Color gamut management method for multi-primary color LED lamp / screen

Abstract

The invention discloses a color gamut management method for a multi-primary-color LED lamp / screen. The color saturation of a corrected light-emitting color point is improved to the maximum extent on the basis of applying a rigid target color gamut space management method. Comprising a method for establishing a unified target color gamut space for a plurality of multi-primary-color LED lamps / screens, and a method for dividing the target color gamut space into a core rigid correction area and a peripheral flexible correction area according to the demand of the market for color saturation under the condition of establishing the target color gamut space. A flexible correction algorithm is introduced into a target light-emitting color point in a peripheral flexible correction area to correct the target light-emitting color point, and the corrected light-emitting color point moves towards the boundary direction of an original color gamut space, so that the color presented by the multi-primary-color LED lamp / screen is richer than the color corrected by adopting a rigid color gamut management method; on the basis of ensuring the consistency of the light-emitting colors of the light-emitting color points in the core rigid correction area, the capability of original high-saturation colored light can be fully exerted.

Description

Technical Field

[0001] The present invention relates to color control of a multi-primary color LED lamp / screen, and in particular to a flexible color gamut management method for a multi-primary color LED lamp / screen. Background Art

[0002] Due to the constraints of materials and manufacturing processes, there is a natural inconsistency in the brightness and chromaticity of LED light-emitting chips, resulting in two or more multi-primary color LED lamps or LED display screens (hereinafter referred to as multi-primary color LED lamps / screens) of the same type (the same type means: the materials, processes, and number of primary colors used in the manufacturing product, and the color coordinates and brightness corresponding to the primary colors are the same, and the production batches can be different) The actual color coordinates and brightness of the corresponding primary colors are not the same, that is, for different luminous color points presented on the multi-primary color LED lamps / screens (the luminous color point is a color presented by the multi-primary color LED lamp / screen, corresponding to a color coordinate on the color gamut diagram) point), when the primary color control signal is the same, the color presented by the luminous color point on different multi-primary color LED lamps / screens may be quite different (for example, a luminous color point is presented by a set mixing ratio of 100% red primary color, 50% green primary color and 20% blue primary color, but when this mixing ratio is applied to two multi-primary color LED lamps / screens of the same type, the color coordinates and brightness of the corresponding primary colors in the two may deviate due to slight differences in materials and manufacturing processes, resulting in a large color difference in the luminous colors presented, causing the two to emit inconsistent luminous colors even though they are the same type of multi-primary color LED lamps / screens).

[0003] In order to solve the problem of color inconsistency, the existing color gamut management method for full-color gamut multi-primary color LED lamps / screens with three primary colors or more primary colors is to first establish a common and unified target color gamut (also called target color gamut space or target color space, its definition is explained below) for multiple multi-primary color LED lamps / screens of the same type, and then the color management unit substitutes the received primary color control signal (C1_value, C2_value,...CN_value) into the target color gamut space for analysis to obtain the color coordinate point corresponding to the luminous color point in the target color gamut space.

[0004] The target color gamut space is set in the CIE1931 standard colorimetry system, wherein the color coordinate point T (T_x, T_y) of the luminous color point is the color coordinate point in the CIE1931 standard colorimetry system.

[0005] Conversely, taking the color coordinate value T (T_x, T_y) of the luminous color point in the target color gamut space as the target, the proportion of each original primary color that needs to participate in the color mixing in the original color gamut space of the multi-primary color LED lamp / screen is solved. Afterwards, the color control signal corresponding to the proportion of each original primary color participating in the color mixing is output to the LED constant current drive unit to control the LED light emission and output light corresponding to the luminous color point (see the invention patent application submitted by the applicant to the State Intellectual Property Office on August 9, 2018, application number: 201810903106.0, entitled: A color space management device and method for LED multi-primary color lamps).

[0006] Glossary:

[0007] The original color gamut space is a polygonal area formed by connecting the color coordinates of each original primary color in the multi-primary color LED lamp / screen on the color gamut diagram, and the luminous color points corresponding to all colors that the multi-primary color LED lamp / screen can present are all located in the polygonal area.

[0008] The original primary colors refer to the primary colors in the original color gamut space.

[0009] The target color gamut space is a polygonal area enclosed by the lines on the color gamut diagram that connect new primary colors (called target primary colors) with the same number of original primary colors of this type of multi-primary LED lamps / screens, selected in the overlapping area of ​​the original color gamut spaces of many multi-primary LED lamps / screens of the same type.

[0010] Note: The color coordinates of the target primary color may be the same as the color coordinates of the original primary color, or they may be completely different.

[0011] The color coordinates T (T_x, T_y) of the luminous color point T corresponding to a specific set of primary color control signals in the target color gamut space are calculated as follows:

[0012]

[0013]

[0014]

[0015] The calculation can only be completed by combining the values ​​of the target color gamut space.

[0016] The target color gamut space of a multi-primary color LED lamp / screen is represented by the following N-row, 3-column matrix:

[0017]

[0018] In the matrix: Ci represents the primary color No. i in the original color gamut space, and the value of i ranges from 1 to N;

[0019] Ci_x and Ci_y represent the target color coordinates x and y of primary color i, respectively; Ci_Y represents the Y stimulus value of primary color i, that is, the brightness;

[0020] x and y are the color coordinate values ​​of the CIE1931 standard colorimetric system;

[0021] X, Y, and Z are the spectral tristimulus values ​​of the CIE 1931 standard colorimetry system.

