CN115862534A - Color correction method, color correction device, electronic device and storage medium - Google Patents

Abstract

The embodiment of the application provides a color correction method and device, electronic equipment and a storage medium. The color correction method includes: the method comprises the steps of obtaining initial pixel data of a plurality of pixel points of an image to be displayed, then determining a correction pixel value of a reference vertex based on a display lookup table and a saturation difference between the pixel point and the reference vertex, wherein the reference vertex is a vertex of a color space formed based on a reference color, further performing linear interpolation processing on the initial pixel data based on the correction pixel value of the reference vertex to obtain correction pixel data corresponding to the pixel point, and the correction pixel data are used for outputting the display image. The embodiment of the application is used for solving the problem of color cast of the gray scale picture of the display image displayed by the current display equipment in the related art.

Description

Color correction method, device, electronic device and storage medium

technical field

The present application relates to the field of display technology, and in particular, the present application relates to a color correction method, device, electronic equipment and storage medium.

Background technique

Different display devices have different display color capabilities, such as different color filters (color filters) for LCDs, different backlight sources, and different light-emitting materials for OLEDs, etc., all of which will affect the performance of the final display device. The displayed color area. Because of this, the same image often has different display colors on different display devices.

In order to solve this problem, CIE (International Commission on Illumination) stipulates a standard color space, such as sRGB, adobeRGB or DCI-P3, etc. The display device processes the input image through a certain color space algorithm, so that the display device displays The picture can match the standard color space. This color space algorithm is generally called color management (color management). For example, the color space algorithm of 3D_LUT (3direction look up table, 3D display lookup table).

However, after the input image is processed by using the existing color space algorithm, the display image displayed by the display device still has the problem of color shift of the gray scale image.

Contents of the invention

Aiming at the shortcomings of the existing methods, the present application proposes a color correction method, device, electronic equipment, and storage medium to solve the problem of color shift in grayscale images of display images displayed by current display equipment in the related art.

In the first aspect, the embodiment of the present application provides a color correction method, including:

Obtain initial pixel data of multiple pixel points of the image to be displayed;

Based on the display lookup table and the saturation difference between the pixel point and a reference vertex, determine the corrected pixel value of the reference vertex, where the reference vertex is a vertex of a color space formed based on a reference color;

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;

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

In a possible implementation manner, the 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 includes:

Determine the first saturation of the pixel point based on the initial pixel data, determine the second saturation of the reference vertex based on the input value of the reference vertex, the input value of the reference vertex is in the original pixel value in color space;

Based on the first saturation and the second saturation, determine the saturation difference between the pixel point and the reference vertex;

A corrected pixel value for the reference vertex is determined based on the display lookup table and the saturation gap.

In a possible implementation manner, the determining the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference includes:

Inputting the input value of the reference vertex 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, the corrected pixel value of the reference vertex is determined.

In a possible implementation manner, the 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:

weighting the saturation difference;

Based on the input value of the reference vertex, the output value of the reference vertex and the weighted saturation difference, the corrected pixel value of the reference vertex is determined.

In a possible implementation manner, the weighting the saturation difference includes:

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

In a possible implementation manner, 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 the corrected pixel data corresponding to the pixel point includes:

Performing cubic 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.

In the second aspect, the embodiment of the present application provides a color correction device, including:

An acquisition module, which acquires the initial pixel data of a plurality of pixels contained in the image to be displayed;

A determining module, configured 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, the reference vertex being a vertex of a color space formed based on a reference color; based on The corrected pixel value of the reference vertex is used to perform linear interpolation processing 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.

In a third aspect, the embodiment of the present application provides an electronic device, including a processor and a memory, and 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 above-mentioned method when invoking the computer program.

In a possible implementation manner, the electronic device further includes a display panel;

The display panel is electrically connected to the processor for receiving corrected pixel data of the image to be displayed output by the processor to output a display image.

