Brightness compensation method and display panel

Abstract

The invention provides a brightness compensation method and a display panel, and the method comprises the steps: obtaining the brightness value of each first region when a monochrome gray scale image of a preset gray scale is displayed, and obtaining a first brightness value matrix; according to the first brightness value matrix, calculating the gradient amplitude of each first region; dividing the display panel into a plurality of second areas according to a relationship between the gradient amplitude of each first area and a preset gradient threshold; acquiring a brightness value of each second area when a monochromatic gray scale picture of a preset gray scale is displayed; a compensation coefficient table is obtained according to the relation between the brightness value of each second area and the brightness value of a reference area, the compensation coefficient table comprises compensation coefficients of each second area under the preset gray scale, and the reference area is one of the multiple second areas; and driving the display panel to display based on the compensation coefficient table. According to the brightness compensation method provided by the embodiment of the invention, the compensation precision can be improved, and the brightness uniformity can be improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a brightness compensation method and a display panel. Background Art

[0002] Due to factors such as the manufacturing process, the display panel may have uneven brightness during display. To improve the display quality, it is usually necessary to perform brightness compensation on the display panel to eliminate the uneven brightness problem.

[0003] Existing display panel brightness compensation technologies, such as frame rate control (FRC) and spatial dithering, achieve brightness and color correction by finely controlling the voltage corresponding to each grayscale value. However, existing brightness compensation technologies are difficult to adapt to display panels with complex brightness distributions (such as those with notch screens and other special-shaped displays), resulting in uneven brightness and color in these display panels. Summary of the Invention

[0004] In view of this, the main purpose of this application is to propose a brightness compensation method and a display panel, aiming to solve the problem that existing brightness compensation technology is difficult to adapt to display panels with complex brightness distribution.

[0005] To achieve the above-mentioned objectives, the first aspect of the present application provides a brightness compensation method, which is used to perform brightness compensation on a display panel, wherein the display panel is divided into a plurality of first areas arranged in an array, and the brightness compensation method includes: obtaining the brightness value of each of the first areas when displaying a monochrome grayscale image of a preset grayscale, and obtaining a first brightness value matrix; calculating the gradient amplitude of each of the first areas according to the first brightness value matrix; dividing the display panel into a plurality of second areas according to the relationship between the gradient amplitude of each of the first areas and a preset gradient threshold; obtaining the brightness value of each of the second areas when displaying a monochrome grayscale image of the preset grayscale; obtaining a compensation coefficient table according to the relationship between the brightness value of each of the second areas and the brightness value of a reference area, wherein the compensation coefficient table includes the compensation coefficient of each of the second areas at the preset grayscale, and the reference area is one of the plurality of second areas; and driving the display panel for display based on the compensation coefficient table.

[0006] The brightness compensation method provided in the embodiment of the present application divides the display panel into multiple second areas according to the relationship between the gradient amplitude of each first area and a preset gradient threshold, obtains the brightness value of each second area when displaying a monochrome grayscale image of a preset grayscale, obtains a compensation coefficient table according to the relationship between the brightness value of each second area and the brightness value of the reference area, and drives the display panel for display based on the compensation coefficient table. In this way, by analyzing the gradient amplitude of each first area of ​​the display panel, the size and shape of the compensation area are adaptively adjusted to re-divide the display panel into multiple second areas, which can achieve the effect of dynamic partition compensation, and can divide the edge area with drastic brightness changes into denser small partitions, while the central area with uniform brightness is divided into larger partitions, thereby improving the compensation accuracy and improving the uniformity of brightness.

[0007] In some embodiments, any second region satisfies one of the following conditions: the second region is one first region; the second region is a region formed by merging multiple first regions; and the second region is a region obtained by dividing one first region.

[0008] In some embodiments, calculating the gradient amplitude of each first region based on the first brightness value matrix includes: determining the corresponding transverse gradient kernel Gx and the corresponding longitudinal gradient kernel Gy based on the first brightness value matrix; performing a convolution operation on the first brightness value matrix using the transverse gradient kernel Gx to obtain the transverse gradient value of each first region; performing a convolution operation on the first brightness value matrix using the longitudinal gradient kernel Gy to obtain the longitudinal gradient value of each first region; and calculating the gradient amplitude of each first region based on the transverse gradient value and the longitudinal gradient value of each first region.

[0009] In some embodiments, the plurality of first regions are arranged in an array of N rows and N columns, where N is an odd number greater than zero; determining the corresponding transverse gradient kernel Gx and the corresponding longitudinal gradient kernel Gy according to the first brightness value matrix includes: calculating an initial transverse gradient kernel Gx1 according to a first calculation formula; wherein the first calculation formula is:

[0010]

[0011] Wherein, σ is a preset standard deviation value, Gx1(m,n) is the transverse gradient value of the element at position (m,n) in the initial transverse gradient kernel Gx1; each element in the initial transverse gradient kernel Gx1 is multiplied by an amplification factor and rounded to the nearest integer, thereby obtaining the transverse gradient kernel Gx corresponding to the first brightness value matrix;

[0012] The initial longitudinal gradient kernel Gy1 is calculated according to the second calculation formula; wherein the second calculation formula is:

[0013]

[0014] Among them, Gy1(m,n) is the longitudinal gradient value of the element at position (m,n) in the initial longitudinal gradient kernel Gy1; each element in the initial longitudinal gradient kernel Gy1 is multiplied by an amplification factor and rounded to the nearest integer, thereby obtaining the longitudinal gradient kernel Gy corresponding to the first brightness value matrix.

