A color difference analysis method, and an analysis device based on the color difference analysis method

Abstract

The application discloses a color difference analysis method and an analysis device based on the color difference analysis method, and comprises the following steps: obtaining a photo of a color difference area, wherein the color difference area comprises a first area, a second area and a standard color plate area; obtaining initial color sampling values of the first area, the second area and the standard color plate; calculating differences between the initial color sampling values of the first area and the initial color sampling values of the standard color plate, differences between the initial color sampling values of the second area and the initial color sampling values of the standard color plate, and a difference between the color sampling values of the first area and the color sampling values of the second area; judging the area causing the color difference and the main reason causing the color difference according to the calculation results; obtaining 6-angle standard color difference values of the standard color plate and the area causing the color difference; calculating standard color plate differences between the initial color sampling values of the standard color plate and the 6-angle standard color difference values of the standard color plate; and judging the angle causing the color difference according to the calculation results.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile coating, in particular to a color difference analysis method and an analysis device based on the color difference analysis method. BACKGROUND

[0002] At present, metallic paint, pearl paint and high chroma color are widely applied to the field of automobiles, etc. However, these paints are accompanied by goniochromatic effect and metamerism problem while being bright in color, thereby causing the problem of color difference matching.

[0003] When color difference occurs, the commonly used method is to measure the color difference data of the color difference component by using a color difference meter and to analyze the color difference data such as dLab / dLCH measured by the color difference meter.

[0004] However, this method has the following problems: 1) the color temperature of the light source causing the color difference needs to be confirmed by professional equipment, and the professional equipment is expensive; 2) when metamerism occurs, it cannot be identified; 3) when goniochromism occurs, it cannot be judged which angle causes the color difference. SUMMARY

[0005] The main purpose of the present application is to provide a color difference analysis method, which aims to solve the problems that the existing technology cannot identify metamerism and cannot judge the angle causing the color difference.

[0006] The present application provides a color difference analysis method, comprising the following steps:

[0007] S10, acquiring a photo of a color difference area, the color difference area comprising a first area, a second area and a standard color plate area placed between the first area and the second area;

[0008] S20, acquiring an initial color value LAB1 of the first area, an initial color value LAB2 of the second area and an initial color value LAB3 of the standard color plate in the photo of the color difference area;

[0009] S30, calculating a difference value LAB4 between the initial color value LAB1 of the first area and the initial color value LAB3 of the standard color plate, a difference value LAB5 between the initial color value LAB2 of the second area and the initial color value of the standard color plate, and a difference value LAB6 between the color value LAB1 of the first area and the color value LAB2 of the second area;

[0010] S40, according to the calculation results, judging that the maximum absolute value in LAB4 and LAB5 is the area causing the color difference, and judging that the maximum absolute value in LAB6 is the main reason causing the color difference;

[0011] S50, obtain the 6-angle standard color difference values of the standard color card and the area causing the color difference, calculate the standard color card difference value between the initial color picking value of the standard color card and the 6-angle standard color difference values of the standard color card, and determine the angle causing the color difference according to the calculation result.

[0012] Optionally, in step S30,

[0013] LAB1 includes L1, A1, B1, LAB2 includes L2, A2, B2, LAB3 includes L3, A3, B3, LAB4 includes L4, A4, B4, LAB5 includes L5, A5, B5, and LAB6 includes L6, A6, B6, wherein L1, L2, and L3 are luminance values, A1, A2, and A3 are red-green phase values, and B1, B2, and B3 are yellow-blue phase values;

[0014] L4 = L1-L3, A4 = A1-A3, B4 = B1-B3, L5 = L2-L3, A5 = A2-A3, B5 = B2-B3, L6 = L2-L1, A6 = A2-A1, and B6 = B2-B1.

[0015] Optionally, in step S40,

[0016] If the maximum absolute value in LAB4 and LAB5 is any one of L4, A4, and B4, it is determined that the first area is the area causing the color difference;

[0017] If the maximum absolute value in LAB4 and LAB5 is any one of L5, A5, and B5, it is determined that the second area is the area causing the color difference;

[0018] If the maximum absolute value in LAB6 is L6, it is determined that the luminance value is the main cause of the color difference;

[0019] If the maximum absolute value in LAB6 is A6, it is determined that the red-green phase value is the main cause of the color difference;

[0020] If the maximum absolute value in LAB6 is B6, it is determined that the yellow-blue phase value is the main cause of the color difference.

[0021] Optionally, step S50 further includes:

[0022] S501, if the maximum absolute value in L6, A6, and B6 is L6, and the maximum absolute value in L4, A4, B4, L5, A5, and B5 is any one of L4, A4, and B4, it is determined that the first area is the area causing the color difference, and the luminance value of the first area is the main factor causing the color difference;

[0023] S502, obtain the type of the paint causing the color difference, and determine the type of the paint.

[0024] Optionally, after step S502, the method further comprises:

[0025] S503, if the color paint causing the color difference is a solid color paint, judging to use D65 light source for color taking;

[0026] S504, obtaining color difference data dL45° of the first area at 45° under D65 light source, and color difference data L*45° of the standard color plate at 45° under D65 light source;

[0027] S505, calculating the ratio of dL45° and L4, and judging the ratio of dL45° and L4: if the ratio of dL45° and L4≥0.25, judging that the lightness value of the first area at 45° under D65 light source is the main cause of the color difference; if the ratio of dL45° and L4<0.25, judging that metromeria occurs, returning to step S503, and replacing D65 light source with A light source and F2 light source respectively.

[0028] Optionally, after step S502, the method further comprises:

[0029] S506, if the color paint causing the color difference is a non-solid color paint, judging to use D65 light source for color taking;

[0030] S507, obtaining color standard values L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° of the standard color plate under D65 light source, and standard color difference values dL-15°, dL15°, dL25°, dL45°, dL75°, dL110° of the first area under D65 light source;

[0031] S508, calculating the difference between L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° and L3;

[0032] S509, judging the angles corresponding to the two values L*X and L*Y with the smallest difference between L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° and L3 as the angle range causing the color difference according to the difference between L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° and L3, and judging X and Y, wherein X, Y are any two different angles in -15°, 15°, 25°, 45°, 75°, 110°.