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

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

In the process of color space conversion, this application adds a saturation parameter to evaluate the influence of the reference vertex on the color of the pixel. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel and the reference vertex. The reference vertex is Based on the vertices of the color space formed by the reference color, the color distance includes a saturation gap, and the saturation gap is used to quantify the color distance between the expressed 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, and the corrected pixel data is used to output the display image; it can improve the grayscale picture of the display image displayed by the display device The color shift can improve the color accuracy of the displayed image displayed by the display device.

Moreover, different display devices can be corrected with different saturation differences, which can balance the differences between different display devices, improve the matching degree of corrected pixel data of pixels and corresponding display devices, and improve the display performance displayed by different display devices. The color accuracy of the image.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and will become apparent from the description, or may be learned by practice of the application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of input values corresponding to 8 reference vertices in the original color space of the 3D_LUT of the related art;

2 is a schematic diagram of output values corresponding to 8 reference vertices in the color space after tuning (color space conversion) of the 3D_LUT of the related art;

FIG. 3 is a schematic diagram of a nonlinear corresponding relationship between input values and output values of pixels in a 3D_LUT of the related art;

Figure 4 is the gamma curve of w/r/g/b of the actually measured OLED screen;

FIG. 5 is a schematic flow chart of a color correction method provided by an embodiment of the present application;

FIG. 6 is a schematic flowchart of determining the corrected pixel value of a reference vertex in a color correction method provided by an embodiment of the present application;

FIG. 7 is a schematic diagram of the saturation of each reference vertex and pixel point provided by the embodiment of the present application;

Fig. 8 is a schematic flowchart of determining the corrected pixel value of the reference vertex in another color correction method provided by the embodiment of the present application;

Fig. 9 is a graph showing the relationship between the weighting coefficient weight1 and the normalized value of the loading amount of the display screen;

Fig. 10 is a schematic diagram of a cube (ie, the color space after tuning) formed by the corrected pixel values of 8 reference vertices;

FIG. 11 is an input-output curve diagram of pixels obtained by an example color correction method provided by the embodiment of the present application;

Fig. 12 is a schematic structural diagram of a color correction device provided by an embodiment of the present application;

FIG. 13 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Detailed ways

Embodiments of the present application are described below with reference to the drawings in the present application. It should be understood that the implementation manner described below in conjunction with the accompanying drawings is an exemplary description for explaining the technical solutions of the embodiments of the present application, and does not limit the technical solutions of the embodiments of the present application.

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 wording "comprising" used in the description of the present application refers to the presence of the features, integers, steps, operations, elements and/or components, but does not exclude the realization of other features and information supported by the technical field. , data, steps, operations, elements, components and/or combinations thereof, etc. 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 ".

In order to make the purpose, technical solution and advantages of the present application clearer, the implementation manners of the present application will be further described in detail below in conjunction with the accompanying drawings.

The existing 3D_LUT (LUT spelled as Look-Up-Table, that is, display look-up 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, which can play a role in the display. The role of color space conversion. RGB three 1D_LUTs form a 3D_LUT, and 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). The color space algorithm is through a certain number of reference colors Carry out color space conversion (that is, tuning), and then apply the result to all colors through cubic linear interpolation, so that standard color space matching can be achieved very well.

Linear interpolation refers to the interpolation method in which the interpolation function is a polynomial, and its interpolation error on the interpolation node is zero. Compared with other interpolation methods, such as parabolic interpolation, linear interpolation is simple and convenient. The geometric meaning of linear interpolation is to approximate the original function by using a straight line passing through point A and point B in the overview diagram. Linear interpolation can be used to approximately replace the original function, and can also be used to calculate values that are not in the table during the table lookup process.

The inventor found that since 3D_LUT is a purely mathematical theoretical calculation, when the color space algorithm of 3D_LUT is applied to the OLED screen for image display, due to the display characteristics of the OLED screen, discoloration will occur in the grayscale transition screen, that is, Color cast problem. In addition, for OLED screens, the color distribution corresponding to the same RGB (optical three primary colors) data is nonlinear, and using cubic linear interpolation to expand colors will inevitably cause color errors.