[0022] T_X, T_Y, and T_Z are the tristimulus values ​​of the above-mentioned luminous color point T, and T_x and T_y are the color coordinates of the above-mentioned luminous color point T.

[0023] The above method has the following shortcomings:

[0024] In order to ensure that several multi-primary color LED lamps / screens of the same type have the same target color gamut space, the color correction method of the above-mentioned prior art (hereinafter referred to as the rigid color gamut management method) will cause the color gamut space of the multi-primary color LED lamp / screen to shrink. Although the rigid color gamut management method can ensure that multiple multi-primary color LED lamps / screens output light colors with good consistency for the same color control signal, it has the disadvantage of sacrificing and cutting the high-saturation color gamut, and cannot fully utilize the original color gamut space of the multi-primary color LED lamp / screen (that is, each luminous color point in the target color gamut space cannot present light colors outside the target color gamut space and that can be presented by the original color gamut space of the corresponding multi-primary color LED lamp / screen). In particular, the more multi-primary color LED lamps / screens involved in management, the worse the consistency of the incoming light color, and the larger the high-saturation color gamut that needs to be sacrificed and cut. The target color gamut space set by some manufacturers in the early stage may become unusable due to the increase in batches of incoming materials and changes in color quality. To ensure the light color consistency of the incoming materials, they can only consider the target color gamut space of the multi-primary color LED lamps / screens shipped in the early stage and combine it with the target color gamut space set for the multi-primary color LED lamps / screens of the later incoming materials to re-set a new target color gamut space suitable for the multi-primary color LED lamps / screens of the early and late batches. This will greatly increase maintenance costs, and high-saturation colors will be sacrificed and cut again, seriously damaging the user experience. Summary of the Invention

[0025] The technical problem to be solved by the present invention is to provide a color gamut management method for multi-primary color LED lamps / screens that maximizes the color saturation of the corrected luminous color points based on the application of a rigid target color gamut space management method.

[0026] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0027] The color gamut management method for a multi-primary color LED lamp / screen of the present invention includes a method for establishing a unified target color gamut space for a plurality of multi-primary color LED lamps / screens having the same number and type of primary colors. The method further includes, when establishing the target color gamut space, dividing the target color gamut space into a core rigid correction region and a peripheral flexible correction region based on market demand for color saturation. The method comprises the following steps:

[0028] 1) Align the original color gamut space of the multi-primary color LED lamp / screen with the target color gamut space in the CIE1931 standard colorimetric system, and use the target color mixing point M1 of the target color gamut space as the center and adjust the flexible correction range coefficient R from the inside to the outside. si The core rigid correction area and the peripheral flexible correction area are sequentially demarcated according to the determined proportions;

[0029] 2) Aligning the original color point in the original color gamut space to the target color point T in the target color gamut space that falls within the core rigid correction area 1i The color coordinates and the matching value of the corresponding target primary color control signal are corrected using a rigid color gamut management method;

[0030] 3) Aligning the original color point in the original color gamut space to the target color point T in the target color gamut space that falls within the peripheral flexible correction area 1i The matching values ​​of the color coordinates and the corresponding target primary color control signals are corrected using a flexible correction algorithm that improves color saturation.

[0031] The soft correction algorithm is to correct the target color point T in the CIE1931 standard colorimetric system. 1i The color point T that is aligned with the CIE 1976 standard colorimetric system and falls within the flexible correction area 2i Correction is made, and the corrected color change point T 2i The color coordinates of the target color mixing point M1 are aligned with the color changing point M2 in the CIE 1976 standard colorimetric system to the color changing point T 2i The extension line of the connection line is shifted toward the boundary of the original color gamut space according to the set amplitude.

[0032] The method for correction using the flexible correction algorithm comprises the following steps:

[0033] 1) Obtain the target color mixing point M1 and target color point T based on the CIE1931 standard colorimetric system 1i The color coordinates of

[0034] 2) Make the target color mixing point M1 to the target color point T 1i The line connecting the two intersects with the inner boundary of the peripheral flexible correction area to obtain the "31-color" flexible inner boundary intersection point S 1i; Extend the line and intersect with the target color gamut space boundary and the original color gamut space boundary to obtain the "31 color" target boundary intersection point A 1i and the original boundary intersection point B of "31 colors" 1i ;

[0035] 3) Set the target color mixing point M1 and target color point T 1i 、"31 colors" flexible inner boundary intersection S 1i 、“31 colors” target boundary intersection point A 1i and the original boundary intersection point B of "31 colors" 1i The color coordinates are converted into the CIE1976 standard colorimetric system and the corresponding mixing point M2 and color point T are calculated by the relevant formula. 2i 、"76 colors" flexible inner boundary intersection S 2i 、“76 colors” target boundary intersection point A 2i and the original boundary intersection point B of "76 colors" 2i The color coordinates of

[0036] 4) In the CIE 1976 standard colorimetric system, the color point T that falls within the flexible correction area 2i According to the flexibility correction amplitude coefficient R so Determine the ratio along the line to the "76 colors" original boundary intersection B 2i Correction can be made by shifting the direction.