[0033] Optionally, after step S509, the method further comprises S510 and S511, or S512 and S513, or S514 and S515, wherein,

[0034] S510 comprises: if X, Y do not contain any one of -15° and 15°, calculating the difference between L4 and dLX and the difference between L4 and dLY:

[0035] S511 includes judging according to the difference between L4 and dLX and the difference between L4 and dLY:

[0036] If the difference between L4 and dLX is the smallest, the ratio of dLX to L4 is calculated, if the ratio of dLX to L4 is ≥0.25, it is judged that the lightness value of the first region at X angle under D65 light source is the main reason causing color difference; if the ratio of dLX to L4 is <0.25, it is judged that metromeria problem occurs, returning to step S506, and D65 light source is replaced by A light source and F2 light source respectively;

[0037] If the difference between L4 and dLY is the smallest, the ratio of dLY to L4 is calculated, if the ratio of dLY to L4 is ≥0.25, it is judged that the lightness value of the first region at Y angle under D65 light source is the main reason causing color difference; if the ratio of dLY to L4 is <0.25, it is judged that metromeria problem occurs, returning to step S506, and D65 light source is replaced by A light source and F2 light source respectively;

[0038] S512 includes if only 15° is contained in X and Y and -15° is not contained, calculating the difference between L4 and dL-15°, dLX and dLY;

[0039] S513 includes judging according to the difference between L4 and dL-15°, dLX and dLY:

[0040] If the difference between L4 and dL-15° is the smallest, the ratio of dL-15° to L4 is calculated, and according to the calculation result, if the ratio of dL-15° to L4 is ≥0.25, it is judged that the lightness value of the first region at -15° angle under D65 light source is the main reason causing color difference; if the ratio of dL-15° to L4 is <0.25, it is judged that metromeria problem occurs, returning to step S506, and D65 light source is replaced by A light source and F2 light source respectively;

[0041] If the difference between L4 and dLX is the smallest, the ratio of dLX to L4 is calculated, and according to the calculation result, if the ratio of dLX to L4 is ≥0.25, it is judged that the lightness value of the first region at X angle under D65 light source is the main reason causing color difference; if the ratio of dLX to L4 is <0.25, it is judged that metromeria problem occurs, returning to step S506, and D65 light source is replaced by A light source and F2 light source respectively;

[0042] If the difference between L4 and dLY is the smallest, the ratio of dLY to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLY to L4 is greater than or equal to 0.25, it is judged that the brightness value of the first region at the Y angle under the D65 light source is the main cause of the color difference. If the ratio of dLY to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned to, and the D65 light source is replaced by the A light source and the F2 light source respectively.

[0043] S514 includes: if only -15° is contained in X and Y and 15° is not contained, the difference between L4 and dL15°, dLX and dLY is calculated.

[0044] S515 includes: a judgment is made according to the difference between L4 and dL15°, dLX and dLY.

[0045] If the difference between L4 and dL15° is the smallest, the ratio of dL15° to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dL15° to L4 is greater than or equal to 0.25, it is judged that the brightness value of the first region at the 15° angle under the D65 light source is the main cause of the color difference. If the ratio of dL15° to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned to, and the D65 light source is replaced by the A light source and the F2 light source respectively.

[0046] If the difference between L4 and dLX is the smallest, the ratio of dLX to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLX to L4 is greater than or equal to 0.25, it is judged that the brightness value of the first region at the X angle under the D65 light source is the main cause of the color difference. If the ratio of dLX to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned to, and the D65 light source is replaced by the A light source and the F2 light source respectively.

[0047] If the difference between L4 and dLY is the smallest, the ratio of dLY to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLY to L4 is greater than or equal to 0.25, it is judged that the brightness value of the first region at the Y angle under the D65 light source is the main cause of the color difference. If the ratio of dLY to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned to, and the D65 light source is replaced by the A light source and the F2 light source respectively.

[0048] Optionally, the step S50 further includes:

[0049] S516, if the maximum absolute value in L6, A6 and B6 is A6, and the maximum absolute value in L4, A4, B4, L5, A5 and B5 is any one of L4, A4 and B4, it is judged that the red-green value of the first region is the main factor causing the color difference, the type of the color paint is judged, the step S501 is returned to, and the brightness value in the step S501 is replaced by the red-green value.

[0050] S517, if the maximum absolute value among L6, A6, B6 is B6, and the maximum absolute value among L4, A4, B4, L5, A5, B5 is any one of L4, A4, B4, L5, A5, B5, it is judged that the yellow-blue phase value of the first region is the main factor causing the color difference, the type of the paint is judged, step S501 is returned, and the lightness value in step S501 is replaced by the yellow-blue phase value.

[0051] Optionally, step S50 further comprises:

[0052] S518, if the maximum absolute value among L6, A6, B6 is L6, and the maximum absolute value among L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the lightness value of the second region is the main factor causing the color difference, the type of the paint is judged, step S501 is returned, and the first region in step S501 is replaced by the second region;

[0053] S519, if the maximum absolute value among L6, A6, B6 is A6, and the maximum absolute value among L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the red-green phase value of the second region is the main factor causing the color difference, the type of the paint is judged, step S501 is returned, and the first region in step S501 is replaced by the second region, and the lightness value is replaced by the red-green phase value;

[0054] S520, if the maximum absolute value among L6, A6, B6 is B6, and the maximum absolute value among L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the yellow-blue phase value of the second region is the main factor causing the color difference, the type of the paint is judged, step S501 is returned, and the first region in step S501 is replaced by the second region, and the lightness value is replaced by the yellow-blue phase value.

[0055] The application further provides an analysis device based on the color difference analysis method, which comprises:

[0056] a shooting device for shooting a color difference photo; and

[0057] a control device in communication connection with the shooting device, the control device comprising a memory, a processor, a display screen, and a color difference analysis control program stored in the memory and executable on the processor, and the color difference analysis control program realizes the steps of the color difference analysis method when executed by the processor.

