WO2022012330A1 - Color correction method and apparatus, color correction device, and storage medium - Google Patents

Abstract

Disclosed are a color correction method and apparatus, a color correction device, and a storage medium. The method comprises: inputting and storing 3D-LUT correction reference color data; inputting original color RGB data to perform 3D-LUT mapping, so as to obtain color data that has been subjected to 3D-LUT mapping; and by using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data, correcting the color data that has been subjected to 3D-LUT mapping, so as to obtain corrected color data.

Description

Color correction method and apparatus, color correction apparatus and storage medium

This application claims the priority of the Chinese Patent Application No. 202010673324.7 and titled "A Color Correction Method and Device, Color Correction Device and Storage Medium" filed on July 14, 2020, the entire contents of which are incorporated by reference in in this application.

technical field

The present invention relates to the field of color correction, in particular to a color correction method and device, a color correction device and a storage medium.

Background technique

As a new type of display technology, LED display (Light Emitting Diode) is more and more favored by users for its advantages of energy saving, environmental protection and high efficiency. However, due to the influence of the production process of LED display, different LED display cannot achieve The range of displayed colors (that is, color gamut) is the same, which leads to differences when different LED displays display the same color. Large-sized LED displays are often spliced by multiple small LED displays due to technology and other reasons. The effect of a small LED display on the same color display is inconsistent, so the display effect of the entire LED display is very poor.

The current solution is to find out the common color gamut (reference color gamut) of different LED displays, that is, the color range that can be displayed by different LED displays, and then achieve the same displayed colors through the color gamut mapping method. The color gamut mapping method is The color gamut of the input color is mapped to the common color gamut, and each input color can find a corresponding color in the common color gamut, so as to achieve the color correction function of multiple LED displays, and then achieve display consistency.

At present, 3D-LUT (3D Look-Up-Table, 3D color look-up table) technology in the field of color gamut mapping is recommended in the LED cinema screen because of its excellent image processing effect and superior processing speed. It is often used for color calibration and toning. In the current color correction method using 3D-LUT, one 3D matrix transformation and two 2D matrix transformations are used to calculate the weight coefficient principle, and the calculation is very complicated; and a large number of multiplications are required for volume calculation. As a result, complex circuits are required for hardware implementation, which consumes a lot of hardware multipliers and RAM resources, and has great restrictions on some systems with strong real-time performance and large amount of data processing, such as the LED display of 8K@60fps video signals. The hardware circuit has high requirements, and a solution to optimize the calculation speed is proposed.

SUMMARY OF THE INVENTION

According to an aspect of the embodiments of the present invention, a color correction method is provided, the method includes: inputting and storing 3D-LUT correction reference color data; inputting original color RGB data to perform 3D-LUT mapping, and obtaining a 3D-LUT mapping The color data after the 3D-LUT mapping is corrected by using the tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain the corrected color data.

According to another aspect of the embodiments of the present invention, a color correction device is provided, the device includes: a storage module, a mapping module, and a correction module, wherein: the storage module is used to input and store a 3D-LUT correction reference color Data; the mapping module is used to input the original color RGB data to carry out 3D-LUT mapping, and obtain the color data after the 3D-LUT mapping; the correction module is used to use the four-sided color data after the 3D-LUT mapping. The volume interpolation algorithm and the 3D-LUT correction reference color data are corrected to obtain corrected color data.

According to another aspect of the embodiments of the present invention, a color correction apparatus is provided, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, the computer program being When the processor is executed, the steps of implementing the color correction method provided in the embodiment of the present invention are realized.

According to another aspect of the embodiments of the present invention, a computer-readable storage medium is provided, where a program of a color correction method is stored on the computer-readable storage medium, and the program of the color correction method is executed by a processor When implementing the steps of the color correction method provided by the embodiment of the present invention.

The details of various embodiments of the invention are set forth in the accompanying drawings and the description below. Those skilled in the art will easily understand other features, problems to be solved, and beneficial effects of the present invention from the description, drawings, and claims.

Description of drawings

In order to better describe and illustrate the embodiments of the present application, reference may be made to one or more drawings, but the additional details or examples used to describe the drawings should not be considered as invention-creations, presently described implementations of the present application A limitation of the scope of any one of the examples or preferred modes.

FIG. 1 is a schematic flowchart of a 3D-LUT color correction method based on a tetrahedral interpolation algorithm provided by an embodiment of the present invention.

FIG. 2 is a schematic diagram of inputting original color RGB data for 3D-LUT mapping according to an embodiment of the present invention.

FIG. 3 is a schematic flowchart of correcting color data after 3D-LUT mapping using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a tetrahedral interpolation provided by an embodiment of the present invention.

FIG. 5 is a schematic diagram of a cube cutting provided by an embodiment of the present invention.

FIG. 6 is a schematic diagram of an A'C direction top view according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of a tetrahedral V4 interpolation provided by an embodiment of the present invention.

FIG. 8 is a schematic structural diagram of a color correction apparatus according to an embodiment of the present invention.

FIG. 9 is a schematic structural diagram of a color correction device according to an embodiment of the present invention.

detailed description

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more comprehensible, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention, but not for limiting the present invention.

In the following description, suffixes such as 'module', 'component' or 'unit' used to represent elements are used only to facilitate the description of the present invention and have no specific meaning per se. Thus, "module", "component" or "unit" may be used interchangeably.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence.

In one embodiment, as shown in FIG. 1 , the present invention provides a 3D-LUT color correction method based on a tetrahedral interpolation algorithm, the method comprising:

S1. Input and store 3D-LUT correction reference color data.