[0037] The color change point T 2i The distance moved is calculated as follows:

[0038] 1) According to the flexible correction amplitude coefficient R so Find the intersection point A of the "76 colors" target boundary 2i Corrected position after outward shift - target boundary correction edge point B' 2i Location;

[0039] 2) Calculate the color change point T according to the following formula 2i The proportional coefficient of outward movement t: (the color change point T 2i To the intersection point S of the flexible inner boundary of "76 colors" 2i The distance between them) / (the intersection of the "76 colors" flexible inner boundary S 2i To the "76 colors" target boundary intersection A 2i the distance between them);

[0040] 3) Correct the edge point B' based on the target boundary 2i As the boundary point, the color change point T is calculated according to the proportional coefficient. 2i The corrected new position - corrected color point T 3i location.

[0041] Correct the color point T 3i The calibrated color point T is obtained in the CIE1931 standard colorimetric system 4i , with the color point T after calibration 4i As the goal, in turn, the matching solution of each original primary color control signal required in the original color gamut space of the multi-primary color LED lamp / screen is obtained, and then the driving unit and LED light-emitting unit of the multi-primary color LED lamp / screen are controlled to output the color point T after calibration. 4i The light of the corresponding color is corrected by the flexible color gamut correction algorithm to obtain a light color output that can moderately improve the color saturation.

[0042] The rigid color gamut management method is:

[0043] 1) The color management unit of the multi-primary color LED lamp / screen substitutes or combines the color coordinates corresponding to the original color point in the original color gamut space and the original color control signal of the color mixing ratio of each original primary color corresponding to the original color point into the target color gamut space for analysis;

[0044] 2) Obtain the target color point T in the target color space corresponding to each original color point 1i The color coordinates of the target color point T are obtained. 1i The target color control signal parameters of each target primary color mixing ratio corresponding to the target color point T in the target color gamut space are 1i The proportional relationship between the color control signals corresponding to the color mixing ratios of the original primary colors in the original color gamut space;

[0045] 3) Then take any target color point T 1i The color coordinate value of the reference target is solved for the target color point T 1i A modified color control signal corresponding to the color mixing ratio of each original primary color in the original color gamut space;

[0046] 4) Afterwards, the modified color control signal is used to control the driving unit of the multi-primary color LED lamp / screen and the modified color point to output light corresponding to the modified color point.

[0047] The multi-primary color LED lamp / screen has at least three primary colors.

[0048] The present invention further improves upon the prior art rigid color gamut management method for color correction of multiple multi-primary LED lamps / screens. The target color gamut space is divided into a core rigid correction region and a peripheral flexible correction region. A flexible correction algorithm is introduced to correct target luminous color points within the peripheral flexible correction region. The corrected luminous color points are shifted toward the boundaries of the original color gamut space, resulting in a richer color presentation for the multi-primary LED lamps / screens compared to colors corrected using the rigid color gamut management method. This method ensures color consistency across multiple multi-primary LED lamps / screens within the core rigid correction region while fully utilizing the inherent high-saturation color capabilities of individual multi-primary LED lamps / screens. The present method can be widely used for color gamut space correction and management of multi-primary LED lamps / screens with three or more primary colors. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the original color gamut space, target color gamut space, core rigid correction area and peripheral flexible correction area in the CIE1931 standard colorimetry system.

[0050] Figure 2 It is a schematic diagram of the original color gamut space, target color gamut space, core rigid correction area and peripheral flexible correction area in the CIE1976 standard colorimetry system. DETAILED DESCRIPTION

[0051] The color gamut management method of the present invention for multi-primary color LED lamps or LED display screens (hereinafter referred to as multi-primary color LED lamps / screens) includes aligning the color gamut spaces of several multi-primary color LED lamps / screens with the same number of primary colors in the CIE1931 standard colorimetry system, establishing a unified target color gamut space for these multi-primary color LED lamps / screens in the CIE1931 standard colorimetry system, and converting the multi-primary color control signals that drive the configuration of the luminous color points in the multi-primary color LED lamps / screens into the target color gamut space for analysis. The color coordinates of the luminous color points in the target color gamut space are T(T_x, T_y).

[0052] The luminous color point is a color presented by the multi-primary color LED lamp / screen, and it corresponds to a color coordinate point on the color gamut diagram (the color gamut diagram is a color gamut diagram that can represent the original color gamut space, the target color gamut space, the CIE1931 standard colorimetry system, the CIE1976 standard colorimetry system and other standard colorimetry systems). Hereinafter, the luminous color point in the original color gamut space of the multi-primary color LED lamp / screen is referred to as the original color point, and the luminous color point in the target color gamut space of the multi-primary color LED lamp / screen that is aligned with the original color point is referred to as the target color point.

[0053] The characteristic of the present invention is that: in the target color gamut space, a core rigid correction area and a peripheral flexible correction area are delineated from the inside to the outside with the target color gamut space mixing point (the mixing point refers to the luminous color point corresponding to each primary color in a certain color gamut space when the primary colors are at maximum brightness output) as the center.

[0054] For a target color point whose color coordinates fall within the core rigid correction region, the matching value of its multi-primary color control signal is corrected using a rigid color gamut management method.

