color gamut matrix calculation unit 110a can acquire first color information from the first display device and second color information from the second display device. Furthermore, if the first and second color information is stored on a server, the color gamut matrix calculation unit 110a can acquire the first and second color information from the server. Also, if the first and second color information can be acquired from image data, the color gamut matrix calculation unit 110a can acquire the first and second color information from image data.

[0048] The determination unit 111a determines whether the range of the first color gamut is included in the range of the second color gamut.

[0049] Correction unit 112a: If the range of the first color gamut is not included in the range of the second color gamut, the correction unit 112a corrects the first color information so that the range of the first color gamut is included in the range of the second color gamut.

[0050] The first RGB value calculation unit 110b calculates a first RGB value corresponding to the gradation value of the image displayed on the first display device based on the first color information. If the first color information does not include X, Y, Z, the first RGB value calculation unit 110b calculates tristimulus values ​​(X, Y, Z) from the xy chromaticity and luminance (x, y, Y) of the first color information, and calculates the first RGB value based on the tristimulus values.

[0051] The first lookup table calculation unit 110c calculates a one-dimensional first lookup table having grayscale levels associated with the first RGB values.

[0052] The second lookup table calculation unit 110d calculates a one-dimensional second lookup table by correcting the gradation levels of the first lookup table based on the color gamut matrix and the first lookup table.

[0053] The writing unit 110e writes the second lookup table to the second display device. By using the second lookup table, the second display device can match the display color and gradation characteristics of the image displayed on the second display device to those of the image displayed on the first display device.

[0054] The confirmation and adjustment unit 110f can display the same image on the second display device and the first display device, on which the second lookup table is written. This allows the user to confirm the display color of the image on both monitors.

[0055] The specific processing in the functional configuration of the control unit 110 will be described in detail below.

[0056] (1. Color Gamut Matrix Calculation Step) (1-1 Acquisition of Color Information of Reference Monitor (First Display Device) and Monitor to be Adjusted (Second Display Device)) Figure 7 is a flowchart illustrating an example of a color matching method between monitors according to this embodiment. In this embodiment, the PC 20B of the monitor to be adjusted 10B is provided with a control unit 110 as an example.

[0057] The color gamut matrix calculation unit 110a may acquire first color information (hereinafter referred to as reference color information) and second color information (hereinafter referred to as target color information) from the display storage unit 6 provided in each monitor (10A and 10B), or it may acquire it from a device that stores color information other than each monitor (10A and 10B) (for example, a server), or it may acquire it using a calibration sensor (monitor-built sensor or external sensor). When acquiring color information using an external calibration sensor, a calibration sensor mounting target window is displayed on each monitor (10A and 10B), the calibration sensor is mounted in the center of the screen, and the color information of the monitors (10A and 10B) is measured and acquired.

[0058] (1-2 Determination Step and Correction Step) The determination unit 111a determines whether the range of the first color gamut (hereinafter referred to as the reference color gamut information) is included in the range of the second color gamut (hereinafter referred to as the target color gamut information).

[0059] The determination unit 111a determines whether the color gamut based on RGB chromaticity in the RGBW chromaticity of the reference monitor 10A (reference panel color gamut) is included in the color gamut based on RGB chromaticity in the RGBW chromaticity of the monitor to be adjusted 10B (target panel color gamut) (S2-1). If it is not included, it determines whether the reference panel color gamut is included in the target panel color gamut by performing a Clipping ON process (accurately representing colors that can be represented, and saturating colors that cannot be represented (using the target color gamut as is)) (S2-2).

[0060] If the range of the reference color gamut information is not included within the range of the target color gamut information, the correction unit 112a corrects the reference chromaticity information so that the range of the reference color gamut information is included within the range of the target color gamut information, and the corrected reference chromaticity information (corrected reference chromaticity information) is obtained.

[0061] If the reference panel color gamut is not contained within the target panel color gamut and Clipping OFF (using a color gamut inscribed within the target color gamut), the correction unit 112a corrects the RGB chromaticity in the RGBW chromaticity of the reference monitor 10A so that the reference panel color gamut is inscribed within the target panel color gamut (S3). Specifically, it performs a process to set the target x and y coordinates to the intersection point where the vertices of the reference panel color gamut located outside the range of the target panel color gamut are inscribed within the target panel color gamut.