[0015] In some embodiments, performing a convolution operation on the first brightness value matrix using the transverse gradient kernel Gx to obtain the transverse gradient value of each first region includes: calculating the transverse gradient value of each first region according to a third calculation formula; wherein the third calculation formula is:

[0016]

[0017] Wherein, G'x(i,j) is the transverse gradient value of the first region with coordinates (i,j), Gx(m,n) is the transverse gradient value of the element at position (m,n) in the transverse gradient kernel Gx, and L(i+m,j+n) is the brightness value of the first region with coordinates (i+m,j+n) in the first brightness value matrix; the convolution operation on the first brightness value matrix using the longitudinal gradient kernel Gy to obtain the longitudinal gradient value of each first region includes:

[0018] The longitudinal gradient value of each of the first regions is calculated according to a fourth calculation formula; wherein the fourth calculation formula is:

[0019]

[0020] Wherein, G'y(i,j) is the longitudinal gradient value of the first region with coordinates (i,j), and Gy(m,n) is the longitudinal gradient value of the element at position (m,n) in the longitudinal gradient kernel Gy; and calculating the gradient amplitude of each first region based on the transverse gradient value and the longitudinal gradient value of each first region includes: calculating the gradient amplitude of each first region according to a fifth calculation formula; wherein the fifth calculation formula is:

[0021]

[0022] Wherein, G'(i,j) is the gradient amplitude of the first region with coordinates (i,j).

[0023] In some embodiments, the preset gradient threshold includes a first preset gradient threshold and a second preset gradient threshold, the first preset gradient threshold is less than the second preset gradient threshold; dividing the display panel into multiple second areas according to the relationship between the gradient amplitude of each first area and the preset gradient threshold includes: when the gradient amplitude of a certain first area is greater than the second preset threshold, dividing the certain first area into multiple second areas; and when the gradient amplitudes of multiple adjacent first areas are all less than or equal to the first preset threshold, merging the multiple adjacent first areas into one second area.

[0024] In some embodiments, when the gradient amplitude of a certain first region is greater than the second preset threshold, dividing the certain first region into a plurality of second regions includes: when the gradient amplitude of a certain first region is greater than the second preset threshold, using the certain first region as the initial parent region, and repeatedly performing a region segmentation step until a segmentation termination condition is satisfied; and determining each sub-region obtained by segmentation as the second region; the region segmentation step includes: dividing the parent region into a plurality of sub-regions; obtaining a luminance value of each sub-region when displaying a monochrome grayscale image of the preset grayscale to obtain a second luminance value matrix; calculating the gradient amplitude of each sub-region based on the second luminance value matrix; and determining whether a segmentation termination condition is satisfied based on the gradient amplitude of each sub-region; if the segmentation termination condition is satisfied, determining each sub-region obtained by segmentation as a second region; and if the segmentation termination condition is not satisfied, performing the region segmentation step again with the region having a gradient amplitude greater than the second preset threshold as a new parent region; wherein the segmentation termination condition is: the gradient amplitudes of all sub-regions obtained by segmenting the certain first region are less than or equal to the second preset threshold.

[0025] In some embodiments, the brightness compensation method further includes: obtaining an ambient light brightness value; and determining the preset gradient threshold value based on the ambient light brightness value; wherein there is a positive correlation between the ambient light brightness value and the preset gradient threshold value.

[0026] In some embodiments, the brightness compensation method further includes: detecting a refresh rate of the display panel; and determining the preset gradient threshold according to the refresh rate; wherein the refresh rate and the preset gradient threshold are negatively correlated.

[0027] A second aspect of the present application further provides a display panel, to which the brightness compensation method described in the first aspect is applied.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a first display panel provided in an embodiment of the present application;

[0030] Figure 2 A flowchart of a brightness compensation method provided in an embodiment of the present application;

[0031] Figure 3 A first schematic diagram of a second display panel provided in an embodiment of the present application;

[0032] Figure 4 A second schematic diagram of a second display panel provided in an embodiment of the present application;

[0033] Figure 5 for Figure 4 The compensation coefficient table of the display panel at 64 gray levels is shown;

[0034] Figure 6 for Figure 4 The compensation coefficient table of the display panel at 127 grayscale is shown;

[0035] Figure 7 A schematic diagram of a third display panel provided in an embodiment of the present application;

[0036] Figure 8 A topological diagram of the display panel provided in an embodiment of the present application.

[0037] The following are the descriptions of the reference numerals:

[0038] Display panel 100

[0039] First area A, A00, A02, A10, A11, A21, A22, A23, A31, A32, A33

[0040] Second area B, B111, B112, B113, B114, B22

[0041] Control module 11

[0042] Processing module 12

[0043] Memory module 13

[0044] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] In addition, the terms "first", "second", etc. in the description of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] It should be noted that, in the absence of conflict, the features in the embodiments of this application can be combined with each other.

[0048] Due to factors such as the manufacturing process, the display panel may have uneven brightness during display. To improve the display quality, it is usually necessary to perform brightness compensation on the display panel to eliminate the uneven brightness problem.