[0055] The rigid color gamut management method is described in the introduction of the "Background Technology" section of this specification and the technical solution disclosed in the invention patent application submitted by the applicant to the State Intellectual Property Office on August 9, 2018 (application number: 201810903106.0, entitled "A color space management device and method for LED multi-primary color lamps").

[0056] The color coordinates of target color points whose color coordinates fall within the outer flexible correction area are corrected using a flexible correction algorithm (also known as a flexible color gamut management method). This flexible color gamut management method shifts the color coordinates of the target color point along the extension of the line connecting the mixing point in the target color gamut space to the target color point toward the boundary of the original color gamut space of the multi-primary color LED lamp / screen.

[0057] In order to clearly express the solution of the present invention, the feature names involved in the solution are explained as follows:

[0058] 1) Target color point T 1i (T_x, T_y) refers to: in the CIE1931 standard colorimetric system, the original color point is aligned with the luminous color point in the target color gamut space.

[0059] 2) The target color mixing point M1 (M_x, M_y) refers to the luminous color point corresponding to each primary color in the target color gamut space when the primary colors are at maximum brightness output in the CIE 1931 standard colorimetric system.

[0060] 3) “31 colors” target boundary intersection point A 1i (A_x, A_y) refers to: in the CIE1931 standard colorimetric system, the color from the mixing point M1 to the target color point T 1i The extension line of the line connecting (T_x, T_y) makes the luminous color point corresponding to the intersection point of the extension line and the boundary of the target color gamut space.

[0061] 4) “31 colors” flexible inner boundary intersection S 1i (S_x, S_y) refers to: in the CIE1931 standard colorimetric system, the mixing point M1 to the "31 color" target boundary intersection point A 1i The luminous color point corresponds to the intersection of the line connecting the inner boundary of the peripheral flexible correction area.

[0062] 5) “31 colors” original boundary intersection point B 1i (B_x, B_y) refers to: in the CIE1931 standard colorimetric system, the color from the mixing point M1 to the target color point T 1i The extension line of the connecting line makes the luminous color point corresponding to the intersection of the extension line and the boundary of the original color gamut space.

[0063] 6) Change color point T 2i (T_u', T_v'), refers to: the target color point T in the CIE1931 standard colorimetry system 1i Convert to the corresponding luminous color point in the CIE1976 standard colorimetry system.

[0064] 7) Correct color point T 3i (T'_u', T'_v') refers to the luminous color point that is moved outward to the new position after the color point is corrected by the flexible correction algorithm.

[0065] 8) Color point T after calibration 4i (T'_x, T'_y) means: in the CIE1976 standard colorimetric system, the corrected color point T after the flexible correction algorithm is modified 3i Then return to the luminous color point under the CIE1931 standard colorimetry system.

[0066] 9) Re-marking the mixing point M2 (M_u', M_v'), which means that the mixing point M1 of the target color gamut space in the CIE1931 standard colorimetry system is marked with the corresponding luminous color point in the CIE1976 standard colorimetry system.

[0067] 10) “76 Colors” Target Boundary Intersection Point A 2i (A_u', A_v'), means: the "31 color" target boundary intersection A 1i The luminous color point is aligned with the CIE 1976 standard colorimetry system.

[0068] 11) "76 colors" flexible inner boundary intersection S 2i (S_u', S_v') refers to: in the CIE1976 standard colorimetric system, the mixing point M2 to the "76 color" target boundary intersection point A 2i The luminous color point corresponds to the intersection of the line connecting the inner boundary of the peripheral flexible correction area.

[0069] 12) “76 colors” original boundary intersection point B 2i (B_u', B_v'), means: the original boundary intersection point B 1i Convert to the corresponding luminous color point in the CIE1976 standard colorimetry system.

[0070] 13) Target boundary correction edge point B' 2i (B'_u', B'_v'), means: the "76 color" target boundary intersection A2 is adjusted according to the flexible correction amplitude coefficient R so The determined ratio is toward the original boundary intersection point B of "76 colors" 2i The point where the direction is shifted.

[0071] In the above naming, the letter subscripts 1, 2, 3, and 4 respectively represent the luminous color point corresponding to the CIE1931 standard colorimetry system, the luminous color point corresponding to the CIE1976 standard colorimetry system, the luminous color point corrected in the CIE1976 standard colorimetry system, and the luminous color point converted back from the corrected luminous color point to the corresponding luminous color point in the CIE1931 standard colorimetry system; i is an integer representing the serial number of the luminous color point.

[0072] The following focuses on the flexible color gamut management method of multi-primary color LED lights / screens

[0073] 1. Technical ideas

[0074] 1. Set flexible correction parameters

[0075] The flexibility correction parameters include the flexibility correction range coefficient R si and the flexibility correction amplitude coefficient R so , where R (English: Rate) represents the ratio, s (English: soft calibration) is the abbreviation of flexible calibration, i (in) and o (out) represent inside and outside respectively, and both parameter values ​​are expressed in 0-100%.

