Color correction method, device, electronic device and storage medium

Abstract

The embodiments of the present application provide a color correction method, device, electronic device, and storage medium. The color correction method includes: obtaining initial pixel data of multiple pixel points of an image to be displayed, and then determining the corrected pixel value of the reference vertex based on a display lookup table and the saturation difference between the pixel point and the reference vertex, wherein the reference vertex is a vertex in a color space formed based on a reference color, and then, based on the corrected pixel value of the reference vertex, performing linear interpolation processing on the initial pixel data to obtain corrected pixel data corresponding to the pixel point, and the corrected pixel data is used to output the display image. The embodiments of the present application are used to solve the color cast problem of the grayscale screen of the display image displayed by the current display device in the related art.

Description

Technical Field

[0001] The present application relates to the field of display technology, and more specifically, to a color correction method, device, electronic device, and storage medium. Background Art

[0002] Different display devices have different color display capabilities. For example, different color filters and backlight sources for LCDs, and different luminescent materials for OLEDs, all affect the color range that the display device can display. Because of this, the same image often displays different colors on different display devices.

[0003] To solve this problem, the CIE (International Commission on Illumination) has established standard color spaces, such as sRGB, AdobeRGB, or DCI-P3. Display devices use certain color space algorithms to process input images so that the displayed image matches the standard color space. This color space algorithm is generally called color management. An example of this is the 3D_LUT (3D display lookup table) color space algorithm.

[0004] However, after the input image is processed using the existing color space algorithm, the display image displayed by the display device still has the problem of grayscale color cast. Summary of the Invention

[0005] In response to the shortcomings of existing methods, the present application proposes a color correction method, device, electronic device and storage medium to solve the color cast problem of the grayscale image displayed by the current display device in the related art.

[0006] In a first aspect, an embodiment of the present application provides a color correction method, comprising:

[0007] Obtaining initial pixel data of a plurality of pixel points of an image to be displayed;

[0008] Determining a corrected pixel value of a reference vertex based on a display lookup table and a saturation difference between the pixel point and a reference vertex, the reference vertex being a vertex in a color space formed based on a reference color;

[0009] Based on the corrected pixel value of the reference vertex, linear interpolation is performed on the initial pixel data to obtain corrected pixel data corresponding to the pixel point;

[0010] The corrected pixel data is used to output a display image.

[0011] In one possible implementation, determining the corrected pixel value of the reference vertex based on a display lookup table and a saturation difference between the pixel point and the reference vertex includes:

[0012] determining a first saturation of the pixel point based on the initial pixel data, and determining a second saturation of the reference vertex based on an input value of the reference vertex, where the input value of the reference vertex is a pixel value of the reference vertex in the original color space;

[0013] Determining a saturation difference between the pixel point and the reference vertex based on the first saturation and the second saturation;

[0014] A corrected pixel value for the reference vertex is determined based on the display lookup table and the saturation difference.

[0015] In one possible implementation, determining the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference includes:

[0016] Inputting the input value of the reference vertex into the display lookup table to obtain the output value of the reference vertex;

[0017] A corrected pixel value of the reference vertex is determined based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference.

[0018] In one possible implementation, determining the corrected pixel value of the reference vertex based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference includes:

[0019] weighting the saturation gap;

[0020] A corrected pixel value of the reference vertex is determined based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference.

[0021] In a possible implementation, weighting the saturation gap includes:

[0022] The saturation difference is weighted based on display characteristics of the display panel.

[0023] In a possible implementation, the image to be displayed includes three color channels; the display lookup table is a three-dimensional display lookup table;

[0024] The step of performing linear interpolation processing on the initial pixel data based on the corrected pixel value of the reference vertex to obtain corrected pixel data corresponding to the pixel point includes:

[0025] The corrected pixel value based on the reference vertex is processed by performing cubic linear interpolation on the initial pixel data to obtain corrected pixel data corresponding to the pixel point.

[0026] In a second aspect, an embodiment of the present application provides a color correction device, comprising:

[0027] An acquisition module, which acquires initial pixel data of a plurality of pixel points included in the image to be displayed;

[0028] A determination module is used to determine the corrected pixel value of the reference vertex based on a display lookup table and the saturation difference between the pixel point and the reference vertex, where the reference vertex is a vertex in a color space formed based on a reference color; based on the corrected pixel value of the reference vertex, linear interpolation is performed on the initial pixel data to obtain corrected pixel data corresponding to the pixel point; the corrected pixel data is used to output a display image.

[0029] In a third aspect, an embodiment of the present application provides an electronic device, including a processor and a memory, wherein the processor and the memory are connected to each other;

[0030] The memory is used to store computer programs;

[0031] The processor is configured to execute the above method when calling the computer program.

[0032] In one possible implementation, the electronic device further includes a display panel;

[0033] The display panel is electrically connected to the processor and is configured to receive the corrected pixel data of the image to be displayed output by the processor, so as to output the display image.

[0034] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the above method.

[0035] The beneficial technical effects brought about by the technical solutions provided by the embodiments of the present application include at least:

[0036] This application adds a saturation parameter to the color space conversion process to evaluate the influence of the reference vertex on the color of the pixel point. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel point and the reference vertex. The reference vertex is a vertex in the color space formed based on the reference color. The color distance includes the saturation difference. The saturation difference is used to quantify the color distance between the pixel point and the reference vertex. Based on the corrected pixel value of the reference vertex, the initial pixel data is linearly interpolated to obtain the corrected pixel data corresponding to the pixel point. The corrected pixel data is used to output the display image; it can improve the color deviation of the grayscale picture of the display image displayed by the display device, and can improve the color accuracy of the display image displayed by the display device.

