Chromatic aberration calculation method, device, system and program product

Abstract

The invention relates to a color difference calculation method, device and system and a program product, and relates to the technical field of display and printing. The chromatic aberration calculation method comprises the following steps: acquiring one or more groups of color stimulants; for each observation view angle, adjusting the primary color proportion of each group of color stimulants until color matching is completed; determining a color difference value of the target color stimulant and the matched color stimulant in each group of color stimulants according to the spectral energy distribution of the target color stimulant, the spectral energy distribution of the matched color stimulant and a color matching function set corresponding to the observation view angle; determining a color difference average value of one or more groups of color stimulants according to the color difference value; dividing a plurality of observation view angles according to the color difference average value, and determining a target color matching function corresponding to each observation view angle interval; and determining a color difference value of the to-be-matched experimental color stimulant group according to the target color matching function, performing fitting according to the color difference value of the to-be-matched experimental color stimulant group, and performing color correction according to fitting parameters.

Description

Technical Field

[0001] This disclosure relates to the fields of display and printing technology, and in particular to a color difference calculation method, apparatus, system and program product. Background Technology

[0002] Color matching functions can quantitatively characterize the spectral response of cone cells on the human retina, and are an important tool for realizing quantitative calculations of color perception. With the development of color reproduction technology, self-emissive display devices with different color rendering methods and display sizes, such as LEDs (Light Emitting Diodes) and OLEDs (Organic Light Emitting Diodes), as well as a wide variety of printed products, are widely used in people's daily lives. Summary of the Invention

[0003] With the development of color reproduction technology, such as the increasing diversity of display sizes and color rendering methods in display devices, the spectral composition of printed products is also becoming more diverse. In the printing and reproduction process, it is often necessary to use displays with different spectral compositions for color transmission. Issues arise regarding the calibration and matching between the colors reproduced on the display and the printed colors (i.e., soft proofing), and the matching of colors from different printing methods, such as digital proofing and printed output. Because the primary color spectral compositions of the different color stimuli in each of these stages differ, metamerism often occurs. This leads to significant differences in color perception between different observers regarding the target color and the matching color at each stage. Therefore, how to perform color correction on color stimuli from different color rendering methods to overcome metamerism is a problem that needs to be solved.

[0004] In view of this, the present disclosure proposes a color difference calculation method. According to some embodiments of the first aspect of the present disclosure, a color difference calculation method is provided, comprising: acquiring one or more sets of color stimuli, wherein each set of color stimuli includes a target color stimulus and a matching color stimulus, the target color stimulus having a first spectral parameter, and the matching color stimulus having a second spectral parameter; adjusting the primary color ratio of each set of color stimuli for each of multiple observation perspectives in an observation strategy until color matching of each set of color stimuli is completed; determining the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli based on the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each set of color stimuli, and a set of color matching functions corresponding to each observation perspective; and determining the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli based on the target color stimulus in each set of color stimuli. The color difference value between the stimulus and the matching color stimulus is used to determine the average color difference of one or more groups of color stimuli corresponding to each observation viewpoint. Based on the average color difference value, multiple observation viewpoints are divided into multiple observation viewpoint intervals. The minimum value of the average color difference of one or more groups of color stimuli corresponding to each observation viewpoint interval is determined, and the color matching function corresponding to the minimum value is determined as the target color matching function for the corresponding observation viewpoint interval. Through the target color matching function, the color difference value of the experimental color stimulus group to be matched in one or more groups of color stimuli is determined under multiple observation viewpoints. Based on the color difference value of the experimental color stimulus group to be matched under multiple observation viewpoints, the fitting parameters are determined. Based on the fitting parameters, the matching color stimuli in the color stimulus group to be corrected are color corrected.

[0005] In some embodiments, determining the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli, based on the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle, includes: inputting the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each group of color stimuli to each color matching function in the set of color matching functions; determining a first chromaticity value of the target color stimulus and a second chromaticity value of the matching color stimulus corresponding to each color matching function; determining the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to each color matching function based on the first chromaticity value and the second chromaticity value; and determining the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to the set of color matching functions based on the color difference value corresponding to each color matching function.

[0006] In some embodiments, determining the color difference value of the experimental color stimulus group to be matched in one or more groups of color stimuli under multiple observation views by means of a target color matching function includes: determining the observation view interval to which each observation view belongs; determining the target color matching function corresponding to the observation view interval according to the observation view interval to which each observation view belongs; determining the color difference value of the experimental color stimulus group to be matched under each observation view by means of the target color matching function; and determining the color difference value of the experimental color stimulus group to be matched under multiple observation views according to the color difference value of the experimental color stimulus group to be matched under each observation view.

[0007] In some embodiments, the experimental color stimulus group to be matched is determined by the following steps: determining the color difference value of each group of color stimuli corresponding to multiple observation perspectives using a target color matching function; determining the minimum and maximum values ​​of the color difference value of each group of color stimuli among the color difference values ​​of each group of color stimuli corresponding to multiple observation perspectives; and selecting the color stimulus group whose ratio of the maximum to the minimum value of the color difference value of each group of color stimuli is greater than a first threshold as the experimental color stimulus group to be matched.

[0008] In some embodiments, color correction of the matching color stimuli in the group of color stimuli to be corrected, based on the fitting parameters, includes: determining color correction parameters based on the fitting parameters; and color correction of the matching color stimuli in the group of color stimuli to be corrected, based on the color correction parameters.

[0009] In some embodiments, the color difference calculation method further includes: determining the color difference value of the color stimulus group to be corrected according to the target color matching function; and determining the ratio of the color difference value of the color stimulus group to be corrected to the color correction parameter to verify the fitting parameter.

[0010] In some embodiments, multiple observation perspectives are controlled by adjusting the color stimulus area of ​​the matching color stimulus in each group of color stimuli and the observation distance in the observation strategy.

[0011] In some embodiments, the angular difference between adjacent viewing angles in a plurality of viewing angles is less than a second threshold.

[0012] In some embodiments, when the color stimulus is reproduced by a display device, the first spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the target color stimulus, and the second spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the matching color stimulus.

[0013] In some embodiments, the spectral half-wave bandwidth in the second spectral parameter is less than the third threshold.

[0014] In some embodiments, the color difference calculation method further includes: when the color stimulus is reproduced by the display device, adjusting the white field parameters of one or more sets of color stimuli to make the colors of one or more sets of color stimuli displayed uniformly.

[0015] In some embodiments, the set of color matching functions corresponding to each observation viewpoint is determined based on multiple observation viewpoints in the observation strategy and the physiological parameters of the observer.

[0016] According to some embodiments of the second aspect of this disclosure, a color difference calculation apparatus is provided, comprising: an acquisition unit configured to acquire one or more sets of color stimuli, wherein each set of color stimuli includes a target color stimulus and a matching color stimulus, the target color stimulus having a first spectral parameter and the matching color stimulus having a second spectral parameter; an adjustment unit configured to adjust the primary color ratio of each set of color stimuli for each of multiple observation perspectives in an observation strategy until color matching of each set of color stimuli is completed; a first determination unit configured to determine the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli based on the spectral energy distribution of the target color stimulus in each set of color stimuli, the spectral energy distribution of the matching color stimulus in each set of color stimuli, and a set of color matching functions corresponding to each observation perspective; and a second determination unit configured to determine the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli based on the spectral energy distribution of the target color stimulus in each set of color stimuli, the spectral energy distribution of the matching color stimulus in each set of color stimuli, and a set of color matching functions corresponding to each observation perspective; and a second determination unit configured to determine the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli based on the spectral energy distribution of the target color stimulus in each set of color stimuli. The system comprises five units: a first unit and a second unit; a third unit; a fourth unit; a fifth unit; a sixth unit; and a seventh unit. The first unit is configured to determine the color difference between the object and the matching color stimulus, and to determine the average color difference of one or more groups of color stimuli corresponding to each observation viewpoint. The second unit is configured to: ...

[0017] According to some embodiments of the third aspect of this disclosure, a color difference calculation apparatus is provided, including: a memory and a processor coupled to the memory, the processor being configured to execute the color difference calculation method of any of the above embodiments based on instructions stored in the memory.

[0018] According to some embodiments of the fourth aspect of this disclosure, a color difference calculation system is provided, comprising: one or more groups of color stimuli; a group of color stimuli to be corrected; and the color difference calculation device in any of the above embodiments.

[0019] According to some embodiments of the fifth aspect of this disclosure, a computer-readable storage medium is provided having computer instructions stored thereon that, when executed by a processor, implement the color difference calculation method of any of the above embodiments.

[0020] According to some embodiments of the sixth aspect of this disclosure, a computer program product is provided, including computer instructions that, when executed by a processor, implement the color difference calculation method in any of the above embodiments.

