CN110567890A - Color measurement reference determination method - Google Patents
Color measurement reference determination method Download PDFInfo
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- CN110567890A CN110567890A CN201910871979.2A CN201910871979A CN110567890A CN 110567890 A CN110567890 A CN 110567890A CN 201910871979 A CN201910871979 A CN 201910871979A CN 110567890 A CN110567890 A CN 110567890A
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Abstract
The embodiment of the invention provides a method for determining a measurement reference of a color, which comprises the following steps: traversing each color block of the preset color gamut area, comparing each first lab value with any second lab value in all color gamut lookup tables, and determining a second rgb value corresponding to the second lab value in all the color gamut lookup tables when the first lab value and the second lab value meet a first preset formula; based on the second rgb value, obtaining a first lab value corresponding to the second rgb value according to the first mapping relation; replacing the second lab value corresponding to the second rgb value in the entire gamut look-up table with the first lab value corresponding to the second rgb value. The method is used for solving the problem that the local precision is sacrificed in order to consider the whole color in the prior art, so that the precision measurement problem of a specific color area can be obviously improved.
Description
Technical Field
the invention relates to the field of color measurement, in particular to a method for determining a measurement reference of color.
background
in the packaging and printing industry, color is an important part of product quality, and defective products or waste products can be caused due to inaccurate product color measurement or inaccurate color difference measurement at different positions, so that economic loss is brought to enterprises. Therefore, a fast and effective color measurement method is needed to accurately measure the color of the product and avoid unnecessary economic loss of enterprises.
in the existing color measurement method, a mapping relation between an RGB color space and a Lab color space is established by utilizing a polynomial regression method, and colors can be converted into the Lab color space which is irrelevant to equipment, so that the colors are effectively measured. The mapping relation established by the method is based on the average color difference meeting most colors, so that the accuracy is sacrificed to take the whole color into consideration, and the method is difficult to meet the current industrial standard in measurement accuracy.
Disclosure of Invention
In order to solve the above technical problem, an embodiment of the present invention provides a method for determining a measurement reference of a color, so as to solve the problem in the prior art that local accuracy is sacrificed in consideration of an overall color, so that an accuracy measurement problem of a specific color region can be significantly improved.
according to a first aspect of embodiments of the present invention, there is provided a method for determining a measurement reference of a color, including the steps of:
Obtaining a first mapping relation between a first rgb value and a first lab value according to a first preset strategy based on measuring the first rgb value and the first lab value of each color block in a preset color gamut area;
traversing each color block in the preset color gamut area, comparing each first lab value with any second lab value in all color gamut lookup tables, and determining a second rgb value corresponding to the second lab value in all the color gamut lookup tables when the first lab value and the second lab value meet a first preset formula;
Based on the second rgb value, obtaining a first lab value corresponding to the second rgb value according to the first mapping relation;
Replacing the second lab value corresponding to the second rgb value in the entire gamut look-up table with the first lab value corresponding to the second rgb value.
optionally, the method comprises the following steps:
the measuring a first rgb value and a first lab value of each color block in a preset color gamut area comprises:
measuring by a first measuring device to obtain the first rgb value;
and measuring by a second measuring device to obtain the first lab value.
Optionally, the first preset policy is:
fitting a model through a first polynomial to the first rgb value and the first lab value to obtain the first mapping relation;
the first polynomial fitting model is:
L＝C0+C1R+C2G+C3B+C4RG+C5RB+C6GB+C7R2+C8G2+C9B2+C10R2G+C11RG2+C12R2B+C13RB2+C14G2B+C15GB2+C16RGB+C17R3+C12G3+C19B3
Wherein L is a corresponding value of L in the first lab value;
The R, G, and B are R, G, and B values corresponding to the first rgb value, respectively.
optionally, the first preset formula is as follows:
Wherein, the l, a and b are the l value, the a value and the b value corresponding to the first lab value respectively;
the l ', a ' and b ' are respectively the l value, the a value and the b value corresponding to the second lab value;
The thread is a predetermined color difference threshold.
Optionally, the method further comprises the following steps:
and obtaining a second mapping relation between the second lab value and the second rgb value according to a second preset strategy based on measuring a second rgb value and a second lab value of each color block in all the color gamut areas, and establishing the all-color gamut lookup table.