S2. Input original color (RGB) data to perform 3D-LUT mapping to obtain color data after 3D-LUT mapping.

S3. Correct the color data mapped by the 3D-LUT using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data.

In this embodiment, the 3D-LUT color correction method based on tetrahedral interpolation is adopted, that is, the input original color data is 3D-LUT mapped and then corrected by the tetrahedral interpolation algorithm and the 3D-LUT correction reference color data, and the correction is obtained. The obtained color data can effectively simplify the calculation of the tetrahedral interpolation coefficient, and in the specific circuit application, only four multipliers are needed to optimize the tetrahedral interpolation algorithm, simplify the implementation of the hardware circuit, and greatly reduce the hardware circuit. The realization difficulty is improved, and the real-time performance of circuit data processing is improved, thereby solving the problem of complicated tetrahedral interpolation calculation and complex interpolation coefficients in the prior art, which complicates hardware circuit implementation.

In one embodiment, before the step S2, the method further includes: reading original color data for correcting the color gamut input display.

In an embodiment, in the step S2, the input original color (RGB) data is subjected to 3D-LUT mapping to obtain the color data after 3D-LUT mapping, including: reading a color gamut input display for correcting the color gamut. Raw color data.

Perform 3D-LUT mapping on the original color number data to obtain color data after 3D-LUT mapping, including:

Input the original color (R, G, B) data, multiply the three RGB components by the color gamut scaling ratio scale, and obtain the mapped color data (R ₀ +f _R , G ₀ +f _G , B ₀ +f _{B )} ), where the scaled position of the 3D-LUT mapping is generally divided into an integer part and a fractional part, R ₀ , G ₀ and B ₀ are the integer parts of the mapped color on the RGB components, f _R , f _G and f _B is the fractional part of the mapped color on the RGB component; the color gamut scaling ratio scale=(M-1)/(2 ⁿ -1), n is the bit width of the input color, and M is the number of single-dimensional sampling points of the 3D-LUT .

Among them, the integer part is used to determine the address of the mapping point at the 8 vertices of the smallest cube of the 3D-LUT. The fractional part is the position of the mapping point inside the smallest cube determined by the integer part. It determines which tetrahedron's four vertex addresses and the interpolation formula the input color value is in the smallest cube, and also participates in the calculation of the interpolation coefficient.

As shown in Figure 2, the 3D-LUT is essentially a 3D (three-dimensional) color lookup table (also called a three-dimensional color map), and any color input can be matched and output from the 3D-LUT table. 3D-LUT color correction is to find the corrected color in the color-corrected 3D color look-up table by inputting color data values, and map the color gamut of the input color to the 3D-LUT. The single-dimensional sampling point number M is used to calculate the scaling ratio, and the color gamut scaling ratio is scale=(M-1)/(2 ⁿ -1).

In this embodiment, by inputting the original color RGB and mapping in the 3D-LUT, the color data after the 3D-LUT mapping is obtained, so that the mapped color can be used to determine the mapping point in the smallest cube of the 3D-LUT. The addresses of the 8 vertices and the addresses of the four vertices of the tetrahedron, as well as the determination of the interpolation formula and interpolation coefficient, help to effectively simplify the calculation of the interpolation coefficient of the tetrahedron, and only four multipliers are required for specific circuit applications. The tetrahedral interpolation algorithm is optimized, the realization of the hardware circuit is simplified, the realization difficulty of the hardware circuit is reduced to a great extent, and the real-time performance of the circuit data processing is improved, so that the complex interpolation coefficient of the tetrahedral interpolation calculation in the prior art can be solved and the realization of the hardware circuit is complicated. ization problem.

In one embodiment, as shown in FIG. 3 , in step S3, the 3D-LUT-mapped color data is corrected using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain a corrected post color data. include:

Step S31: Determine the interpolation coefficient and the interpolation formula of the tetrahedral interpolation algorithm according to the fractional part in the color data mapped by the 3D-LUT.

Step S32: Determine the addresses of the four vertices of the tetrahedral interpolation algorithm according to the integer part in the color data mapped by the 3D-LUT.

Step S33: Search the 3D-LUT correction reference color data according to the four vertex addresses to obtain the color values of the four vertex addresses of the tetrahedron where the original color is located.

Step S34, according to the color values of the addresses of the four vertices of the tetrahedron and the interpolation coefficients of the four vertices of the tetrahedron, use the interpolation formula to perform weighted calculation to obtain the color values (R ₁ , G ₁ , B ₁ ) after interpolation correction, and finally Output corrected color values (R ₁ , G ₁ , B ₁ ).

In this embodiment, the interpolation coefficient and interpolation formula of the tetrahedral interpolation algorithm are determined by the fractional part in the color data mapped by the 3D-LUT, and the addresses of the four vertices of the tetrahedral interpolation algorithm are determined by the integer part. The four vertex addresses are searched in the 3D-LUT correction reference color data to obtain the color value of the four vertex addresses of the tetrahedron where the original color is located, and then the color value of the four vertex addresses of the tetrahedron where it is located is based on the interpolation of the four vertices of the tetrahedron. The coefficients are weighted by the interpolation formula to obtain the color value after interpolation correction; that is, the input original color data is mapped by 3D-LUT, and then the tetrahedral interpolation algorithm and the 3D-LUT correction reference color data are used for correction, and the corrected color data is obtained. , which can effectively simplify the calculation of the tetrahedral interpolation coefficient, and in the specific circuit application, only four multipliers are needed to optimize the tetrahedral interpolation algorithm, simplify the implementation of the hardware circuit, greatly reduce the difficulty of hardware circuit implementation, and improve the The real-time performance of circuit data processing can solve the problem of complicated tetrahedral interpolation calculation interpolation coefficients and complicated hardware circuit implementation in the prior art.