[0021] In the above embodiments, by acquiring one or more sets of color stimuli and performing color matching on them, a diverse and accurate matching environment is constructed for the color matching method. This helps ensure the accuracy and versatility of the color correction process and makes the subsequently determined color matching function applicable to the color correction of various color stimuli. By determining the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each set of color stimuli, the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli corresponding to each color matching function at each observation angle is determined, as well as the target color difference value in all sets of color stimuli corresponding to each color matching function at each observation angle. The average color difference between the stimulus and the matching color stimulus helps in the subsequent division of observation viewpoints and the selection of target color matching functions corresponding to the observation viewpoint intervals based on the average color difference. This provides feasibility for assigning different color matching functions to different observation viewpoint intervals to ensure the accuracy of the color correction process. By dynamically dividing multiple observation viewpoints based on the average color difference to obtain multiple observation viewpoint intervals, and determining different color matching functions for different observation viewpoint intervals, the accuracy and flexibility of the color correction process can be improved, and the universality of the color matching functions can also be ensured. Color correction can improve the consistency and accuracy of colors of different color stimuli, which helps to meet the needs of high-quality color display, transmission, and reproduction. Attached Figure Description

[0022] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0023] This disclosure can be more clearly understood with reference to the accompanying drawings and the following detailed description.

[0024] Figure 1 Schematic diagrams illustrating some embodiments of the color difference calculation method of this disclosure are shown.

[0025] Figure 2 Schematic diagrams illustrating some embodiments of the RGB three primary color spectral energy distribution curves of a target device in one or more display devices of this disclosure.

[0026] Figure 3 Schematic diagrams illustrating some embodiments of the RGB three primary color spectral energy distribution curves of matching devices in one or more sets of display devices disclosed herein.

[0027] Figure 4 The diagram illustrates some embodiments of the color difference values ​​determined by a subset of the color matching functions in this disclosure for each matching color stimulus at each viewing angle.

[0028] Figure 5 The diagram illustrates some embodiments of the target color matching function of this disclosure for each matching color stimulus at each viewing angle, showing the color difference value.

[0029] Figure 6 Schematic diagrams showing some embodiments of the color difference calculation apparatus of this disclosure are provided.

[0030] Figure 7 Schematic diagrams showing other embodiments of the color difference calculation apparatus of this disclosure are shown.

[0031] Figure 8 Schematic diagrams illustrating some embodiments of the color difference calculation system of this disclosure are shown. Detailed Implementation

[0032] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0033] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0034] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0035] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0036] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0038] With the development of display devices, the demand for large color gamuts in display devices is increasing. Large color gamuts can enrich color expression and enhance visual experience. However, the red, green and blue primary colors of large color gamut display devices need to have narrow spectral bandwidth. That is, large color gamut display devices rely on narrow band spectra and expand color mixing paths, which significantly increases the diversity of spectral combinations, thereby amplifying the metamerism phenomenon observed by the observer.

[0039] Similarly, in the packaging and printing industry, when workers are mixing inks, the spectral differences between printed samples and standard samples due to variations in ink composition between batches of printed products can lead to metamerism. This spectral difference can amplify metamerism to some extent, meaning that different observers may perceive different color differences between standard and printed samples under the same observation conditions. In particular, as observers age, their lenses and macula of the retina undergo varying degrees of aging, which can amplify metamerism between younger and older observers.

[0040] The CIE (International Commission on Illumination) proposed the CIE 1931 2° color matching function in 1931, applicable to color calculations within a viewing angle range of 1° to 4°. In 1964, it proposed the CIE 1964 10° color matching function, applicable to color calculations within a viewing angle range greater than 4°. In 2006, it proposed the CIE 2006 color matching function calculation model, taking into account the observer's age (20 to 80 years) and viewing angle (1° to 10°). Based on the 2006 color matching function, in 2015, the CIE recommended the use of two sets of color matching functions: CIE 2006 2° (viewing angle less than 4°) and CIE 2006 10° (viewing angle greater than 4°), for the chromaticity calculation of color stimuli (such as display devices and printed products).

[0041] Currently, color management software often uses the CIE 1931 2° color matching function to calculate and correct colors between different displays, between displays and reflective colors, and between reflective colors. When the target color stimulus and the matching color stimulus have the same (or similar) chromaticity values, the human eye's visual perception will have a large inconsistency (called observer metamerism), and color difference calculation defects have appeared.

[0042] Considering the color display differences among diverse color stimuli (observer metamerism), selecting an appropriate color matching function to perform color correction between different color stimuli (i.e., between display devices, between display screens and reflected colors, and between reflected colors and reflected colors) has become a technical challenge that urgently needs to be solved in this field.

[0043] The following are specific methods for color correction of color stimuli to overcome observer metamerism.

[0044] Figure 1 Schematic diagrams illustrating some embodiments of the color difference calculation method of this disclosure are shown.

[0045] like Figure 1 As shown, the color difference calculation method includes steps 110 to 190, and the color difference calculation method is executed by a color difference calculation device.

[0046] In step 110, one or more sets of color stimuli are obtained, wherein each set of color stimuli includes a target color stimulus and a matching color stimulus, the target color stimulus having a first spectral parameter and the matching color stimulus having a second spectral parameter.

[0047] For example, color stimuli include at least one of display devices and printed products.

[0048] In some embodiments, when the color stimulus is reproduced by a display device, the first spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB (red, green, blue) primary colors of the target color stimulus, and the second spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the matching color stimulus.

[0049] For example, the target color stimulus in one or more sets of color stimuli can be presented by different brands and models of display devices commonly used in commercial applications, such as mobile phones, tablets and office displays. The presentation methods of the target color stimulus are also diverse, such as LCD (Liquid Crystal Display), LED or OLED.

[0050] In some embodiments, the target color stimulus may also be a variety of commercially available printed products.

[0051] In some embodiments, when the color stimulus is reproduced by the display device, the brightness of the target color stimulus and the matching color stimulus in one or more sets of display devices (color stimuli) can be adjusted to the highest level in order to better represent the color rendering performance of one or more sets of display devices.

[0052] For example, a first spectral parameter of the target color stimulus and a second spectral parameter of the matching color stimulus in one or more groups of color stimuli can be measured by a spectroradiometer, thereby determining the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each group of color stimuli.

[0053] In some embodiments, the first spectral parameters of the target color stimulus and the second spectral parameters of the matching color stimulus are different. Taking the color stimulus reproduced by a display device as an example, the difference between the first spectral parameters of the target color stimulus and the second spectral parameters of the matching color stimulus is mainly the shift in the peak wavelength positions of the three primary colors of red, green and blue. Such a setting provides feasibility for creating observer metamerism and can amplify the observer metamerism between the target color stimulus and the matching color stimulus.

[0054] Color stimuli are not limited to colors reproduced by display devices and printing methods, but include any color reproduced by a color rendering method with a different primary color spectrum.

[0055] In step 120, for each of the multiple observation perspectives in the observation strategy, the primary color ratio of each group of color stimuli is adjusted until the color matching of each group of color stimuli is completed.

[0056] If the color stimuli are reproduced by a display device, the primary colors of each set of color stimuli are the RGB primary colors (red, green, and blue). If the color stimuli are reproduced by printing, the primary colors of each set of color stimuli are the CMYK primary colors (cyan, magenta, yellow, and black).

[0057] For example, multiple observation perspectives are controlled by adjusting the area of ​​the matching color stimulus in each group of color stimuli and the observation distance in the observation strategy.

[0058] In step 130, the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli is determined based on the spectral energy distribution of the target color stimulus in each group of color stimuli, the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle.

[0059] In some embodiments, the set of color matching functions corresponding to each observation viewpoint is determined based on multiple observation viewpoints in the observation strategy and the physiological parameters of the observer.

[0060] By taking into account the observer's physiological parameters in determining the set of color matching functions corresponding to each observation viewpoint, the accuracy of the set of color matching functions is ensured, thereby improving the accuracy and robustness of the target color matching function and ensuring the accuracy and robustness of the color correction process.

[0061] For example, the set of color matching functions includes the CIE 1931 2° color matching function, the CIE 1964 10° color matching function, the CIE 2006 1° to 10° color matching functions, and the classification observer color matching function optimized by changing 10 physiological parameters such as the observer's age and perspective based on Asano's observer physiological model.

[0062] In some application examples, the set of color matching functions includes the CIE-recommended color matching functions (CIE 193 12° and CIE 196 4 10°, CIE 2006 1° to 10°), as well as the categorical color matching functions A1 to A10 for 2° and 10° viewing angles generated by Asano based on the following formula (1), and the categorical color matching functions S1 to S8 for 10° viewing angles obtained by Sarkar based on cluster analysis, totaling 40 color matching functions.