Optionally, the method comprises the following steps:
the measuring of the second rgb values and the second lab values of each color block in all the gamut areas comprises:
Measuring by a third measuring device to obtain the second rgb value;
and measuring by a fourth measuring device to obtain the second lab value.
optionally, the second preset policy is:
Obtaining a second mapping relation for the second rgb value and the second lab value through a second polynomial fitting model, and establishing the all-color gamut lookup table;
The second polynomial fitting model is:
L＝C0+C1R+C2G+C3B+C4RG+C5RB+C6GB+C7R2+C8G2+C9B2+C10R2G+C11RG2+C12R2B+C13RB2+C14G2B+C15GB2+C16RGB+C17R3+C18G3+C19B3
In the second polynomial fitting model, L is the corresponding value of/in the second lab values;
In the second polynomial fitting model, R, G and B are the r, g, and B values respectively corresponding to the second rgb value.
optionally, in all color blocks corresponding to the whole color gamut, the color blocks are divided into two groups:
one set is a calculation set, and the second rgb values and the second lab values of all color patches of the calculation set are fitted through the second polynomial fitting model;
and one group is a check group, and the fitting results are checked by the second rgb values and the second lab values of all the color blocks of the check group to obtain check results.
optionally, based on the check result, a color block whose color difference satisfies a preset range is marked as an abnormal point.
Optionally, in the calculation group, color blocks corresponding to the abnormal points are excluded, and the remaining color blocks are fitted again by the second polynomial fitting model.
in an embodiment of the present invention, a method for determining a measurement reference of a color is provided, including the following steps:
obtaining a first mapping relation between a first rgb value and a first lab value according to a first preset strategy based on measuring the first rgb value and the first lab value of each color block in a preset color gamut area;
traversing each color block in the preset color gamut area, comparing each first lab value with any second lab value in all color gamut lookup tables, and determining a second rgb value corresponding to the second lab value in all the color gamut lookup tables when the first lab value and the second lab value meet a first preset formula;
based on the second rgb value, obtaining a first lab value corresponding to the second rgb value according to the first mapping relation;
replacing the second lab value corresponding to the second rgb value in the entire gamut look-up table with the first lab value corresponding to the second rgb value.
in the above method, on the basis of all the color gamut lookup tables that have been established, a color gamut area that is desired to be improved in accuracy may be determined as a color patch of a blue color gamut, for example, for a specific color area. For this, the first lab value and the first rgb value of each color block are measured, and the first mapping relationship is established. By the method, under the condition of meeting a preset rule, all the color gamut lookup tables are updated through the first mapping relation, so that the problem that local precision is sacrificed to consider the whole color in the prior art is solved, and the precision measurement problem of a specific color area can be remarkably improved.
it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a flow chart illustrating a method of measuring a reference for a color according to an exemplary embodiment of the present invention;
fig. 2 is a flowchart illustrating a method for determining a measurement reference of a color according to an exemplary embodiment of the present invention to establish an all-gamut lookup table;
Fig. 3 is a flowchart illustrating a method of determining a measurement reference of a color according to an exemplary embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
in some of the flows described in the present specification and claims and in the above figures, a number of operations are included that occur in a particular order, but it should be clearly understood that these operations may be performed out of order or in parallel as they occur herein, with the order of the operations being indicated as 101, 102, etc. merely to distinguish between the various operations, and the order of the operations by themselves does not represent any order of performance. Additionally, the flows may include more or fewer operations, and the operations may be performed sequentially or in parallel. It should be noted that, the descriptions of "first", "second", etc. in this document are used for distinguishing different messages, devices, modules, etc., and do not represent a sequential order, nor limit the types of "first" and "second" to be different.
the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
fig. 1 is a flowchart illustrating a method of measuring reference determination of a color according to an exemplary embodiment of the present invention. As shown in fig. 1, in one embodiment of the present invention, there is provided a measurement reference determining method of color, including the steps of:
step S101, obtaining a first mapping relation between a first lab value and a first rgb value according to a first preset strategy based on measuring the first rgb value and the first lab value of each color block in a preset color gamut area;
step S102, traversing each color block in a preset color gamut area, comparing each first lab value with any second lab value in all color gamut lookup tables, and determining a second rgb value corresponding to the second lab value in all the color gamut lookup tables when the first lab value and the second lab value meet a first preset formula;
step S103, based on the second rgb value, obtaining a first lab value corresponding to the second rgb value according to the first mapping relation;
And step S104, replacing the second lab value corresponding to the second rgb value in the whole color gamut lookup table by the first lab value corresponding to the second rgb value.