In this embodiment, the application of the tetrahedral interpolation algorithm in color gamut scaling is to calculate the ratio of the volume of the four small tetrahedra formed by mapping points to the four faces of the large tetrahedron to the volume of the large tetrahedron as the interpolation coefficient, and take the tetrahedron as the interpolation coefficient. The color values of the four vertices of the body are weighted with the corresponding interpolation coefficients to obtain the color values of the mapping points.

As shown in Figure 4, the four vertices ABCD of the tetrahedron, the mapping point P is in the tetrahedron ABCD, then the mapping point P and each face of the large tetrahedron can form a small tetrahedron, PBCD, PACD, PABD and PABC, and then Let A', B', C', D', P' be the RGB color values corresponding to the five points of ABCDP, a, b, c, d are the four tetrahedrons PBCD, PACD, PABD, The volume ratio (ie the interpolation coefficient) of PABC and the large tetrahedron ABCD respectively, then the calculation formula of the color value of the mapping point P (ie the interpolation formula) can be expressed as:

P’=a×A’+b×B’+c×C’+d×D’

It can be seen from the above calculation formula that the relationship between the interpolation coefficient and the multiplied vertex is the color value of the vertex multiplied by the ratio of the tetrahedron volume formed by the opposite face of the vertex and the mapping point P to the large tetrahedron (ie, the interpolation coefficient).

Among them, the tetrahedral interpolation algorithm involves the volume calculation formula of the tetrahedron, and the formula is:

V=h×S/3

In the above formula, V represents the volume of the desired tetrahedron, h represents the vertical distance from any vertex to the plane where the vertex is opposite to the plane of the triangle, and S is the area of the triangle on the vertex opposite.

The tetrahedron interpolation algorithm is to cut the cube into 6 congruent tetrahedrons. The way of cutting the tetrahedron is to pass through (0,0,0) and (1,1,1) to make the square diagonal of the three pairs of parallel faces of the cube. wire cutting. As shown in Figure 5, the A'BCD' section is made through the parallel planes ABB'A' and DCC'D', and A'C must be on the section, so it can only be A'BCD'; similarly, make the section ACC'A' and A'B'CD, the intersection line of these three tangent planes is A'C, at this time, the three tangent planes cut the cube into 6 congruent tetrahedra A'ABC(V1), A'DAC(V2), A' D'DC(V3), A'C'D'C(V4), A'B'C'C(V5), A'BB'C(V6), the content in brackets represents the abbreviation of the tetrahedron, such as shown in Figure 6.

四面体的各个面积都可以计算出来，通过前述缩放映射计算的小数部分f _R、f _G和f _B，可以求得映射点P到正方体上的两个面的体积，只要计算出映射点P到两个切面的高度，就可以求出所有体积。 Figure 6 is the top view of Figure 5 in the direction of A'C. The cube is divided into 6 equal parts. It can be seen from Figure 4 that each tetrahedron has two faces on two of the cube faces, and the other two faces. on two of the three cut planes. The two faces on the cube have the same area (1/2×1×1), and the two faces on the tangent have the same area

Each area of the tetrahedron can be calculated. Through the fractional parts f _R , f _G and f _B calculated by the aforementioned scaling mapping, the volume of the mapping point P to the two faces on the cube can be obtained, as long as the mapping point P is calculated to The height of the two cut planes can be used to find all volumes.

In one embodiment, in the step S31, determining the interpolation coefficient and interpolation formula of the tetrahedral interpolation algorithm according to the fractional part in the color data mapped by the 3D-LUT includes:

Step S311 , compare the _{size relationship between f R} , f _G and f _{B of} the fractional part to determine the tetrahedron where the mapping point P is located and the relative position of the tetrahedron vertex on the cube.

Step S312: Determine the interpolation coefficients and interpolation formulas of the four vertices of the tetrahedron where the mapping point P is located _{according to f R} , f _G and f _{B of the fractional part.}

Repeat the above steps S311 to S312 to determine the interpolation coefficients and interpolation formulas of all six tetrahedra.

In one embodiment, in the step S311, the comparison of the _{size relationship between f R} , f _G and f _{B of} the fractional part determines the tetrahedron where the mapping point P is located and the relative position of the tetrahedron vertex on the cube; Including: using the three-dimensional projection dimension reduction method to determine the tetrahedron where the mapping point P is located, including:

Select the first vertex of the cube, project the mapping point P on the plane perpendicular to the direction along the direction of the first vertex as the starting point, and determine that the mapping point P is at the opposite corner formed by the other vertex that forms the direction on the plane. The line is above or below the straight line, so as to exclude the tetrahedron on both sides of the tangent plane formed by the straight line in the direction and the angle line as the two sides; wherein, it is judged that the mapping point P is in order to form the direction of the tetrahedron. The diagonal line formed by the other vertex on the plane is above or below the straight line, which is determined by comparing the magnitude relationship between the two related values of the fractional part, thereby determining the tetrahedron where the mapping point P is located;

If the tetrahedron where the mapping point P is located cannot be determined after the above steps, the mapping point P is projected along another direction with the first vertex as the starting point to a plane perpendicular to the direction, and the above steps are repeated until the mapping point P is determined. tetrahedron.