[0063] lms-CMFs=f(a,v,d lens ,d macula ,d L ,d M ,d S ,s L ,s M ,s S (1)

[0064] Here, lms-CMFs represents the cone cell responses at different wavelengths (L, M, S), i.e., color matching function responses. 'a' represents the observer's age, and 'v' represents the viewing angle. Additionally, eight physiological parameters were added to simulate the cone cell spectral responses of observers with normal color vision, specifically the lens pigment density d. lens macular pigment density d macula d L d M d S The optical pigment density shift of L, M, and S cone cells; s L s M s S The peak wavelength positions of L, M, and S cone cells are λ. max Offset. Substitute the physiological parameter model in formula (1) for calculation, and optimize the peak wavelength offset and peak value of the classification color matching functions A1 to A10 generated by Asano based on formula (1) at 2° and 10° viewpoints in the L, M, and S channels according to the experimental results and optimization objectives.

[0065] In step 140, the average color difference of one or more groups of color stimuli corresponding to each observation angle is determined based on the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli.

[0066] In step 150, multiple viewing angles are divided according to the average color difference to obtain multiple viewing angle intervals.

[0067] For example, multiple viewing angle intervals can be small, medium, and large viewing angle intervals. These intervals are divided based on the average color difference at different viewing angles, and different viewing angle intervals can correspond to different color matching functions. Taking multiple viewing angles of 2°, 4°, 6°, and 8° as an example, assuming the minimum average color difference for 2° and 4° corresponds to the same color matching function, then 2° and 4° can be divided into one viewing angle interval. Assuming the minimum average color difference for 6° and 8° corresponds to different color matching functions, then 6° is divided into one viewing angle interval, and 8° into another. Those skilled in the art should understand that this is merely an example, and viewing angle intervals can be divided according to actual circumstances.

[0068] In step 160, the minimum value of the average color difference of the set or more sets of color stimuli corresponding to each observation viewpoint in each observation viewpoint interval is determined, and the color matching function corresponding to the minimum value is determined as the target color matching function for the corresponding observation viewpoint interval.

[0069] In some embodiments, the target color matching function corresponding to each viewing angle range can be the same.

[0070] In step 170, the color difference values ​​of the color stimulus group to be matched in one or more groups of color stimuli are determined from multiple viewing angles by using the target color matching function.

[0071] For example, the set of color stimuli to be matched can be a set of color stimuli selected from one or more sets of color stimuli that can amplify the observer's metamerism.

[0072] In step 180, fitting parameters are determined based on the color difference values ​​of the color stimulus group to be matched under multiple viewing angles.

[0073] For example, the process of determining the fitting parameters involves fitting a mathematical regression relationship between multiple observation viewpoints and the color difference values ​​of the color stimulus group to be matched under the corresponding observation viewpoints. That is, drawing a scatter plot of the color difference values ​​of multiple observation viewpoints and the color stimulus group to be matched under the corresponding observation viewpoints, and performing mathematical regression fitting. The optimization objective of the mathematical regression relationship is to minimize the average absolute value of the difference between the predicted color difference calculated based on the fitting parameters under different observation viewpoints and the color difference value calculated by the target color matching function determined based on the color matching experiment (i.e., the color difference values ​​of the color stimulus group to be matched under multiple observation viewpoints).

[0074] In step 190, color correction is performed on the matching color stimuli in the group of color stimuli to be corrected, based on the fitting parameters.

[0075] By fitting parameters, the matching color stimuli in the set of color stimuli to be corrected are color corrected so that the color difference calculation results can be consistent with human visual perception, which is a color difference that is just perceptible to the human eye.

[0076] In the above embodiments, by acquiring one or more sets of color stimuli and performing color matching on them, a diverse and accurate matching environment is constructed for the color matching method. This helps ensure the accuracy and versatility of the color correction process and helps the subsequently determined color matching function to be applicable to the color correction of various color stimuli. By determining the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each set of color stimuli, the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli corresponding to each color matching function at each observation angle is determined, as well as the color difference value between the target color stimulus and the matching color stimulus in all sets of color stimuli corresponding to each color matching function at each observation angle. The average color difference between viewing angles helps in subsequent segmentation of viewing angles and the selection of target color matching functions corresponding to the viewing angle intervals based on the average color difference. This provides feasibility for assigning different color matching functions to different viewing angle intervals to ensure the accuracy of the color correction process. By dynamically segmenting multiple viewing angles based on the average color difference, multiple viewing angle intervals are obtained, and different color matching functions are determined for different viewing angle intervals. This improves the accuracy and flexibility of the color correction process and ensures the universality of the color matching functions. Color correction can improve the consistency and accuracy of different color stimuli (e.g., self-emissive colors presented by display devices or different printing colors), which helps to meet the needs of high-quality color display, transmission, and reproduction.

[0077] The following describes how to obtain one or more sets of color stimuli and how to complete the color matching of each set of color stimuli. The following description takes the display device reproduction based on the color stimuli as an example. The same applies to printed products, which will not be repeated here. The specific steps are as follows: (1) to (7).

[0078] In step (1), multiple commercially available display devices (e.g., 55 mobile phones of different brands and models) are selected as target devices, and the display brightness of the target devices is adjusted to the highest level. A spectroradiometer is used to measure the spectral energy distribution of the red, green and blue primary colors of the target devices to obtain the first spectral parameters of different target devices.

[0079] For example, set three uniform color patches that the target device can display: the most saturated red (R=255, G=0, B=0), green (R=0, G=255, B=0), and blue (R=0, G=0, B=255). Use a spectroradiometer to measure and plot the spectral energy distribution curve of the target device.

[0080] Figure 2 Schematic diagrams illustrating some embodiments of the RGB three primary color spectral energy distribution curves of a target device in one or more display devices of this disclosure.

[0081] In some application examples, 55 mobile devices of different brands and models (named No. 1 to No. 55) were selected as target devices, involving LCD, LED, and OLED color rendering methods. With the display brightness set to maximum, a spectroradiometer was used to measure the spectral energy distribution of the red, green, and blue primary colors of the target devices, obtaining the first spectral parameters of the target devices. The measurement results are as follows: Figure 2 As shown, the range of primary color spectra of commonly used mobile phone displays of different brands and models currently on the market is as follows: red channel (201): 616nm-630nm, green channel (202): 528nm-540nm, and blue channel (203): 449nm-465nm. Since the range of green and blue channels of each target device does not exceed 16nm, for convenience, they can be uniformly regarded as display devices of the same spectral parameter type. In subsequent analysis, the average peak values ​​of the red, green and blue primary colors of the above target devices are taken as 625nm-533nm-460nm, respectively.

[0082] In step (2), a display device with spectral parameters different from the first spectral parameter of the target device is selected as a matching device, forming multiple combinations of target devices and matching devices.

[0083] Figure 3 Schematic diagrams illustrating some embodiments of the RGB three primary color spectral energy distribution curves of matching devices in one or more sets of display devices disclosed herein.

[0084] In some applications, a six-channel (R1R2G1G2B1B2) LED self-emissive panel is selected as a matching device in one or more display devices. A spectroradiometer is used to measure the spectral energy distribution of the red, green, and blue primary colors in the matching device. Combining different primary colors from the six-channel LED panel can create four matching devices: L1 (R1G2B1), L2 (R2G2B1), L3 (R1G1B1), and L4 (R1G2B2). For example... Figure 3 As shown, the half-wave spectral bandwidth of the L1 to L4 matching devices does not exceed 35 nm, and the spectral curves are relatively smooth, belonging to the narrow spectral bandwidth category. Figure 3 As shown, the spectral peak position of channel R2 is 676nm, the spectral peak position of channel R1 is 636nm, the spectral peak position of channel G2 is 524nm, the spectral peak position of channel G1 is 508nm, the spectral peak position of channel B2 is 472nm, and the spectral peak position of channel B1 is 448nm. The spectral peak positions of these six channels are all different. The L2, L3, and L4 matching devices changed the red, green, and blue primary colors respectively compared to the L1 matching device, and their spectral peaks were shifted accordingly.

[0085] The primary color spectrum and white parameters (white field chromaticity information) of the matching device are shown in Table 1, and the differences between the first spectral parameters of the target device and the second spectral parameters of the matching device are shown in Table 2.

[0086] Table 1. Primary color spectrum and white field chromaticity information of the matching device

[0087]

[0088] Table 2. Differences between the first and second spectral parameters.