[0062] (1-3. Color Gamut Matrix Calculation) The color gamut matrix calculation unit 110a calculates the color gamut matrix M from the RGBW chromaticity of the reference monitor 10A (or the corrected RGBW chromaticity) and the RGBW chromaticity of the monitor to be adjusted 10B (S4). The calculation of the color gamut matrix M will be described in detail below.

[0063] (1-3-1 Each gain value (R Gａｉｎ G Gａｉｎ and B Gａｉｎ )Calculation) The color gamut matrix calculation unit 110a adjusts the RGB gain M of the target monitor 10B so that it becomes the white point chromaticity of the reference monitor 10A. Gain (Equation (1): The gain of the red component is R) Gain The gain of the green component is G Gain The gain of the blue component is B GainCalculate the value. You may also adjust the RGB gain using a calibration sensor (monitor built-in sensor or external sensor). In that case, set the color gamut matrix of the monitor 10B to be adjusted to through (identity matrix).

[0064]

[0065] Below, each gain (R Gａｉｎ G Gａｉｎ and B Gａｉｎ The calculation method for ) will be explained in detail.

[0066] (1-3-1-1 Calculation of X, Y, Z values ​​for monochromatic and white when color temperature is OFF) The color gamut matrix calculation unit 110a acquires self-correction matrix data (formula (2)), color balance data, self-correction gradation data, and chromacity data from the monitor 10B to be adjusted. The following explanation will take the case where the predetermined color temperature of the self-correction matrix data is 7500K as an example, but the predetermined color temperature may be a different temperature. The predetermined color temperature is, for example, 6000 to 9000K, specifically, for example, 6500 to 15000K (for example, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, 11000, 12000, 13000, 14000 and 15000K), and may be a range between any two of the values ​​exemplified here.

[0067] (1-3-1-1-1 7500K matrix data)

[0068]

[0069] (1-3-1-1-2 Self-corrected gradation data) R: R0, R1, ..., Rl, ..., R254, R255 (l is (M １１ ( / 512) * value closest to 255) G: G0, G1, ..., Gm, ..., G254, G255 (m is (M ２２ ( / 512) * value closest to 255) B: B0, B1, ..., Bn, ..., B254, B255 (n is (M ３３ ( / 512) * (The value closest to 255) * M １１ , M ２２ , M ３３ Let's assume one of them is 512.

[0070] (1-3-1-1-3 7500K color balance data) R:RR, G:GR, B:BR R value, G value and B value for R single color when color temperature is OFF R value: R_R_off = L ＭＨ *(RR*(R255 / Rl)) / (RR+GR+BR) G value: G_R_off=L ＭＨ *(GR*(G0 / Gm)) / (RR+GR+BR) B value: B_R_off=L ＭＨ * (BR * (B0 / Bn)) / (RR + GR + BR) R value, G value, and B value for G monochromatic color when color temperature is OFF R value: R_G_off = L ＭＨ *(RR*(R0 / Rl)) / (RR+GR+BR) G value: G_G_off=L ＭＨ *(GR*(G255 / Gm)) / (RR+GR+BR) B value: B_G_off=L ＭＨ * (BR * (B0 / Bn)) / (RR + GR + BR) R, G, and B values ​​for B monochromatic color when color temperature is OFF. R value: R_B_off = L ＭＨ *(RR*(R0 / Rl)) / (RR+GR+BR) G value: G_B_off=L ＭＨ *(GR*(G0 / Gm)) / (RR+GR+BR) B value: B_B_off=L ＭＨ * (BR * (B255 / Bn)) / (RR + GR + BR) R, G, and B values ​​for white when color temperature is OFF R value: R_W_off = L ＭＨ *(RR*(R255 / Rl)) / (RR+GR+BR) G value: G_W_off=L ＭＨ *(GR*(G255 / Gm)) / (RR+GR+BR) B value: B_W_off=L ＭＨ *(BR*(B255 / Bn)) / (RR+GR+BR)

[0071] (1-3-1-1-4 Chromaticity Data) x, y in R monocolor: x_R_off, y_R_off x, y in G monocolor: x_G_off, y_G_off x, y in B monocolor: x_B_off, y_B_off x, y in white: x_W_off, y_W_off