[0058] The color difference analysis method comprises the following steps: S10, acquiring a photo of a color difference area, wherein the color difference area comprises a first area, a second area and a standard color plate area arranged between the first area and the second area; S20, acquiring an initial color value LAB1 of the first area, an initial color value LAB2 of the second area and an initial color value LAB3 of the standard color plate in the photo of the color difference area; S30, calculating a difference value LAB4 between the initial color value LAB1 of the first area and the initial color value LAB3 of the standard color plate, a difference value LAB5 between the initial color value LAB2 of the second area and the initial color value of the standard color plate, and a difference value LAB6 between the color value LAB1 of the first area and the color value LAB2 of the second area; S40, judging the maximum absolute value in LAB4 and LAB5, that is, the area causing the color difference, and judging the maximum absolute value in LAB6, that is, the main reason causing the color difference; S50, acquiring 6-angle standard color difference values of the standard color plate and the area causing the color difference, calculating a standard color plate difference value between the initial color value of the standard color plate and the 6-angle standard color difference value of the standard color plate, and judging the angle causing the color difference according to the calculation result.

[0059] The color difference analysis method provided by the application can determine the area, type and angle causing the color difference and distinguish the angles of metamerism and goniochromism by acquiring a color difference photo, taking color and analyzing the color difference values in the photo, judging the area causing the color difference according to the absolute value of the difference value between the first color difference area and the standard color plate and the difference value between the second color difference area and the standard color plate, judging the type of the color difference according to the absolute value of the difference value between the first color difference area and the second color difference area, and judging the angle causing the color difference according to the standard color plate difference value between the initial color value of the standard color plate and the 6-angle standard color difference value of the standard color plate. BRIEF DESCRIPTION OF DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of the drawings shown.

[0061] Figure 1 The flow chart of an embodiment of the color difference analysis method provided by the present application.

[0062] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] Currently, metallic paints, pearlescent paints, and high-chroma colors are widely used in the automotive industry. However, while these paints offer vibrant colors, they also present challenges such as angle-dependent color variation and metamerism, leading to difficulties in color matching. When color differences occur, a common method is to use a colorimeter to measure the color difference data of the components and analyze the dLab / dLCH values ​​obtained from the colorimeter. However, this method has the following problems: 1) the color temperature of the light source causing the color difference requires specialized equipment, which is expensive; 2) it cannot identify metamerism; 3) it cannot determine the angle of color difference when angle-dependent color variation occurs. Therefore, this invention proposes a color difference analysis method to solve the problems of not being able to identify metamerism and determine the angle of color difference in existing technologies. Figure 1 As shown, the color difference analysis method includes the following steps:

[0065] S10. Obtain a photograph of the color difference area, wherein the color difference area includes a first area, a second area, and a standard color swatch area placed between the first area and the second area;

[0066] S20. Obtain the initial color value LAB1 of the first region, the initial color value LAB2 of the second region, and the initial color value LAB3 of the standard color swatch in the color difference area photo.

[0067] S30. Calculate the difference between the initial color value LAB1 of the first region and the initial color value LAB3 of the standard color difference chart, the difference between the initial color value LAB2 of the second region and the initial color value of the standard color difference chart, and the difference between the color value LAB1 of the first region and the color value LAB2 of the second region, LAB6.

[0068] S40, according to the calculation result, the maximum value of the absolute value in LAB4 and LAB5 is the area causing the color difference, and the maximum value of the absolute value in LAB6 is the main reason causing the color difference;

[0069] S50, the 6-angle standard color difference values of the standard color card and the area causing the color difference are obtained, the standard color card difference value between the initial color picking value of the standard color card and the 6-angle standard color difference value of the standard color card is calculated, and the angle causing the color difference is judged according to the calculation result.

[0070] In the technical scheme of the present application, the color difference photo is obtained, and the color difference values in the photo are picked and analyzed, the area causing the color difference is judged by the absolute value size of the color difference value difference between the first color difference area and the standard color card and the color difference value difference between the second color difference area and the standard color card, the type of the color difference is judged by the absolute value size of the color difference value difference between the first color difference area and the second color difference area, and the angle causing the color difference is judged by the standard color card difference value between the initial color picking value of the standard color card and the 6-angle standard color difference value of the standard color card, so that the area, type and angle causing the color difference can be determined, and the angle of metamerism and goniochromism can be distinguished.

[0071] In the embodiment of the present application, in step S30:

[0072] LAB1 includes L1, A1 and B1, LAB2 includes L2, A2 and B2, LAB3 includes L3, A3 and B3, LAB4 includes L4, A4 and B4, LAB5 includes L5, A5 and B5, and LAB6 includes L6, A6 and B6, wherein L1, L2 and L3 are lightness values, A1, A2 and A3 are red-green phase values, and B1, B2 and B3 are yellow-blue phase values;

[0073] L4=L1-L3, A4=A1-A3, B4=B1-B3, L5=L2-L3, A5=A2-A3, B5=B2-B3, L6=L2-L1, A6=A2-A1 and B6=B2-B1. By picking the color difference values of the lightness values, red-green phase values and yellow-blue phase values respectively, the type of the color difference can be accurately distinguished, the area causing the color difference can be judged by calculating the absolute value size of the color difference value difference between each color difference area and the standard color card, and it can be accurately judged that which type of color picking value causes the color difference by comparing the color difference value difference between the two color difference areas.

[0074] In the embodiment of the present application, in step S40:

[0075] If the maximum value of the absolute value in LAB4 and LAB5 is any one of L4, A4 and B4, it is determined that the first area is the area causing the color difference;

[0076] If the maximum value of the absolute value in LAB4 and LAB5 is any one of L5, A5 and B5, it is determined that the second region is the region causing the color difference;

[0077] If the maximum value of the absolute value in LAB6 is L6, it is determined that the lightness value is the main reason causing the color difference;

[0078] If the maximum value of the absolute value in LAB6 is A6, it is determined that the red-green phase value is the main reason causing the color difference;

[0079] If the maximum value of the absolute value in LAB6 is B6, it is determined that the yellow-blue phase value is the main reason causing the color difference.