[0089]

[0090] In step (3), the target device and the matching device are preheated for a specific time (e.g., the target device and the matching device are turned on and made to display colors for 30 minutes). After the target device and the matching device are stable, the white point parameters of the target device and the matching device are adjusted so that the white point parameters of the target device and the matching device are the same or similar (e.g., the color temperature can be adjusted to the range of 5000K to 7000K, and the luminous intensity can be adjusted to 85cd / m²). 2 ~95cd / m 2 Within the range), and ensure that the white field parameters of the target device and the matching device meet the requirements of the color matching experiment.

[0091] For example, to ensure color display stability, measurements should begin 30 minutes after power-on, once the color displays of both the target and matching devices have stabilized. Using a spectroradiometer, at a distance of 40-60cm from the color center (the measurement distance can be adjusted according to the size of the color area), perpendicular to the color center, collect spectral energy distributions at four positions: upper left, upper right, lower left, and lower right. Substitute these spectral energy distributions into the CIE 1964 10° color matching function to calculate the chromaticity value. Compare this chromaticity difference with the color at the center of the display screen. When the color difference value Δ(u'v') calculated based on the CIE 1964 10° color matching function is within one just-perceptible color difference threshold range (≈0.004), the uniformity of the target or matching device is considered to meet the requirements of the color matching experiment.

[0092] In step (4), white is selected as the target color and displayed in full screen on the target device.

[0093] For example, the display size for full-screen display is generally 7cm × 7cm.

[0094] Display a white close to the white point on the target device to facilitate white point parameter adjustment for different target devices and matching devices. The white is displayed in full screen on the target device.

[0095] In step (5), observers with normal color vision are organized to conduct color matching experiments between different display devices (target device and matching device) involving different viewing angles.

[0096] For example, an observer with normal color vision could be a young observer with normal color vision.

[0097] In some embodiments, before the color matching experiment, a color matching experimental setup is constructed, and the target device and the matching device are placed side by side. The size of the color displayed on the target device remains unchanged. According to different observation angle requirements, square windows of different sizes are set to change the size of the color displayed on the matching device. The size of the colors displayed on the target device and the matching device may be the same or different. To ensure the accuracy of the color matching experiment, the target device and the matching device should be placed without gaps, and the color displayed on the matching device should be at the same height from the observation plane as the color displayed on the target device. During the experiment, to avoid interference from other stray light, the observation environment is a dark room. The observer performs color matching by adjusting the red (R), green (G), and blue (B) primary color driving values ​​of the matching device until the color displayed in the center of the matching device is perceived to be the same as the color displayed on the target device, thus achieving color matching.

[0098] Different viewing angles need to take into account different forms of commercial electronic display products, such as mobile phones, tablets, and office displays. They need to cover continuously changing viewing angles such as 2°, 4°, 6°, 8°, and 10°, and the viewing angle range needs to be greater than 20°.

[0099] In some application examples, 77 young observers with normal color vision were organized. Each observer used their own mobile phone as the target device and conducted a color matching experiment with the four matching devices determined in step (2). The center of the color stimulus presented by the matching device and the center of the color stimulus presented by the target device were at the same height from the horizontal table where the display device was placed. A white stimulus was displayed on the target device, and the observer sat directly in front of the display device to perform color matching. The observer's line of sight had to be perpendicular to the display device.

[0100] In step (6), after the observer completes the color matching, the spectral energy distribution of the currently displayed color on the target device and the spectral energy distribution of the color after the observer has performed color matching on different matching devices are measured by a spectroradiometer.

[0101] For example, in the process of measuring the first and second spectral parameters using a spectroradiometer, the spectroradiometer can be used at the observer's visual observation position, at a distance of 50cm from the target device and the matching device (where 50cm is just an example and the measurement distance can be adjusted according to the size of the color area). The measurement direction of the spectroradiometer's measuring head must be perpendicular to the color displayed in the central area of ​​the display device.

[0102] In step (7), the size of the target device (or the light-emitting area of ​​the target device) is kept constant. By changing the size of the light-emitting area of ​​the matching device and the distance between the observer and the display device (i.e., the group of display devices) (i.e., the observation distance), different viewing angles that gradually increase from small to large are obtained. Steps (5) to (6) are repeated to conduct color matching experiments under different viewing angles, and the spectral energy distribution of the current display color of the target device and the spectral energy distribution of the color after the observer has performed color matching on different matching devices are obtained under different viewing angles.

[0103] For example, the target color stimulus and the matching color stimulus can have the same or different areas. When switching between different viewing angles, the observer's gaze direction remains perpendicular to the center of the displayed color (i.e., the central area of ​​the color stimulus), requiring only adjustments to the size of the displayed color or the viewing distance. Specifically, if the color stimulus is reproduced using a display device, the area of ​​the color stimulus refers to the light-emitting area of ​​the display device; if the color stimulus is reproduced using a printing method, the area of ​​the color stimulus refers to the area of ​​the printed product.

[0104] The following application example will be described using color stimuli as an example of display device reproduction.

[0105] In some applications, by changing the size of the luminous area of ​​the matching device and the observation distance, 11 different viewing angles are formed, specifically: 2°, 4°, 6°, 8°, 10°, 12.6°, 16°, 19.3°, 24°, 28° and 32°; the changes in the viewing angle are continuous and involve 3 angles greater than 20°; Table 3 shows the correspondence between the viewing angle, the size of the luminous area of ​​the matching device (also known as the window size), and the observation distance.

[0106] Table 3 shows the viewing angle determined by the window size and viewing distance of the matching equipment.

[0107]

[0108]

[0109] In some application examples, among 77 observers, 11 conducted color matching experiments based on 11 viewing angles across 4 matching devices, with each participant repeating the experiment 3 times. The remaining 66 observers were divided into two groups: one group of 33 observers conducted color matching experiments based on L1 and L3 matching devices, and the other group of 33 observers conducted color matching experiments based on L2 and L4 matching devices, with each participant performing one match. Based on each set of display devices, a total of 66 sets of matching data were collected across 11 viewing angles; for the 4 matching devices, a total of 2904 sets of experimental data were collected (i.e., 11 viewing angles × 66 sets of matching data × 1 color stimulus × 4 matching devices). Subsequently, the spectral energy distribution of the 66 sets of matching data will be substituted into a set of color matching functions to obtain the first chromaticity value (the chromaticity value of the target device in each set of display devices) and the second chromaticity value (the chromaticity value of the matching device in each set of display devices) calculated by different color matching functions at each viewing angle for each set of display devices.

[0110] The following describes how to determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli, as follows.

[0111] In some embodiments, determining the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli, based on the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle, includes: inputting the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each group of color stimuli to each color matching function in the set of color matching functions; determining a first chromaticity value of the target color stimulus and a second chromaticity value of the matching color stimulus corresponding to each color matching function; determining the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to each color matching function based on the first chromaticity value and the second chromaticity value; and determining the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to the set of color matching functions based on the color difference value corresponding to each color matching function.

[0112] For example, the first chromaticity value of the target color stimulus corresponding to each color matching function under each observation view can be the chromaticity value of white presented on the target device, and the second chromaticity value of the matching color stimulus can be the chromaticity value of white matched by the observer under different viewpoints. The first and second chromaticity values ​​include XYZ (tristimulus values) and u'v' (chromaticity coordinates).

[0113] In some embodiments, the color difference value corresponding to each color matching function is the color difference between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to each color matching function under each observation view. If there are multiple observers for a certain group of color stimuli, the color difference value corresponding to each color matching function for a certain group of color stimuli is the mean of the color difference values ​​corresponding to the colors matched by all observers under each color matching function under each observation view. That is, different color matching functions are used to calculate the Δ(u'v') value (i.e., the color difference value corresponding to each color matching function) between the colors matched by all observers for the same group of target color stimuli and matching color stimuli (i.e., the same group of color stimuli) under a given observation view; based on the calculated minimum Δ(u'v') value, a color matching function suitable for color correction under different observation views between the target color stimulus and matching color stimuli (i.e., the group of color stimuli) is recommended, where different observation views can correspond to different color matching functions.

[0114] For example, the color matching function corresponding to the smallest color difference value in each set of color stimuli can be determined as the color matching function that best matches the spectral response of the observer's cone cells under the current viewing angle, based on the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli corresponding to each color matching function.

[0115] Figure 4 The diagram illustrates some embodiments of the color difference values ​​determined by a subset of the color matching functions in this disclosure for each matched color stimulus at each viewing angle, with the example of the color stimulus being reproduced by a display device.