[0049] In existing display panel brightness compensation technologies, such as Frame Rate Control (FRC) and spatial dithering, brightness and color correction are achieved by more precisely controlling the voltage corresponding to each grayscale value. Figure 1 As shown, Figure 1 Schematic diagram of the first display panel provided in the embodiment of the present application. Existing brightness compensation technology usually divides the display panel into multiple rectangular partitions M and compensates each rectangular partition M separately. However, for display panels with complex brightness distribution (such as special-shaped screens such as notch screens), for example Figure 3 The display panel shown is difficult to adapt to existing brightness compensation technology, and the brightness of the edge area is much lower than that of the center area, resulting in uneven brightness and color.

[0050] In view of this, the present application provides a brightness compensation method, which is used to perform brightness compensation on the display panel 100 .

[0051] Please also read Figures 2 and 3 , Figure 2A flowchart of a brightness compensation method provided in an embodiment of the present application; Figure 3 This is a first schematic diagram of the second display panel provided in an embodiment of the present application.

[0052] The display panel 100 is divided into a plurality of first areas A arranged in an array. For example, Figure 3 As shown, the embodiment of the present application takes the display panel 100 as being divided into 5×5 first areas A as an example. For ease of description, the first area located in the i+1th row and j+1th column is labeled Aij herein. The number of pixel units included in each of the first areas A may be equal or unequal. The first area A may be completely located in the display area, such as the first area A20, or partially located in the display area and partially located in the non-display area, such as the first area A00, or completely located in the non-display area, such as the first area A02.

[0053] like Figure 2 As shown, the brightness compensation method includes steps S1 to S6, which are described in detail as follows:

[0054] Step S1, obtaining the brightness value of each of the first areas A when displaying a monochrome grayscale image of a preset grayscale, to obtain a first brightness value matrix L;

[0055] Step S2, calculating the gradient amplitude of each of the first areas A according to the first brightness value matrix L;

[0056] Step S3, dividing the display panel 100 into a plurality of second areas B according to the relationship between the gradient amplitude of each first area A and a preset gradient threshold;

[0057] Step S4, obtaining the brightness value of each second area B when displaying the monochrome grayscale image of the preset grayscale;

[0058] Step S5: obtaining a compensation coefficient table based on a relationship between the brightness value of each second region B and the brightness value of a reference region, wherein the compensation coefficient table includes a compensation coefficient for each second region B at the preset grayscale, and the reference region is one of the plurality of second regions B;

[0059] Step S6: driving the display panel 100 to display based on the compensation coefficient table.

[0060] The brightness compensation method provided in the embodiment of the present application divides the display panel 100 into multiple second areas B according to the relationship between the gradient amplitude of each first area A and a preset gradient threshold, obtains the brightness value of each second area B when displaying a monochrome grayscale image of a preset grayscale, obtains a compensation coefficient table according to the relationship between the brightness value of each second area B and the brightness value of the reference area, and drives the display panel 100 for display based on the compensation coefficient table. In this way, by analyzing the gradient amplitude of each first area A of the display panel 100, the size and shape of the compensation area are adaptively adjusted to re-divide the display panel 100 into multiple second areas B, which can achieve the effect of dynamic partition compensation, and can divide the edge area with drastic brightness changes into denser small partitions, while the central area with uniform brightness is divided into larger partitions, thereby improving the compensation accuracy and improving the uniformity of brightness.

[0061] Among them, the first area A displays a monochrome grayscale image of a preset grayscale, which means that the target grayscale of all pixel units in the first area A is the preset grayscale. Under ideal circumstances, when displaying the monochrome grayscale image of the preset grayscale, the brightness values ​​of each of the first areas A are the same. However, as mentioned above, due to the influence of factors such as the process, the actual brightness values ​​of different areas may be inconsistent.

[0062] The preset grayscale may include at least one intermediate grayscale between a minimum grayscale and a maximum grayscale supported by the display panel 100 .

[0063] Illustratively, the minimum grayscale is grayscale 0, and the maximum grayscale is grayscale 255. The preset grayscales may be grayscale 5, grayscale 10, grayscale 16, grayscale 20, grayscale 25, grayscale 32, grayscale 40, grayscale 50, grayscale 64, grayscale 100, grayscale 125, grayscale 127, grayscale 150, grayscale 200, grayscale 224, grayscale 250, and the like.

[0064] For example, a high-precision optical sensor (such as Minolta CA-410) can be used to obtain the brightness value of each first area A using a grid sampling method. It is easy to understand that when a first area is completely located in the non-display area, for example Figure 3 If A13 is set in the first region, the brightness value of the first region is 0. The unit of the brightness value may be cd / m2.

[0065] In some embodiments, the plurality of first regions are arranged in an array of N rows and N columns, where N>0. In this case, the first brightness value matrix L is a square matrix with a dimension of N×N. For example, Figure 3 The first brightness value matrix L of the display panel 100 when displaying a preset grayscale is:

[0066]

[0067] In some embodiments, the multiple first regions are arranged in an array of C rows and D columns, where C>0, D>0, and C≠D. The luminance values ​​of the multiple first regions form a matrix of dimension C×D. In this case, zero padding can be used to obtain a square matrix of dimension N×N as the first luminance value matrix L, where N=max(C,D). For example, when C=3 and D=4, the luminance values ​​of the multiple first regions form a 3×4 matrix. In this case, a row of data 0 can be padded after the last row of this 3×4 matrix to obtain a 4×4 square matrix as the first luminance value matrix L.