[0080] That is, the maximum value of the absolute value of the difference can determine which region and which type of value is the reason causing the color difference, and the analysis process is simple and fast.

[0081] In the embodiment of the application, step S50 further comprises:

[0082] S501, if the maximum value of the absolute value in L6, A6 and B6 is L6, and the maximum value of the absolute value in L4, A4, B4, L5, A5 and B5 is any one of L4, A4 and B4, it is determined that the first region is the region causing the color difference, and the lightness value of the first region is the main factor causing the color difference;

[0083] S502, the type of the color paint causing the color difference is obtained, and the type of the color paint is determined.

[0084] Optionally, step S502 further comprises:

[0085] S503, if the type of the color paint causing the color difference is the solid color paint, it is determined that the D65 light source is used for color taking;

[0086] S504, the color difference data dL45° of the first region at 45° under the D65 light source is obtained, and the color difference data L*45° of the standard color plate at 45° under the D65 light source is obtained;

[0087] S505, the ratio of dL45° to L4 is calculated, and the ratio of dL45° to L4 is determined: if the ratio of dL45° to L4 is greater than or equal to 0.25, it is determined that the lightness value of the first region at 45° under the D65 light source is the main reason causing the color difference; if the ratio of dL45° to L4 is less than 0.25, it is determined that metamerism occurs, and the process returns to step S503, and the D65 light source is replaced by the A light source and the F2 light source respectively.

[0088] That is, when the color paint type is a solid color paint, only the 45° color difference value needs to be considered to determine whether metamerism occurs or any one of the L, A, and B values deviates to cause color difference, or color difference occurs due to different light sources, for example, when the D65 light source cannot be determined, the A light source or the F light source is considered to be replaced, wherein the D65 light source is a standard light source, the A light source is a warm light source, and the F light source is a cold light source. As long as it is a solid color paint, whether it is the first color difference region or the second color difference region, whether it is the brightness value or the red-green value or the yellow-blue value, the judgment logic is the same, and only the data of the judgment region causing the color difference needs to be replaced. The present application will not be described one by one.

[0089] In addition, the ratio of dL45° and L4 is judged, if the ratio of dL45° and L4 is greater than or equal to 0.25, it is judged that the first region under the D65 light source at 45° is the main reason for causing the color difference, if the ratio of dL45° and L4 is less than 0.25, it is judged that metamerism occurs, which can further improve the accuracy of the analysis method.

[0090] In the embodiment of the present application, step S502 further includes:

[0091] S506, if the color paint type causing the color difference is a non-solid color paint, it is judged that the D65 light source is used for color taking;

[0092] S507, the color standard values L*-15°, L*15°, L*25°, L*45°, L*75°, and L*110° of the standard color plate under the D65 light source at 6 angles, and the standard color difference values dL-15°, dL15°, dL25°, dL45°, dL75°, and dL110° of the first region under the D65 light source at 6 angles are obtained;

[0093] S508, the difference values of L*-15°, L*15°, L*25°, L*45°, L*75°, L*110°, and L3 are calculated;

[0094] S509, according to the difference values of L*-15°, L*15°, L*25°, L*45°, L*75°, L*110°, and L3, the angle range corresponding to the two values L*X and L*Y with the smallest difference value is judged, wherein X and Y are any two different angles in -15°, 15°, 25°, 45°, 75°, and 110°.

[0095] After the color difference region and the color difference type are judged, the 6 angles of the standard color plate under the standard light source are taken, so as to find the angle range corresponding to the standard value closest to the initial value of the standard color plate, which is the range causing the color difference. The range causing the color difference can be quickly determined.

[0096] In the embodiment of the present application, after step S509, further comprising:

[0097] S510, if none of -15° and 15° is contained in X, Y, calculating the difference between L4 and dLX and the difference between L4 and dLY:

[0098] S511, judging according to the difference between L4 and dLX and the difference between L4 and dLY:

[0099] If the difference between L4 and dLX is the smallest, calculating the ratio of dLX to L4, if the ratio of dLX to L4 is greater than or equal to 0.25, judging that the lightness value of the first region at X angle under D65 light source is the main reason causing the color difference; if the ratio of dLX to L4 is less than 0.25, judging that metromeria occurs, returning to step S506, and replacing D65 light source with A light source and F2 light source respectively;

[0100] If the difference between L4 and dLY is the smallest, calculating the ratio of dLY to L4, if the ratio of dLY to L4 is greater than or equal to 0.25, judging that the lightness value of the first region at Y angle under D65 light source is the main reason causing the color difference; if the ratio of dLY to L4 is less than 0.25, judging that metromeria occurs, returning to step S506, and replacing D65 light source with A light source and F2 light source respectively.

[0101] When the angle range causing the color difference is obtained, in order to further find the specific angle causing the color difference, the value of the color difference causing region corresponding to the range is compared with the difference between the initial color difference region and the color value of the standard color plate, and the closest one is the angle causing the color difference. In order to improve the accuracy of the judgment, the ratio between the closest value and the difference between the initial color difference region and the color value of the standard color plate is judged, when the ratio is greater than or equal to 0.25, the angle under D65 light source is the angle causing the color difference, when the ratio is less than 0.25, judging that metromeria occurs, repeating S506 to further judge after changing the light source, thereby improving the accuracy of the judgment and quickly finding the angle causing the color difference.

[0102] In the embodiment of the present application, after step S509, further comprising:

[0103] S512, if only 15° is contained in X, Y, calculating the difference between L4 and dL-15°, dLX and dLY:

[0104] S513, judging according to the difference between L4 and dL-15°, dLX and dLY:

[0105] If the difference between L4 and dL-15° is the smallest, the ratio of dL-15° to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dL-15° to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at a -15° angle under the D65 light source is the main cause of the color difference. If the ratio of dL-15° to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source, respectively.