[0037] Moreover, different display devices can use different saturation gaps for correction, which can balance the differences between different display devices, improve the matching degree between the corrected pixel data of the pixel points and the corresponding display device, and improve the color accuracy of the displayed images displayed by different display devices.

[0038] Additional aspects and advantages of the present application will be given in part in the following description, which will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0040] Figure 1 Schematic diagram of input values corresponding to eight reference vertices in the original color space of a 3D_LUT in the related art;

[0041] Figure 2 Schematic diagram of output values corresponding to eight reference vertices in a color space after tuning (color space conversion) of a 3D_LUT in the related art;

[0042] Figure 3 A schematic diagram of the nonlinear correspondence between the input value and the output value of a pixel point in a 3D_LUT of the related art;

[0043] Figure 4 This is the actual measured gamma curve of the w / r / g / b of the OLED screen;

[0044] Figure 5 A schematic diagram of a color correction method according to an embodiment of the present invention;

[0045] Figure 6 A schematic diagram of a process for determining a corrected pixel value of a reference vertex in a color correction method provided in an embodiment of the present application;

[0046] Figure 7 A schematic diagram of the saturation of each reference vertex and pixel provided in an embodiment of the present application;

[0047] Figure 8 A schematic diagram of a process for determining a corrected pixel value of a reference vertex in another color correction method provided in an embodiment of the present application;

[0048] Figure 9 is a curve diagram showing the relationship between the weighting coefficient weigh1 and the normalized value of the display screen load;

[0049] Figure 10 Schematic diagram of a cube consisting of corrected pixel values of 8 reference vertices (i.e., the color space after tuning);

[0050] Figure 11 An input-output curve diagram of a pixel point obtained by an exemplary color correction method provided in an embodiment of the present application;

[0051] Figure 12 A schematic structural diagram of a color correction device provided in an embodiment of the present application;

[0052] Figure 13 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] The following describes the embodiments of the present application in conjunction with the accompanying drawings. It should be understood that the embodiments described below in conjunction with the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0054] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a", "an", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the implementation of other features, information, data, steps, operations, elements, components and / or combinations thereof supported by the technical field. The term "and / or" used herein refers to at least one of the items defined by the term, for example, "A and / or B" can be implemented as "A", or as "B", or as "A and B".

[0055] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0056] The existing 3D_LUT (LUT is the full spelling of Look-Up-Table, that is, display lookup table. Whenever a signal is input, an address is input to look up the table, and the content corresponding to the address is found and output. For the display, it can play the role of color space conversion. RGB three 1D_LUTs form a 3D_LUT. The input RGB three-channel color values are mapped according to the three display lookup tables of the 3D_LUT to obtain the converted color) color space algorithm, which is achieved by color space conversion (that is, tuning) of a certain number of reference colors, and then applying the results to all colors through cubic linear interpolation, so as to achieve good standard color space matching.

[0057] Linear interpolation is an interpolation method where the interpolation function is a linear polynomial, resulting in zero interpolation error at the interpolation nodes. Compared to other interpolation methods, such as parabolic interpolation, linear interpolation is simpler and more convenient. The geometric meaning of linear interpolation is that a straight line passing through points A and B in the overview diagram approximates the original function. Linear interpolation can be used to approximate the original function or to calculate values not in a table during a lookup.

[0058] The inventors discovered that because 3D_LUT is a purely mathematical theoretical calculation, when the 3D_LUT color space algorithm is applied to OLED screens for image display, discoloration occurs during grayscale transitions due to the display characteristics of OLED screens, a problem known as color shift. Furthermore, for OLED screens, the color distribution corresponding to the same RGB (optical primary colors) data is nonlinear, and using cubic linear interpolation to expand the color will inevitably cause color errors.

[0059] Specifically, such as Figure 1 and Figure 2 As shown, Figure 1 is the input value of 3D_LUT (original color space), Figure 2 is the output value of 3D_LUT (the color space after tuning). For simplicity, the color space is taken as a cube as an example.

[0060] See also Figure 1 , the reference colors are red, green and blue, the vector coordinates of red are (256,0,0), the vector coordinates of green are (0,256,0), and the vector coordinates of blue are (0,0,256). The three vectors can form a three-dimensional space. Specifically, the three reference colors red, green and blue form the original color space (i.e., Figure 1 cube shown).

[0061] Continue to see Figure 1, based on the color space formed by the three reference colors red, green and blue (i.e., Figure 1 The eight vertices of the cube (shown in Figure 1) are reference vertices. The input values of the eight reference vertices LUT0 through LUT7 are (0,0,0), (256,0,0), (0,256,0), (0,0,256), (256,256,0), (256,0,256), (0,256,256), and (256,256,256), respectively. The input value of pixel point P is (R, G, B), where R, G, and B represent the red, green, and blue components of the input value of point P, respectively.

[0062] See also Figure 2 , the input values of the 8 reference vertices LUT0 to LUT7 are tuned (color space conversion, that is, mapped according to the display lookup table of 3D_LUT), and the output values of the 8 reference vertices LUT0 to LUT7 are (r0, g0, b0), (r1, g1, b1), (r2, g2, b2), (r3, g3, b3), (r4, g4, b4), (r5, g5, b5), (r6, g6, b6), (r7, g7, b7). In other words, the output value LUTi of the i-th reference vertex is (ri, gi, bi), where ri, gi, and bi are the red component, green component, and blue component of the output value of the i-th reference vertex, respectively. The output value of point P is (R', G', B'), where R', G', and B' are the red component, green component, and blue component of the output value of point P, respectively.

[0063] That is, the output values of the eight reference vertices LUT0 to LUT7 are the eight vertices of the color space after tuning.

[0064] When the input values of the eight reference vertices LUT0 to LUT7 are known, the output values of the eight reference vertices LUT0 to LUT7 are obtained through color space conversion (ie, tuning).