Specifically, as shown in FIG. 1 and FIG. 2 , FIG. 1 shows the input value of 3D_LUT (original color space), and FIG. 2 shows the output value of 3D_LUT (color space after tuning). For a simple explanation, the color space is taken as an example here.

See Figure 1, the reference colors are red, green and blue respectively, 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 of red, green and blue form the original color space (ie, the cube shown in FIG. 1 ).

Continuing to refer to FIG. 1 , eight vertices of the color space (ie, the cube shown in FIG. 1 ) formed based on the three reference colors of red, green and blue are reference vertices. The input values of the 8 reference vertices LUT0~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). The input value of the pixel point P is (R, G, B), and R, G, and B are respectively the red component, the green component and the blue component of the input value of the P point.

Referring to Figure 2, the input values of the 8 reference vertices LUT0~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~LUT7 are respectively (r0, g0 , b0), (r1, g1, b1), (r2, g2, b2), (r3, g3, b3), (r4, g4, b4), (r5, g5, b5), (r6, g6, b6 ), (r7, g7, b7). That is to say, the output value LUTi of the i-th reference vertex=(ri, gi, bi), ri, gi, 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 P point (R', G', B'), R', G', B' are the red component, green component and blue component of the output value of P point respectively.

That is to say, the output values of the eight reference vertices LUT0-LUT7 are respectively the eight vertices of the color space after tuning.

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

When the input value of point P is known as (R, G, B), the output value of point P (R’, G’, B’) can be obtained through trilinear interpolation.

Table 1 shows the values of LUT0-LUT7 obtained from the actual tuning (color space conversion) of an OLED screen, that is, the corrected pixel values of the reference vertices.

LUTs 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

Table 1

As shown in Figure 3, 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 of point P and the input value is obtained through trilinear interpolation calculation.

Usually 8 bits are used to represent a pixel, so there are a total of 256 gray levels (pixel values are between 0 and 255), and each level represents a different brightness. Point P is input as a gray scale image, R=G=B (that is, the red component is equal to the green component is equal to the blue component), therefore, the point P can be expressed as 0-255.

In other feasible embodiments, 10 bits can also be used to represent a pixel. At this time, the input value of point P changes from (0,0,0) to (1023,1023,1023), and point P is input as a grayscale image , R=G=B, therefore, the point P can be expressed as 0-1023. Of course, other bits may also be used to represent a pixel, which is not limited here.

The so-called gray scale is to divide the brightness change between the brightest and the darkest into several parts. In order to facilitate the screen brightness control corresponding to the signal input. For each sub-pixel, the light source behind it can show different brightness levels. The gray scale represents the level of brightness from the darkest to the brightest.

For a color image, each pixel contains multiple color components, and each color component is called a channel (Channel). The number of channels of all pixels in the image is the same, that is, each channel can be represented as a component image with the same content as the original image but with different colors. Taking a color image in RGB format as an example, a complete image can be divided into monochrome images of three primary colors of blue (B component), green (G component), and red (R component).

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.

In Figure 3, r, g, and b are the input-output curves drawn with red components, the input-output curves drawn with green components, and the input-output curves drawn with blue components.

It can be seen from Figure 3 that as the input gray scale increases, the three r/g/b curves show different trends. At the position close to the 250 gray scale, there is even a situation where the relative positions of g and b are exchanged.

Since the final color of the OLED screen depends on the mixture of the three colors r, g, and b, when the ratio of the three colors changes or even reverses the ratio, it will inevitably lead to a change in the final color. The phenomenon of color cast. Especially in the case of low brightness and sensitive human eyes, this phenomenon will be more obvious.

In addition, Fig. 4 is the gamma curve of w/r/g/b of the actually measured OLED screen.