[0068] In some embodiments, calculating the gradient magnitude of each first area A according to the first brightness value matrix L includes:

[0069] Determine the corresponding transverse gradient kernel Gx and the corresponding longitudinal gradient kernel Gy according to the first brightness value matrix L;

[0070] Performing a convolution operation on the first brightness value matrix L using the transverse gradient kernel Gx to obtain a transverse gradient value of each first area A;

[0071] Performing a convolution operation on the first brightness value matrix L using the longitudinal gradient kernel Gy to obtain a longitudinal gradient value of each of the first areas A;

[0072] According to the transverse gradient value and the longitudinal gradient value of each first region A, the gradient amplitude of each first region A is calculated.

[0073] Among them, the transverse gradient kernel (also known as the horizontal gradient kernel) and the longitudinal gradient kernel (also known as the vertical gradient kernel) are convolution kernels used to calculate the gradients of the image in the horizontal and vertical directions. Their core function is to approximately calculate the first-order derivative of the image through convolution operations, thereby identifying areas with sudden changes in brightness (such as edges and lines). Common gradient kernels include the Sobel gradient kernel, the Prewitt gradient kernel, and the Roberts cross gradient kernel.

[0074] In some embodiments, the plurality of first regions A are arranged in an array of N rows and N columns, where N is an odd number greater than zero.

[0075] The determining of the corresponding transverse gradient kernel Gx and the corresponding longitudinal gradient kernel Gy according to the first brightness value matrix L includes:

[0076] According to the first calculation formula, the initial transverse gradient kernel Gx1 is calculated;

[0077] Wherein, the first calculation formula is:

[0078]

[0079] Wherein, σ is a preset standard deviation value, Gx1(m,n) is the transverse gradient value of the element at position (m,n) in the initial transverse gradient kernel Gx1;

[0080] Multiplying each element in the initial transverse gradient kernel Gx1 by a magnification factor and rounding to the nearest integer, thereby obtaining the transverse gradient kernel Gx corresponding to the first brightness value matrix L;

[0081] According to the second calculation formula, the initial longitudinal gradient kernel Gy1 is calculated;

[0082] Wherein, the second calculation formula is:

[0083]

[0084] Wherein, Gy1(m,n) is the longitudinal gradient value of the element at position (m,n) in the initial longitudinal gradient kernel Gy1;

[0085] Each element in the initial longitudinal gradient kernel Gy1 is multiplied by an amplification factor and rounded to the nearest integer, thereby obtaining the longitudinal gradient kernel Gy corresponding to the first brightness value matrix L.

[0086] It should be noted that in the initial transverse gradient kernel Gx1, transverse gradient kernel Gx, initial longitudinal gradient kernel Gy1, and longitudinal gradient kernel Gy, the origin of the system coordinates (m, n) is located at the center of the gradient kernel. Taking the 5×5 gradient kernel as an example, the element with coordinates (-2, -2) is the element located in the first row and the first column of the matrix, and the element with coordinates (0, 0) is the origin, that is, the element located in the third row and the third column of the matrix.

[0087] Exemplarily, σ=(N-1) / 6. Taking N=5 as an example, the coordinate matrices of the initial transverse gradient kernel Gx1, the transverse gradient kernel Gx, the initial longitudinal gradient kernel Gy1, and the longitudinal gradient kernel Gy are all:

[0088]

[0089] The horizontal gradient kernel Gx corresponding to the first 5×5 brightness value matrix L is calculated by the above first calculation formula:

[0090]

[0091] The longitudinal gradient kernel Gy corresponding to the first 5×5 brightness value matrix L is calculated by the second calculation formula above:

[0092]

[0093] It should be noted that the first and second calculation formulas above use a Gaussian function to calculate the gradient kernel. This combines the smoothness of the Gaussian function with its precise derivative calculation capabilities, effectively reducing the impact of noise on gradient calculations and improving the accuracy and robustness of edge detection. Furthermore, by adjusting the standard deviation σ of the Gaussian function, the smoothness of the gradient calculation and the scale of the detected edge can be flexibly controlled. Furthermore, by rounding off the transverse gradient kernel Gx and the longitudinal gradient kernel Gy, calculations can be simplified and the complexity of floating-point operations can be reduced.

[0094] In some embodiments, performing a convolution operation on the first brightness value matrix L using the transverse gradient kernel Gx to obtain the transverse gradient value of each first area A includes:

[0095] According to the third calculation formula, the transverse gradient value of each of the first areas A is calculated.

[0096] Wherein, the third calculation formula is:

[0097]

[0098] Where G'x(i,j) is the transverse gradient value of the first region A at coordinates (i,j), that is, the transverse gradient value of the first region Aij. Gx(m,n) is the transverse gradient value of the element at position (m,n) in the transverse gradient kernel Gx, and L(i+m,j+n) is the luminance value of the first region A at coordinates (i+m,j+n) in the first luminance value matrix L.

[0099] The step of performing a convolution operation on the first brightness value matrix L using the longitudinal gradient kernel Gy to obtain the longitudinal gradient value of each first area A includes:

[0100] According to the fourth calculation formula, the longitudinal gradient value of each of the first areas A is calculated.