Specifically:

Step S3111, select the first vertex of the cube, project the mapping point P along the first direction from the first vertex to the first plane perpendicular to the first direction, and determine that the mapping point P is in order to form the first direction. The second vertex is above or below the diagonal line formed by the first plane as the first straight line, so as to exclude the two planes formed by the straight line in the first direction and the plane formed by the two sides as the tangent plane. side tetrahedron. Wherein, judging that the mapping point P is above or below the first straight line with the diagonal line formed by the second vertex forming the first direction on the first plane as the first straight line is by comparing the two correlation values of the fractional part. size relationship.

Step S3112, then project the mapping point P along the second direction with the first vertex as the starting point to the second plane perpendicular to the second direction, and determine that the mapping point P is in the third vertex to form the second direction. The diagonal formed by the second plane is above or below the second straight line, so as to exclude the tetrahedron with the two sides of the tangent plane formed by the straight line in the second direction and the second straight line as two sides. Wherein, judging that the mapping point P is above or below the first straight line with the diagonal line formed by the second vertex forming the first direction on the first plane as the first straight line is by comparing the two correlation values of the fractional part. size relationship.

Step S3113, project the mapping point P to the third plane perpendicular to the third direction along the third direction of the first vertex as the starting point, and judge that the mapping point P is in the fourth vertex to form the third direction in the third direction. The diagonal line formed by the three planes is above or below the third straight line, so as to exclude the tetrahedron whose two sides of the tangent plane are formed by the straight line in the third direction and the third straight line as the two sides. Wherein, judging that the mapping point P is above or below the first straight line with the diagonal line formed by the second vertex forming the first direction on the first plane as the first straight line is by comparing the two correlation values of the fractional part. size relationship.

After the above steps S3111 to S3113, the tetrahedron where the mapping point P is located can be determined.

Further, as shown in Fig. 7, the vertex A' of the cube is selected as an example to further illustrate the tetrahedron where the mapping point P is located.

Project the mapping point P on the plane DCC'D' along the A'D' direction, and determine whether the mapping point P is above or below the straight line CD', so as to exclude half of the tetrahedrons on both sides of the tangent plane A'BCD'. Determine whether the mapping point P is above or below the straight line CD' by comparing the _{sizes of f B} and f _G , because the straight line CD' is on the straight line y=x of the plane DCC'D', if x>y, then the mapping point P is on the straight line CD'', on the contrary, the mapping point P is above the straight line CD'.

Then project the mapping point P to the plane BB'C'C along the A'B' direction, and judge whether the mapping point P is above or below the straight line B'C, so as to exclude one or two of the remaining three tetrahedra . At this time, it is determined by comparing the _{magnitudes of f B} and f _{R that the} mapping point P is above or below the straight line B'C, because the straight line B'C is also on the straight line y=x. If only one tetrahedron can be excluded after this step, the tetrahedron where the mapped point P is located needs to be determined by doing another projection process along the AA' direction.

After the above processing, it is finally determined that the tetrahedron where the mapping point P is located can be determined _{only by comparing the size relationship among f R} , f _G and f _{B .}

In one embodiment, in the step S312, the interpolation coefficients and interpolation formulas of the four vertices of the tetrahedron where the mapping point P is located are determined _{according to f R} , f _G and f _{B of the fractional part.}

In this embodiment, the interpolation coefficient and the interpolation formula for determining the four vertices of the tetrahedron where the mapping point P is located are described by taking the mapping point P in the tetrahedron A'C'D'C(V4) as an example.

In the aforementioned step S311, the tetrahedron where the mapping point P is located has been determined, and the next step is to determine the volumes of the four small tetrahedra formed by the mapping point P to the four faces of the large tetrahedron. Six have been given above. For the area of the four faces of the congruent tetrahedron, the interpolation coefficient can be obtained as long as the height of the mapping point P to the four faces is calculated.

As shown in Figure 7. Extract the tetrahedron where the mapping point P is located from the large tetrahedron, because the plane A'C'D' and the plane CC'D' are on the face of the cube, the distance from the mapping point P to the plane A'C'D' can be obtained is f _B , the distance to the plane CC'D' is (1-f _R ). The distance between the mapping point P and the two tangent planes is calculated by the three-dimensional projection dimensionality reduction method. The distance between the mapping point P and the plane A'CD' can be projected on the tangent plane CDD'C' for calculation, because the plane A'CD' is in the tangent plane A' On BCD' and perpendicular to the tangent plane CDD'C', the projected plane A'CD' becomes a straight line CD', and the mapping point P is projected into a point P1, then the distance from the mapping point P to the plane A'CD' can be converted In order to find the distance from the point P1 to the straight line CD', the coordinates of the point P1 on the tangent plane CDD'C' are (f _G , f _B ), and the equation of the straight line CD' is y=x, which is converted into the form of the distance from the point to the straight line is xy=0.

According to the distance formula from the point (x0, y0) to the straight line Ax+By+C=0:

同理可以算得点P2(f _R，f _G)到直线A’C’的距离为

So the distance from point P1 to line CD' is

Similarly, the distance from the point P2(f _R , f _G ) to the straight line A'C' can be calculated as

The areas of the four surfaces are expressed as S _A'C'D' , S _CC'D' , S _A'CD' , S _A'CC' , respectively, then there are:

S _CC'D' =1/2×1×1

S _A'C'D' =1/2×1×1

The distance from the mapping point P to the four faces is expressed as da1, dc1, dd1 and dc, which can be obtained according to the previous calculation:

da1 = 1-f _R

dc=f _B .