[0076] Flexible correction range coefficient R si and the flexibility correction amplitude coefficient R so , can be determined and solidified by the manufacturer according to the customer's demand for color saturation before leaving the factory, and can also be set by the end user as a dynamic parameter. Manufacturers and users of multi-primary color LED lights / screens can flexibly adjust the parameter R si and R so , so that it can switch between full correction, no correction, traditional rigid correction and flexible correction of different ranges and amplitudes as needed. It can flexibly adjust parameters according to the requirements of different scenes for lighting consistency and color saturation, compare the effects, and dynamically select, so as to achieve the beneficial effect of no longer unilaterally sacrificing saturation like the rigid color gamut management method.

[0077] 1) R siA numerical value, expressed in "%", which reflects the boundary between the core rigid correction area and the peripheral flexible correction area. It indicates how much proportion of the target color gamut space is set as the core rigid correction area and how much proportion of the target color gamut space is set as the peripheral flexible correction area when extending from the mixing point of the target color gamut space to the boundary of the target color gamut space.

[0078] Located less than or equal to R si The target color point within the numerical range is defined as the luminous color point that falls within the core rigid correction area, and the light color output is strictly in accordance with the aforementioned rigid color gamut management method.

[0079] And is greater than R si The target color point in the numerical area is defined as the luminous color point that falls within the outer flexible correction area. Within this range, the flexible correction algorithm is applied to correct the color coordinates of the target color point (the flexible correction algorithm mainly modifies (shifts) the color coordinates of the target luminous color point defined by the target color gamut space, and then calculates the ratio value of the original primary color control signal required for the color coordinate based on the modified color coordinates, and ultimately achieves the beneficial effect of no or little sacrifice in saturation) so that the target color point is shifted along the direction of the line connecting the mixing point in the target color gamut space to the target color point toward the boundary of the original color gamut space of the corresponding multi-primary color LED lamp / screen, thereby improving the saturation.

[0080] R si The value can also be understood as: the target color gamut space is linearly contracted inward with a certain ratio value around the color mixing point, forming the core rigid correction area. The ratio value of this linear contraction is R si .

[0081] That is, when the R si When it is 0, it means that the core rigid correction area is zero. In this case, the multi-primary color LED lamp / screen outputs according to the original color gamut space, and there is no need to correct the color according to the rigid color gamut management method.

[0082] When setting R si When it is 1, it means that the peripheral flexible correction area is zero. In this case, the multi-primary color LED lamp / screen strictly follows the definition of the target color gamut space to output light color, that is, the rigid color gamut management method is used to correct the color.

[0083] When setting R si When the value is between 0-100%, there are two cases:

[0084] a. When [(the length of the line connecting the mixing point and the target color point) / (the length of the line connecting the mixing point through the target color point to the boundary of the target color gamut space)] is less than or equal to R siWhen , it indicates that the target color point is within the core rigid correction area. At this time, the color of the target color point is strictly corrected according to the aforementioned rigid color gamut management method and the light color is output;

[0085] b. When [(the length of the line connecting the mixing point and the target color point) / (the length of the line connecting the mixing point through the target color point to the boundary of the target color gamut space)] is greater than R si When , it indicates that the target color point is located in the peripheral flexible correction area. At this time, the color of the target color point is corrected according to the flexible color gamut management method and the light color is output (see the flexible correction algorithm described later).

[0086] The corrected target color point will be moved a certain distance toward the boundary of the original color gamut space of the corresponding multi-primary color LED lamp / screen along the direction of the line connecting the mixing point in the target color gamut space and the target color point, thereby improving the color saturation of the target color gamut space of the multi-primary color LED lamp / screen.

[0087] 2) R so Used to adjust the target color point of the peripheral soft correction area to move outward to expand the saturation range. so It is defined as the proportion of the outer boundary of the peripheral flexible correction area (i.e. the target color gamut space boundary) shifting toward the original color gamut space boundary on the extension line of the line connecting the target color gamut space mixing point to the target color point after correction by the flexible correction algorithm, which is expressed in "%".

[0088] When setting R so When it is 0, it means: no saturation expansion is performed on the peripheral flexible correction area, and the color of the target color point is strictly corrected according to the aforementioned rigid color gamut management method and the light color is output.

[0089] When setting R so When it is 100%, after correction by the flexible correction algorithm, the outer boundary of the peripheral flexible correction area will be extended to the boundary of the original color gamut space (that is, the boundary of the target color gamut space in this direction will be extended to the boundary of the original color gamut space in disguise), and the original color gamut space of the multi-primary color LED lamp / screen will be maximized.

[0090] Setting R so When the value is between 0-100%, the boundary of the target color space will expand outward along the extension line of the line from the target color space mixing point to the target color point, and the expansion range is the set R so .

[0091] 2. Correct the target color points that fall within the outer flexible correction area

[0092] First, the target color point T under the CIE1931 standard colorimetric system 1iThe color coordinate point (T_x, T_y) is converted to the CIE1976 standard colorimetric system and the re-standard color point T is obtained. 2i The color coordinates of (T_u', T_v') are then converted to the color point T using the flexible correction algorithm. 2i The color coordinates of (T_u', T_v') are corrected and the corrected color point T after shifting is obtained 3i is the color coordinate of (T'_u', T'_v');

[0093] 3. Control the output light color of multi-primary color LED lamp / screen based on the result corrected by flexible correction algorithm.