[0106] If the difference between L4 and dLX is the smallest, the ratio of dLX to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLX to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at an X angle under the D65 light source is the main cause of the color difference. If the ratio of dLX to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source, respectively.

[0107] If the difference between L4 and dLY is the smallest, the ratio of dLY to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLY to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at a Y angle under the D65 light source is the main cause of the color difference. If the ratio of dLY to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source, respectively.

[0108] Since 15° and -15° are relatively special angles, in order to improve the accuracy of the judgment, when the angle corresponding to the standard color value closest to the initial value of the standard color plate contains 15° but does not contain -15°, the standard color value of the standard color plate corresponding to -15° needs to be introduced for comparison to avoid omission and improve the accuracy of the judgment.

[0109] In the embodiments of the present application, after the step S509, the following steps are further included:

[0110] S514, if only -15° is contained in X and Y and 15° is not contained, the difference between L4 and dL15°, dLX and dLY is calculated;

[0111] S515, a judgment is made according to the difference between L4 and dL15°, dLX and dLY:

[0112] If the difference between L4 and dL15° is the smallest, the ratio of dL15° to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dL15° to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at a 15° angle under the D65 light source is the main cause of the color difference. If the ratio of dL15° to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source, respectively.

[0113] If the difference between L4 and dLX is the minimum, the ratio of dLX to L4 is calculated, and a judgment is made according to the calculation result; if the ratio of dLX to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the X angle under the D65 light source is the main cause of the color difference; if the ratio of dLX to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source, respectively.

[0114] If the difference between L4 and dLY is the minimum, the ratio of dLY to L4 is calculated, and a judgment is made according to the calculation result; if the ratio of dLY to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the Y angle under the D65 light source is the main cause of the color difference; if the ratio of dLY to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source, respectively.

[0115] Since 15° and -15° are relatively special angles, in order to improve the accuracy of the judgment, when the angle corresponding to the standard color value closest to the initial value of the standard color plate contains -15° but does not contain 15°, the standard color value of the standard color plate corresponding to 15° needs to be introduced for comparison to avoid omission and improve the accuracy of the judgment.

[0116] In the embodiment of the present application, the step S50 further comprises:

[0117] S516, if the maximum of the absolute values of L6, A6 and B6 is A6, and the maximum of the absolute values of L4, A4, B4, L5, A5 and B5 is any one of L4, A4 and B4, it is judged that the red-green phase value of the first region is the main factor causing the color difference, the type of the color paint is judged, the step S501 is returned, and the lightness value in the step S501 is replaced by the red-green phase value;

[0118] S517, if the maximum of the absolute values of L6, A6 and B6 is B6, and the maximum of the absolute values of L4, A4, B4, L5, A5 and B5 is any one of L4, A4 and B4, it is judged that the yellow-blue phase value of the first region is the main factor causing the color difference, the type of the color paint is judged, the step S501 is returned, and the lightness value in the step S501 is replaced by the yellow-blue phase value.

[0119] When the red-green phase value of the first region is the main factor causing the color difference, and the yellow-blue phase value of the first region is the main factor causing the color difference, only the red-green phase value is replaced by the lightness value, and the yellow-blue phase value is replaced by the lightness value, and then the step S502 is returned, so that the same color difference analysis method can be used to find the color difference generation angle and the color difference generation light source under the same region and different color difference types, so that the analysis method has spectral and universality.

[0120] In the embodiment of the present application, step S50 further comprises:

[0121] S518, if the maximum absolute value of L6, A6, B6 is L6, and the maximum absolute value of L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the lightness value of the second region is the main factor causing the color difference, the type of the color paint is judged, step S501 is returned, and the first region in step S501 is replaced by the second region;

[0122] S519, if the maximum absolute value of L6, A6, B6 is A6, and the maximum absolute value of L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the red-green phase value of the second region is the main factor causing the color difference, the type of the color paint is judged, step S501 is returned, and the first region in step S501 is replaced by the second region, and the lightness value is replaced by the red-green phase value;

[0123] S520, if the maximum absolute value of L6, A6, B6 is B6, and the maximum absolute value of L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the yellow-blue phase value of the second region is the main factor causing the color difference, the type of the color paint is judged, step S501 is returned, and the first region in step S501 is replaced by the second region, and the lightness value is replaced by the yellow-blue phase value.

[0124] When the lightness value of the second region is the main factor causing the color difference, the yellow-blue phase value of the second region is the main factor causing the color difference, and the yellow-blue phase value of the second region is the main factor causing the color difference, only the first region is replaced by the second region, the lightness value is replaced by the red-green phase value, the first region is replaced by the second region, the lightness value is replaced by the red-green phase value, and the first region is replaced by the second region, the lightness value is replaced by the yellow-blue phase value, and then returning to step S502 can realize finding the color difference generation angle and the color difference generation light source under different regions and different color difference types by using the same color difference analysis method, so that the analysis method has spectral nature and universality.

[0125] The present application further provides an analysis device based on the color difference analysis method, which comprises:

[0126] a shooting device for shooting a color difference photo; and

[0127] a control device in communication connection with the shooting device, the control device comprising a memory, a processor, a display screen, and a color difference analysis control program stored in the memory and executable on the processor, the color difference analysis control program realizing the steps of the color difference analysis method when executed by the processor.

[0128] The photographing device can be a camera, and the camera is used to take a picture of the area to be analyzed for color difference, and the position and angle of the picture are consistent with the angle of the color difference evaluation. Specifically, the picture can be imported into a computer, and the sample color can be restored to the visual perception in the display after color correction. If there is deviation from the visual perception, the color camera with better color accuracy is replaced until the picture taken by the camera can restore the visual perception in the display after color correction. The display after color correction is used as a color accuracy detection device for the photographing device, so that a photographing device meeting the requirements can be selected. Then, the photographing device is used to solidify the visual subjective perception of the color difference of the human eye under the current light source and sample state into a picture file that can be quantitatively analyzed, and the picture file is used as a color information carrier for subsequent analysis. In order to avoid interference with the subsequent analysis process and reduce errors, the operator wears light-colored clothes such as white clothes when taking pictures to avoid light pollution.