According to the tetrahedral volume formula V=h×S/3, the four tetrahedral volumes divided by the mapping point P are:

V _PA'C'D' =dc×S _A'C'D' /3=(f _B ×1/2)/3=f _B /6

V _PCC'D' =da1×S _CC'D' /3=((1-f _R )×1/2)/3=(1-f _R )/6

_{The volume of the large tetrahedron A 'CC'D'} (V4) where the mapping point P is located:

V _A'CC'D' =CC'×S _A'C'D' /3=(1 x 1/2)/3=1/6

From this, the volume ratio of the four tetrahedrons divided by the mapping point P (that is, the interpolation coefficient) can be obtained:

U _A1 =V _PCC'D' /V _A'CC'D' =((1-f _R )/6)/(1/6)=1-f _R

U _C1 =V _PA'CD' /V _A'CC'D' =((f _G -f _B )/6)/(1/6)=f _G -f _B

U _D1 =V _PA'CC' /V _A'CC'D' =((f _R -f _G )/6)/(1/6)=f _R -f _G

U _C =V _PA'C'D' /V _A'CC'D' =(f _B /6)/(1/6)=f _B

According to the tetrahedral interpolation formula given above: P’=a×A’+b×B’+c×C’+d×D’, the interpolation formula of the tetrahedron V4 where the mapping point P is located is:

Pp=Pa1×U _A1 +Pc1×U _C1 +Pd1×U _D1 +Pc×U _C

Among them, the color values corresponding to the four vertices CA'C'D' of the large tetrahedron A'CC'D' are Pc, Pa1, Pc1, and Pd1.

Substitute the value of the interpolation coefficient of the above tetrahedron V4 into the above interpolation formula to obtain the interpolation formula of the mapping point P in the tetrahedron V4:

Pp=Pa1×(1-f _R )+Pc1×(f _G –f _B )+Pd1×(f _R -f _G )+Pc×f _B

Similarly, after extracting the remaining 5 congruent tetrahedrons, the interpolation formula of each tetrahedron can be calculated. Set the color values corresponding to the 8 vertices ABCDA'B'C'D' of the cube to Pa, Pb, Pc, Pd, Pa1, Pb1, Pc1, Pd1, and the final interpolation formula is organized as the following table:

Decimal Comparison Conditions The tetrahedron where the point P is located Interpolation formula f _B >f _G ≥f _R A'ABC(V1) (1-f _B )Pa1+(f _B -f _G )Pa+(f _G -f _R )Pb+(f _R )Pc f _B >f _R >f _G A'DAC(V2) (1-f _B )Pa1+(f _B -f _R )Pa+(f _R -f _G )·Pd+(f _G )Pc f _R ≥ f _B ≥ f _G A'D'DC(V3) (1-f _R )Pa1+(f _R -f _B )Pd1+(f _B -f _G )Pd+(f _G )Pc f _R ≥f _G >f _B A'C'D'C(V4) (1-f _R )Pa1+(f _R -f _G )Pd1+(f _G -f _B )Pc1+(f _B )Pc f _G >f _R ≥f _B A'B'C'C(V5) (1-f _G )Pa1+(f _G -f _R )Pb1+(f _R -f _B )Pc1+(f _B )Pc f _G ≥f _B ≥f _R A'BB'C(V6) (1-f _G )Pa1+(f _G -f _B )Pb1+(f _B -f _R )Pb+(f _R )Pc

In this embodiment, the interpolation coefficient and interpolation formula of the tetrahedral interpolation algorithm are determined by the fractional part in the color data mapped by the 3D-LUT, and the addresses of the four vertices of the tetrahedral interpolation algorithm are determined by the integer part. The four vertex addresses are searched in the 3D-LUT correction reference color data to obtain the color value of the four vertex addresses of the tetrahedron where the original color is located, and then the color value of the four vertex addresses of the tetrahedron where it is located is based on the interpolation of the four vertices of the tetrahedron. The coefficients are weighted by the interpolation formula to obtain the color value after interpolation correction; that is, the input original color data is mapped by 3D-LUT, and then the tetrahedral interpolation algorithm and the 3D-LUT correction reference color data are used for correction, and the corrected color data is obtained. , which can effectively simplify the calculation of the tetrahedral interpolation coefficient, and in the specific circuit application, only four multipliers are needed to optimize the tetrahedral interpolation algorithm, simplify the implementation of the hardware circuit, greatly reduce the difficulty of hardware circuit implementation, and improve the The real-time performance of circuit data processing can solve the problem of complicated tetrahedral interpolation calculation interpolation coefficients and complicated hardware circuit implementation in the prior art.

In an embodiment, in the step S32, the determining the addresses of the four vertices of the tetrahedral interpolation algorithm according to the integer part of the color data mapped by the 3D-LUT includes:

Step S321 , according to the integer part (R ₀ , G ₀ , B ₀ ), determine the addresses of the eight vertices of the mapping point P in the smallest cube of the 3D-LUT.

Step S322: Obtain four vertex addresses of the tetrahedron where the original color is located from the eight vertex addresses according to the relative position of the tetrahedron where the vertex of the tetrahedron is located determined by the fractional part from the eight vertex addresses.

In one embodiment, in the step S321, the determining of the eight vertex addresses of the mapping point P in the smallest cube of the 3D-LUT _{according to the integer part (R 0} , G ₀ , B _{0 ) includes:}

In the above interpolation formula, Pa, Pb, Pc, Pd, Pa1, Pb1, Pc1, and Pd1 are the integer part of the color value calculated by the previous color gamut mapping to obtain the coordinates of the corresponding A' point of the 3D-LUT, because the 3D-LUT The data storage is continuous, so the coordinates of the other 7 points of the minimum cube can be calculated according to the coordinates of the corresponding point A'.