[0116] In some application examples, under different viewing angles (FOVs) (2°, 4°, 6°, 8°, 10°, 12.6°, 16°, 19.3°, 24°, 28°, 32°), based on four different matching devices (L1 to L4), the mean Δ(u'v') value (i.e., the color difference value corresponding to each color matching function) of all observers matching white (using white as an example, other colors are also acceptable) is calculated. The color matching function with the smallest Δ(u'v') value (i.e., the smallest color difference value corresponding to each color matching function) is determined as the most suitable color matching function for that group of targets and matching devices (i.e., that group of display devices) under that viewing condition. Figure 4 Using L1 to L4 as matching devices, the top 11 preferred color matching functions (denoted as No.1 to No.11) are selected (wherein, the top 11 color matching functions refer to the color matching functions with the smallest color difference values ​​between the target device and the matching device in each group of display devices, corresponding to each color matching function). A line graph is calculated showing the Δ(u'v') (i.e., the color difference value corresponding to each color matching function) of white matched with the target device under different viewing angles.

[0117] like Figure 4 As shown, Figure 4 (a) in the graph shows the Δ(u'v') line graph of the L1 matching device and the target device matching white under different viewing angles, calculated by the top 11 preferred color matching functions. Figure 4 (b) shows a line graph of the Δ(u'v') of the L2 matching device and the target device matching white under different viewing angles, calculated using the top 11 preferred color matching functions. Figure 4 (c) in the graph represents the Δ(u'v') line graph of the L3 matching device and the target device matching white under different viewing angles, calculated using the top 11 preferred color matching functions. Figure 4 (d) is the preferred top 11 color matching functions that calculate the Δ(u'v') line graph of white matching between the L4 matching device and the target device under different viewing angles.

[0118] Depend on Figure 4It can be seen that, under various observation views, the color difference values ​​corresponding to each color matching function between the target device and the L1 matching device, and between the target device and the L2 matching device, are relatively small and stable for each of the top 11 color matching functions. This indicates that there is no significant observer metamerism between the target device and the L1 matching device, nor between the target device and the L2 matching device. However, under some observation views, the color difference values ​​corresponding to each of the top 11 color matching functions between the target device and the L3 matching device, and between the target device and the L4 matching device, are relatively large and unstable. This indicates that there is significant observer metamerism between the target device and the L3 matching device, and also between the target device and the L4 matching device.

[0119] In addition, taking the reproduction of color stimuli by a display device as an example, according to Figure 4 As shown in the results, when selecting display devices to be matched from one or more groups of display devices (also known as groups of color stimuli to be matched or groups of display devices to be matched), the target device and L3 matching device, and the target device and L4 matching device can be identified as display devices to be matched.

[0120] In some embodiments, the average color difference of one or more sets of color stimuli corresponding to each observation viewpoint in step 140 is the average of the color difference values ​​of all color stimuli corresponding to each color matching function under each observation viewpoint. If there are multiple observers for a certain set of color stimuli, the average color difference is the mean of the average color difference of the colors matched by all observers for all color stimuli corresponding to each color matching function under each observation viewpoint. That is, based on the color difference value corresponding to each color matching function, under the condition of the same observation viewpoint, the average value of the Δ(u'v') value of the colors matched by all observers based on the combination of all target color stimuli and matching color stimuli (all sets of color stimuli) is taken (i.e., the average color difference); the calculation results of the average Δ(u'v') value between all target color stimuli and matching color stimuli under different observation viewpoints are statistically analyzed; based on the calculated minimum Δ(u'v') value, the color matching function under different observation viewpoints is preferred, and the selection of the color matching function is independent of the spectral differences between the target color stimuli and the matching color stimuli.

[0121] In some embodiments, the color matching function corresponding to the minimum average color difference can be determined by the average color difference of one or more sets of color stimuli corresponding to each viewing angle. This color matching function is the one that best matches the spectral response of the observer's cone cells under the current viewing angle, based on the average color difference of one or more sets of color stimuli.

[0122] The following application example is described using the reproduction of color stimuli by a display device.

[0123] In some application examples, taking color matching functions No.1 to No.11 as examples, the average color difference of one or more sets of display devices (i.e. all display devices) corresponding to each viewing angle refers to the average color difference value of all observers based on the four matching device combinations from L1 to L4 and corresponding to each color matching function under different viewing angles, as shown in Table 4.

[0124] Table 4. Calculation performance of different color matching functions under different viewing angles.

[0125]

[0126] As shown in Table 4, for an observation angle of 2°, the average color difference of all display devices calculated by color matching function No.9 is the smallest, indicating that color matching function No.9 performs best. The average color difference of all display devices calculated by color matching functions No.1 and No.10 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.1 and No.10 perform reasonably well.

[0127] For a viewing angle of 4°, the average color difference of all display devices calculated by color matching function No.2 is the smallest, indicating that color matching function No.2 performs best. The average color difference of all display devices calculated by color matching functions No.3 and No.9 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.3 and No.9 perform reasonably well.

[0128] For a viewing angle of 6°, the average color difference of all display devices calculated by color matching function No.3 is the smallest, indicating that color matching function No.3 performs best. The average color difference of all display devices calculated by color matching functions No.2 and No.4 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.2 and No.4 perform reasonably well.

[0129] For an 8° viewing angle, the average color difference of all display devices calculated by color matching function No.4 is the smallest, indicating that color matching function No.4 performs best. The average color difference of all display devices calculated by color matching functions No.3 and No.5 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.3 and No.5 perform reasonably well.

[0130] For a viewing angle of 10°, the average color difference of all display devices calculated by color matching function No.4 is the smallest, indicating that color matching function No.4 performs best. The average color difference of all display devices calculated by color matching functions No.3 and No.5 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.3 and No.5 perform reasonably well.

[0131] For a viewing angle of 12.6°, the average color difference of all display devices calculated by color matching function No.11 is the smallest, indicating that color matching function No.11 performs best. The average color difference of all display devices calculated by color matching functions No.5 and No.6 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.5 and No.6 perform reasonably well.

[0132] For a viewing angle of 16°, the average color difference of all display devices calculated by color matching function No.11 is the smallest, indicating that color matching function No.11 performs best. The average color difference of all display devices calculated by color matching functions No.5 and No.6 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.5 and No.6 perform reasonably well.

[0133] For an observation angle of 19.3°, the average color difference of all display devices calculated by color matching function No.11 is the smallest, which means that color matching function No.11 performs best. The average color difference of all display devices calculated by color matching functions No.6 and No.7 is less than the average color difference calculated by other color matching functions, which means that color matching functions No.6 and No.7 perform reasonably well.

[0134] For a viewing angle of 24°, the average color difference of all display devices calculated by color matching function No.11 is the smallest, indicating that color matching function No.11 performs best. The average color difference of all display devices calculated by color matching functions No.6 and No.7 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.6 and No.7 perform reasonably well.

[0135] For a viewing angle of 28°, the average color difference of all display devices calculated by color matching function No.11 is the smallest, indicating that color matching function No.11 performs best. The average color difference of all display devices calculated by color matching functions No.7 and No.8 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.7 and No.8 perform reasonably well.

[0136] For a viewing angle of 32°, the average color difference of all display devices calculated by color matching function No.11 is the smallest, indicating that color matching function No.11 performs best. The average color difference of all display devices calculated by color matching functions No.7 and No.8 is less than the average color difference calculated by other color matching functions, indicating that color matching functions No.7 and No.8 perform reasonably well.

[0137] In step 150, multiple viewing angles are divided to obtain multiple viewing angle intervals. Taking the average color difference of one or more display devices shown in Table 4 as an example, the viewing angles can be divided into three viewing angle intervals: small viewing angle interval (≤4°), medium viewing angle interval (4° to 10°), and large viewing angle interval (>10°). Color matching functions suitable for different viewing angle intervals are selected respectively, namely No.9 (small viewing angle interval), No.3 (medium viewing angle interval) and No.11 (large viewing angle interval).

[0138] The target color matching function corresponding to the observation viewpoint interval is described below with reference to Table 4.

[0139] Taking the small viewing angle range (≤4°), medium viewing angle range (4° to 10°), and large viewing angle range (>10°) as examples, for the small viewing angle range, the original target color matching function is the No.9 color matching function; for the medium viewing angle range, the original target color matching function is the No.3 color matching function; and for the large viewing angle range, the original target color matching function is the No.11 color matching function.

[0140] Table 4 shows that the No.9 color matching function calculates relatively small color difference values ​​for each display device in the narrow viewing angle range, but relatively large color difference values ​​in the medium and wide viewing angle ranges. The No.3 color matching function calculates relatively small color difference values ​​for each display device in the medium viewing angle range, and the differences are similar in the narrow and wide viewing angle ranges. The No.11 color matching function calculates relatively small color difference values ​​for each display device in the wide viewing angle range, but relatively large color difference values ​​in the narrow and medium viewing angle ranges.