[0065] When the input value of point P is known to be (R, G, B), the output value of point P (R', G', B') can be obtained by trilinear interpolation.

[0066] Table 1 shows the values of LUT0 to LUT7 obtained by actual tuning (color space conversion) of an OLED screen, that is, the corrected pixel values of the reference vertex.

[0067] LUT r g b LUT0 0 0 0 LUT1 218 40 33 LUT2 117 237 71 LUT3 251 246 83 LUT4 55 0 233 LUT5 227 41 237 LUT6 133 244 245 LUT7 255 246 243

[0068] Table 1

[0069] like Figure 3As shown, considering the grayscale transition picture, when the input value of point P changes from (0, 0, 0) to (255, 255, 255), the relationship between the output value and the input value of point P is obtained by trilinear interpolation.

[0070] Typically, 8 bits are used to represent a pixel, resulting in a total of 256 grayscale levels (pixel values range from 0 to 255), each representing a different brightness. Point P is used as a grayscale input, with R = G = B (i.e., the red component equals the green component equals the blue component), so point P can be represented as 0 to 255.

[0071] In other feasible embodiments, a pixel may be represented by 10 bits. In this case, the input value of point P varies from (0, 0, 0) to (1023, 1023, 1023). Point P is input as a grayscale image, with R = G = B. Therefore, point P can be expressed as 0 to 1023. Of course, other bit numbers may also be used to represent a pixel, and this is not limited here.

[0072] Grayscale is the process of dividing the brightness range between brightest and darkest into several parts. This allows for screen brightness control based on the input signal. Each sub-pixel can display a different brightness level due to the light source behind it. Grayscale represents the different levels of brightness from darkest to brightest.

[0073] For color images, each pixel contains multiple color components, each of which is called a channel. All pixels in an image have the same number of channels, meaning each channel can be represented as a component image with the same content as the original image but different colors. For example, a color image in RGB format can be segmented into monochrome images of the three primary colors: blue (B component), green (G component), and red (R component).

[0074] The color change of each point on the screen is actually caused by the grayscale change of the three RGB sub-pixels that make up this point.

[0075] Figure 3 Here, r, g, and b are the input-output curves drawn with the red component, the input-output curves drawn with the green component, and the input-output curves drawn with the blue component, respectively.

[0076] Depend on Figure 3 It can be seen that as the input grayscale increases, the three curves r / g / b show different changing trends. At a position close to grayscale 250, the relative positions of g and b are even swapped.

[0077] Because the final color displayed by an OLED screen depends on the mixture of the three colors r, g, and b, when the ratio of these three colors changes or even reverses, it will inevitably lead to a change in the final color, which is visually manifested as a color cast. This phenomenon is particularly noticeable in low-light conditions where the human eye is sensitive.

[0078] in addition, Figure 4 This is the actual measured w / r / g / b gamma curve of the OLED screen.

[0079] Figure 4 Where w_gamma, r_gamma, g_gamma, and b_gamma are the white gamma curve, red gamma curve, green gamma curve, and blue gamma curve of the OLED screen, respectively. The horizontal axis is the grayscale input to the display, and the vertical axis is the ratio of the current brightness output on the display to the maximum brightness.

[0080] The gamma curve is a special tone curve. When the gamma value is equal to 1, the curve is a straight line at a 45-degree angle to the coordinate axis, indicating that the input and output densities are the same. Gamma values higher than 1 will cause the output to be darkened, while gamma values lower than 1 will cause the output to be brightened.

[0081] from Figure 4 It can be seen that the gamma curves of r / g / b are inconsistent, that is, the trend from r / g / b data to the final brightness contribution is inconsistent and nonlinear. Therefore, if r / g / b are not distinguished in the 3D_LUT solution and linear interpolation is fully used, there will inevitably be a deviation between the final rendered color and the ideal color.

[0082] The color correction method, device, electronic device, and computer-readable storage medium provided in this application are intended to solve the above technical problems in related technologies.

[0083] The following describes several exemplary embodiments to illustrate the technical solutions of the embodiments of the present application and the technical effects produced by the technical solutions of the present application. It should be noted that the following embodiments can refer to, draw on, or combine with each other, and the same terms, similar features, and similar implementation steps in different embodiments will not be repeated.

[0084] The present application embodiment provides a color correction method, such as Figure 5 As shown, it can be applied to a terminal or a server, and the method includes:

[0085] S101: Acquire initial pixel data of a plurality of pixels of an image to be displayed.

[0086] Specifically, the terminal or server for performing color correction downloads initial pixel data of a plurality of pixels of an image to be displayed from an image acquisition device, an image storage device or a cloud storage.

[0087] The image acquisition device may include a camera, a video camera, a scanner or other devices with a camera function. The image storage device may include a hard disk or a USB flash drive.

[0088] Cloud storage is a model of online storage that stores data on multiple virtual servers, typically hosted by a third party, rather than dedicated servers. Data center operators prepare virtualized storage resources on the back end based on customer needs and offer them as a storage pool. Customers can then use this storage pool to store their files or objects. In practice, these resources may be distributed across numerous server hosts. Cloud storage services are accessed through a web application programming interface (API) or a web-based user interface.

[0089] Every image has one or more color channels. The default number of color channels in an image depends on its color mode. That is, an image's color mode determines the number of color channels it has. Each color channel stores information about a color element in the image. The colors from all color channels are combined to produce the color of each pixel in the image.

[0090] In this embodiment, the image to be displayed can be an RGB image. An RGB image has three color channels: a red channel, a green channel, and a blue channel. In other words, each pixel contains three primary colors: blue (B component), green (G component), and red (R component). The initial pixel data for each pixel can be expressed as (R, G, B).