[0072] (1-3-1-1-5 Calculation of Y values ​​for each single color and white when color temperature is OFF) The color gamut matrix calculation unit 110a calculates the matrix data and color balance data for 7500K, as well as the self-correction gradation data and the luminance data (L) for 7500K. ＭＨ ) Calculate the Y value of each single color and white when the color temperature is OFF. The formula for calculating the Y value is as follows: Y for single color R: Y_R_off Y_R_off = L ＭＨ * (RR * (R255 / Rl) + GR * (G0 / Gm) + BR * (B0 / Bn)) / (RR + GR + BR) Y in single color G: Y_G_off Y_G_off = L ＭＨ * (RR * (R0 / Rl) + GR * (G255 / Gm) + BR * (B0 / Bn)) / (RR + GR + BR) Y in monochromatic B: Y_B_off Y_B_off = L ＭＨ * (RR * (R0 / Rl) + GR * (G0 / Gm) + BR * (B255 / Bn)) / (RR + GR + BR) Y in white: Y_W_off Y_W_off = L ＭＨ *(RR*(R255 / Rl)+GR*(G255 / Gm)+BR*(B255 / Bn)) / (RR+GR+BR)

[0073] (1-3-1-1-6 Calculation of X, Y, and Z values ​​for each single color) The color gamut matrix calculation unit 110a calculates the X, Y, and Z values ​​for each single color from the x and y values ​​of each single color in the chromaticity data and the Y value of each single color when the color temperature is OFF.

[0074] (I) X, Y, Z in R monocolor when color temperature is OFF: X_R_off, Y_R_off, Z_R_off X_R_off = Y_R_off * x_R_off / y_R_off = L ＭＨ *(RR*(R255 / Rl)+GR*(G0 / Gm)+BR*(B0 / Bn)) / (RR+GR+BR)*x_R_off / y_R_off Y_R_off=Y_R_off =L ＭＨ *(RR*(R255 / Rl)+GR*(G0 / Gm)+BR*(B0 / Bn)) / (RR+GR+BR) Z_R_off=Y_R_off*(1-x_R_off-y_R_off) / y_R_off =L ＭＨ*(RR*(R255 / Rl)+GR*(G0 / Gm)+BR*(B0 / Bn)) / (RR+GR+BR)*(1-x_R_off-y_R_off) / y_R_off

[0075] (II) X, Y, Z in single G color when color temperature is OFF: X_G_off, Y_G_off, Z_G_off X_G_off = Y_G_off * x_G_off / y_G_off = L ＭＨ *(RR*(R0 / Rl)+GR*(G255 / Gm)+BR*(B0 / Bn)) / (RR+GR+BR)*x_G_off / y_G_off Y_G_off=Y_G_off =L ＭＨ *(RR*(R0 / Rl)+GR*(G255 / Gm)+BR*(B0 / Bn)) / (RR+GR+BR) Z_G_off=Y_G_off*(1-x_G_off-y_G_off) / y_G_off =L ＭＨ *(RR*(R0 / Rl)+GR*(G255 / Gm)+BR*(B0 / Bn)) / (RR+GR+BR)*(1-x_G_off-y_G_off) / y_G_off

[0076] (III) X, Y, Z in monochromatic B when color temperature is OFF: X_B_off, Y_B_off, Z_B_off X_B_off = Y_B_off * x_B_off / y_B_off = L ＭＨ *(RR*(R0 / Rl)+GR*(G0 / Gm)+BR*(B255 / Bn)) / (RR+GR+BR)*x_B_off / y_B_off Y_B_off=Y_B_off =L ＭＨ *(RR*(R0 / Rl)+GR*(G0 / Gm)+BR*(B255 / Bn)) / (RR+GR+BR) Z_B_off=Y_B_off*(1-x_B_off-y_B_off) / y_B_off =L ＭＨ *(RR*(R0 / Rl)+GR*(G0 / Gm)+BR*(B255 / Bn)) / (RR+GR+BR)*(1-x_B_off-y_B_off) / y_B_off

[0077] (1-3-1-2 XYZ value -> RGB conversion table matrix M') XYZtoRGBThe color gamut matrix calculation unit 110a calculates the XYZ value -> RGB conversion table matrix M' from the monochromatic value based on equations (3) to (5). XYZtoRGB Calculate.