[0141] In summary, color matching functions No. 9 or No. 11 can be assigned as the target color matching functions for the small, medium, and large viewing angle ranges. Alternatively, color matching function No. 9 can be assigned to the small viewing angle range, color matching function No. 3 to the medium viewing angle range, and color matching function No. 11 to the large viewing angle range. Those skilled in the art should understand that this is merely an example; color matching functions can be assigned according to actual conditions, as long as accurate fitting parameters are obtained. Furthermore, if the original target color matching function corresponding to each viewing angle range is assigned, the fitting parameters do not need to be verified, saving computational costs in the color difference calculation process.

[0142] Taking the reproduction of color stimuli by printing as an example, for reflected colors reproduced by printing, since the composition of its primary color spectrum is relatively flat, and the evaluation of the color quality of the product mainly involves a large area of ​​uniform color, it is generally recommended to use the No.11 color matching function to calculate the chromaticity value and color difference of the product, which can effectively avoid the phenomenon of metamerism between observers in different application scenarios.

[0143] The following describes how to determine the color difference values ​​of the set of color stimuli to be matched under multiple viewing angles, as detailed below.

[0144] In some embodiments, determining the color difference value of a group of color stimuli to be matched in one or more groups of color stimuli under multiple viewing angles by using a target color matching function includes: determining the viewing angle interval to which each viewing angle belongs in the multiple viewing angles; determining a target color matching function corresponding to the viewing angle interval to which each viewing angle belongs; determining the color difference value of the group of color stimuli to be matched under each viewing angle by using the target color matching function; and determining the color difference value of the group of color stimuli to be matched under multiple viewing angles by using the color difference value of the group of color stimuli to be matched under each viewing angle.

[0145] For example, a set of color stimuli to be matched refers to a set of color stimuli in which the observer shows significant metamerism among one or more sets of color stimuli.

[0146] Determining different target color matching functions for different observation viewpoints allows for the allocation of color matching functions based on specific attributes of color difference values ​​within the observation viewpoint range. This improves the accuracy and robustness of the fitting parameters, thereby effectively ensuring the accuracy and robustness of the color difference calculation method.

[0147] The method for determining the set of color stimuli to be matched is described below.

[0148] In some embodiments, the color difference value of each group of color stimuli corresponding to multiple viewing angles is determined by a target color matching function; the minimum and maximum values ​​of the color difference value of each group of color stimuli are determined among the color difference values ​​of each group of color stimuli corresponding to multiple viewing angles; and the color stimulus group whose ratio of the maximum to the minimum color difference value of each group of color stimuli is greater than a first threshold is selected as the color stimulus group to be matched.

[0149] For example, the first threshold can be 2.5.

[0150] By determining the color difference value of each group of color stimuli, the degree of observer metamerism of each group of color stimuli is determined. Color stimuli with a higher degree of observer metamerism are selected as the group of color stimuli to be matched. Subsequently, the color difference value of the group of color stimuli to be matched is used for fitting, which helps to improve the robustness and accuracy of the fitting parameters, thereby improving the robustness and accuracy of the color difference calculation process.

[0151] In some embodiments, the color difference value of each set of color stimuli is calculated using the target color matching function corresponding to the observation view interval to which each observation view belongs.

[0152] Figure 5 The diagram illustrates some embodiments of the target color matching function of this disclosure for each matched color stimulus at each viewing angle. For example, the color stimulus includes an autoreflective color reproduced by a display device, as illustrated by the example of a color stimulus reproduced by a display device.

[0153] In some applications, the color difference value of each display device at each viewing angle can be calculated separately using a color matching function applicable to a small viewing angle range (target color matching function) and a color matching function applicable to a large viewing angle range (target color matching function).

[0154] Figure 5 In the diagram, (a) represents the color matching function (No. 9) applicable to the small viewing angle range, calculating the color difference value for each display device at each viewing angle. Figure 5 In the diagram, (b) represents the color matching function (No. 11) applicable to a wide viewing angle range, which calculates the color difference value for each set of display devices at each viewing angle.

[0155] like Figure 5 As shown, for L1 and L2 matching devices, the calculation result of the color matching function is not significantly related to the viewing angle. Three color matching functions corresponding to any three viewing angle intervals can be selected for calculation.

[0156] The following example, using the reproduction of color stimuli by a display device, illustrates the process of fitting the color difference values ​​of the set of color stimuli to be matched under multiple viewing angles.

[0157] like Figure 5 As shown, the color stimulus group to be matched includes the combination of the target device and the L3 matching device, and the combination of the target device and the L4 matching device. In order to improve the universality of the calculation results, the average of the Δ(u'v') values ​​calculated under the L3 and L4 matching devices can be taken as the device combination in the color stimulus group to be matched. By drawing scatter plots of the color difference values ​​of the color stimulus group to be matched under different observation angles, the numerical regression relationship shown in formula (2) is fitted. The fitting parameters obtained by fitting different color matching functions are shown in Table 5.

[0158] ΔE Predict =a×FOV b +c (2)

[0159] Where FOV represents the viewing angle, ΔE Predict This represents the color difference value of the set of color stimuli to be matched at each viewing angle, calculated by the target color matching function. This color difference value can be the Euclidean distance (Δ(u'v')) between the chromaticity coordinates of the target color stimulus and the matching color stimulus, or the ΔE value based on the CIELAB color space. * ab Value, or ΔE 00 Values, etc.

[0160] Table 5. Fitting parameter results for different color difference calculation formulas.

[0161]

[0162] The following describes how to perform color correction based on the fitted parameters.

[0163] In some embodiments, color correction of the matching color stimuli in the group of color stimuli to be corrected, based on the fitting parameters, includes: determining color correction parameters based on the fitting parameters; and color correction of the matching color stimuli in the group of color stimuli to be corrected, based on the color correction parameters.

[0164] For example, the accuracy of color correction can be determined by verifying the fitting effect of the fitting parameters.

[0165] In some embodiments, the color difference value of the color stimulus group to be corrected is determined according to the target color matching function; the ratio of the color difference value of the color stimulus group to be corrected to the color correction parameter is determined to verify the fitting parameter, as shown in formula (3).

[0166]

[0167] Where, ΔE final To verify the results, ΔEfinal The closer the value is to 1, the higher the accuracy of the color difference calculation. ΔE is the color difference value calculated using the target color matching function, and can be a Δ(u'v') value. * ab Color difference value, ΔE 00 Color difference value.

[0168] In some embodiments, the difference between adjacent viewing angles in a plurality of viewing angles is less than a second threshold.

[0169] For example, when the viewing angle is less than 10°, the second threshold can be set to a smaller value (e.g., 2°), and when the viewing angle is greater than 10°, the second threshold can be set to a larger value (e.g., 4°). Here, 10°, 2° and 4° are just examples, and the specific values ​​can be set according to the actual situation.

[0170] By setting the difference between adjacent viewing angles to be less than a second threshold, discrete viewing angles with similar intervals are set, which can cover the user's viewing angle when observing color stimuli as comprehensively as possible, ensuring the universality and accuracy of the color difference calculation method.

[0171] In some embodiments, the spectral half-wave bandwidth in the second spectral parameter is less than the third threshold.

[0172] For example, the third threshold can be 30nm or 35nm.

[0173] By making the spectral half-wave bandwidth in the second spectral parameter less than the third threshold, the RGB primary colors of the matching devices in one or more sets of display devices have narrow spectral bandwidths. Setting the narrow spectral bandwidth enables the matching devices to achieve a large color gamut, which helps to improve the user's experience with the display devices. In addition, by setting the narrow spectral bandwidth of the primary colors of the matching devices, a more severe observer metamerism phenomenon is created for the color difference calculation process, which helps to improve the robustness and accuracy of the color difference calculation process.

[0174] In some embodiments, when the color stimuli are reproduced by the display device, the white field parameters of one or more sets of color stimuli may be adjusted before adjusting the primary color ratio (i.e., RGB ratio) of each set of color stimuli, so as to make the colors of one or more sets of color stimuli displayed uniformly.

[0175] For example, color stimuli are reproduced by display devices, and white point parameters include the color temperature and brightness of the display devices. Adjusting the white point parameters of one or more sets of display devices refers to adjusting the color temperature of the target device and matching device in one or more sets of display devices to 5000K or 6500K, or adjusting the color temperature of the target device and matching device to a specified color temperature according to specific usage requirements; and adjusting the brightness of the target device and matching device to 80 cd / cm². 2-120cd / cm 2 Simultaneously, the color temperature variation range between the target device and the matching device is required to be ±100K, and the brightness variation range is required to be ±10cd / cm². 2 .

[0176] By adjusting the white field parameters of each set of display devices, the target device and the matching device can display colors uniformly, providing a highly accurate and robust experimental environment for color matching, thereby improving the accuracy and robustness of the color difference calculation process.