[0091] In this embodiment, 8 bits can be used to represent one pixel, resulting in a total of 256 grayscale levels (pixel values between 0 and 255), each representing a different brightness. In other words, the pixel values of each channel in the initial pixel data of each pixel can be represented by 0 to 255.

[0092] S102: Determine a corrected pixel value of a reference vertex based on a display lookup table and a saturation difference between the pixel point and the reference vertex.

[0093] The reference vertex is a vertex in a color space formed based on a reference color.

[0094] Color saturation refers to the vividness of a color. It's also a measure of its purity. Highly saturated colors encompass a very narrow set of wavelengths. Therefore, based on the saturation difference between a pixel and a reference vertex, the color cast of the reference vertex can be adjusted. This prevents color cast issues in the displayed image when applying the corrected pixel data from the reference vertex.

[0095] S103: Based on the corrected pixel value of the reference vertex, perform linear interpolation processing on the initial pixel data to obtain corrected pixel data corresponding to the pixel point.

[0096] The corrected pixel data is used to output a display image.

[0097] Those skilled in the art will understand that the “terminal” used here may be a mobile phone, a tablet computer, a PDA (Personal Digital Assistant), an MID (Mobile Internet Device), etc.; the “server” may be implemented as an independent server or a server cluster consisting of multiple servers.

[0098] This application adds a saturation parameter to the color space conversion process to evaluate the influence of the reference vertex on the color of the pixel point. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel point and the reference vertex. The reference vertex is a vertex in the color space formed based on the reference color. The color distance includes the saturation difference. The saturation difference is used to quantify the color distance between the pixel point and the reference vertex. Based on the corrected pixel value of the reference vertex, the initial pixel data is linearly interpolated to obtain the corrected pixel data corresponding to the pixel point. The corrected pixel data is used to output the display image; it can improve the color deviation of the grayscale picture of the display image displayed by the display device, and can improve the color accuracy of the display image displayed by the display device.

[0099] Moreover, different display devices can use different saturation gaps for correction, which can balance the differences between different display devices, improve the matching degree between the corrected pixel data of the pixel points and the corresponding display device, and improve the color accuracy of the displayed images displayed by different display devices.

[0100] In the embodiment of the present application, a possible implementation method is provided, such as Figure 6 As shown, based on the display lookup table and the saturation difference between the pixel point and the reference vertex, the corrected pixel value of the reference vertex is determined, including:

[0101] S201: Determine a first saturation of a pixel point based on initial pixel data, and determine a second saturation of a reference vertex based on an input value of the reference vertex.

[0102] The input value of the reference vertex is the pixel value of the reference vertex in the original color space.

[0103] Since the saturation formula is: saturation = 1-min(r,g,b) / max(r,g,b), where saturation is the saturation, r, g, and b are the red component, green component, and blue component of the pixel respectively, min(r,g,b) is the minimum value of the red component, green component, and blue component, and max(r,g,b) is the maximum value of the red component, green component, and blue component.

[0104] For the 8 reference vertices LUT0~LUT7, the input values of LUT0~LUT7 can refer to Figure 1 Specifically, the input values of LUT0 to LUT7 are (0,0,0), (256,0,0), (0,256,0), (0,0,256), (256,256,0), (256,0,256), (0,256,256), (256,256,256), respectively.

[0105] At this time, the saturation of LUT0 is S0=0, the saturation of LUT7 is S7=0, and the saturation of other points (LUT1~LUT6) is S1=S2=S3=S4=S5=S6=1. For details, see Figure 7 .

[0106] That is to say, the second saturation of the reference vertex includes the saturations of multiple reference vertices, namely S0, S1, S2, S3, S4, S5, S6, and S7, where S1=S7=0, S1=S2=S3=S4=S5=S6=1.

[0107] Figure 1 The input values of the eight reference vertices LUT0 to LUT7 shown represent color space conversion (i.e., tuning) based on red (256, 0, 0), green (0, 256, 0), and blue (0, 0, 256). The converted results of red (256, 0, 0), green (0, 256, 0), and blue (0, 0, 256) are then applied to all colors through cubic linear interpolation.

[0108] It should be noted that in other feasible embodiments, the input values of the eight reference vertices LUT0 to LUT7 may also use other values. For example, color space conversion can be performed based on red (245, 0, 0), green (0, 250, 0) and blue (0, 0, 254). At this time, the input values of the eight reference vertices LUT0 to LUT7 are (0, 0, 0), (245, 0, 0), (0, 250, 0), (0, 0, 254), (245, 250, 0), (245, 0, 254), (0, 250, 254), and (245, 250, 254).

[0109] For the pixel point corresponding to the initial pixel data, taking point P as an example, the input value of point P is (R, G, B), and the saturation of point P is Sp = 1-min(R, G, B) / max(R, G, B).

[0110] That is, the input value of the initial pixel data is (R, G, B), and the first saturation of the pixel point is Sp=1-min(R, G, B) / max(R, G, B).

[0111] S202: Determine a saturation difference between the pixel point and the reference vertex based on the first saturation and the second saturation.

[0112] In this embodiment, the saturation difference may include the difference between the first saturation of the pixel point and the second saturation of each reference vertex. Specifically, the saturation difference may include DeltaS0...DeltaS7, where:

[0113] DeltaS0=(Sp-S0);

[0114] DeltaS1=(Sp-S1);

[0115] DeltaS2 = (Sp - S2);

[0116] DeltaS3 = (Sp - S3);

[0117] DeltaS4 = (Sp - S4);

[0118] DeltaS5 = (Sp - S5);

[0119] DeltaS6 = (Sp - S6);

[0120] DeltaS7 = (Sp - S7).