In Figure 4, w_gamma, r_gamma, g_gamma, and b_gamma are the white gamma (gamma) curve, red gamma curve, green gamma curve and blue gamma curve of the OLED screen respectively. Wherein, the abscissa is the grayscale input to the display, and the ordinate is the ratio of the current luminance output on the display to the maximum luminance.

The Gamma curve is a special tone curve. When the Gamma value is equal to 1, the curve is a straight line at 45° to the coordinate axis, which means that the input and output densities are the same. Gamma values above 1 will darken the output, and Gamma values below 1 will lighten the output.

It can be seen from Figure 4 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 non-linear. Therefore, if r/g is used in the 3D_LUT scheme /b does not distinguish, and fully utilizes the linear interpolation method, which will inevitably lead to a deviation between the final rendered color and the ideal color.

The color correction method, device, electronic equipment, and computer-readable storage medium provided by the present application aim to solve the above technical problems of related technologies.

The following describes the technical solutions of the embodiments of the present application and the technical effects produced by the technical solutions of the present application by describing several exemplary implementations. It should be pointed out that the following embodiments may refer to, learn from or combine with each other, and the same terms, similar features, and similar implementation steps in different embodiments will not be described repeatedly.

The embodiment of the present application provides a color correction method, as shown in FIG. 5, which can be applied to a terminal or a server. The method includes:

S101: Acquire initial pixel data of multiple pixel points of an image to be displayed.

Specifically, the terminal or server used for color correction downloads the initial pixel data of multiple pixel points of the image to be displayed from the image acquisition device, image storage device or cloud storage.

Wherein, 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 U disk, and the like.

Cloud storage is a mode of online online storage (Cloud storage), that is, data is stored on multiple virtual servers usually hosted by a third party, rather than on a dedicated server. According to the needs of customers, data center operators prepare storage virtualized resources at the back end and provide them in the form of storage resource pools (storage pools), and customers can use the storage resource pools to store files or objects. In fact, these resources may be distributed across numerous server hosts. Cloud storage is a service that is accessed through a Web service Application Programming Interface (API), or through a Web-based user interface.

Each image has one or more color channels, and the default number of color channels in an image depends on its color mode, that is, the color mode of an image will determine the number of its color channels. Each color channel stores information about the color elements in the image. An additive mix of colors from all color channels produces the color of the pixels in the image.

In this embodiment, the image to be displayed may be an RGB image, and the RGB image has three color channels, namely a red channel, a green channel and a blue channel. That is to say, each pixel contains three primary colors of blue (B component), green (G component), and red (R component). The initial pixel data of each pixel can be expressed as (R, G, B).

In this embodiment, 8 bits can be used to represent a pixel, so there are 256 gray levels in total (pixel values are between 0 and 255), and each level represents a different brightness. That is to say, the pixel value of each channel in the initial pixel data of each pixel can be represented by 0-255.

S102: Based on the display lookup table and the saturation difference between the pixel point and the reference vertex, determine the corrected pixel value of the reference vertex.

Wherein, the reference vertex is a vertex of the color space formed based on the reference color.

The saturation of a color refers to the vividness of the color. The saturation of a color is a measure of its purity. A highly saturated color will contain a very narrow set of wavelengths. Therefore, based on the saturation difference between the pixel point and the reference vertex, the color shift of the reference vertex can be adjusted, thereby avoiding the problem of color shift of the displayed picture by applying the corrected pixel data obtained by applying the corrected pixel value of the reference vertex.

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.

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

Those skilled in the art can understand that the "terminal" used here can be a mobile phone, a tablet computer, a PDA (Personal Digital Assistant, a personal digital assistant), a MID (Mobile Internet Device, a mobile Internet device), etc.; It can be realized by an independent server or a server cluster composed of multiple servers.

In the process of color space conversion, this application adds a saturation parameter to evaluate the influence of the reference vertex on the color of the pixel. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel and the reference vertex. The reference vertex is Based on the vertices of the color space formed by the reference color, the color distance includes a saturation gap, and the saturation gap is used to quantify the color distance between the expressed 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, and the corrected pixel data is used to output the display image; it can improve the grayscale picture of the display image displayed by the display device The color shift can improve the color accuracy of the displayed image displayed by the display device.