[0094] 1) The corrected color point T obtained in the CIE 1976 standard colorimetric system 3i The color coordinates of (T'_u', T'_v') are then converted into the CIE1931 standard colorimetric system to obtain the calibrated color point T in the CIE1931 standard colorimetric system. 4i Color coordinates of (T'_x, T'_y);

[0095] 2) Take the color point T after calibration 4i (T'_x, T'_y) is the target, and in turn the matching solution of each original primary color control signal required in the original color gamut space of the multi-primary color LED lamp / screen is obtained. Then, the driving unit and LED light-emitting unit of the multi-primary color LED lamp / screen are controlled to output the color point T after calibration. 4i The light of the color corresponding to (T'_x, T'_y) completes the light color output that can moderately improve the color saturation after being corrected by the flexible color gamut correction algorithm.

[0096] 2. Determine the target color point T in the CIE1931 standard colorimetry system 1i A method for calculating whether (T_x, T_y) falls within the peripheral flexible correction area of ​​the target color gamut space.

[0097] 1. Calculate the color coordinates of the color mixing point M1 (M_x, M_y) in the target color space and convert it into the following formula based on formulas (1)-(3):

[0098]

[0099] Where:

[0100]

[0101] 2. In the CIE 1931 standard colorimetric system, a color mixing point M1 in the target color gamut space is drawn to the target color point T. 1iThe extension line of the line connecting (T_x, T_y) is used to make the intersection point A of the extension line intersecting with the boundary of the target color gamut space. 1i (Hereinafter, this intersection is referred to as the "31-color" target boundary intersection A 1i );

[0102] 3. Since the CIE1976 standard colorimetric system is a standard color space with uniform color difference, the distance between two color points can usually better represent its color difference value. Therefore, Figure 1 、 2 As shown, the present invention converts the mixed color point M1 (M_x, M_y) of the target color gamut space in the CIE1931 standard color space and the target color point T in the target color gamut space into 1i (T_x, T_y) and the "31-color" target boundary intersection A 1i (A_x, A_y) are converted to the CIE1976 standard colorimetric system, and the mixed color point M2 (M_u', M_v') and the color point T are obtained respectively. 2i (T_u', T_v') and the "76-color" target boundary intersection A 2i (A_u',A_v').

[0103] In this way, the target color space is transformed from a uniform, reduced, rigid color space to an adjustable, flexible color space that adapts to the unique characteristics of each multi-primary color point. The flexible correction of the target color coordinates is calculated within the uniform color difference space of the CIE 1976 standard colorimetric system, ensuring a natural and smooth color transition without sacrificing the original saturation and maintaining the hue starting from the mixing point.

[0104] The color point coordinates (x, y) in the CIE1931 standard color space are converted to the color point coordinates (u', v') in the CIE1976 standard colorimetry system using the following formula:

[0105]

[0106] Where: x and y represent the abscissa and ordinate in the CIE1931 standard colorimetric system respectively;

[0107] u' and v' represent the abscissa and ordinate in the CIE 1976 standard colorimetric system, respectively;

[0108] It should be noted that the CIE1931 standard colorimetry system is a space with severely uneven color differences. That is, within this standard color space, the color differences presented by three color points that are on the same straight line and are equally spaced do not change uniformly. Therefore, when the CIE1931 standard colorimetry system calculates and determines the peripheral flexible correction area and corrects the coordinates, it will cause defects such as uneven and non-smooth transitions in the color gamut space.

[0109] After conversion to the CIE1976 standard colorimetry system, the calculation is performed. Since the color difference uniformity of the CIE1976 standard colorimetry system is greatly improved (the color difference presented by three color points on the same straight line and with equal spacing varies evenly), in addition, the inner edge of the peripheral flexible correction area marked in the standard color space (i.e., the outer edge of the core rigid color gamut space) is formed by the linear contraction of the target color gamut space polygon (i.e., the opposite sides of the two polygonal color gamut spaces are completely parallel), the peripheral flexible correction area formed is consistent in all directions, the color difference transition is smooth, and it is more in line with the perception of the human eye.

[0110] 4. Determine the color change point T 2i The position of (T_u', T_v')

[0111] Let r = MT / MA

[0112] MT is: from the mixing point M2 to the color changing point T 2i distance between them;

[0113] MA is the distance between the color-changing mixing point M2 and the "76-color" target boundary intersection point A2.

[0114]

[0115] If r> the set flexibility correction range coefficient R si , then the color change point T 2i The corresponding target color point T 1i Located in the outer flexible correction area, the color of the target color point is corrected according to the flexible color gamut management method;

[0116] If r≤the set flexibility correction range coefficient R si , then the color change point T 2i The corresponding target color point T 1i Located within the core rigid correction area outside the peripheral flexible correction area.

[0117] 5. The steps for correction using the flexible correction algorithm are as follows:

[0118] 1) In the CIE 1976 standard colorimetric system, find the color point S where the line segment MA intersects the inner boundary of the peripheral flexibility correction area. 2i The color coordinate point of (S_u', S_v') (hereinafter referred to as the "76-color" flexible inner boundary intersection point);

[0119] S_u'=M_u'+Rs_i*(A_u'-M_u')

[0120] S_v'=M_v'+Rs_i*(A_v'-M_v') (10)

[0121] Where: R si is the flexibility correction range coefficient, A 2i (A_u', A_v') is the intersection point of the "76-color" target boundary.