[0121] That is, the saturation difference of any reference vertex is DeltaSi=(Sp-Si), where Si is the saturation of the i-th reference vertex.

[0122] S203: Determine a corrected pixel value of the reference vertex based on the display lookup table and the saturation difference.

[0123] In one possible implementation, determining the corrected pixel value of a reference vertex based on a display lookup table and a saturation difference may include: inputting the input value of the reference vertex into the display lookup table to obtain an output value of the reference vertex; and determining the corrected pixel value of the reference vertex based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference.

[0124] In one possible implementation, determining the corrected pixel value of a reference vertex based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference may include: weighting the saturation difference; and determining the corrected pixel value of the reference vertex based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference. By weighting the saturation difference, the influence of each reference vertex on the pixel can be better balanced.

[0125] For ease of understanding, the following Figure 8 To explain:

[0126] S301: Input the input value of the reference vertex into the display lookup table to obtain the output value of the reference vertex.

[0127] The input value of the reference vertex is the pixel value of the reference vertex in the original color space, and the output value of the reference vertex represents the pixel value of the reference vertex in the converted color space (i.e., the color space formed by the reference color). The display lookup table includes the correspondence between the input value of the reference vertex and the output value of the reference vertex.

[0128] In this embodiment, the display lookup table can be a three-dimensional display lookup table, and the input values of the eight reference vertices can refer to Figure 1 As shown, through tuning, the output values corresponding to the 8 reference vertices can be referenced Figure 2 shown.

[0129] S302: Weighting the saturation difference.

[0130] Specifically, the weighted saturation difference may include DeltaS0'...DeltaS7', where:

[0131] DeltaS0'=(Sp-S0)*weigh1;

[0132] DeltaS1'=(Sp-S1)*weigh2;

[0133] DeltaS2'=(Sp-S2)*weigh3;

[0134] DeltaS3'=(Sp-S3)*weigh4;

[0135] DeltaS4'=(Sp-S4)*weigh5;

[0136] DeltaS5'=(Sp-S5)*weigh6;

[0137] DeltaS6'=(Sp-S6)*weigh7;

[0138] DeltaS7'=(Sp-S7)*weigh8.

[0139] That is, the saturation difference of any reference vertex is DeltaSi'=(Sp-Si)*weighi.

[0140] Among them, weighi is the weight coefficient of the i-th reference vertex, weigh1…weigh8 are the weight coefficients of the eight reference vertices LUT0~LUT7 respectively.

[0141] In practical applications, weigh1…weigh8 can be pre-set based on actual needs. If the display screen to which the color correction method is applied is an LCD screen, weigh1-weigh8 can all be equal to 1. If the display screen to which the color correction method is applied is an OLED screen, weigh1-weigh8 can be set based on the display characteristics of the OLED screen (e.g., voltage drop characteristics).

[0142] In this embodiment, weighting the saturation difference may include weighting the saturation difference based on the display characteristics of the display panel. In other words, different weighting coefficients (weigh1…weigh8) may be set based on the display characteristics of the display panel to better adapt to different display screens.

[0143] Furthermore, weighting the saturation difference based on the display characteristics of the display panel can include weighting the saturation difference based on the voltage drop characteristics of the display panel. Because sub-pixels of different colors have different effects on the voltage drop of the display screen, the display screen loading varies when displaying different images. Therefore, the settings of weigh1 to weigh8 can take into account the voltage drop characteristics of the display screen and make further subtle corrections to color deviations.

[0144] In practical applications, the weight curves for weigh1 to weigh8 can be determined based on the measurement results of the color displayed on the current screen. Specifically, when displaying several sample screens (each sample screen has a different display screen load), the weight coefficients for each sample screen, weigh1 to weigh8, can be adjusted based on experience. Based on the weight coefficients weighi (which can be weigh1 to weigh8) of the multiple sample screens, a curve is obtained showing the relationship between each weight coefficient weighi and the normalized value of the display screen loading.

[0145] For example, based on the weighting coefficient weigh1 of each sample image, a relationship curve between the weighting coefficient weigh1 and the normalized value of the display screen loading is obtained. Based on the weighting coefficient weigh2 of each sample image, a relationship curve between the weighting coefficient weigh2 and the normalized value of the display screen loading is obtained.

[0146] like Figure 9 As shown, Figure 9 The graph is a relationship curve between the weighting coefficient weigh1 and the normalized value of the display screen loading, wherein the horizontal axis is the normalized value of the display screen loading, and the vertical axis is the value of the weighting coefficient weigh1.

[0147] When loading is maximum (i.e., loading = 1), weigh1 is maximum; when loading is minimum (i.e., loading = 0), weighi is minimum. The current value of weigh1 is obtained based on the normalized value of the display's current loading. As the display image changes, the normalized value of the display's loading changes accordingly, and the value of weigh1 also changes accordingly.

[0148] In addition, the method for determining the weighting coefficients Weigh2…weigh8 is similar to that for determining the weighting coefficient Weigh1, and will not be repeated here.

[0149] S303: Determine a corrected pixel value of the reference vertex based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference.

[0150] In this embodiment, the corrected pixel values of the reference vertices include LUT0_S…LUT7_S, where:

[0151] LUT0_S=(0,0,0)*DeltaS0'+(r0,g0,b0)*(1-DeltaS0');

[0152] LUT1_S=(256,0,0)*DeltaS1'+(r1,g1,b1)*(1-DeltaS1');

[0153] LUT2_S=(0,256,0)*DeltaS2'+(r2,g2,b2)*(1-DeltaS2');

[0154] LUT3_S=(0,0,256)*DeltaS3'+(r3,g3,b3)*(1-DeltaS3');

[0155] LUT4_S=(0,0,256)*DeltaS4'+(r4,g4,b4)*(1-DeltaS4');

[0156] LUT5_S=(256,0,256)*DeltaS5'+(r5,g5,b5)*(1-DeltaS5');

[0157] LUT6_S=(0,256,256)*DeltaS6'+(r6,g6,b6)*(1-DeltaS6');

[0158] LUT7_S=(256,256,256)*DeltaS7'+(r7,g7,b7)*(1-DeltaS7').