In the above method, on the basis of all the color gamut lookup tables that have been established, a color gamut area that is desired to be improved in accuracy may be determined as a color patch of a blue color gamut, for example, for a specific color area. For this, the first lab value and the first rgb value of each color block are measured, and the first mapping relationship is established. By the method, under the condition of meeting a preset rule, all the color gamut lookup tables are updated through the first mapping relation, so that the problem that local precision is sacrificed to consider the whole color in the prior art is solved, and the precision measurement problem of a specific color area can be remarkably improved.
it should be noted that, in the four terms of the first lab value, the first rgb value, the second lab value, the second rgb value, etc., the expressions "first" and "second" are only used for distinguishing. In fact, in the embodiment of the present invention, the second Lab value and the second RGB value are RGB and Lab of the full color gamut color chart data, and the first Lab value and the first RGB value are RGB and Lab of the partial color gamut color chart data.
In the above embodiment, we first describe how to build the whole gamut lookup table.
As shown in fig. 2, fig. 2 is a flowchart illustrating a measurement reference determining method for color according to an exemplary embodiment of the present invention to establish an entire color gamut lookup table.
In an embodiment of the present invention, based on measuring the second rgb values and the second lab values of each color block in all the color gamut regions, a second mapping relationship between the second lab values and the second rgb values is obtained according to a second preset strategy, and a whole color gamut lookup table is established.
in this embodiment, a second rgb value is obtained by a third measuring device measurement; and measuring by a fourth measuring device to obtain a second lab value. The third measuring device may be an industrial camera, the fourth measuring device may be a color difference meter, but is not limited thereto, and other measuring devices capable of measuring to obtain the rgb value and the lab value should also be within the scope of the present invention. It should be noted that, in the present invention, in order to ensure an error, the first measurement device and the third measurement device may be the same industrial camera, and the second measurement device and the fourth measurement device may be the same colorimeter. Of course, the above-described apparatus may be different in cases where the error requirement is not too precise, and the present invention is not limited thereto and thus is within the scope of the present invention.
As shown in fig. 2, the method comprises the following steps:
In step S201, RGB data of the color card, that is, the second RGB values of the above-described embodiment of the present invention, is obtained, specifically, an RGB value of each color in the color card is obtained by capturing a full-color gamut color card image by an industrial camera.
step S202, obtaining the Lab value of the color chart, i.e. the second Lab value of the above embodiment of the present invention, specifically, measuring the Lab value of each color in the color chart by the color difference meter.
The RGB to Lab data for the partial color cards obtained are as follows:
| color block | R | G | B | L | a | b |
| 1 | 122 | 86 | 35 | 57.14 | 13.02 | 71.5 |
| 2 | 130 | 125 | 127 | 73.44 | 0.26 | -1.44 |
| 3 | 79 | 122 | 61 | 66.96 | -50.4 | 40.14 |
| 4 | 66 | 34 | 28 | 26.87 | 45.63 | 18.99 |
| 5 | 48 | 34 | 87 | 23.62 | 40.86 | -55.5 |
| 6 | 37 | 50 | 32 | 33.16 | -36.22 | 32.92 |
| 7 | 30 | 27 | 27 | 6.85 | 1.02 | -2.4 |
| … | … | … | … | … | … | … |
and step S203, performing polynomial fitting, and performing polynomial fitting on the color card through the obtained RGB and Lab to solve the mapping relation of the color space. That is, in the embodiment of the present invention,
The second preset strategy is:
Obtaining a second mapping relation for the second rgb value and the second lab value through a second polynomial fitting model, and establishing a look-up table of all color gamuts;
the second polynomial fitting model is:
L＝C0+C1R+C2G+C3B+C4RG+C5RB+C6GB+C7R2+C8G2+C9B2+C10R2G+C11RG2+C12R2B+C13RB2+C14G2B+C1SGB2+C16RGB+C17R3+C18G3+C19B3
in the second polynomial fit model, L is the corresponding value of/in the second lab value;
In the second polynomial fitting model, R, G and B are the r, g, and B values corresponding to the second rgb values, respectively.