[0122] 2) In the CIE1931 standard colorimetric system, make a color gradient from the mixing point M1 in the target color gamut space to the target color point T 1i The extension line of the line connecting the two colors is made to intersect with the boundary of the original color gamut space to obtain color point B. 1i The color coordinates of (B_x, B_y) (hereinafter referred to as B 1i The color point is called the original boundary intersection point of "31 colors". Apply formulas (7) and (8) to calculate the original boundary intersection point B of "31 colors". 1i Convert to the corresponding intersection point B in the CIE1976 standard colorimetric system 2i The color coordinates of (B_u', B_v') (hereinafter referred to as B 2i The color point is called the "76-color" original boundary intersection).

[0123] 3) In the CIE 1976 standard colorimetric system, the flexible correction algorithm is applied to obtain the corrected color point T 3i (T 3i _u',T 3i The color coordinates of _v') are calculated as follows:

[0124] a. According to the set value of the flexible correction amplitude coefficient R so , adjust the "76 colors" target boundary intersection point A 2i (A_u', A_v') to apply the flexibility correction amplitude coefficient R so Corrected target boundary edge point B' 2i , calculate B' 2i Color coordinates of the point (B'_u', B'_v');

[0125] B'_u'=A_u'+Rs_o*(B_u'-A_u')

[0126] B'_v'=A_v'+Rs_o*(B_v'-A_v') (11)

[0128] When R so When it is 100%, the target boundary is corrected at the edge point B' 2i Intersection point B with the original boundary of "76 colors" 2i Overlap, that is, the outer edge of the target color gamut after correction is expanded to the maximum extent and overlaps with the outer edge of the original color gamut without sacrificing the saturation of the original color gamut space. so When B' is 0%, 2iPoint and A 2i The points coincide, that is, the target color gamut is not expanded after correction, which is the same as the result of the original rigid color gamut correction method. so Between 0 and 100%, the outer edge of the target color gamut space is expanded to a corresponding degree.

[0129] Calculate the ratio t of the ST segment to the SA segment;

[0130]

[0131] b. The corrected color point T after correction by the flexible correction algorithm 3i The color coordinates of (T,_u,,T,_v,) are calculated according to the following formula:

[0132] T'_u'=S_u'+t*(B'_u'-S_u')

[0133] T'_v'=S_v'+t*(B'_v'-S_v') (13)

[0135] Where: t is the ratio of the length of line segment ST to the length of line segment SA in the uniform color difference space of the CIE 1976 standard colorimetry system;

[0136] Line segment ST: is the color change point T 2i To the intersection point S of the flexible inner boundary of "76 colors" 2i the distance between them;

[0137] Line segment SA: is the intersection point S of the "76-color" flexible inner boundary 2i To the "76 colors" target boundary intersection A 2i The distance between them refers to the width of the peripheral flexible correction area in the direction of the extension line;

[0138] Line segment SB': is the intersection point S of the "76-color" flexible inner boundary 2i To the corrected target color gamut edge point B' 2i The distance between the inner boundary of the peripheral flexible correction area and the outer boundary of the target color gamut processed by the flexible correction algorithm in the direction of the extension line;

[0139] It can be seen from formula (13) that in the direction of the extension line, the color point T 2i Corrected color point T after correction 3i Move toward the boundary of the original color gamut space.

[0140] That is, the ratio of line segment ST relative to line segment SA is converted to line segment SB', that is, the points on line segment SA are linearly extended to line segment SB' in proportion.

[0141] Through this step, the peripheral flexible correction area within the target color gamut space will be smoothly expanded in a controllable manner toward the boundary of the original color gamut space of the current LED lamp / screen, without sacrificing the original saturation. The hue starting from the mixing point remains unchanged, so as to give full play to the high-saturation color light capability of the LED lamp / screen.

[0142] 4) If the multi-primary color LED lamp / screen is a three-primary color LED lamp / screen, the required primary color control signal ratio solution in the original color gamut space is unique; if it is a multi-primary color LED lamp / screen with four primary colors or more, the primary color control signal ratio solution is infinite. You can choose the maximum brightness algorithm, the optimal color rendering index algorithm, and the optimal light output efficiency algorithm as needed to find the optimal solution for the primary color ratio required by the current multi-primary color LED lamp / screen in the original color gamut space that meets the predetermined goals.

[0143] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention relates, any equivalent substitutions or obvious modifications that do not depart from the concept of the present invention and have the same performance or use should be deemed to fall within the scope of patent protection of the present invention as determined by the submitted claims.

Claims

1. A color gamut management method for a multi-primary color LED lamp / screen, comprising establishing a unified target color gamut space for a plurality of multi-primary color LED lamps / screens having the same number and type of primary colors, characterized by: The method further includes, when the target color gamut space is established, dividing the target color gamut space into a core rigid correction area and a peripheral flexible correction area according to market demand for color saturation, the steps of which are as follows: 1) Align the original color gamut space of the multi-primary color LED lamp / screen with the target color gamut space in the CIE1931 standard colorimetric system, and use the target color mixing point M1 of the target color gamut space as the center and adjust the flexible correction range coefficient R from the inside to the outside. si The core rigid correction area and the peripheral flexible correction area are sequentially demarcated according to the determined proportions; 2) Aligning the original color point in the original color gamut space to the target color point T in the target color gamut space that falls within the core rigid correction area 1i The color coordinates and the matching value of the corresponding target primary color control signal are corrected using a rigid color gamut management method; 3) Aligning the original color point in the original color gamut space to the target color point T in the target color gamut space that falls within the peripheral flexible correction area 1i The matching values ​​of the color coordinates and the corresponding target primary color control signals are corrected using a flexible correction algorithm that improves color saturation.