[0159] That is to say, the corrected pixel value of any reference vertex is LUTi_S = (input value of the i-th reference vertex) * DeltaSi' + (ri, gi, bi) * (1-DeltaSi'), where (ri, gi, bi) is the output value of the i-th reference vertex. Specifically, the input value of each reference vertex can refer to Figure 1 , the output value of each reference vertex can refer to Figure 2 .

[0160] It should be noted that there is no fixed order between step S301 and step S302. Step S301 may be performed first and then step S302, or step S302 may be performed first and then step S301. This is not limited here.

[0161] When weigh1…weigh8 are all 1, and the input value of point P changes from (0,0,0) to (255,255,255) (that is, R, G, B are equal and Sp is 0), the actual calculated LUT0_S to LUT7_S can be referred to Table 2:

[0162]

[0163]

[0164] Table 2

[0165] The previous section describes how to determine the corrected pixel value of a reference vertex. The following section describes how to apply the corrected pixel value of the reference vertex to all pixels to achieve color correction for each pixel of the image to be displayed.

[0166] In this embodiment, the image to be displayed may include three color channels, and the display lookup table may be a three-dimensional display lookup table. Based on the corrected pixel value of the reference vertex, linear interpolation processing is performed on the initial pixel data to obtain the corrected pixel data corresponding to the pixel point, including: based on the corrected pixel value of the reference vertex, cubic linear interpolation processing is performed on the initial pixel data to obtain the corrected pixel data corresponding to the pixel point.

[0167] like Figure 10 As shown, Figure 10 It is a cube composed of the corrected pixel values of 8 reference vertices (i.e., the color space after tuning). First, assume that the left-hand coordinate system is used. The x-axis, y-axis, and z-axis refer to Figure 10 .

[0168] Figure 10 In , the corrected pixel values of the 8 reference vertices are C000, C100, C010, C001, C101, C011, C110, and C111 respectively.

[0169] In the x-direction, the four edges are interpolated using the x-coordinate values of the initial pixel data to obtain the values of the four points on each edge, C00, C01, C10, and C11. Specifically, C000 and C100 are interpolated to obtain C00; C001 and C101 are interpolated to obtain C01; C010 and C110 are interpolated to obtain C10; and C011 and C111 are interpolated to obtain C11.

[0170] Then, in the y direction, the y coordinate values of the initial pixel data are used to interpolate the four points C00, C01, C10, and C11 to obtain the values C0 and C1 of the two line segments and the two points in the middle.

[0171] Finally, in the z direction, the z coordinate values of the initial pixel data are used to interpolate the two points C0 and C1 to obtain the final value of point C (ie, the corrected pixel data corresponding to the pixel point).

[0172] Considering the grayscale transition, when the input value of point P changes from (0,0,0) to (255,255,255), the relationship between the output value and input value of point P is obtained by cubic linear interpolation using the correction pixel values LUT0_S~LUT7_S of the reference vertex. Figure 11shown.

[0173] The input value of point P represents the initial pixel data of the pixel point, and the output value of point P represents the corrected pixel data corresponding to the pixel point.

[0174] Figure 11 Here, r, g, and b are the input-output curves drawn with the red component, the input-output curves drawn with the green component, and the input-output curves drawn with the blue component, respectively.

[0175] See also Figure 11 It can be seen that the three curves of r / g / b all show a linear change trend, and the relative ratio is fixed, which can improve the color cast of the display image finally presented by the OLED screen.

[0176] This application adds a saturation parameter to the color space conversion process to evaluate the influence of the reference vertex on the color of the pixel point. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel point and the reference vertex. The reference vertex is a vertex in the color space formed based on the reference color. The color distance includes the saturation difference. The saturation difference is used to quantify the color distance between the pixel point and the reference vertex. Based on the corrected pixel value of the reference vertex, the initial pixel data is linearly interpolated to obtain the corrected pixel data corresponding to the pixel point. The corrected pixel data is used to output the display image; it can improve the color deviation of the grayscale picture of the display image displayed by the display device, and can improve the color accuracy of the display image displayed by the display device.

[0177] Moreover, different display devices can use different saturation gaps for correction, which can balance the differences between different display devices, improve the matching degree between the corrected pixel data of the pixel points and the corresponding display device, and improve the color accuracy of the displayed images displayed by different display devices.

[0178] Based on the same inventive concept, the embodiment of the present application provides a color correction device, such as Figure 12 As shown, the color correction device includes: an acquisition module 401 and a determination module 402.

[0179] The acquisition module 401 acquires initial pixel data of a plurality of pixels included in the image to be displayed;

[0180] Determination module 402 is used to determine the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference between the pixel point and the reference vertex, where the reference vertex is a vertex in the color space formed based on the reference color; based on the corrected pixel value of the reference vertex, linear interpolation processing is performed on the initial pixel data to obtain corrected pixel data corresponding to the pixel point; the corrected pixel data is used to output the display image.

[0181] In one possible implementation, when determining the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference between the pixel point and the reference vertex, the determination module 402 is configured to:

[0182] Determining a first saturation of the pixel point based on the initial pixel data, and determining a second saturation of the reference vertex based on an input value of the reference vertex, where the input value of the reference vertex is a pixel value of the reference vertex in the original color space;

[0183] Determine a saturation difference between the pixel point and a reference vertex based on the first saturation and the second saturation;

[0184] Based on the display lookup table and the saturation difference, a corrected pixel value for the reference vertex is determined.