[0129] In order to improve the accuracy of the color difference analysis method, the analysis device further comprises a display screen, and the dE value of the display screen is less than or equal to 1.5. In this way, the color accuracy of the photographing device can be detected, and the appropriate photographing device can be adjusted through the display screen.

[0130] The analysis device based on the color difference analysis method has all the technical solutions of the color difference analysis method, and therefore has all the beneficial effects of the color difference analysis method. The present application will not be described again.

[0131] It should be noted that when the control device extracts and analyzes the color difference value in the color difference picture, the following operations can be performed: the image processing software is opened and the color is extracted by the straw tool. The color is extracted from the A region and the B region with matching color difference and the color card, so that the corresponding Lab absolute value can be obtained, and the color extraction value LAB of the A region is recorded, and the data is indicated by the name L1, A1 and B1. The color extraction value LAB of the B region is recorded, and the data is indicated by the name L2, A2 and B2. The color extraction value of the standard color card is recorded, and the data is indicated by the name L3, A3 and B3.

[0132] In the judgment step, when measuring the 6-angle standard color value, a color difference meter is used to measure the 6-angle standard color difference value of the standard color board under different light sources. Through the standard color board as a medium, according to the judgment of the initial value difference, the area and type causing the color difference are found, the range causing the color difference is found according to the closeness of the standard value of the standard color board under the standard light source and the initial value, and the final angle causing the color difference is found by comparing the color difference area value of the corresponding range and the initial value of the color difference area. Whether the metamerism occurs is judged through the ratio of the color difference area value of the corresponding range and the initial value of the color difference area, whether the color difference is caused by different light sources, so that the area, type, angle, light source and the like causing the color difference are accurately found, and the color difference is accurately and quickly found.

[0133] The technical solutions of the present application will be further described in detail below in combination with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present application and do not limit the present application.

[0134] Embodiment 1

[0135] A certain high-chroma orange car has obvious visual color difference in the indoor traffic light state, and the car body and the bumper appear obvious visual color difference. The following method is used to analyze the cause of the color difference:

[0136] 1) Prepare a professional display screen, and use a color calibration instrument to calibrate the display screen, so that the maximum dE is controlled within 1.5. This step is to prepare a device that can detect the color accuracy of the shooting device;

[0137] 2) The standard color board is tightly attached between the car body and the bumper with color difference, and a professional digital camera is used to take pictures of the car body and the bumper. The position and angle of the camera are kept consistent with the evaluation state;

[0138] 3) Import the photos into the computer, and confirm that the sample color can be restored in the display after color calibration. This step uses the shooting device to solidify the visual subjective feeling of the human eye to the color difference under the current light source and sample state into a photo file that can be quantitatively analyzed, and uses the photo file as a color information carrier for subsequent analysis;

[0139] 4) Use the pipette tool in the image processing software to take color, name the car body as the first color difference area, and name the bumper as the second color difference area. The color difference data is shown in Table 1:

[0140] Table 1 Color difference values of car body, bumper and standard color board

[0141] L value A value B value L1, A1, B1 46 39 51 L2, A2, B2 49 30 49 L3, A3, B3 46 39 52 L4, A4, B4 0 0 -1 L5, A5, B5 3 -9 -3 L6, A6, B6 -3 -9 -2

[0142] 5), analysis data can know, L6, A6, B6 absolute value biggest for A6, A value is the main factor causing this time chromatic aberration, and L4, A4, B4, L5, A5, B5 absolute value biggest value for A5, so bumper red green phase is the main reason causing this time chromatic aberration;

[0143] 6), high chroma orange is solid color paint, so only need to determine the standard color difference value under D65 light source and bumper 45 degree color difference value, and the color difference data is shown in table 2:

[0144] Table 2 A value of bumper and standard color plate under D65 light source

[0145] Item A value under D65 light 45° A* value of standard color chart 50 Bumper dA45° value -0.38

[0146] 7), judge the ratio of dA(-0.38) and A5(value is-9) under D65 light source, less than 0.25, metachromatism occurs, replace D65 light source with A light source, and return to step 6), measure the 45 degree color difference value of bumper under A light source, and the color difference data is shown in table 3:

[0147] Table 3 45 degree A value of bumper under A light source

[0148] Item A value under A light Bumper dA45° value -4.3

[0149] 8), judge the ratio of dA(value is-4.3) and A5(value is-9) under A light source, greater than 0.25, judge the reason causing color difference is the bumper red green phase value deviation under A light source;

[0150] 9), adjust the bumper red green phase value under A light source, adjust the dA value of bumper under A light source to within ±1, so as to successfully solve the color difference problem.

[0151] Example 2

[0152] A blue metal paint truck appears color difference problem between truck and body accessories, the following method is used to analyze the reason of color difference:

[0153] 1), prepare a professional display screen, calibrate the display screen with colorimeter, and control the maximum dE within 1.5, this step is to prepare a device that can detect the color accuracy of the shooting equipment;

[0154] 2), tightly paste the standard color plate between the body and accessories with color difference, use professional digital camera to take pictures of the body and accessories, and the position and angle of shooting are consistent with the visual evaluation state;

[0155] 3) Import the photo into the computer, and confirm the sample color can be restored in the display of the color correction. The purpose of this step is to use the photo equipment to solidify the visual subjective feeling of the human eye to the color difference under the current light source and sample state into a photo file that can be quantitatively analyzed, and use the photo file as a color information carrier for subsequent analysis;

[0156] 4) Use the pipette tool in the image processing software to take color, name the car body as the first color difference area, and name the car body accessories as the second color difference area. The color difference data is shown in Table 4:

[0157] Table 4 Color difference values of car body, car body accessories and standard color plate

[0158] L value A value B value L1, A1, B1 91 -12 -14 L2, A2, B2 98 -13 -15 L3, A3, B3 92 -12 -14 L4, A4, B4 -1 0 0 L5, A5, B5 6 -1 -1 L6, A6, B6 7 -1 -1