[0101] Wherein, the fourth calculation formula is:

[0102]

[0103] Wherein, G'y(i,j) is the longitudinal gradient value of the first region with coordinates (i,j), that is, the longitudinal gradient value of the first region Aij. Gy(m,n) is the longitudinal gradient value of the element at position (m,n) in the longitudinal gradient kernel Gy.

[0104] The step of calculating the gradient amplitude of each of the first regions A according to the transverse gradient value and the longitudinal gradient value of each of the first regions A includes:

[0105] According to the fifth calculation formula, the gradient amplitude of each of the first areas A is calculated.

[0106] Wherein, the fifth calculation formula is:

[0107]

[0108] Here, G'(i, j) is the gradient amplitude of the first region A with coordinates (i, j), that is, the gradient amplitude of the first region Aij.

[0109] It should be noted that in G'x(i,j), G'y(i,j), G'(i,j), and the first luminance value matrix L, the origin is located in the upper left corner of the matrix. That is, the element with coordinates (0,0) is the origin, that is, the element located in row 1 and column 1 in the matrix. When calculating the horizontal gradient value and vertical gradient value of each first area A, when L(i+m,j+n) exceeds the first luminance value matrix L, the value of L(i+m,j+n) is 0. That is, when i+m>N-1, or i+m<0, or j+n>N-1, or j+n<0, L(i+m,j+n)=0.

[0110] Exemplarily, taking N=5 as an example, the coordinate matrices of G'x(i,j), G'(i,j) and the first brightness value matrix L are all:

[0111]

[0112] In some embodiments, a Roberts gradient kernel may also be used to calculate the gradient magnitude of each first region A. Specifically, the plurality of first regions are arranged in an array of K rows and H columns, where K>0 and H>0, and the first luminance value matrix is ​​a K×H matrix. Calculating the gradient magnitude of each first region based on the first luminance value matrix includes:

[0113] Zero-filling the first brightness value matrix to obtain an expanded matrix L1 with a dimension of (K+2)×(H+2);

[0114] Performing a convolution operation on the expanded matrix L1 using the Roberts transverse gradient kernel Gx_1 to obtain transverse gradient values ​​of each of the first regions;

[0115] Performing a convolution operation on the expanded matrix L1 using the Roberts longitudinal gradient kernel Gy_1 to obtain longitudinal gradient values ​​of each of the first regions;

[0116] The gradient amplitude of each first region is calculated according to the transverse gradient value and the longitudinal gradient value of each first region.

[0117] Wherein, the Roberts transverse gradient kernel Gx_1 is:

[0118]

[0119] The Roberts longitudinal gradient kernel Gy_1 is:

[0120]

[0121] The convolution operation is performed on the expansion matrix L1 using the Roberts transverse gradient kernel Gx_1 to obtain the transverse gradient value of each first region, including:

[0122] According to the sixth calculation formula, the transverse gradient value of each of the first regions A is calculated.

[0123] Wherein, the sixth calculation formula is:

[0124] G'x(i,j)=L1(i+1,j+1)-L1(i,j);

[0125] Among them, 1≤i≤K, 1≤j≤H.

[0126] The convolution operation is performed on the expansion matrix L1 using the Roberts longitudinal gradient kernel Gy_1 to obtain the longitudinal gradient value of each first region, including:

[0127] According to the seventh calculation formula, the transverse gradient value of each of the first regions A is calculated.

[0128] Wherein, the seventh calculation formula is:

[0129] G'y(i,j)=L1(i+1,j)-L1(i,j+1);

[0130] The step of calculating the gradient amplitude of each of the first regions A according to the transverse gradient value and the longitudinal gradient value of each of the first regions A includes:

[0131] According to the fifth calculation formula, the gradient amplitude of each first area A is calculated.

[0132] Exemplarily, it is assumed that the first brightness value matrix L is:

[0133]

[0134] The first brightness value matrix is ​​zero-filled, and the obtained expansion matrix L1 is:

[0135]

[0136] The gradient magnitude matrix G' of each of the first regions A finally obtained by calculation is:

[0137]

[0138] It should be noted that, in other embodiments, other types of gradient kernels may also be used to calculate the gradient amplitude of each first region A, which is not limited here.

[0139] In some embodiments, any second region B satisfies one of the following conditions:

[0140] The second area B is one of the first areas A;

[0141] The second area B is an area formed by merging multiple first areas A;

[0142] The second region B is a region obtained by dividing the first region A.

[0143] In this way, the display panel 100 can be re-divided into the plurality of second areas B by making corresponding adjustments to the plurality of first areas A, and the division efficiency is high.

[0144] In some embodiments, the preset gradient threshold includes a first preset gradient threshold and a second preset gradient threshold, and the first preset gradient threshold is smaller than the second preset gradient threshold;

[0145] The display panel 100 is divided into a plurality of second areas B according to the relationship between the gradient amplitude of each first area A and the preset gradient threshold, including:

[0146] When the gradient amplitude of a certain first region A is greater than the second preset threshold, dividing the certain first region A into a plurality of second regions B;

[0147] When the gradient amplitudes of a plurality of adjacent first regions A are all less than or equal to the first preset threshold, the plurality of adjacent first regions A are merged into one second region B.