Suppose the number of 3D-LUT sampling points is M, and the RGB integer parts of the mapping point P are R ₀ , G ₀ and B _{0 respectively} , then the addresses of the eight vertices of the mapping point P in the smallest cube of the 3D-LUT are as follows:

Address of vertex A'=R ₀ +M×G ₀ +M×M×B ₀

Address of vertex B'=address of vertex A'+M

Address of vertex C'=address of vertex A'+M+1

Address of vertex D' = address of vertex A' + 1

Address of vertex A = address of vertex A' + M×M

Address of vertex B = address of vertex A'+M×M+M

Address of vertex C = address of vertex A'+M×M+M+1

Address of vertex D=address of vertex A'+M×M+1.

Then, the corresponding 3D-LUT color values are extracted from the 3D-LUT correction reference color data through the above coordinates to obtain Pa, Pb, Pc, Pd, Pa1, Pb1, Pc1, and Pd1. Then the interpolation formula can be substituted for the interpolation weighting calculation to obtain the color value after interpolation correction.

In one embodiment, in step S322, the four vertex addresses of the tetrahedron where the original color is located are obtained from the 8 vertex addresses at the relative position of the cube where the vertex of the tetrahedron determined by the fractional part is located, including:

Take the mapping point P in V4 as an example for description.

The four vertices of the large tetrahedron A'CC'D' (V4) where the mapping point P is located are A', C, C', and D'. Assuming that the number of 3D-LUT sampling points is M, and the RGB integer parts of the mapping point P are R ₀ , G ₀ and B _{0 respectively} , then the four vertex addresses of the tetrahedron where the original color is obtained from the eight vertex addresses are respectively :

Address of vertex A'=R ₀ +M×G ₀ +M×M×B ₀

Address of vertex C'=address of vertex A'+M+1

Address of vertex D' = address of vertex A' + 1

Address of vertex C=address of vertex A'+M×M+M+1.

In this embodiment, the addresses of the four vertices of the tetrahedral interpolation algorithm are determined for the integer part in the color data mapped by the 3D-LUT, and the 3D-LUT correction reference color data is searched according to the four vertex addresses. Obtain the color value of the four vertex addresses of the tetrahedron where the original color is located, and then use the interpolation formula to perform weighted calculation according to the color value of the four vertex addresses of the tetrahedron and the interpolation coefficient of the four vertices of the tetrahedron to obtain the color after interpolation correction. value; that is, the input original color data is 3D-LUT mapped and then corrected using the tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain the corrected color data, which can effectively simplify the calculation of the tetrahedral interpolation coefficient, and in the In specific circuit applications, only four multipliers are needed to optimize the tetrahedral interpolation algorithm, simplify the implementation of hardware circuits, greatly reduce the difficulty of hardware circuit implementation, and improve the real-time performance of circuit data processing, thereby solving the problems in the prior art. The tetrahedral interpolation calculation of the interpolation coefficient is complex, and the hardware circuit is complicated to realize the problem.

In one embodiment, the method further includes: outputting the corrected color values (R1, G1, B1) to the LED display screen for display.

In one embodiment, the method further includes: collecting color data of the LED display screen to detect the color gamut.

The color gamut detection is performed by sequentially collecting the display data of each LED display screen to detect whether the color gamut of each display screen is consistent. If they are consistent, the calibration is successful; if they are inconsistent, the calibration is unsuccessful.

In this embodiment, by _{outputting the corrected color values (R 1} , G ₁ , B ₁ ) to the LED display screen for display, and sequentially collecting the display data of each LED display screen for color gamut detection, it can effectively Check whether the color gamut of each display screen is consistent, so as to verify whether the color correction is successful.

In one embodiment, as shown in FIG. 8, the present invention provides a color correction device, the device includes: a storage module 10, a mapping module 20, and a correction module 30, wherein:

The storage module 10 is used for inputting and storing 3D-LUT calibration reference color data;

Described mapping module 20, is used for inputting original color RGB data to carry out 3D-LUT mapping, obtains the color data after 3D-LUT mapping;

The correction module 30 is configured to correct the color data mapped by the 3D-LUT using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data.

In this embodiment, the 3D-LUT color correction method based on tetrahedral interpolation is adopted, that is, the input original color data is 3D-LUT mapped and then corrected by the tetrahedral interpolation algorithm and the 3D-LUT correction reference color data, and the correction is obtained. The obtained color data can effectively simplify the calculation of the tetrahedral interpolation coefficient, and in the specific circuit application, only four multipliers are needed to optimize the tetrahedral interpolation algorithm, simplify the implementation of the hardware circuit, and greatly reduce the hardware circuit. The realization difficulty is improved, and the real-time performance of circuit data processing is improved, thereby solving the problem of complicated tetrahedral interpolation calculation and complex interpolation coefficients in the prior art, which complicates hardware circuit implementation.

It should be noted that the above apparatus embodiments and method embodiments belong to the same concept, and the specific implementation process is detailed in the method embodiments, and the technical features in the method embodiments are correspondingly applicable in the apparatus embodiments, which will not be repeated here.

In addition, an embodiment of the present invention also provides a 3D-LUT color correction device, as shown in FIG. 9 , including: a memory, a processor, and one or more computer programs stored in the memory and executable on the processor , when the one or more computer programs are executed by the processor to implement the following steps of the 3D-LUT color correction method based on the tetrahedral interpolation algorithm provided by the embodiment of the present invention:

S1. Input and store 3D-LUT correction reference color data.