It should be noted that, since the three channels l, a, b are independent of each other, the polynomials in the three channels have the same form but different coefficientsThe above formula only takes channel l as an example. For its C in channel a and channel b0-C19The coefficients are also calculated according to the polynomial fitting model described above.
And step S204, carrying out color verification and removing the interference of the abnormal points. Specifically, based on the check result, the color blocks whose color difference satisfies the preset range are marked as outliers.
How to operate to obtain the corresponding polynomial C in the second polynomial fitting model0-C19in one embodiment of the invention, can do so:
In all color blocks corresponding to the whole color gamut, the color blocks are divided into two groups:
One group is a calculation group, and second rgb values and second lab values of all color blocks of the calculation group are fitted through a second polynomial fitting model;
And one group is a check group, and the fitting results are checked by the second rgb values and the second lab values of all the color blocks of the check group to obtain check results.
Specifically, 540 color patches are preselected as a data supply source for building a look-up table of the whole color gamut. The measurement of 540 color blocks by an industrial camera and a color difference meter can obtain 540 sets of RGB and Lab data in the above table. In one embodiment, 90%, i.e., 486% of the data are selected as the calculation groups and the remaining 10%, i.e., 54% of the data are selected as the check groups.
Substituting 486 sets of data into the first polynomial fitting model to obtain an optimal solution through an overdetermined equation set, thereby obtaining C0-C19The optimal solution of (1).
During verification, at C0-C19under the premise of becoming known, substituting the RGB data of the group of data of the calibration group 54 into the first polynomial fitting model to respectively obtain corresponding Lab values, and solving the color difference between the calculated Lab values and the actually measured Lab values by the color difference meter.
And marking color blocks with color differences meeting the preset range as abnormal points based on the checking result. For example, the color of the first 5% (the percentage is not a fixed value) where the color difference is the largest is marked as an outlier.
Further, as shown in fig. 2,
Step S204 performs polynomial fitting again on the non-outlier points. Specifically, polynomial fitting is performed again on colors except for the abnormal points, interference of the abnormal points is eliminated, and a fitting polynomial with higher precision is obtained. In other words, in the calculation group, the color blocks corresponding to the abnormal points are excluded, and the remaining color blocks are fitted again through the second polynomial fitting model.
comparing polynomial coefficients before and after excluding outliers (from top to bottom, C0 to C19 respectively):
| Before the exception point is eliminated | after the abnormal point is eliminated |
| -36.5365 | -35.1258 |
| -27.2277 | -29.7093 |
| 95.5641 | 96.2214 |
| 4.65257 | 7.0023 |
| 45.7616 | 42.8961 |
| 2.52421 | 2.5007 |
| 6.34691 | 6.08323 |
| -16.035 | -15.3422 |
| -49.7649 | -48.9027 |
| -6.32324 | -3.76143 |
| 7.50328 | 9.01762 |
| -17.0515 | -15.8609 |
| -3.75153 | -5.28219 |
| -1.52931 | -0.9826 |
| -2.9483 | -1.06521 |
| -1.39151 | -2.5646 |
| 9.40431 | 10.67473 |
| -0.181502 | 0.87926 |
| 9.98207 | 10.06539 |
| 1.2543 | 1.6259 |
Step S206, a full-value lookup table is generated, which is the all-gamut lookup table read by the embodiment of the present invention. Specifically, the Lab measurement value of the color on the panchromatic color chart is directly stored in the lookup table, and the Lab values obtained by calculating other colors through fitting polynomial are stored in the corresponding positions in the lookup table, so that the establishment of the full-value lookup table is completed.