[0177] Figure 6 Schematic diagrams showing some embodiments of the color difference calculation apparatus of this disclosure are provided.

[0178] like Figure 6 As shown, the color difference calculation device 60 includes an acquisition unit 61, an adjustment unit 62, a first determination unit 63, a second determination unit 64, a division unit 65, a third determination unit 66, a fourth determination unit 67, a fifth determination unit 68, and a correction unit 69.

[0179] The acquisition unit 61 is configured to acquire one or more sets of color stimuli, wherein each set of color stimuli includes a target color stimulus and a matching color stimulus, the target color stimulus having a first spectral parameter and the matching color stimulus having a second spectral parameter.

[0180] In some embodiments, when the color stimulus is reproduced by a display device, the first spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the target color stimulus, and the second spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the matching color stimulus.

[0181] The adjustment unit 62 is configured to adjust the primary color ratio of each set of color stimuli for each of the multiple observation perspectives in the observation strategy until the color matching of each set of color stimuli is completed.

[0182] In some embodiments, multiple observation perspectives are controlled by adjusting the area of ​​the matching color stimulus in each group of color stimuli and the observation distance in the observation strategy.

[0183] The first determining unit 63 is configured to determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli based on the spectral energy distribution of the target color stimulus in each group of color stimuli, the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle.

[0184] In some embodiments, the set of color matching functions corresponding to each observation viewpoint is determined based on multiple observation viewpoints in the observation strategy and the physiological parameters of the observer.

[0185] The second determining unit 64 is configured to determine the average color difference of one or more groups of color stimuli corresponding to each observation viewpoint based on the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli.

[0186] The division unit 65 is configured to divide multiple viewing angles based on the average color difference, thereby obtaining multiple viewing angle intervals.

[0187] The third determining unit 66 is configured to determine the minimum value among the average color difference values ​​of one or more sets of color stimuli corresponding to each observation viewpoint in each observation viewpoint interval, and to determine the color matching function corresponding to the minimum value as the target color matching function for the corresponding observation viewpoint interval.

[0188] The fourth determining unit 67 is configured to determine the color difference value of the group of color stimuli to be matched in one or more groups of color stimuli under multiple observation views by means of a target color matching function.

[0189] The fifth determining unit 68 is configured to determine fitting parameters based on the color difference values ​​of the color stimulus group to be matched under multiple observation angles.

[0190] The correction unit 69 is configured to perform color correction on the matching color stimuli in the group of color stimuli to be corrected based on the fitting parameters.

[0191] In the above embodiments, by acquiring one or more sets of color stimuli and performing color matching on them, a diverse and accurate matching environment is constructed for the color matching method. This helps ensure the accuracy and versatility of the color correction process and makes the subsequently determined color matching function applicable to the color correction of various color stimuli. By determining the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each set of color stimuli, the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli corresponding to each color matching function at each observation angle is determined, as well as the target color difference value in all sets of color stimuli corresponding to each color matching function at each observation angle. The average color difference between the stimulus and the matching color stimulus helps in the subsequent division of observation viewpoints and the selection of target color matching functions corresponding to the observation viewpoint intervals based on the average color difference. This provides feasibility for assigning different color matching functions to different observation viewpoint intervals to ensure the accuracy of the color correction process. By dynamically dividing multiple observation viewpoints based on the average color difference to obtain multiple observation viewpoint intervals, and determining different color matching functions for different observation viewpoint intervals, the accuracy and flexibility of the color correction process can be improved, and the universality of the color matching functions can also be ensured. Color correction can improve the consistency and accuracy of colors of different color stimuli, which helps to meet the needs of high-quality color display, transmission, and reproduction.

[0192] In some embodiments, the adjustment unit 62 is further configured to adjust the white field parameters of one or more sets of color stimuli when the color stimuli are reproduced by the display device, so as to make the colors of one or more sets of color stimuli displayed uniformly.

[0193] In some embodiments, the first determining unit 63 is further configured to input the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each group of color stimuli to each color matching function in the color matching function set, determine the first chromaticity value of the target color stimulus and the second chromaticity value of the matching color stimulus corresponding to each color matching function; determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to each color matching function based on the first chromaticity value and the second chromaticity value; and determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to each color matching function based on the color difference value corresponding to each color matching function.

[0194] In some embodiments, the fourth determining unit 67 is further configured to: determine the observation view interval to which each observation view belongs among a plurality of observation viewpoints; determine a target color matching function corresponding to the observation view interval based on the observation view interval to which each observation view belongs; determine the color difference value of the color stimulus group to be matched under each observation viewpoint using the target color matching function; and determine the color difference value of the color stimulus group to be matched under multiple observation viewpoints based on the color difference value of the color stimulus group to be matched under each observation viewpoint.

[0195] In some embodiments, the fifth determining unit 68 is further configured to determine the color difference value of each group of color stimuli corresponding to multiple viewing angles through a target color matching function; determine the minimum and maximum values ​​of the color difference values ​​of each group of color stimuli among the color difference values ​​of each group of color stimuli corresponding to multiple viewing angles; and select the color stimulus group whose ratio of the maximum to the minimum value of the color difference value of each group of color stimuli is greater than a first threshold as the color stimulus group to be matched.

[0196] In some embodiments, the correction unit 69 is further configured to determine color correction parameters based on the fitting parameters; and to perform color correction on the matching color stimuli in the group of color stimuli to be corrected based on the color correction parameters.

[0197] In some embodiments, the color difference calculation device 60 further includes a verification unit configured to determine the color difference value of the color stimulus group to be corrected according to the target color matching function; and to determine the ratio of the color difference value of the color stimulus group to be corrected to the color correction parameter in order to verify the fitting parameter.

[0198] In some embodiments, the difference between adjacent viewing angles in a plurality of viewing angles is less than a second threshold.

[0199] In some embodiments, the spectral half-wave bandwidth in the second spectral parameter is less than the third threshold.

[0200] Figure 7 Schematic diagrams showing other embodiments of the color difference calculation apparatus of this disclosure are shown.

[0201] like Figure 7 As shown, the color difference calculation device 70 of this embodiment includes: a memory 71 and a processor 72 coupled to the memory 71. The processor 72 is configured to execute the color difference calculation method of any of the foregoing embodiments based on instructions stored in the memory 71.

[0202] The memory 71 may include, for example, system memory, fixed non-volatile storage media, etc. The system memory stores, for example, the operating system, application programs, boot loader, and other programs.

[0203] The color difference calculation device 70 may also include an input / output interface 73, a network interface 74, and a storage interface 75. These interfaces 73, 74, and 75, as well as the memory 71 and processor 72, can be connected via, for example, a bus 76. The input / output interface 73 provides a connection interface for input / output devices such as monitors, mice, keyboards, touchscreens, microphones, and speakers. The network interface 74 provides a connection interface for various networked devices. The storage interface 75 provides a connection interface for external storage devices such as SD cards and USB flash drives.

[0204] In the above embodiments, by acquiring one or more sets of color stimuli and performing color matching on them, a diverse and accurate matching environment is constructed for the color matching method. This helps ensure the accuracy and versatility of the color correction process and makes the subsequently determined color matching function applicable to the color correction of various color stimuli. By determining the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each set of color stimuli, the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli corresponding to each color matching function at each observation angle is determined, as well as the target color difference value in all sets of color stimuli corresponding to each color matching function at each observation angle. The average color difference between the stimulus and the matching color stimulus helps in the subsequent division of observation viewpoints and the selection of target color matching functions corresponding to the observation viewpoint intervals based on the average color difference. This provides feasibility for assigning different color matching functions to different observation viewpoint intervals to ensure the accuracy of the color correction process. By dynamically dividing multiple observation viewpoints based on the average color difference to obtain multiple observation viewpoint intervals, and determining different color matching functions for different observation viewpoint intervals, the accuracy and flexibility of the color correction process can be improved, and the universality of the color matching functions can also be ensured. Color correction can improve the consistency and accuracy of colors of different color stimuli, which helps to meet the needs of high-quality color display, transmission, and reproduction.

[0205] Figure 8 Schematic diagrams illustrating some embodiments of the color difference calculation system of this disclosure are shown.

[0206] like Figure 8 As shown, the color difference calculation system 80 includes one or more sets of color stimuli 81, a set of color stimuli to be corrected 82, and the color difference calculation device 60 in any of the above embodiments.

[0207] One or more sets of color stimuli are used to determine the target color matching function corresponding to the observation viewpoint range, and to determine the fitting parameters.