[0185] In one possible implementation, when determining the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference, the determination module 402 is configured to:

[0186] Input the input value of the reference vertex into the display lookup table to obtain the output value of the reference vertex;

[0187] A corrected pixel value for the reference vertex is determined based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference.

[0188] In one possible implementation, when determining the corrected pixel value of the reference vertex based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference, the determination module 402 is configured to:

[0189] Weighting the saturation gap;

[0190] A corrected pixel value of the reference vertex is determined based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference.

[0191] In one possible implementation, when determining the weighted saturation gap, the determination module 402 is configured to:

[0192] The saturation difference is weighted based on the display characteristics of the display panel.

[0193] In a possible implementation, the image to be displayed includes three color channels; the display lookup table is a three-dimensional display lookup table;

[0194] The determination module 402 performs linear interpolation processing on the initial pixel data based on the corrected pixel value of the reference vertex to obtain the corrected pixel data corresponding to the pixel point, which is used to:

[0195] Based on the corrected pixel value of the reference vertex, the initial pixel data is subjected to cubic linear interpolation processing to obtain the corrected pixel data corresponding to the pixel point.

[0196] The device of the embodiment of the present application can execute the method provided by the embodiment of the present application, and its implementation principle is similar. The actions performed by each module in the device of each embodiment of the present application correspond to the steps in the method of each embodiment of the present application. For the detailed functional description of each module of the device, please refer to the description in the corresponding method shown in the previous text, and will not be repeated here.

[0197] This application adds a saturation parameter to the color space conversion process to evaluate the influence of the reference vertex on the color of the pixel point. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel point and the reference vertex. The reference vertex is a vertex in the color space formed based on the reference color. The color distance includes the saturation difference. The saturation difference is used to quantify the color distance between the pixel point and the reference vertex. Based on the corrected pixel value of the reference vertex, the initial pixel data is linearly interpolated to obtain the corrected pixel data corresponding to the pixel point. The corrected pixel data is used to output the display image; it can improve the color deviation of the grayscale picture of the display image displayed by the display device, and can improve the color accuracy of the display image displayed by the display device.

[0198] Moreover, different display devices can use different saturation gaps for correction, which can balance the differences between different display devices, improve the matching degree between the corrected pixel data of the pixel points and the corresponding display device, and improve the color accuracy of the displayed images displayed by different display devices.

[0199] Based on the same inventive concept, an embodiment of the present application provides an electronic device comprising a processor and a memory, the processor and the memory being interconnected, the memory being used to store a computer program, the processor being configured to execute the steps of the above method when the computer program is called, and compared to the related art, the following can be achieved: a saturation parameter is added during the color space conversion process to evaluate the influence of a reference vertex on the color of a pixel point, specifically determining a corrected pixel value of the reference vertex based on the saturation difference between the pixel point and the reference vertex, the reference vertex being a vertex in a color space formed based on a reference color, the color distance including the saturation difference, and the saturation difference being used to quantify the color distance between the pixel point and the reference vertex. Based on the corrected pixel value of the reference vertex, linear interpolation is performed on the initial pixel data to obtain corrected pixel data corresponding to the pixel point, and the corrected pixel data is used to output a display image; the corrected pixel data can improve the color cast of the grayscale image displayed by the display device, and can improve the color accuracy of the display image displayed by the display device. Moreover, different display devices can use different saturation differences for correction, which can balance the differences between different display devices, improve the matching degree between the corrected pixel data of the pixel point and the corresponding display device, and improve the color accuracy of the display image displayed by different display devices.

[0200] In an alternative embodiment, an electronic device is provided, such as Figure 13 As shown, Figure 13 The electronic device 50 shown includes a processor 501 and a memory 503 , wherein the processor 501 and the memory 503 are connected, for example, via a bus 502 .

[0201] In a possible implementation, the electronic device 50 may further include a display panel, which is electrically connected to the processor 501 and configured to receive corrected pixel data of an image to be displayed output by the processor 501 to output a display image.

[0202] Optionally, the electronic device 50 may further include a transceiver 504, which may be used for data exchange between the electronic device and other electronic devices, such as data transmission and / or data reception. It should be noted that in actual applications, the number of transceivers 504 is not limited to one, and the structure of the electronic device 50 does not constitute a limitation on the embodiments of the present application.

[0203] The processor 501 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor 501 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0204] The bus 502 may include a path for transmitting information between the above components. The bus 502 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 502 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 12 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0205] The memory 503 can be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory) or other optical disk storage, optical disk storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, other magnetic storage devices, or any other medium that can be used to carry or store computer programs and can be read by a computer, without limitation here.

[0206] The memory 503 is used to store the computer program for executing the embodiments of the present application, and the execution is controlled by the processor 501. The processor 501 is used to execute the computer program stored in the memory 503 to implement the steps shown in the above method embodiments.

[0207] The electronic devices include, but are not limited to, mobile terminals such as mobile phones, notebook computers, PADs, etc., and fixed terminals such as digital TVs, desktop computers, etc.

[0208] Based on the same inventive concept, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it can implement the steps and corresponding contents of the aforementioned method embodiment.

[0209] The present invention provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, so that when the computer device executes the computer instructions, the following conditions are achieved:

[0210] Obtaining initial pixel data of a plurality of pixel points of an image to be displayed;

[0211] Determining a corrected pixel value of a reference vertex based on a display lookup table and a saturation difference between the pixel point and a reference vertex, where the reference vertex is a vertex in a color space formed based on the reference color;

[0212] Based on the corrected pixel value of the reference vertex, linear interpolation is performed on the initial pixel data to obtain the corrected pixel data corresponding to the pixel point;

[0213] The corrected pixel data is used to output a display image.