[0078]

[0079]

[0080]

[0081] (1-3-1-3 XYZ value -> RGB conversion table matrix M) XYZtoRGB The color gamut matrix calculation unit 110a performs white correction from the value of 7500K white, and the final conversion table M XYZtoRGB Calculate the conversion table M. XYZtoRGB The method for calculating this is detailed below.

[0082] (1-3-1-3-1 X,Y,Z: Calculation of X_cl, Y_cl, Z_cl) The color gamut matrix calculation unit 110a calculates Y=L at 7500K (x_cl=0.299, y_cl=0.315) MH Calculate X, Y, Z (X_cl, Y_cl, Z_cl). X_cl = Y_cl * x_cl / y_cl = L MH *0.299 / 0.315 Y_cl=L MH Z_cl=Y_cl*(1-x_cl-y_cl) / y_cl=L MH *0.386 / 0.315

[0083] (1-3-1-3-2 R, G, B: Calculation of R_cl, G_cl, B_cl) The color gamut matrix calculation unit 110a calculates Y=L at 7500K (x_cl=0.299, y_cl=0.315) MH In R, G, B: R_cl, G_cl, B_cl, M' XYZtoRGB It is calculated using [this method].

[0084]

[0085] (1-3-1-3-3 Calculation of white correction coefficients KR, KG, KB) The color gamut matrix calculation unit 110a calculates the white correction coefficients KR, KG, and KB from the color balance data and luminance data at 7500K and the above R_cl, G_cl, and B_cl. White correction coefficient for R value: KR MH * (RR / (RR + GR + BR)) / R_cl White correction coefficient for G value: KG MH * (GR / (RR + GR + BR)) / G_cl White correction coefficient for B value: KB MH * (BR / (RR + GR + BR)) / B_cl

[0086] (1-3-1-3-4 XYZ value -> RGB conversion table matrix M) XYZtoRGB The color gamut matrix calculation unit 110a calculates the final XYZ value -> RGB conversion table matrix M from the white correction matrix C ｗ (Equation (7)) (Equation (8)). XYZtoRGB

[0087]

[0088]

[0089] (1-3-1-4 Gain values (R ｇａｉｎ , G ｇａｉｎ and B ｇａｉｎ ) calculation) The color gamut matrix calculation unit 110a obtains the ratios of TR, TG, and TB based on the R, G, B values at white when the color temperature is OFF: R_W_off, G_W_off, B_W_off. TR / R_W_off: TG / G_W_off: TB / B_W_off = TR / (RR * (R255 / Rl): TG / (GR * (G255 / Gm): TB / (BR * (B255 / Bn)

[0090] The color gamut matrix calculation unit 110a normalizes the largest value among TR / (RR * (R255 / Rl), TG / (GR * (G255 / Gm), and TB / (BR * (B255 / Bn)) to 65535. The gain value of the color that becomes the largest value (R Ｇａｉｎ , G​Ｇａｉｎ or B Ｇａｉｎ )shall be set to a maximum of 512. For the other two colors, the color gamut matrix calculation unit 110a refers to the self-corrected gradation data: Rlt, Gmt, Bnt that is the closest value, and the reference panel gradation = M ** / 512 to obtain the gain value.

[0091] (1-3-2 Calculation of Color Gamut Matrix) The color gamut matrix calculation unit 110a calculates the RGB->XYZ conversion matrix (TergetGamut RGB2XYZ Matrix) M of the target Gamut in the RGBW chromaticity (or corrected RGBW chromaticity) of the reference monitor 10A TGRGBtoXYZ is calculated. M TGRGBtoXYZ is the inverse matrix (XYZ->RGB conversion matrix) M of the TergetGamut XYZ Matrix of the reference monitor TGXYZ is obtained, and the white correction matrix C obtained so as to be the W chromaticity of the reference monitor ｗ is multiplied and calculated (Equation (9)).

[0092]

[0093] The color gamut matrix calculation unit 110a calculates the XYZ->RGB conversion matrix (PanelChroma XYZ2RGB Matrix) M of PanelChroma (the Gamut of the panel) in the RGBW chromaticity of the LCD panel of the adjustment target monitor 10B PCXYZtoRGB is calculated.