[0148] The larger the gradient amplitude, the more dramatic the image brightness change at that location, typically corresponding to edges, boundaries, or areas rich in detail. Therefore, when the gradient amplitude of a first region A is greater than a second preset threshold, the first region A is divided into multiple second regions B. Thus, targeted brightness compensation is performed on each second region B, improving the brightness uniformity of the entire display. Furthermore, when the gradient amplitudes of multiple adjacent first regions A are all less than or equal to the first preset threshold, it indicates that the image brightness change at that location is small. Therefore, the same compensation coefficient can be used for brightness compensation, thereby merging the multiple adjacent first regions A into a single second region B. This reduces the computational complexity of each module and improves the response speed of the display panel.

[0149] For example, taking N=5, the first preset gradient threshold is 0.2, and the second preset gradient threshold is 0.5, assuming Figure 3 The calculation results of the gradient amplitude of each of the first areas A in the display panel 100 are as follows:

[0150]

[0151] Then, according to the relationship between the gradient amplitude of each of the first regions A and the preset gradient threshold, Figure 3 Based on the above, the display panel 100 is divided into Figure 4 The plurality of second regions B shown, specifically, Figure 3 The gradient amplitude of the first region A10 in the figure is 0.4. If it is greater than 0.2 and less than 0.5, no adjustment is made and it is directly used as Figure 4 The second area B10 in. Figure 3 The gradient amplitude of the first region A11 in the equation is 0.6, which is greater than 0.5. Then the first region A11 is divided into Figure 4 The second area B111, the second area B112, the second area B113 and the second area B114. Figure 3 The first area A21, the first area A22, the first area A23, the first area A31, the first area A32, and the first area A33 in the first area A21 are all smaller than or equal to 0.2 and are adjacent to each other, and are then merged into Figure 4 The second area B22 in FIG. By analogy, the display panel 100 can be divided into Figure 4 Multiple second regions in.

[0152] In some embodiments, when the gradient amplitude of a certain first region A is greater than the second preset threshold, dividing the certain first region A into a plurality of second regions B includes:

[0153] When the gradient amplitude of a certain first region A is greater than the second preset threshold, the region segmentation step is repeated with the certain first region A as the initial parent region until the segmentation termination condition is met;

[0154] Each sub-region obtained by segmentation is determined as the second region.

[0155] The region segmentation step comprises:

[0156] dividing the parent region into a plurality of sub-regions;

[0157] Obtaining the brightness value of each of the sub-areas when displaying the monochrome grayscale image of the preset grayscale, to obtain a second brightness value matrix;

[0158] Calculating the gradient amplitude of each of the sub-regions according to the second brightness value matrix;

[0159] Determining whether a segmentation termination condition is met based on the gradient amplitude of each sub-region;

[0160] If the segmentation termination condition is met, each of the sub-regions obtained by segmentation is determined as a second region B;

[0161] If the segmentation termination condition is not met, the region with a gradient amplitude greater than the second preset threshold is used as a new parent region and the region segmentation step is performed again.

[0162] The segmentation termination condition is that the gradient amplitudes of all sub-regions obtained by segmenting the first region A are less than or equal to the second preset threshold.

[0163] The calculation method of the gradient amplitude of each sub-region is the same as the calculation method of the gradient amplitude of each first region in the above text, and will not be repeated here.

[0164] If the area of ​​a certain sub-region is smaller than the detection lens size of the optical sensor, it can be controlled so that only the sub-region displays the monochrome grayscale image of the preset grayscale, while other areas do not display the image, and then the brightness value of the sub-region is measured by the optical sensor.

[0165] In this way, it can be ensured that the gradient amplitudes of all the segmented sub-regions are less than or equal to the second preset threshold, thereby ensuring that the brightness values ​​of the second regions are close when displaying a monochrome grayscale image of the preset grayscale.

[0166] In some embodiments, obtaining the compensation coefficient table according to the relationship between the brightness values ​​of each of the second regions B and the brightness value of the reference region includes:

[0167] The compensation coefficient table is obtained by dividing the brightness value of the base area by the brightness value of each second area B. For example, when the brightness value of the base area is 100 and the brightness value of another second area B is 80, the compensation coefficient of the base area is 1, and the compensation coefficient of the another second area B is 1.25.

[0168] The compensation coefficient table includes compensation coefficients for each second region B. When a second region B is formed by merging multiple first regions A, the brightness value of the second region B is an average of the brightness values ​​of the first regions A in the second region B.

[0169] The reference area may be a second area B where the geometric center of the display panel 100 is located, for example, Figure 4 The reference area in is the second area B22.

[0170] For example, see Figures 5 and 6 , Figure 5 for Figure 4 The compensation coefficient table of the display panel at 64 gray levels is shown. Figure 6 for Figure 4 The compensation coefficient table of the display panel at 127 gray levels is shown.

[0171] In some embodiments, driving the display panel to display based on the compensation coefficient table includes:

[0172] Obtaining a target grayscale for each pixel unit in the display panel;

[0173] Calculating the actual driving grayscale of each pixel unit based on the target grayscale of each pixel unit and the compensation coefficient table;

[0174] The display panel is driven to perform display based on the actual driving grayscale of each pixel unit.

[0175] Exemplarily, when the target grayscale of a pixel unit is the preset grayscale, the actual driving grayscale of the pixel unit is the product of the preset grayscale and the compensation coefficient of the second region B where the pixel unit is located. For example, if the target grayscale of a pixel unit is grayscale 64 and the compensation coefficient of the second region B where the pixel unit is located is 1.38, the actual driving grayscale of the pixel unit is grayscale 88.32, and thus a data voltage corresponding to grayscale 88.32 is output to the pixel unit.