the accuracy of the established full-value lookup table is as follows, and the color difference is Δ E:
| average Delta E | maximum Delta E | Minimum Delta E | |
| before the exception point is eliminated | 2.8519 | 13.6701 | 0.3029 |
| after the abnormal point is eliminated | 2.1292 | 9.4172 | 0.2304 |
The complete full value lookup table would have 2563The data amount is too large for group data, so only part of the content is given as an example. The following table is partial data of the lookup table, in which only the L, a, b values of the color are presented, the row number in the lookup table is the index, and the value is calculated by the following formula for the RGB value of the corresponding color:
nIndex＝2562R+256G+B
| … | … | … |
| 23.15 | 40.25 | -54.9 |
| 22.83 | 40.24 | -54.73 |
| 23.13 | 40.18 | -54.95 |
| 23.07 | 40.35 | -55.37 |
| 22.91 | 40.46 | -55.18 |
| 23.3 | 40.73 | -55.57 |
| 23 | 40.68 | -55.37 |
| 23.28 | 41.02 | -55.69 |
| … | … | … |
as shown in fig. 3, fig. 3 is a flowchart illustrating a method for determining a measurement reference of a color according to an exemplary embodiment of the present invention.
In another embodiment of the invention, as shown in FIG. 3:
Step S301, a small color gamut color chart, that is, a color chart corresponding to the preset color gamut region according to the present invention, is manufactured.
specifically, it should be noted that the preset color gamut area may be a specific blue color gamut, a specific green color gamut, or other color gamut areas, and may of course include two or more color gamut areas. In this embodiment, we will explain the blue color gamut as an example.
In step S302, RGB data of the color card, i.e. the first RGB values of the above-mentioned embodiment of the present invention, is obtained, specifically, an RGB value of each color in the color card is obtained by capturing a full-color gamut color card image by an industrial camera.
Step S303, acquiring the Lab value of the color chart, i.e. the first Lab value of the above embodiment of the present invention, specifically, measuring the Lab value of each color in the color chart by the color difference meter.
specifically, in the above embodiment, we can obtain a first rgb value by the first measurement device measurement; and measuring by a second measuring device to obtain a first lab value. The first measuring device may be an industrial camera, the second measuring device may be a color difference meter, but is not limited thereto, and other measuring devices capable of measuring to obtain the rgb value and the lab value should be within the scope of the present invention.
and step S304, performing polynomial fitting by using the RGB values and the Lab values obtained in the two steps to obtain a fitting polynomial of the new color card.
Further, how to establish the mapping relationship between the first lab value and the first rgb value after obtaining the first lab value and the first rgb value, the embodiment of the present invention provides the following method:
the first preset strategy is:
Fitting a model through a first polynomial to the first rgb value and the first lab value to obtain a first mapping relation;
The first polynomial fitting model is:
L＝C0+C1R+C2G+C3B+C4RG+C5RB+C6GB+C7R2+C8G2+C9B2+C10R2G+C11RG2+C12R2B+C13RB2+C14G2B+C15GB2+C16RGB+C17R3+C18G3+C19B3
Wherein, L is the corresponding L value in the first lab value;
r, G and B are the r, g, and B values respectively corresponding to the first rgb value.
The accuracy after fitting to the small gamut color chip is as follows:
| Average Delta E | Maximum Delta E | minimum Delta E |
| 0.69033 | 2.36897 | 0.09775 |
In the above embodiment, the formula that can be updated is further set. For example, the first predetermined formula is:
Wherein, l, a and b are the l value, the a value and the b value corresponding to the first lab value respectively;
l ', a ' and b ' are respectively a value l, a value a and a value b corresponding to the second lab value;
thread is a predetermined color difference threshold.
Specifically, in the actual operation, the actual operation is a dual cycle, the outer cycle is to traverse the colors of the small color cards, and the inner cycle is to traverse the full-value lookup table. Traversing the full-value lookup table once every time a certain color of the small color card is searched, respectively solving the color difference by using the color value of the small color card and all the color values in the lookup table, when the color difference is smaller than a threshold value, taking out the RGB value corresponding to the color value in the full-value lookup table at the moment, substituting the RGB value into the fitting polynomial of the small color card, solving a new Lab value to replace the original Lab value in the lookup table, and finishing the updating; and when the color difference is not less than the threshold value, not updating. And then continuing to circulate, repeating the process until the circulation is finished, and finishing the updating of the lookup table.
the innovative point of the algorithm is that the fitting result is verified once during each polynomial fitting, and the color value which has a large influence on the fitting result is eliminated, so that the fitting precision is improved. Secondly, the target color area can be selected according to the actual situation to be locally updated, and then the measurement precision is improved. In consideration of the actual color measurement scene, all colors are not required to be measured with high precision, so that the method can be used for updating the interested color range in a targeted manner, and the measurement precision of the color to be detected is improved purposefully.