[0094] The color gamut matrix calculation unit 110a calculates the inverse matrix (XYZ->RGB conversion matrix) M of the color gamut matrix (PanelChroma XYZ Matrix) M' of PanelChroma of the adjustment target monitor 10B PCXYZ and multiplies it by the white correction matrix C obtained so as to be the W chromaticity of the reference monitor 10A PCXYZ to calculate the RGB->XYZ conversion matrix (PanelChroma RGB2XYZ Matrix) M of PanelChroma (the Gamut of the panel) (Equation (10)). ｗ PCRGBtoXYZ is calculated (Equation (10)). ​

[0095]

[0096] The color gamut matrix calculation unit 110a calculates the PanelChroma (panel gamut) XYZ->RGB conversion matrix (PanelChroma XYZ2RGB Matrix) M PCXYZtoRGB Calculate M PCXYZtoRGB M PCRGBtoXYZ The inverse matrix M PCRGBtoXYZ -1 It is calculated by determining (Equation (11)). Note that M PCXYZtoRGB The gain matrix M Gain M calculated at the time of calculation XYZtoRGB It is the same as this.

[0097]

[0098] The color gamut matrix M is M PCXYZtoRGB and M TGRGBtoXYZ It is calculated by multiplying by (Equation (12)).

[0099]

[0100] The color gamut matrix calculation unit 110a writes the calculated color gamut matrix M to the display storage unit 6 of the monitor 1B to be adjusted.

[0101] (2. First RGB Value Calculation Step) Calculation of the First RGB Value (Target RGB Value) The first RGB value calculation unit 110b calculates the X, Y, Z values ​​for each grayscale of the reference monitor 10A and converts them from X, Y, Z to R, G, B; TR, TG, TB values ​​(hereinafter referred to as the target RGB value). Specifically, the target RGB value is calculated as follows: X, Y, Z (Xt, Yt, Zt) is calculated from the x, y, Y (xt, yt, Yt) of the reference monitor 10A, and the calculated X, Y, Z is calculated based on formula (13) (XYZ value -> RGB conversion table matrix M XYZtoRGB (See equation (8)). If the first color information includes the XYZ values ​​for each gradation, then the target RGB values ​​for each color can be calculated using these values. Xt = Yt * xt / yt Yt = Yt Zt = Yt * (1 - xt - yt) / yt

[0102]

[0103] Furthermore, the target luminance Yt is expressed from TR, TG, and TB as follows: Yt = TR + TG + TB TR = Yt * (TR / (TR + TG + TB) TG = Yt * (TG / (TR + TG + TB) TB = Yt * (TB / (TR + TG + TB)

[0104] (3. First Lookup Table Calculation Step) The first lookup table calculation unit 110c calculates the LUTs 6a, 6b, and 6c for each color in the monitor 10B to be adjusted (S6). Calibration may also be performed using a calibration sensor (monitor built-in sensor or external sensor). In that case, the color gamut matrix of the monitor 10B to be adjusted is set to through (identity matrix).

[0105] Figure 8 is a flowchart showing an example of the LUT calculation process. First, the maximum brightness L ＴＭＡＸ The maximum brightness L is obtained from the reference monitor 10A (S61). ＴＭＡＸ This may be obtained by measurement.

[0106] The first lookup table calculation unit 110c calculates the brightness L stored in the display storage unit 6 of the monitor 10B to be adjusted. ＭＨ , L ＭＬ and output value AD Ｈ AD Ｌ Read out the luminance L ＭＨ , L ＭＬ and output value AD Ｈ AD Ｌ and maximum brightness L ＴＭＡＸ Based on equations (14) and (15), the maximum brightness L ＴＭＡＸ The output value AD is Ｔ Calculate (S62).

[0107]

[0108] The first lookup table calculation unit 110c calculates the ratio of luminances of the three primary colors RR:GR:BR (self-corrected color balance data for target white). RR, GR, and BR can be calculated from TR, TG, and TB as follows: RR = TR / (TR + TG + TB) GR = TG / (TR + TG + TB) BR = TB / (TR + TG + TB) In this example, the ratio of luminances was calculated when the luminance liquid crystal material has the maximum controllable transmittance, but the ratio of luminances when the liquid crystal material has a predetermined transmittance may also be calculated.