Moreover, different display devices can be corrected with different saturation differences, which can balance the differences between different display devices, improve the matching degree of corrected pixel data of pixels and corresponding display devices, and improve the display performance displayed by different display devices. The color accuracy of the image.

In a possible implementation mode provided in the embodiment of the present application, as shown in FIG. 6, 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:

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 a reference vertex.

Wherein, the input value of the reference vertex is the pixel value of the reference vertex in the original color space.

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 and green component of the pixel respectively. component and blue component, min(r,g,b) is the minimum value among red component, green component and blue component, max(r,g,b) is the maximum among red component, green component and blue component value.

For the eight reference vertices LUT0-LUT7, the input values of LUT0-LUT7 can be referred to as shown in FIG. 1 . Specifically, the input values of LUT0~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).

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, see FIG. 7 for details.

That is to say, the second saturation of the reference vertex includes the saturation of a plurality of reference vertexes, respectively S0, S1, S2, S3, S4, S5, S6, S7, wherein, S1=S7=0, S1=S2= S3=S4=S5=S6=1.

The input values of the eight reference vertices LUT0~LUT7 shown in Figure 1 are characterized by color space conversion based on red (256,0,0), green (0,256,0) and blue (0,0,256) (that is, tuning ), and then apply the converted results of red (256,0,0), green (0,256,0) and blue (0,0,256) to all colors by cubic linear interpolation.

It should be noted that, in some other feasible embodiments, the input values of the eight reference vertices LUT0-LUT7 can also adopt other values, for example, it can be based on red (245,0,0), green (0,250,0) and Blue (0,0,254) performs color space conversion. At this time, the input values of the eight reference vertices LUT0~LUT7 are (0,0,0), (245,0,0), (0,250,0), ( 0,0,254), (245,250,0), (245,0,254), (0,250,254), (245,250,254).

For the pixel point corresponding to the initial pixel data, take 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).

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

S202: Based on the first saturation and the second saturation, determine a saturation difference between the pixel point and the reference vertex.

In this embodiment, the saturation difference may include a difference between the first saturation of the pixel and the second saturation of each reference vertex. Specifically, the saturation difference may include DeltaS0...DeltaS7, wherein,

DeltaS0=(Sp-S0);

DeltaS1 = (Sp-S1);

DeltaS2=(Sp-S2);

DeltaS3=(Sp-S3);

DeltaS4=(Sp-S4);

DeltaS5=(Sp-S5);

DeltaS6=(Sp-S6);

DeltaS7=(Sp-S7).

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

S203: Based on the display lookup table and the saturation difference, determine the corrected pixel value of the reference vertex.

In a possible implementation, determining the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference may include: inputting the input value of the reference vertex into the display lookup table to obtain the output value of the reference vertex; The input value, the output value of the reference vertex, and the saturation gap determine the corrected pixel value for the reference vertex.

In a 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 may include: weighting the saturation difference; based on the input value of the reference vertex, The output value of the reference vertex and the weighted saturation difference determine the corrected pixel value of the reference vertex. By weighting the saturation difference, the influence of each reference vertex on the pixel can be better balanced.

For ease of understanding, the following will be described in conjunction with Figure 8:

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

Wherein, 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 (ie, the color space formed by the reference color). The display lookup table includes correspondences between input values of the reference vertices and output values of the reference vertices.

In this embodiment, the display lookup table may be a three-dimensional display lookup table, and the input values of the eight reference vertices may refer to FIG. 1 . Through tuning, the output values corresponding to the eight reference vertices may refer to FIG. 2 .

S302: Weighting the saturation difference.