S2. Input original color (RGB) data to perform 3D-LUT mapping to obtain color data after 3D-LUT mapping.

S3. Correct the color data mapped by the 3D-LUT using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data.

The methods disclosed in the above embodiments of the present invention may be applied to the processor 901 or implemented by the processor 901 . The processor 901 may be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above-mentioned method can be completed by an integrated logic circuit of hardware in the processor 901 or an instruction in the form of software. The processor 901 may be a general-purpose processor, a DSP, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. The processor 901 may implement or execute the methods, steps, and logical block diagrams disclosed in the embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the method disclosed in conjunction with the embodiments of the present invention can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, and the storage medium is located in the memory 902, and the processor 901 reads the information in the memory 902, and completes the steps of the foregoing method in combination with its hardware.

It can be understood that the memory 902 in this embodiment of the present invention may be a volatile memory or a non-volatile memory, and may also include both volatile and non-volatile memory. Among them, the non-volatile memory can be a read-only memory (ROM, Read-Only Memory), a programmable read-only memory (PROM, Programmable Read-Only Memory), an erasable programmable read-only memory (EPROM, Erasable Read-Only Memory) Only Memory), Electrically Erasable Programmable Read-Only Memory (EEPROM, Electrically Erasable Programmable Read-Only Memory), Magnetic Random Access Memory (FRAM, Ferromagnetic Random Access Memory), Flash Memory (Flash Memory) or other memory technologies, CD-ROM Read-Only Memory (CD-ROM, Compact Disk Read-Only Memory), Digital Versatile Disk (DVD, Digital Video Disk) or other optical disk storage, magnetic cassette, tape, magnetic disk storage or other magnetic storage device; volatile memory may be random access Access memory (RAM, Random Access Memory), by way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM, Static Random Access Memory), static random access memory (SSRAM, Synchronous Static Random Access Memory), Dynamic Random Access Memory (DRAM, Dynamic Random Access Memory), Synchronous Dynamic Random Access Memory (SDRAM, Synchronous Dynamic Random Access Memory), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM, Double Data Rate Synchronous Dynamic Random Access Memory), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM, Enhanced Synchronous Dynamic Random Access Memory), Synchronous Link Dynamic Random Access Memory (SLDRAM, SyncLink Dynamic Random Access Memory), Direct Memory Bus Random Memory Access memory (DRRAM, Direct Rambus Random Access Memory). The memory described in the embodiments of the present invention is intended to include, but not be limited to, these and any other suitable types of memory.

It should be noted that the above device embodiments and method embodiments belong to the same concept, and the specific implementation process is detailed in the method embodiments, and the technical features in the method embodiments are correspondingly applicable in the device embodiments, which will not be repeated here.

In addition, an embodiment of the present invention further provides a computer-readable storage medium, where a program of a 3D-LUT color correction method based on a tetrahedral interpolation algorithm is stored on the computer-readable storage medium. When the program of the algorithmic 3D-LUT color correction method is executed by the processor, the following steps of the 3D-LUT color correction method based on the tetrahedral interpolation algorithm provided by the embodiment of the present invention are implemented:

S1. Input and store 3D-LUT correction reference color data.

S2. Input original color (RGB) data to perform 3D-LUT mapping to obtain color data after 3D-LUT mapping.

S3. Correct the color data mapped by the 3D-LUT using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data.

It should be noted that the program embodiment and the method embodiment of a 3D-LUT color correction method based on a tetrahedral interpolation algorithm on the above-mentioned computer-readable storage medium belong to the same concept, and the specific implementation process is detailed in the method embodiment, and The technical features in the method embodiments are all correspondingly applicable in the above-mentioned computer-readable storage medium embodiments, and will not be repeated here.

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements, It also includes other elements not expressly listed or inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages or disadvantages of the embodiments.

From the description of the above embodiments, those skilled in the art can clearly understand that the method of the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is better implementation. Based on this understanding, the technical solutions of the present invention can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products are stored in a storage medium (such as ROM/RAM, magnetic disk, CD), including several instructions to make a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) execute the methods described in the various embodiments of the present invention.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the scope of protection of the present invention and the claims, many forms can be made, which all belong to the protection of the present invention.

Claims (16)