[0109] The first lookup table calculation unit 110c calculates the normalized first color brightness R stored in the display storage unit 6 of the monitor 10B to be adjusted. ０ / R １０２３ , R １ / R １０２３ ,..., R １０２３ / R １０２３ , second color luminance G ０ / G １０２３ , G １ / G １０２３ ,..., G １０２３ / G １０２３ , third color brightness B ０ / B １０２３ , B １ / B １０２３ ,..., B １０２３ / B １０２３ The first color luminance R read out, ０ / R １０２３ , R １ / R １０２３ ,..., R １０２３ / R １０２３ , second color luminance G ０ / G １０２３ , G １ / G １０２３ ,..., G １０２３ / G １０２３ , third color brightness B ０ / B １０２３ , B １ / B １０２３ ,..., B １０２３ / B １０２３ RR, GR, BR, and maximum brightness L ＴＭＡＸ By multiplying each of these, the maximum brightness L ＴＭＡＸThe panel gradation characteristic value L for each color in this case. ＴＭＡＸ RR・R ０ / R １０２３ / Rl,L ＴＭＡＸ RR・R １ / R １０２３ / Rl,...,L ＴＭＡＸ RR・R １０２３ / R １０２３ / Rl, L ＴＭＡＸ GR・G ０ / G １０２３ / Gm, L ＴＭＡＸ GR・G １ / G １０２３ / Gm, ..., L ＴＭＡＸ GR・G １０２３ / G １０２３ / Gm, L ＴＭＡＸ BR・B ０ / B １０２３ / Bn,L ＴＭＡＸ BR・B １ / B １０２３ / Bn, ..., L ＴＭＡＸ BR・B １０２３ / B １０２３ Calculate / Bn (S63).

[0110] The first lookup table calculation unit 110c uses the XYZ of each grayscale of the reference monitor 10A calculated in the process of calculating the target RGB value to perform an XYZ->RGB conversion based on equations (3) to (5), and calculates the maximum brightness L ＴＭＡＸ Target RGB values ​​TR for each color at that time ０ , TR １ ,..., TR ２５５ TG ０ TG １ ,..., TG ２５５ , TB ０ , TB １ ,...,TB ２５５ The system calculates the target RGB values ​​for each color (S64), compares the calculated target RGB values ​​for each color with the calculated panel gradation characteristics for each color to generate LUTs 6a, 6b, and 6c, and stores them in the display storage unit 6 (S65). If the first color information includes the XYZ values ​​for each gradation, the system uses these values ​​to calculate the maximum brightness L. ＴＭＡＸ You just need to calculate the target RGB values ​​for each color at that time.

[0111] Next, the generation and storage processes of the LUTs 6a, 6b, and 6c described above will be explained in more detail. Figure 9 is a flowchart showing an example of the LUT generation / storage process.

[0112] The first lookup table calculation unit 110c calculates the RGB signal C i The signals of each color in (TR i TG i , TB i ) and panel gradation characteristic value L ＴＭＡＸ L ｋ / L １０２３ The difference value (C) from (k = 0, 1, ..., 1023) i -L ＴＭＡＸ L ｋ / L １０２３ Calculate (S651). The absolute value of the calculated difference | C i -L ＴＭＡＸ ・L ｋ / L １０２３ The combination of grayscale level i and input level k that minimizes | is extracted for each grayscale level i (S652).

[0113] The first lookup table calculation unit 110c stores the first lookup tables (LUTs 6a, 6b, 6c (red first lookup table, green first lookup table, blue first lookup table)) in the display storage unit 6, where the calculated gradation level i is the index value of each LUT and the input level k is the value value of each LUT (S653). Note that the difference value (C i -L ＴＭＡＸ L ｋ / L １０２３ The LUT is shown as the combination of gradation level i and input level k that minimizes the absolute value of the difference (C), but it is not limited to this, and the difference value (C) i -L ＴＭＡＸ L ｋ / L １０２３ The LUT may be configured such that the combination of gradation level i and input level k results in the smallest positive (or negative) value.

[0114] (4. Second Lookup Table Calculation Step) If the calculated first lookup table is written directly to the second lookup table, there is a problem that the gradation characteristics of the monochrome image will be distorted during the subsequent processing of the color gamut matrix M. As mentioned above, the requirements for the gradation characteristics of monochrome images in medical settings are strict, and it is necessary to calculate a second lookup table that is not affected by the matrix M and does not distort the gradation characteristics. The calculation step for the second lookup table for this purpose is described below. Refer to the flowchart in Figure 7. The second lookup table calculation unit 110d calculates a second lookup table that includes index values ​​that take the color gamut into consideration (LUT_Rn', LUT_Gn', LUT_Bn', n=0, 1, ..., 255) based on the index values ​​(LUT_Rn, LUT_Gn', LUT_Bn', n=0, 1, ..., 255) of the extracted first lookup table and the calculated color gamut matrix M (S7). Specifically, as shown in equation (16) below, the index value considering the color gamut is calculated using the index value of the second lookup table and the inverse matrix of the calculated color gamut matrix M. However, this calculation is performed only for combinations of LUT_Rn, LUT_Gn, and LUT_Bn with the same tonal range.