Specifically, the weighted saturation difference may include DeltaS0'...DeltaS7', where,

DeltaS0'=(Sp-S0)*weight1;

DeltaS1'=(Sp-S1)*weight2;

DeltaS2'=(Sp-S2)*weight3;

DeltaS3'=(Sp-S3)*weight4;

DeltaS4'=(Sp-S4)*weight5;

DeltaS5'=(Sp-S5)*weight6;

DeltaS6'=(Sp-S6)*weight7;

DeltaS7'=(Sp-S7)*weight8.

That is to say, the saturation difference DeltaSi'=(Sp-Si)*weighti of any reference vertex.

Among them, weighti is the weighting coefficient of the i-th reference vertex, and weight1...weight8 are the weighting coefficients of the eight reference vertices LUT0-LUT7 respectively.

In practical applications, weight1...weight8 can be preset according to actual needs. If the display screen to which the color correction method is applied is an LCD screen, weight1 to weight8 may all be equal to 1. If the display screen to which the color correction method is applied is an OLED screen, weight1 to weight8 may be set based on display characteristics (eg, voltage drop characteristics) of the OLED screen.

In this embodiment, weighting the saturation difference may include: weighting the saturation difference based on display characteristics of the display panel. That is to say, based on the display characteristics of the display panel, different weighting coefficients weight1...weight8 can be set to better adapt to different display screens.

Further, weighting the saturation difference based on the display characteristics of the display panel may include: weighting the saturation difference based on the voltage drop characteristic of the display panel. Since the sub-pixels of different colors have different effects on the voltage drop of the display screen, the loading (load) of the display screen is different when different images are displayed. Therefore, the setting of weight1~weight8 can consider the voltage drop characteristics of the display screen and affect the color. Deviations are further fine-tuned.

In practical applications, the weight curves of weight1-weight8 can be determined according to the measurement results of the colors displayed on the current screen. Specifically, when several sample pictures are displayed (when each sample picture is displayed, the load of the display screen is different), the weighting coefficients weight1...weight8 corresponding to the sample pictures may be adjusted according to experience. According to the weight coefficients weighti (which may be weight1-weight8) of a plurality of sample images, a graph of the relationship between each weight coefficient weighti and the normalized value of the display screen loading (load) is obtained.

For example, according to the weighting coefficient weight1 of each sample picture, a graph of the relationship between the weighting coefficient weight1 and the normalized value of the display screen loading (load) is obtained. According to the weighting coefficient weight2 of each sample picture, a graph of the relationship between the weighting coefficient weight2 and the normalized value of the display screen loading (load) is obtained.

As shown in FIG. 9 , FIG. 9 is a graph showing the relationship between the weighting coefficient weight1 and the normalized value of the loading amount of the display screen. Wherein, the abscissa is the normalized value of loading (load) of the display screen, and the ordinate is the value of the weighting coefficient weight1.

When loading is the largest (ie loading=1), weight1 is the maximum value; when loading is the smallest (ie loading=0), weighti is the minimum value. According to the normalized value of the current loading of the display, the current value of weight1 is obtained. As the display screen changes continuously, the normalized value of the loading of the display screen changes accordingly, and the value of weight1 also changes accordingly.

In addition, the method of determining the weighting coefficients Weigh2...weight8 is similar to that of the weighting coefficient Weigh1, and will not be repeated here.

S303: Based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference, determine the corrected pixel value of the reference vertex.

In this embodiment, the corrected pixel values of the reference vertices include LUT0_S...LUT7_S, where,

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

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

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

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

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

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

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

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

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 FIG. 1 , and the output value of each reference vertex can refer to FIG. 2 .

It should be noted that there is no fixed sequence between step S301 and step S302, step S301 may be performed first and then step S302 may be performed, or step S302 may be performed first and then step S301 is performed, which is not limited herein.

When weight1...weight8 take the average value of 1, and the input value of point P changes from (0,0,0) to (255,255,255) (that is, R, G, B are equal, Sp is 0), the actual calculated LUT0_S～ LUT7_S can refer to Table 2:

Table 2

The previous section introduces how to determine the corrected pixel value of the reference vertex, and then introduces 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.