[0159] 5) The analysis data shows that the maximum absolute value of L6, A6 and B6 is L6 value, and the L value is the main factor causing the color difference. The maximum absolute value of L4, A4, B4, L5, A5 and B5 is L5, so the car body accessory lightness value is the main reason causing the color difference;

[0160] 6) The blue metal paint is a non-solid color paint, so it is necessary to measure the 6-angle standard color difference value and accessory color difference value under D65 light source. The color difference data is shown in Table 5:

[0161] Table 5 L value of 6-angle under D65 light source of accessories and standard color plate

[0162]

[0163] 7) The angle corresponding to the L value of the standard color plate closest to L3 (92) is 15° (103.27) and 25° (85.59). At this time, it is necessary to consider -15°, -1.2 (-15°), 11.49 (15°), 0.39 (25°), and the L value closest to L5 (6) is 11.49, corresponding to the angle of 15°;

[0164] 8) The ratio of dL15° (value 11.49) to L5 (value 6) is greater than 0.25, and the cause of the color difference is the lightness value of the accessory at 15°. Adjust the L value of the accessory at 15°, and the color difference problem is solved.

[0165] The color difference analysis method of the present application obtains a color difference photo, and performs color picking and analysis on the color difference values in the photo, judges the area where color difference occurs through the absolute value size of the color difference value difference between the first color difference area and the standard color plate and the color difference value difference between the second color difference area and the standard color plate, judges the type of color difference through the absolute value size of the color difference value difference between the first color difference area and the second color difference area, judges the angle causing the color difference through the standard color plate difference value of the initial color picking value of the standard color plate and the 6-angle standard color difference value of the standard color plate, so that the area, type and angle of color difference can be determined, and the angle of metamerism and goniochromism can be distinguished.

[0166] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the patent protection scope of the present application.

Claims

1. A color difference analysis method characterized by, The method comprises the following steps: S10, acquiring a photo of a color difference area, the color difference area comprising a first area, a second area, and a standard color plate area placed between the first area and the second area; S20, acquiring initial color values LAB1 of the first area, initial color values LAB2 of the second area, and initial color values LAB3 of the standard color plate in the photo of the color difference area; S30, calculating a difference value LAB4 between the initial color values LAB1 of the first area and the initial color values LAB3 of the standard color plate, a difference value LAB5 between the initial color values LAB2 of the second area and the initial color values of the standard color plate, and a difference value LAB6 between the color values LAB1 of the first area and the color values LAB2 of the second area; S40, according to the calculation results, determining that the maximum absolute value in LAB4 and LAB5 is the area causing the color difference, and determining that the maximum absolute value in LAB6 is the main reason causing the color difference; S50, acquiring the color paint type of the area causing the color difference, determining an angle standard color difference value method, acquiring angle standard color difference values of the standard color plate and the area causing the color difference by the angle standard color difference value method, calculating a standard color plate difference value between the initial color values of the standard color plate and the angle standard color difference values of the standard color plate, and determining the angle causing the color difference according to the calculation results: if the color paint type causing the color difference is a solid color paint, determining that a 45° standard color difference value method under a D65 light source is adopted; if the color paint type causing the color difference is a non-solid color paint, determining that a 6-angle standard color difference value method under a D65 light source is adopted.

2. The color difference analysis method according to claim 1, characterized by, In step S30: LAB1 comprises L1, A1, and B1, LAB2 comprises L2, A2, and B2, LAB3 comprises L3, A3, and B3, LAB4 comprises L4, A4, and B4, LAB5 comprises L5, A5, and B5, and LAB6 comprises L6, A6, and B6, wherein L1, L2, and L3 are lightness values, A1, A2, and A3 are red-green values, and B1, B2, and B3 are yellow-blue values; L4=L1-L3, A4=A1-A3, B4=B1-B3, L5=L2-L3, A5=A2-A3, B5=B2-B3, L6=L2-L1, A6=A2-A1, and B6=B2-B1. In step S40:

3. The color difference analysis method according to claim 2, characterized by, if the maximum absolute value in LAB4 and LAB5 is any one of L4, A4, and B4, it is determined that the first area is the area causing the color difference; if the maximum absolute value in LAB4 and LAB5 is any one of L5, A5, and B5, it is determined that the second area is the area causing the color difference; if the maximum absolute value in LAB6 is L6, it is determined that the lightness value is the main reason causing the color difference; if the maximum absolute value in LAB6 is A6, it is determined that the red-green value is the main reason causing the color difference; if the maximum absolute value in LAB6 is B6, it is determined that the yellow-blue value is the main reason causing the color difference. Step S50 further comprises:

4. The color difference analysis method according to claim 3, characterized by, ​ S501, if the maximum absolute value of L6, A6, B6 is L6, and the maximum absolute value of L4, A4, B4, L5, A5, B5 is any one of L4, A4, B4, it is judged that the first region is the region causing color difference, and the lightness value of the first region is the main factor causing color difference; S502, the type of color paint causing color difference is obtained, and the type of color paint is judged.

5. The color difference analysis method according to claim 4, characterized by, After step S502, it further includes: S503, if the type of color paint causing color difference is solid color paint, it is judged to use D65 light source for color taking; S504, the color difference data dL45° of the first region under 45° of D65 light source is obtained, and the color difference data L*45° of the standard color plate under 45° of D65 light source is obtained; S505, the ratio of dL45° and L4 is calculated, and the ratio of dL45° and L4 is judged: if the ratio of dL45° and L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region under 45° of D65 light source is the main reason causing color difference; if the ratio of dL45° and L4 is less than 0.25, it is judged that metromeria occurs, returns to step S503, and D65 light source is replaced by A light source and F2 light source respectively.