2. The color gamut management method for a multi-primary color LED lamp / screen according to claim 1, characterized in that: The soft correction algorithm is to correct the target color point T in the CIE1931 standard colorimetric system. 1i The color point T that is aligned with the CIE 1976 standard colorimetric system and falls within the flexible correction area 2i Correction is made, and the corrected color change point T 2i The color coordinates of the target color mixing point M1 are aligned with the color changing point M2 in the CIE 1976 standard colorimetric system to the color changing point T 2i The extension line of the connection line is shifted toward the boundary of the original color gamut space according to the set amplitude.

3. The color gamut management method for a multi-primary color LED lamp / screen according to claim 2, characterized in that: The method for correction using the flexible correction algorithm comprises the following steps: 1) Obtain the target color mixing point M1 and target color point T based on the CIE1931 standard colorimetric system 1i The color coordinates of 2) Make the target color mixing point M1 to the target color point T 1i The line connecting the inner boundary of the outer flexible correction area intersects to obtain the "31 color" flexible inner boundary intersection point S 1i The connecting line is extended and intersected with the target color gamut space boundary and the original color gamut space boundary to obtain the "31 color" target boundary intersection A1 and the "31 color" original boundary intersection B 1i ; 3) Set the target color mixing point M1 and target color point T 1i , "31 colors" flexible inner boundary intersection S1, "31 colors" target boundary intersection A1 and "31 colors" original boundary intersection B 1i The color coordinates are converted into the CIE1976 standard colorimetric system and the corresponding mixing point M2 and color point T are calculated by the relevant formula. 2i 、"76 colors" flexible inner boundary intersection S 2i , "76 colors" target boundary intersection point A2 and "76 colors" original boundary intersection point B 2i The color coordinates of 4) In the CIE 1976 standard colorimetric system, the color point T that falls within the flexible correction area 2i According to the flexibility correction amplitude coefficient R so Determine the ratio along the line to the "76 color" original boundary intersection B 2i Correction can be made by shifting the direction.

4. The color gamut management method for a multi-primary color LED lamp / screen according to claim 3, characterized in that: The color change point T 2i The distance moved is calculated as follows: 1) According to the flexible correction amplitude coefficient R so Calculate the corrected position of the "76-color" target boundary intersection point A2 after moving outward - the target boundary correction edge point B' 2i Location; 2) Calculate the color change point T according to the following formula 2i The proportional coefficient of outward movement t: (the color change point T 2i To the intersection point S of the "76 colors" flexible inner boundary 2i The distance between them) / (the intersection of the "76 colors" flexible inner boundary S 2i To the "76 colors" target boundary intersection A 2i the distance between them); 3) Correct the edge point B' with the target boundary 2i As the boundary point, the color change point T is calculated according to the proportional coefficient. 2i The corrected new position - corrected color point T 3i location.

5. The color gamut management method for a multi-primary color LED lamp / screen according to claim 4, characterized in that: Correct the color point T 3i The calibrated color point T is obtained in the CIE1931 standard colorimetric system 4i , with the color point T after calibration 4i As the goal, in turn, the matching solution of each original primary color control signal required in the original color gamut space of the multi-primary color LED lamp / screen is obtained, and then the driving unit and LED light-emitting unit of the multi-primary color LED lamp / screen are controlled to output the color point T after calibration. 4i The light of the corresponding color is corrected by the flexible color gamut correction algorithm to obtain a light color output that can moderately improve the color saturation.

6. The color gamut management method for a multi-primary color LED lamp / screen according to claim 2, characterized in that: The rigid color gamut management method is: 1) The color management unit of the multi-primary color LED lamp / screen substitutes or combines the color coordinates corresponding to the original color point in the original color gamut space and the original color control signal of the color mixing ratio of each original primary color corresponding to the original color point into the target color gamut space for analysis; 2) Obtain the target color point T in the target color space corresponding to each original color point 1i The color coordinates of the target color point T are obtained. 1i The target color control signal parameters of each target primary color mixing ratio corresponding to the target color point T in the target color gamut space are 1i The proportional relationship between the color control signals corresponding to the color mixing ratios of the original primary colors in the original color gamut space; 3) Then take any target color point T 1i The color coordinate value of the reference target is solved for the target color point T 1i A modified color control signal corresponding to the color mixing ratio of each original primary color in the original color gamut space; 4) Afterwards, the modified color control signal is used to control the driving unit of the multi-primary color LED lamp / screen and the modified color point to output light corresponding to the modified color point.

7. The color gamut management method for a multi-primary color LED lamp / screen according to any one of claims 1 to 6, characterized in that: The multi-primary color LED lamp / screen has at least three primary colors.

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