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, the initial pixel data is linearly interpolated to obtain the corrected pixel data corresponding to the pixel. , including: performing cubic 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.

As shown in FIG. 10 , FIG. 10 is a cube formed by the corrected pixel values of 8 reference vertices (that is, the color space after tuning). First assume that a left-handed coordinate system is used, see Figure 10 for the x-axis, y-axis, and z-axis.

In FIG. 10 , the corrected pixel values of the eight reference vertices are C000, C100, C010, C001, C101, C011, C110, and C111, respectively.

In the x direction, use the x coordinate value of the initial pixel data to interpolate the four edges to obtain the values C00, C01, C10, and C11 of the four points on each edge. 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; C011 and C111 are interpolated to obtain C11.

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

Finally, in the z direction, the two points C0 and C1 are interpolated using the z coordinate value of the initial pixel data to obtain the final value of point C (ie, the corrected pixel data corresponding to the pixel point).

Considering the excessive gray scale, when the input value of point P changes from (0,0,0) to (255,255,255), use the corrected pixel values LUT0_S~LUT7_S of the reference vertex to calculate the output value of point P through cubic linear interpolation The relationship with the input value is shown in Figure 11.

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.

In Fig. 11, r, g, and b are the input-output curves drawn with red components, the input-output curves drawn with green components, and the input-output curves drawn with blue components, respectively.

Referring to FIG. 11 , it can be seen that the three curves of r/g/b all present a linear change trend, and the relative ratio is fixed, so that the color shift phenomenon of the final display screen presented by the OLED screen can be improved.

In the process of color space conversion, this application adds a saturation parameter to evaluate the influence of the reference vertex on the color of the pixel. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel and the reference vertex. The reference vertex is Based on the vertices of the color space formed by the reference color, the color distance includes a saturation gap, and the saturation gap is used to quantify the color distance between the expressed 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, and the corrected pixel data is used to output the display image; it can improve the grayscale picture of the display image displayed by the display device The color shift can improve the color accuracy of the displayed image displayed by the display device.

Moreover, different display devices can be corrected with different saturation differences, which can balance the differences between different display devices, improve the matching degree of corrected pixel data of pixels and corresponding display devices, and improve the display performance displayed by different display devices. The color accuracy of the image.

Based on the same inventive concept, an embodiment of the present application provides a color correction device. As shown in FIG. 12 , the color correction device includes: an acquisition module 401 and a determination module 402 .

Wherein, the acquiring module 401 acquires initial pixel data of a plurality of pixel points contained in the image to be displayed;

The determination module 402 is configured 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. The reference vertex is the vertex of the color space formed based on the reference color; the corrected pixel based on the reference vertex Value, linear interpolation processing is performed on the initial pixel data to obtain the corrected pixel data corresponding to the pixel point; the corrected pixel data is used to output the display image.

In a possible implementation, the 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:

Determining the first saturation of the pixel point based on the initial pixel data, determining the second saturation of the reference vertex based on the input value of the reference vertex, 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, determine the saturation difference between the pixel point and the reference vertex;

Based on the display lookup table and the saturation gap, the corrected pixel value for the reference vertex is determined.

In a possible implementation manner, when the determination module 402 determines the corrected pixel value of the reference vertex based on the display lookup table and the saturation difference, it is used to:

Input the input value of the reference vertex 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.

In a possible implementation manner, 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 used for:

weighting the saturation difference;

Based on the input value of the reference vertex, the output value of the reference vertex, and the weighted saturation difference, the corrected pixel value of the reference vertex is determined.

In a possible implementation manner, when the determining module 402 weights the saturation difference, it is used to:

Saturation differences are weighted based on the display characteristics of the display panel.

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

The determination module 402 performs linear interpolation processing on the initial pixel data based on the corrected pixel value of the reference vertex, and when obtaining the corrected pixel data corresponding to the pixel point, it is used for:

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.