[0176] In some embodiments, the display panel 100 includes a backlight module 101, which is divided into multiple backlight areas E. Each backlight area E corresponds to a second area B of the display panel 100 and is used to provide backlight to the corresponding second area B. Each backlight area E is controlled by an independent switch tube.

[0177] The brightness compensation method further includes: generating a driving signal for each of the backlight areas E based on the compensation coefficient table, so as to drive each of the backlight areas E to adjust the backlight brightness.

[0178] Specifically, the backlight brightness of each backlight area E and the compensation coefficient of the second area B corresponding to the backlight area E are positively correlated.

[0179] In this way, by synchronously controlling the data voltage and the driving signal of the backlight area, combined with grayscale compensation and backlight brightness adjustment, the display uniformity can be further improved.

[0180] In some embodiments, the brightness compensation method further includes:

[0181] Get the ambient light brightness value;

[0182] The preset gradient threshold is determined according to the ambient light brightness value.

[0183] There is a positive correlation between the ambient light brightness value and the preset gradient threshold value, that is, the higher the ambient light brightness value, the larger the first preset gradient threshold value and the second preset gradient threshold value.

[0184] In this way, increasing the threshold to merge partitions in high-brightness environments can reduce the amount of computation required by each module, while decreasing the threshold to subdivide partitions in low-brightness environments can improve the accuracy of brightness compensation.

[0185] In some embodiments, the brightness compensation method further includes:

[0186] detecting a refresh rate of the display panel 100;

[0187] The preset gradient threshold is determined based on the refresh rate. That is, the higher the refresh rate, the smaller the first preset gradient threshold and the second preset gradient threshold. The gradient thresholds at the refresh rates F1, F2, and F3 of the display panel are preset to be T1, T2, and T3, respectively, and F1 < F2 < F3, and T1 > T2 > T3.

[0188] There is a negative correlation between the refresh rate and the preset gradient threshold.

[0189] For example, when the refresh rate is increased from 60Hz to 120Hz, the available time for each frame is reduced from approximately 16.7ms to 8.3ms. The charging time of the pixel unit (i.e., the time to reach the target voltage) is insufficient, which may cause the pixel units farther away from the driving circuit to be unable to complete sufficient charging within the shorter frame time due to signal transmission delays or increased resistance, resulting in lower brightness than the center area.

[0190] Therefore, in this embodiment, by detecting the refresh rate of the display panel and dynamically adjusting the preset gradient threshold, the problem of uneven display caused by insufficient brightness compensation of the display panel when using a fixed gradient threshold at a high refresh rate can be avoided.

[0191] Based on the same inventive concept, an embodiment of the present application further provides a display panel 100 , and the brightness compensation method described in any of the above embodiments is applied to the display panel 100 .

[0192] The display panel 100 includes a memory module 13 , a processing module 12 , and a control module 11 . The processing module 12 is electrically connected to the memory module 13 and the control module 11 .

[0193] The memory module 13 is used to obtain the brightness value of each first area when displaying a monochrome grayscale image of a preset grayscale, obtain a first brightness value matrix, calculate the gradient amplitude of each first area based on the first brightness value matrix, divide the display panel into multiple second areas based on the relationship between the gradient amplitude of each first area and a preset gradient threshold, obtain the brightness value of each second area when displaying a monochrome grayscale image of the preset grayscale, and obtain a compensation coefficient table based on the relationship between the brightness value of each second area and the brightness value of the reference area, wherein the compensation coefficient table includes the compensation coefficient of each second area at the preset grayscale, and the reference area is one of the multiple second areas.

[0194] The processing module 12 is used to obtain the actual driving grayscale of each pixel unit based on the compensation coefficient table, and output the actual driving grayscale of each pixel unit to the control module 11, so that the control module 11 drives the display panel to display based on the actual driving grayscale of each pixel unit.

[0195] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A brightness compensation method for performing brightness compensation on a display panel, characterized in that: The display panel is divided into a plurality of first areas arranged in an array, and the brightness compensation method includes: Obtaining brightness values ​​of each of the first regions when displaying a monochrome grayscale image of a preset grayscale, to obtain a first brightness value matrix; Calculating the gradient amplitude of each of the first regions according to the first brightness value matrix; dividing the display panel into a plurality of second areas according to a relationship between a gradient amplitude of each of the first areas and a preset gradient threshold; Acquire the brightness value of each second area when displaying the monochrome grayscale image of the preset grayscale; Obtaining a compensation coefficient table based on a relationship between a brightness value of each second region and a brightness value of a reference region, wherein the compensation coefficient table includes a compensation coefficient of each second region at the preset grayscale, and the reference region is one of the plurality of second regions; and Based on the compensation coefficient table, the display panel is driven to perform display.

2. The brightness compensation method according to claim 1, wherein: Any of the second regions satisfies one of the following conditions: The second area is one of the first areas; The second area is an area formed by merging a plurality of the first areas; and The second region is a region divided from one of the first regions.

3. The brightness compensation method according to claim 1, wherein: The calculating the gradient magnitude of each of the first regions according to the first brightness value matrix includes: Determine the corresponding transverse gradient kernel Gx and the corresponding longitudinal gradient kernel Gy according to the first brightness value matrix; Performing a convolution operation on the first brightness value matrix using the transverse gradient kernel Gx to obtain a transverse gradient value of each of the first regions; Performing a convolution operation on the first brightness value matrix using the longitudinal gradient kernel Gy to obtain a longitudinal gradient value of each of the first regions; and The gradient amplitude of each first region is calculated according to the transverse gradient value and the longitudinal gradient value of each first region.