A color correction method, the method comprising: Input and store 3D-LUT calibration reference color data; Input the original color RGB data for 3D-LUT mapping, and obtain the color data after 3D-LUT mapping; The 3D-LUT-mapped color data is corrected using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data. The method according to claim 1, characterized in that, before performing 3D-LUT mapping on the input original color RGB data, the method further comprises: reading original color data for correcting the color gamut input display. The method according to claim 1, wherein the 3D-LUT-mapped color data is corrected using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data; comprising: Determine the interpolation coefficient and interpolation formula of the tetrahedral interpolation algorithm according to the fractional part of the color data after 3D-LUT mapping; Determine the addresses of the four vertices of the tetrahedral interpolation algorithm according to the integer part in the color data mapped by the 3D-LUT; According to the four vertex addresses, the color value of the four vertex addresses of the tetrahedron where the original color is obtained is obtained by searching in the 3D-LUT correction reference color data; According to the color values of the addresses of the four vertices of the tetrahedron and the interpolation coefficients of the four vertices of the tetrahedron, a weighted calculation is performed using an interpolation formula to obtain the color value R ₁ G ₁ B ₁ after interpolation correction. The method according to claim 3, wherein, performing 3D-LUT mapping on the input original color RGB data to obtain color data after 3D-LUT mapping, comprising: Input the original color (R, G, B) data, multiply the three RGB components by the color gamut scaling ratio scale, and obtain the mapped color data (R ₀ +f _R , G ₀ +f _G , B ₀ +f _{B )} ); wherein, R ₀ , G ₀ and B ₀ are the integer parts of the mapped colors on the RGB components, and f _R , f _G and f _B are the fractional parts of the mapped colors on the RGB components; The color gamut scaling ratio scale=(M-1)/(2 ⁿ -1), where n is the bit width of the input color, and M is the number of single-dimensional sampling points of the 3D-LUT. The method according to claim 4, wherein, determining the interpolation coefficient and interpolation formula of the tetrahedral interpolation algorithm according to the fractional part in the color data after 3D-LUT mapping, comprising: _{Compare the size relationship between f R} , f _G and f _{B of} the fractional part to determine the tetrahedron where the mapping point is located and the relative position of the tetrahedron vertex in the cube; The interpolation coefficients and interpolation formulas of the four vertices of the tetrahedron where the mapping point is located are determined according to f _R , f _G and f _{B of the fractional part.} The method according to claim 5, wherein the comparing the _{size relationship between f R} , f _G and f _{B of} the fractional part determines the tetrahedron where the mapping point is located and the relative position of the tetrahedron vertex on the cube, comprising: Select the first vertex of the cube, project the mapping point on the plane perpendicular to the direction along the direction of the first vertex as the starting point, and determine that the mapping point is on the diagonal formed by the other vertex forming the direction on the plane as the Above or below the line, determines the tetrahedron where the mapping point is located. The method of claim 5, wherein the interpolation coefficients are: U _A1 = 1 – f _R U _C1 = f _G – f _B U _D1 = f _R – f _G U _C =f _B . The method of claim 7, wherein the interpolation formula is: Pp=Pa1×(1-f _R )+Pc1×(f _G –f _B )+Pd1×(f _R -f _G )+Pc×f _B Among them, Pc, Pa1, Pc1, and Pd1 are the color values corresponding to the four vertices of the tetrahedron where the mapping point is located; According to the above method, the interpolation formula of the remaining 5 congruent tetrahedra is obtained. The method according to claim 4, wherein the determining the addresses of the four vertices of the tetrahedral interpolation algorithm according to the integer part in the color data after the 3D-LUT mapping comprises: According to the integer part (R ₀ , G ₀ , B ₀ ), determine the addresses of the 8 vertices of the minimum cube of the 3D-LUT where the mapping point is located; The four vertex addresses of the tetrahedron where the original color is located are obtained from the eight vertex addresses according to the relative position of the tetrahedron where the vertex of the tetrahedron is located determined by the fractional part. The method according to claim 9, wherein the determining the mapping point at the 8 vertex addresses of the smallest cube of the 3D-LUT _{according to the integer part (R 0} , G ₀ , B _{0 ), comprises:} Assuming that the number of 3D-LUT sampling points is M, and the RGB integer parts of the mapping points are R ₀ , G ₀ and B _{0 respectively} , then the mapping points are located in the 8 vertex addresses of the smallest cube of the 3D-LUT as follows: Address of vertex A'=R ₀ +M×G ₀ +M×M×B ₀ ; Address of vertex B'=address of vertex A'+M; Address of vertex C'=address of vertex A'+M+1; The address of vertex D'=address of vertex A'+1; The address of vertex A = the address of vertex A'+M×M; The address of vertex B = the address of vertex A'+M×M+M; Address of vertex C=address of vertex A'+M×M+M+1; Address of vertex D=address of vertex A'+M×M+1. The method according to claim 10, wherein the four vertex addresses of the tetrahedron where the original color is located are obtained from the eight vertex addresses at the relative position of the cube where the vertex of the tetrahedron where the original color is located, including: Assuming that the number of 3D-LUT sampling points is M, and the RGB integer parts of the mapping points are R ₀ , G ₀ and B _{0 respectively} , then the four vertex addresses of the tetrahedron where the original color is obtained from the eight vertex addresses are: Address of vertex A'=R ₀ +M×G ₀ +M×M×B ₀ ; Address of vertex C'=address of vertex A'+M+1; The address of vertex D'=address of vertex A'+1; Address of vertex C=address of vertex A'+M×M+M+1. The method according to any one of claims 1 to 11, wherein the method further comprises: outputting the corrected color values (R ₁ , G ₁ , B ₁ ) to the LED display screen for display. The method according to claim 12, wherein the method further comprises: collecting color data of the LED display screen to detect the color gamut, comprising: Color gamut detection is performed by sequentially collecting the display data of each LED display screen to detect whether the color gamut of each display screen is consistent. If they are consistent, the calibration is successful; if they are inconsistent, the calibration is unsuccessful. A color correction device, the device is applied to a color correction method according to any one of claims 1 to 13, the device comprises: a storage module, a mapping module, and a correction module, wherein: The storage module is used for inputting and storing 3D-LUT correction reference color data; Described mapping module, is used for inputting original color RGB data to carry out 3D-LUT mapping, obtains the color data after 3D-LUT mapping; The correction module is configured to correct the color data mapped by the 3D-LUT using a tetrahedral interpolation algorithm and the 3D-LUT correction reference color data to obtain corrected color data. A color correction apparatus, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, the computer program being executed by the processor to achieve as claimed in claims 1 to 13 The steps of any one of the color correction methods. A storage medium on which a program of a color correction method is stored, and when the program of the color correction method is executed by a processor, a program according to any one of claims 1 to 13 is implemented. steps of a color correction method.

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