6. The color difference analysis method according to claim 4, characterized by, After step S502, it further includes: S506, if the type of color paint causing color difference is non-solid color paint, it is judged to use D65 light source for color taking; S507, the color standard value L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° of the standard color plate under 6 angles of D65 light source is obtained, and the standard color difference value dL-15°, dL15°, dL25°, dL45°, dL75°, dL110° of the first region under 6 angles of D65 light source is obtained; S508, the difference value of L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° and L3 is calculated; S509, according to the difference value of L*-15°, L*15°, L*25°, L*45°, L*75°, L*110° and L3, the angle corresponding to the two smallest difference values L*X and L*Y is judged as the angle range causing color difference, and X and Y are judged, wherein X, Y are any two different angles in-15°, 15°, 25°, 45°, 75°, 110°.

7. The color difference analysis method according to claim 6, characterized by, After step S509, it further includes: S510 and S511, or S512 and S513, or S514 and S515, wherein, S510 includes: if X, Y does not contain any one of-15° and 15°, the difference value of L4 and dLX and L4 and dLY is calculated: S511 includes: judging according to the difference value of L4 and dLX and L4 and dLY: If the difference between L4 and dLX is the smallest, the ratio of dLX to L4 is calculated, if the ratio of dLX to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the X angle under the D65 light source is the main cause of the color difference; if the ratio of dLX to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source respectively; If the difference between L4 and dLY is the smallest, the ratio of dLY to L4 is calculated, if the ratio of dLY to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the Y angle under the D65 light source is the main cause of the color difference; if the ratio of dLY to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source respectively; S512 comprises: if only 15° is contained in X and Y and-15° is not contained, the difference between L4 and dL-15°, dLX and dLY is calculated; S513 comprises: judging according to the difference between L4 and dL-15°, dLX and dLY: If the difference between L4 and dL-15° is the smallest, the ratio of dL-15° to L4 is calculated, and the judgment is made according to the calculation result, if the ratio of dL-15° to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the-15° angle under the D65 light source is the main cause of the color difference; if the ratio of dL-15° to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source respectively; If the difference between L4 and dLX is the smallest, the ratio of dLX to L4 is calculated, and the judgment is made according to the calculation result, if the ratio of dLX to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the X angle under the D65 light source is the main cause of the color difference; if the ratio of dLX to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source respectively; If the difference between L4 and dLY is the smallest, the ratio of dLY to L4 is calculated, and the judgment is made according to the calculation result, if the ratio of dLY to L4 is greater than or equal to 0.25, it is judged that the lightness value of the first region at the Y angle under the D65 light source is the main cause of the color difference; if the ratio of dLY to L4 is less than 0.25, it is judged that metamerism occurs, and the step S506 is returned, and the D65 light source is replaced by the A light source and the F2 light source respectively; S514 comprises: if only-15° is contained in X and Y and 15° is not contained, the difference between L4 and dL15°, dLX and dLY is calculated; S515 comprises: judging according to the difference between L4 and dL15°, dLX and dLY: If the difference between L4 and dL15° is the minimum, the ratio of dL15° to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dL15° to L4 is ≥0.25, it is judged that the lightness value of the first region at 15° angle under D65 light source is the main cause of the color difference. If the ratio of dL15° to L4 is <0.25, it is judged that metamerism occurs, and the process returns to step S506, and D65 light source is replaced by A light source and F2 light source respectively; If the difference between L4 and dLX is the minimum, the ratio of dLX to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLX to L4 is ≥0.25, it is judged that the lightness value of the first region at X angle under D65 light source is the main cause of the color difference. If the ratio of dLX to L4 is <0.25, it is judged that metamerism occurs, and the process returns to step S506, and D65 light source is replaced by A light source and F2 light source respectively; If the difference between L4 and dLY is the minimum, the ratio of dLY to L4 is calculated, and a judgment is made according to the calculation result. If the ratio of dLY to L4 is ≥0.25, it is judged that the lightness value of the first region at Y angle under D65 light source is the main cause of the color difference. If the ratio of dLY to L4 is <0.25, it is judged that metamerism occurs, and the process returns to step S506, and D65 light source is replaced by A light source and F2 light source respectively.

8. The color difference analysis method according to claim 4, characterized by, Step S50 further comprises: S516, if the maximum of absolute values in L6, A6, B6 is A6, and the maximum of absolute values in L4, A4, B4, L5, A5, B5 is any one of L4, A4, B4, it is judged that the red-green phase value of the first region is the main factor causing the color difference, the type of the color paint is judged, the process returns to step S501, and the lightness value in step S501 is replaced by the red-green phase value; S517, if the maximum of absolute values in L6, A6, B6 is B6, and the maximum of absolute values in L4, A4, B4, L5, A5, B5 is any one of L4, A4, B4, it is judged that the yellow-blue phase value of the first region is the main factor causing the color difference, the type of the color paint is judged, the process returns to step S501, and the lightness value in step S501 is replaced by the yellow-blue phase value.

9. The color difference analysis method according to claim 4, characterized by, Step S50 further comprises: S518, if the maximum of absolute values in L6, A6, B6 is L6, and the maximum of absolute values in L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the lightness value of the second region is the main factor causing the color difference, the type of the color paint is judged, the process returns to step S501, and the first region in step S501 is replaced by the second region; S519, if the maximum of absolute values in L6, A6, B6 is A6, and the maximum of absolute values in L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the red-green phase value of the second region is the main factor causing the color difference, the type of the color paint is judged, the process returns to step S501, and the first region in step S501 is replaced by the second region, and the lightness value is replaced by the red-green phase value; S520, if the maximum absolute value of L6, A6, B6 is B6, and the maximum absolute value of L4, A4, B4, L5, A5, B5 is any one of L5, A5, B5, it is judged that the yellow-blue phase value of the second region is the main factor causing the color difference, the type of the paint is judged, step S501 is returned, the first region in step S501 is replaced by the second region, and the lightness value is replaced by the yellow-blue phase value.

10. An analysis apparatus based on a color difference analysis method, characterized by comprising: The analysis device based on the color difference analysis method comprises: a shooting device for shooting a color difference photo; and a control device in communication connection with the shooting device, the control device comprising a memory, a processor, a display screen, and a color difference analysis control program stored in the memory and executable on the processor, and the color difference analysis control program, when executed by the processor, implements the steps of the color difference analysis method according to any one of claims 1 to 9.

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