[0115]

[0116] In formula (16), M -1LUT_Rn represents the inverse matrix of the color gamut matrix, LUT_Gn represents the tonal level (index value) of the first red lookup table, LUT_Bn represents the tonal level (index value) of the first green lookup table, LUT_Rn' represents the tonal level (index value) of the first blue lookup table, LUT_Rn' represents the tonal level (index value) of the second red lookup table, LUT_Gn' represents the tonal level (index value) of the second green lookup table, and LUT_Bn' represents the tonal level (index value) of the second blue lookup table. Since the levels multiplied by the inverse matrix are processed by the color gamut matrix M, the color gamut matrix M is effectively bypassed, and the output is identical to the tonal level of the first lookup table. However, as mentioned above, the inverse matrix is ​​applied only to combinations of LUT_Rn, LUT_Gn, and LUT_Bn with the same gradation, i.e., monochrome images. Therefore, this pseudo-color gamut matrix M bypass occurs only with monochrome images. For color images where the gradation levels of each color are different, color conversion processing is performed without bypassing matrix M, making it possible to display the desired color. By performing this inverse matrix operation, it is possible to achieve matrix M bypass without providing a circuit to bypass matrix M, and without rewriting matrix M for monochrome and color images.

[0117] (5. Writing Step) The writing unit 110e writes the index values ​​of the second lookup table, which take into account the calculated color gamut, to the display storage unit 6 of the monitor 10B to be adjusted (S8).

[0118] (6. Confirmation Step) The confirmation and adjustment unit 110f can display images based on the same image data on the adjustment target monitor 10B and the reference monitor 10A, on which the second lookup table has been written, thereby allowing the user to confirm the display color of the images between the monitors (S9).

[0119] The confirmation and adjustment unit 110f can display a confirmation screen on either monitor, and the confirmation screen may include a confirmation button to press if the display colors of the images between the monitors match, and an adjustment button to press if the display colors of the images between the monitors do not match. When the confirmation button is pressed, the confirmation and adjustment unit 110f sends a signal to the control unit 110 to terminate the color matching process, and the color matching process ends. When the adjustment button is pressed, the confirmation and adjustment unit 110f can display an adjustment mode on the monitor to be adjusted 10B for manually adjusting the display colors of the images between the monitors.

[0120] In adjustment mode, the user can manually adjust the color tone of the image displayed on the target monitor 10B by comparing the image displayed on the reference monitor 10A with the image displayed on the target monitor 10B. The adjustment mode may also be a mode in which the display colors of images between monitors can be further matched by comparing the image displayed on the reference monitor 10A with multiple images with different color tones displayed on the target monitor 10B (for example, by visual inspection or using an external sensor), and by selecting the image displayed on the target monitor 10B that has the same or similar color tone as the image displayed on the reference monitor 10A (manually or by a signal output by an external sensor).

[0121] By using the method described above, color matching between the reference monitor 10A and the monitor to be adjusted 10B can be performed automatically.

[0122] In this embodiment, an example of performing this method between two monitors was shown using the PC 20B of the monitor to be adjusted 10B, but this method can also be applied to multiple monitors to be adjusted 10B. Furthermore, this method can be performed even if the reference monitor 10A and the monitor to be adjusted 10B are located in distant locations from each other. The device that performs this method may be the PC 20A connected to the reference monitor 10A, a server to which the PC 20A of the reference monitor 10A and the PC 20B of the monitor to be adjusted 10B are connected via a network line, or the display control unit 2 of the display device 10 (reference monitor 10A or monitor to be adjusted 10B).

[0123] Furthermore, this method can also be applied to image data instead of the reference monitor 10A. That is, this method can be performed by obtaining color information from color information data attached to the image data or from a color information file attached to the image data. Alternatively, color information can be obtained from monitor quality control software on the local or ground.