The data in the lookup table are marked and can be identified as a measured value and a non-measured value, and only the non-measured value is updated during updating, and the measured value is an accurate value measured by standard equipment, so that updating is not needed (wherein, the abnormal points in the above step are all measured values and are directly filled in the lookup table without updating).
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods of the various embodiments or some parts of the embodiments.
finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. a method for determining a measurement reference for color, comprising the steps of:
obtaining a first mapping relation between a first rgb value and a first lab value according to a first preset strategy based on measuring the first rgb value and the first lab value of each color block in a preset color gamut area;
Traversing each color block of the preset color gamut area, comparing each first lab value with any second lab value in all color gamut lookup tables, and determining a second rgb value corresponding to the second lab value in all the color gamut lookup tables when the first lab value and the second lab value meet a first preset formula;
Based on the second rgb value, obtaining a first lab value corresponding to the second rgb value according to the first mapping relation;
Replacing the second lab value corresponding to the second rgb value in the entire gamut look-up table with the first lab value corresponding to the second rgb value.
2. the measurement reference determination method according to claim 1, characterized by comprising the steps of:
The measuring a first rgb value and a first lab value of each color block in a preset color gamut area comprises:
Measuring by a first measuring device to obtain the first rgb value;
And measuring by a second measuring device to obtain the first lab value.
3. the measurement reference determination method according to claim 1, wherein the first preset strategy is:
fitting a model through a first polynomial to the first rgb value and the first lab value to obtain the first mapping relation;
the first polynomial fitting model is:
L＝C0+C1R+C2G+C3B+C4RG+C5RB+C6GB+C7R2+C3G2+C9B2+C10R2G+C11RG2+C12R2B+C13RB2+C14G2B+C15GB2+C16RGB+C17R3+C18G3+C19B3
wherein L is a corresponding 1 value in the first lab value;
the R, G, and B are R, G, and B values corresponding to the first rgb value, respectively.
4. the measurement reference determination method according to claim 1, wherein the first preset formula is:
Wherein, the 1, a and b are respectively a 1 value, an a value and a b value corresponding to the first lab value;
The 1 ', a ' and b ' are respectively a 1 value, an a value and a b value corresponding to the second lab value;
The thread is a predetermined color difference threshold.
5. The measurement reference determination method according to any one of claims 1 to 4, further comprising the steps of:
and obtaining a second mapping relation between the second lab value and the second rgb value according to a second preset strategy based on measuring a second rgb value and a second lab value of each color block in all the color gamut areas, and establishing the all-color gamut lookup table.
6. the measurement reference determination method according to claim 5, characterized by comprising the steps of:
The measuring of the second rgb values and the second lab values of each color block in all the gamut areas comprises:
measuring by a third measuring device to obtain the second rgb value;
and measuring by a fourth measuring device to obtain the second lab value.
7. The measurement reference determination method of claim 6, wherein the second preset strategy is:
Obtaining a second mapping relation for the second rgb value and the second lab value through a second polynomial fitting model, and establishing the all-color gamut lookup table;
the second polynomial fitting model is:
L＝C0+C1R+C2G+C3B+C4RG+C5RB+C6GB+C7R2+C8G2+C9B2+C10R2G+C11RG2+C12R2B+C13RB2+C14G2B+C15GB2+C16RGB+C17R3+C18G3+C19B3
in the second polynomial fitting model, L is a corresponding 1 value of the second lab values;
In the second polynomial fitting model, R, G and B are the r, g, and B values respectively corresponding to the second rgb value.
8. the measurement reference determining method according to claim 7, wherein, of all color patches corresponding to the entire color gamut, the color patches are divided into two groups:
one set is a calculation set, and the second rgb values and the second lab values of all color patches of the calculation set are fitted through the second polynomial fitting model;
And one group is a check group, and the fitting results are checked by the second rgb values and the second lab values of all the color blocks of the check group to obtain check results.
9. The measurement reference determination method according to claim 8, wherein a patch whose color difference satisfies a preset range is marked as an outlier based on the verification result.
10. The measurement reference determination method according to claim 9, wherein in the calculation group, color blocks corresponding to the abnormal points are excluded, and remaining color blocks are fitted again by the second polynomial fitting model.
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