[0208] In the above embodiments, by acquiring one or more sets of color stimuli and performing color matching on them, a diverse and accurate matching environment is constructed for the color matching method. This helps ensure the accuracy and versatility of the color correction process and makes the subsequently determined color matching function applicable to the color correction of various color stimuli. By determining the spectral energy distribution of the target color stimulus and the spectral energy distribution of the matching color stimulus in each set of color stimuli, the color difference value between the target color stimulus and the matching color stimulus in each set of color stimuli corresponding to each color matching function at each observation angle is determined, as well as the target color difference value in all sets of color stimuli corresponding to each color matching function at each observation angle. The average color difference between the stimulus and the matching color stimulus helps in the subsequent division of observation viewpoints and the selection of target color matching functions corresponding to the observation viewpoint intervals based on the average color difference. This provides feasibility for assigning different color matching functions to different observation viewpoint intervals to ensure the accuracy of the color correction process. By dynamically dividing multiple observation viewpoints based on the average color difference to obtain multiple observation viewpoint intervals, and determining different color matching functions for different observation viewpoint intervals, the accuracy and flexibility of the color correction process can be improved, and the universality of the color matching functions can also be ensured. Color correction can improve the consistency and accuracy of colors of different color stimuli, which helps to meet the needs of high-quality color display, transmission, and reproduction.

[0209] In some embodiments, a computer program product is protected, comprising a computer program or instructions that, when executed by a processor, implement the speed planning method described above. The computer program product includes a computer program carried on a computer-readable medium, containing program code for performing the methods shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network via a color difference calculation device, or installed from a storage device, or installed from ROM. When the computer program is executed by a CPU, it performs the functions defined in the methods of embodiments of this disclosure.

[0210] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0211] This concludes the detailed description of the color difference calculation method, apparatus, system, and program products disclosed herein. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0212] The methods and systems of this disclosure may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0213] While specific embodiments of this disclosure have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A method for calculating color difference, comprising: Obtain one or more sets of color stimuli, wherein each set of color stimuli includes a target color stimulus and a matching color stimulus, the target color stimulus having a first spectral parameter and the matching color stimulus having a second spectral parameter; For each of the multiple observation perspectives in the observation strategy, adjust the primary color ratio of each group of color stimuli until the color matching of each group of color stimuli is completed. Based on the spectral energy distribution of the target color stimulus in each group of color stimuli, the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle, the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli is determined. Based on the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli, determine the average color difference of the one or more groups of color stimuli corresponding to each observation angle; Based on the average color difference, the multiple viewing angles are divided to obtain multiple viewing angle intervals; Determine the minimum value among the average color difference values ​​of one or more sets of color stimuli corresponding to each observation viewpoint in each observation viewpoint interval, and determine the color matching function corresponding to the minimum value as the target color matching function for the corresponding observation viewpoint interval; The target color matching function is used to determine the color difference value of the group of color stimuli to be matched in one or more groups of color stimuli under the multiple viewing angles. The fitting parameters are determined based on the color difference values ​​of the group of color stimuli to be matched under the multiple viewing angles. Based on the fitting parameters, color correction is performed on the matching color stimuli in the group of color stimuli to be corrected.

2. The color difference calculation method according to claim 1, wherein, Based on the spectral energy distribution of the target color stimulus in each group of color stimuli, the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle, the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli is determined, including: The spectral energy distribution of the target color stimulus in each group of color stimuli and the spectral energy distribution of the matching color stimulus in each group of color stimuli are input to each color matching function in the color matching function set to determine the first chromaticity value of the target color stimulus and the second chromaticity value of the matching color stimulus corresponding to each color matching function; Based on the first chromaticity value and the second chromaticity value, determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to each color matching function; Based on the color difference value corresponding to each color matching function, determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli corresponding to the color matching function set.

3. The color difference calculation method according to claim 1, wherein, Determining the color difference values ​​of the group of color stimuli to be matched in the one or more groups of color stimuli under the multiple viewing angles using the target color matching function includes: Determine the observation view range to which each of the plurality of observation viewpoints belongs; Based on the observation view range to which each observation view belongs, determine the target color matching function corresponding to the observation view range; The color difference value of the set of color stimuli to be matched under each viewing angle is determined by the target color matching function. Based on the color difference value of the color stimulus group to be matched under each observation view, the color difference value of the color stimulus group to be matched under multiple observation view is determined.

4. The color difference calculation method according to claim 1, wherein, The set of color stimuli to be matched is determined through the following steps: The color difference value of each group of color stimuli corresponding to the multiple viewing angles is determined by the target color matching function. Determine the minimum and maximum values ​​of the color difference values ​​for each group of color stimuli from the multiple viewing angles corresponding to the color difference values ​​of each group of color stimuli. The color stimulus group whose ratio of the maximum to the minimum color difference value of each group of color stimuli is greater than a first threshold is selected as the color stimulus group to be matched.

5. The color difference calculation method according to any one of claims 1 to 4, wherein, Based on the fitting parameters, color correction of the matching color stimuli in the group of color stimuli to be corrected includes: Based on the fitting parameters, determine the color correction parameters; Based on the color correction parameters, color correction is performed on the matching color stimuli in the group of color stimuli to be corrected.

6. The color difference calculation method according to claim 5 further includes: The color difference value of the group of color stimuli to be corrected is determined according to the target color matching function; The ratio of the color difference value of the color stimulus group to be corrected to the color correction parameter is determined to verify the fitting parameter.

7. The color difference calculation method according to any one of claims 1 to 4, wherein, The multiple observation perspectives are controlled by adjusting the area of ​​the matching color stimulus in each group of color stimuli and the observation distance in the observation strategy.

8. The color difference calculation method according to any one of claims 1 to 4, wherein, The difference between adjacent observation viewpoints among the plurality of observation viewpoints is less than the second threshold.

9. The color difference calculation method according to any one of claims 1 to 4, wherein, When the color stimulus is reproduced by a display device, the first spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the target color stimulus, and the second spectral parameter includes the spectral shape, peak wavelength position, and spectral half-wave bandwidth of the RGB primary colors of the matching color stimulus.

10. The color difference calculation method according to claim 9, wherein, The spectral half-wave bandwidth in the second spectral parameter is less than the third threshold.

11. The color difference calculation method according to any one of claims 1 to 4, further comprising, when the color stimulus is reproduced by a display device: Adjust the white field parameters of the one or more sets of color stimuli to make the colors of the one or more sets of color stimuli displayed uniformly.

12. The color difference calculation method according to any one of claims 1 to 4, wherein, The set of color matching functions corresponding to each observation viewpoint is determined based on multiple observation viewpoints and the physiological parameters of the observer in the observation strategy.

13. A color difference calculation device, comprising: The acquisition unit is configured to acquire one or more sets of color stimuli, wherein each set of color stimuli includes a target color stimulus and a matching color stimulus, the target color stimulus having a first spectral parameter and the matching color stimulus having a second spectral parameter; The adjustment unit is configured to adjust the primary color ratio of each set of color stimuli for each of the multiple observation perspectives in the observation strategy until the color matching of each set of color stimuli is completed. The first determining unit is configured to determine the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli based on the spectral energy distribution of the target color stimulus in each group of color stimuli, the spectral energy distribution of the matching color stimulus in each group of color stimuli, and the set of color matching functions corresponding to each viewing angle. The second determining unit is configured to determine the average color difference of one or more groups of color stimuli corresponding to each observation angle based on the color difference value between the target color stimulus and the matching color stimulus in each group of color stimuli. The segmentation unit is configured to divide the multiple viewing angles according to the average color difference to obtain multiple viewing angle intervals; The third determining unit is configured to determine the minimum value among the average color difference values ​​of the one or more sets of color stimuli corresponding to each observation viewpoint in each observation viewpoint interval, and to determine the color matching function corresponding to the minimum value as the target color matching function for the corresponding observation viewpoint interval. The fourth determining unit is configured to determine the color difference value of the group of color stimuli to be matched in the group or groups of color stimuli under the multiple viewing angles by means of the target color matching function. The fifth determining unit is configured to determine fitting parameters based on the color difference values ​​of the group of color stimuli to be matched under the multiple viewing angles; The correction unit is configured to perform color correction on the matching color stimuli in the group of color stimuli to be corrected, based on the fitting parameters.

14. A color difference calculation device, comprising: Memory; and a processor coupled to the memory, the processor being configured to execute the color difference calculation method of any one of claims 1 to 12 based on instructions stored in the memory.

15. A color difference calculation system, comprising: One or more groups of color stimuli; Color stimulus group to be corrected; The color difference calculation device as described in claim 13 or 14.

16. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the color difference calculation method according to any one of claims 1 to 12.

17. A computer program product comprising a computer program that, when executed by a processor, implements the color difference calculation method according to any one of claims 1 to 12.

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