[0124] 1: Display system, 2: Display control unit, 3: ROM, 4: RAM, 5: Display operation unit, 5a: Brightness adjustment execution key, 5b: Brightness setting key, 6: Display memory unit, 7: Signal input / output unit, 8: Liquid crystal drive circuit, 8a: Gate driver, 8b: Source driver, 9: Liquid crystal panel, 10: Display device, 10A: Reference monitor, 10B: Monitor to be adjusted, 11: Backlight, 12: Light sensor, 14: Backlight power supply circuit, 15: Bus, 1 6: Electronic circuit, 30: Communication cable, 40: Signal cable, 110: Control unit, 110a: Color gamut matrix calculation unit, 110b: First RGB value calculation unit, 110c: First lookup table calculation unit, 110d: Second lookup table calculation unit, 110e: Writing unit, 110f: Confirmation and adjustment unit, 111a: Judgment unit, 112a: Correction unit, 120: Storage unit, 130: Communication unit, 140: Operation input unit, 150: System bus

Claims

1. A display system that enables matching the display color of an image displayed on a first display device to the display color of an image displayed on a second display device, comprising: a color gamut matrix calculation unit that calculates a color gamut matrix for matching the display color of the second display device to the display color of the first display device based on first color information relating to the display color of an image displayed on the first display device and second color information relating to the display color of an image displayed on the second display device; a first RGB value calculation unit that calculates first RGB values ​​corresponding to the gradation values ​​of an image displayed on the first display device based on the first color information; a first lookup table calculation unit that calculates a one-dimensional first lookup table having gradation levels associated with the first RGB values; a second lookup table calculation unit that calculates a one-dimensional second lookup table with the gradation levels of the first lookup table modified based on the color gamut matrix and the first lookup table; and a writing unit that writes the second lookup table to the second display device.

2. The display system according to claim 1, further comprising: a determination unit that determines whether the range of the first color gamut is included in the range of the second color gamut, the first color information includes a first color gamut relating to the first color information, the second color information includes a second color gamut relating to the second color information, and if the range of the first color gamut is not included in the range of the second color gamut, a modification unit that modifies the first color information so that the range of the first color gamut is included in the range of the second color gamut.

3. The display system according to claim 1, wherein in the second lookup table calculation unit, the second lookup table is calculated by modifying the gradation levels of the first lookup table based on the inverse matrix of the color gamut matrix.

4. The display system according to claim 3, wherein the first lookup table includes a red first lookup table, a green first lookup table, and a blue first lookup table, and the second lookup table includes a red second lookup table, a green second lookup table, and a blue second lookup table, and the second lookup table is calculated based on the following formula (16). (In the formula, M represents the color gamut matrix, LUT_Rn represents the tonal level of the first red lookup table, LUT_Gn represents the tonal level of the first green lookup table, LUT_Bn represents the tonal level of the first blue lookup table, LUT_Rn' represents the tonal level of the second red lookup table, LUT_Gn' represents the tonal level of the second green lookup table, and LUT_Bn' represents the tonal level of the second blue lookup table.) 5. The display system according to claim 1, further comprising a verification and adjustment unit that verifies whether the display color of the image displayed on the first display device matches the display color of the image displayed on the second display device on which the second lookup table is written.

6. The display system according to claim 1, wherein the first color information includes the first chromaticity of an image displayed on the first display device, and the second color information includes the second chromaticity of an image displayed on the second display device.

7. A method for color matching between display devices, which matches the display color of an image displayed on a first display device to the display color of an image displayed on a second display device, comprising: a color gamut matrix calculation step of calculating a color gamut matrix for matching the display color of the second display device to the display color of the first display device based on first color information relating to the display color of an image displayed on the first display device and second color information relating to the display color of an image displayed on the second display device; a first RGB value calculation step of calculating first RGB values ​​corresponding to the gradation values ​​of an image displayed on the first display device based on the first color information; a first lookup table calculation step of calculating a one-dimensional first lookup table having gradation levels associated with the first RGB values; a second lookup table calculation step of calculating a one-dimensional second lookup table with the gradation levels of the first lookup table modified based on the color gamut matrix and the first lookup table; and a writing step of writing the second lookup table to the second display device.

8. A color matching program that causes a processor to execute the color matching method described in claim 7.

Images