4. The brightness compensation method according to claim 3, wherein: The plurality of first regions are arranged in an array of N rows and N columns, where N is an odd number greater than zero; The determining, according to the first brightness value matrix, a corresponding transverse gradient kernel Gx and a corresponding longitudinal gradient kernel Gy includes: According to the first calculation formula, the initial transverse gradient kernel Gx1 is calculated; wherein the first calculation formula is: Wherein, σ is a preset standard deviation value, Gx1(m,n) is the transverse gradient value of the element at position (m,n) in the initial transverse gradient kernel Gx1; Multiplying each element in the initial transverse gradient kernel Gx1 by an amplification factor and rounding to the nearest integer, thereby obtaining a transverse gradient kernel Gx corresponding to the first brightness value matrix; The initial longitudinal gradient kernel Gy1 is calculated according to the second calculation formula; wherein the second calculation formula is: Wherein, Gy1(m,n) is the longitudinal gradient value of the element at position (m,n) in the initial longitudinal gradient kernel Gy1; Each element in the initial longitudinal gradient kernel Gy1 is multiplied by an amplification factor and rounded to the nearest integer, thereby obtaining the longitudinal gradient kernel Gy corresponding to the first brightness value matrix.

5. The brightness compensation method according to claim 4, wherein: The step of performing a convolution operation on the first brightness value matrix using the transverse gradient kernel Gx to obtain a transverse gradient value of each of the first regions includes: The lateral gradient value of each of the first regions is calculated according to a third calculation formula; wherein the third calculation formula is: Wherein, G'x(i,j) is the transverse gradient value of the first region with coordinates (i,j), Gx(m,n) is the transverse gradient value of the element at position (m,n) in the transverse gradient kernel Gx, and L(i+m,j+n) is the brightness value of the first region with coordinates (i+m,j+n) in the first brightness value matrix; The step of performing a convolution operation on the first brightness value matrix using the longitudinal gradient kernel Gy to obtain the longitudinal gradient value of each of the first regions includes: The longitudinal gradient value of each of the first regions is calculated according to a fourth calculation formula; wherein the fourth calculation formula is: Wherein, G'y(i,j) is the longitudinal gradient value of the first region with coordinates (i,j), and Gy(m,n) is the longitudinal gradient value of the element at position (m,n) in the longitudinal gradient kernel Gy; Calculating the gradient amplitude of each of the first regions according to the transverse gradient value and the longitudinal gradient value of each of the first regions includes: The gradient amplitude of each of the first regions is calculated according to a fifth calculation formula; wherein the fifth calculation formula is: Wherein, G'(i,j) is the gradient amplitude of the first region with coordinates (i,j).

6. The brightness compensation method according to claim 2, wherein: The preset gradient threshold includes a first preset gradient threshold and a second preset gradient threshold, wherein the first preset gradient threshold is smaller than the second preset gradient threshold; The step of dividing the display panel into a plurality of second areas according to a relationship between a gradient magnitude of each of the first areas and a preset gradient threshold value comprises: When the gradient amplitude of a certain first region is greater than the second preset threshold, dividing the certain first region into a plurality of second regions; as well as When the gradient amplitudes of multiple adjacent first regions are all less than or equal to the first preset threshold, the multiple adjacent first regions are merged into one second region.

7. The brightness compensation method according to claim 6, wherein: When the gradient amplitude of a certain first region is greater than the second preset threshold, dividing the certain first region into a plurality of second regions includes: When the gradient amplitude of a certain first region is greater than the second preset threshold, taking the certain first region as the initial mother region, repeatedly performing the region segmentation step until a segmentation termination condition is met; and determining each sub-region obtained by segmentation as the second region; The region segmentation step comprises: dividing the parent region into a plurality of sub-regions; Obtaining the brightness value of each of the sub-areas when displaying the monochrome grayscale image of the preset grayscale, to obtain a second brightness value matrix; Calculating the gradient amplitude of each of the sub-regions according to the second brightness value matrix; Determining whether a segmentation termination condition is met based on the gradient amplitude of each sub-region; If the segmentation termination condition is satisfied, each of the sub-regions obtained by segmentation is determined as a second region; and If the segmentation termination condition is not met, the region with a gradient amplitude greater than the second preset threshold is used as a new parent region and the region segmentation step is performed again; The segmentation termination condition is that the gradient amplitudes of all sub-regions obtained by segmenting the first region are less than or equal to the second preset threshold.

8. The brightness compensation method according to claim 1, wherein: The brightness compensation method further includes: Get the ambient light brightness value; and The preset gradient threshold is determined according to the ambient light brightness value; wherein there is a positive correlation between the ambient light brightness value and the preset gradient threshold.

9. The brightness compensation method according to claim 1, wherein: The brightness compensation method further includes: detecting a refresh rate of the display panel; and The preset gradient threshold is determined according to the refresh rate; wherein the refresh rate and the preset gradient threshold are negatively correlated.

10. A display panel, characterized in that: The brightness compensation method according to any one of claims 1 to 9 is applied to the display panel.

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