[0214] The terms "first," "second," "third," "fourth," "1," "2," and the like (if any) in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the application described herein can be implemented in an order other than that shown or described in the drawings.

[0215] It should be understood that, although each operation step is indicated by arrows in the flowchart of the embodiment of the present application, the order of implementation of these steps is not limited to the order indicated by the arrows. Unless otherwise clearly stated herein, in some implementation scenarios of the embodiment of the present application, the implementation steps in each flowchart can be performed in other orders according to demand. In addition, some or all of the steps in each flowchart can include multiple sub-steps or multiple stages based on actual implementation scenarios. Some or all of these sub-steps or stages can be executed at the same time, and each sub-step or stage in these sub-steps or stages can also be executed at different times respectively. Under different scenarios at the execution time, the execution order of these sub-steps or stages can be flexibly configured according to demand, and the embodiment of the present application does not limit this.

[0216] The above are only optional implementation methods for some implementation scenarios of this application. It should be pointed out that for ordinary technicians in this technical field, without departing from the technical concept of the solution of this application, other similar implementation methods based on the technical ideas of this application also fall within the protection scope of the embodiments of this application.

Claims

1. A color correction method, characterized in that: include: Obtaining initial pixel data of a plurality of pixel points of an image to be displayed; The first saturation of the pixel point is determined based on the initial pixel data and the saturation formula, and the second saturation of the reference vertex is determined based on the input value of the reference vertex and the saturation formula, wherein the saturation formula is: S=1-min(r, g, b) / max(r, g, b), S is the saturation of the pixel, r, g, b are the red component, green component and blue component of the pixel respectively, min(r, g, b) is the minimum value of the red component, green component and blue component of the pixel, max(r, g, b) is the maximum value of the red component, green component and blue component of the pixel, the reference vertex is the vertex of the color space formed based on the reference color, and the The input value of the reference vertex is the pixel value of the reference vertex in the original color space; based on the first saturation and the second saturation, a saturation difference between the pixel point and the reference vertex is determined, wherein the saturation difference includes the difference between the first saturation of the pixel point and the second saturation of each reference vertex; the input value of the reference vertex is input into the display lookup table to obtain the output value of the reference vertex; based on the input value of the reference vertex, the output value of the reference vertex and the saturation difference, a corrected pixel value of the reference vertex is determined, wherein the corrected pixel value of the i-th reference vertex is LUTi_S=(input value of the i-th reference vertex) DeltaSi'+(output value of the i-th reference vertex) (1-DeltaSi'), DeltaSi' is the saturation difference of the i-th reference vertex; Based on the corrected pixel value of the reference vertex, linear interpolation is performed on the initial pixel data to obtain corrected pixel data corresponding to the pixel point; The corrected pixel data is used to output a display image.

2. The method according to claim 1, characterized in that The determining, based on the input value of the reference vertex, the output value of the reference vertex, and the saturation difference, a corrected pixel value of the reference vertex includes: weighting the saturation gap; A corrected pixel value of the reference vertex is determined based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference.

3. The method according to claim 2, characterized in that The weighting of the saturation gap includes: The saturation difference is weighted based on display characteristics of the display panel.

4. The method according to claim 1, wherein The image to be displayed includes three color channels; the display lookup table is a three-dimensional display lookup table; The step of performing linear interpolation processing on the initial pixel data based on the corrected pixel value of the reference vertex to obtain corrected pixel data corresponding to the pixel point includes: The corrected pixel value based on the reference vertex is processed by performing cubic linear interpolation on the initial pixel data to obtain corrected pixel data corresponding to the pixel point.

5. A color correction device, characterized in that: include: An acquisition module, which acquires initial pixel data of a plurality of pixel points included in the image to be displayed; A determination module is configured to determine a first saturation of the pixel based on the initial pixel data and a saturation formula, and to determine a second saturation of the reference vertex based on an input value of the reference vertex and a saturation formula, wherein the reference vertex is a vertex in a color space formed based on a reference color, wherein the saturation formula is: S = 1-min(r, g, b) / max(r, g, b), where S is the saturation of the pixel, r, g, and b are the red component, green component, and blue component of the pixel, respectively, min(r, g, b) is the minimum value of the red component, green component, and blue component of the pixel, and max(r, g, b) is the maximum value of the red component, green component, and blue component of the pixel. value, the input value of the reference vertex is the pixel value of the reference vertex in the original color space; based on the first saturation and the second saturation, determining the saturation difference between the pixel point and the reference vertex, the saturation difference including the difference between the first saturation of the pixel point and the second saturation of each reference vertex; inputting the input value of the reference vertex into the display lookup table to obtain the output value of the reference vertex; determining the corrected pixel value of the reference vertex based on the input value of the reference vertex, the output value of the reference vertex and the saturation difference, wherein the corrected pixel value of the i-th reference vertex is LUTi_S=(the input value of the i-th reference vertex) DeltaSi'+(output value of the i-th reference vertex) (1-DeltaSi'), DeltaSi' is the saturation difference of the i-th reference vertex; based on the corrected pixel value of the reference vertex, the initial pixel data is linearly interpolated to obtain the corrected pixel data corresponding to the pixel point; the corrected pixel data is used to output the display image.

6. An electronic device, characterized in that: comprising a processor and a memory, wherein the processor and the memory are connected to each other; The memory is used to store computer programs; The processor is configured to execute the method according to any one of claims 1 to 4 when calling the computer program.

7. The electronic device according to claim 6, wherein: Also includes a display panel; The display panel is electrically connected to the processor and is configured to receive the corrected pixel data of the image to be displayed output by the processor, so as to output the display image.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the method according to any one of claims 1 to 4.

Images