The device in the embodiment of the present application can execute the method provided in the embodiment of the present application, and its implementation principle is similar. The actions performed by the modules in the device in the embodiments of the present application are the same as the steps in the methods of the embodiments of the present application Correspondingly, for the detailed functional description of each module of the device, reference may be made to the description in the corresponding method shown above, which will not be repeated here.

In the process of color space conversion, this application adds a saturation parameter to evaluate the influence of the reference vertex on the color of the pixel. Specifically, the corrected pixel value of the reference vertex is determined based on the saturation difference between the pixel and the reference vertex. The reference vertex is Based on the vertices of the color space formed by the reference color, the color distance includes a saturation gap, and the saturation gap is used to quantify the color distance between the expressed 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, and the corrected pixel data is used to output the display image; it can improve the grayscale picture of the display image displayed by the display device The color shift can improve the color accuracy of the displayed image displayed by the display device.

Moreover, different display devices can be corrected with different saturation differences, which can balance the differences between different display devices, improve the matching degree of corrected pixel data of pixels and corresponding display devices, and improve the display performance displayed by different display devices. The color accuracy of the image.

Based on the same inventive concept, an embodiment of the present application provides an electronic device, including a processor and a memory, the processor and the memory are connected to each other, the memory is used to store a computer program, and the processor is configured to execute such as The steps of the above-mentioned method, compared with related technologies, can be realized: in the process of color space conversion, a saturation parameter is added to evaluate the influence of the reference vertex on the color of the pixel, specifically based on the saturation gap between the pixel and the reference vertex To determine the corrected pixel value of the reference vertex, the reference vertex is the vertex of the color space formed based on the reference color, the color distance includes the saturation gap, and the saturation gap is used to quantify the color distance between the expressed 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, and the corrected pixel data is used to output the display image; it can improve the grayscale picture of the display image displayed by the display device The color shift can improve the color accuracy of the displayed image displayed by the display device. Moreover, different display devices can be corrected with different saturation differences, which can balance the differences between different display devices, improve the matching degree of corrected pixel data of pixels and corresponding display devices, and improve the display performance displayed by different display devices. The color accuracy of the image.

An optional embodiment provides an electronic device. As shown in FIG. 13 , the electronic device 50 shown in FIG. 13 includes: a processor 501 and a memory 503 . Wherein, the processor 501 is connected to the memory 503 , such as through a bus 502 .

In a possible implementation manner, the electronic device 50 may further include a display panel, and the display panel is electrically connected to the processor 501 for receiving corrected pixel data of the image to be displayed output by the processor 501 to output a display image.

Optionally, the electronic device 50 may further include a transceiver 504, and the transceiver 504 may be used for data interaction between the electronic device and other electronic devices, such as sending data and/or receiving data. It should be noted that, in practical applications, the transceiver 504 is not limited to one, and the structure of the electronic device 50 does not limit the embodiment of the present application.

The processor 501 can be a CPU (Central Processing Unit, central processing unit), a general-purpose processor, a DSP (Digital Signal Processor, a data signal processor), an ASIC (Application Specific Integrated Circuit, an application specific integrated circuit), an FPGA (Field Programmable Gate Array, field programmable gate array) or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various illustrative logical blocks, modules and circuits described in connection with the present disclosure. 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.

Bus 502 may include a path for communicating information between the components described above. The bus 502 may be a PCI (Peripheral Component Interconnect, Peripheral Component Interconnect Standard) bus or an EISA (Extended Industry Standard Architecture, Extended Industry Standard Architecture) bus or the like. The bus 502 can be divided into address bus, data bus, control bus and so on. For ease of representation, only one thick line is used in FIG. 12 , but it does not mean that there is only one bus or one type of bus.

Memory 503 may be ROM (Read Only Memory, read-only memory) or other types of static storage devices that can store static information and instructions, RAM (Random Access Memory, random access memory) or other types of memory that can store information and instructions A dynamic storage device can also be EEPROM (Electrically Erasable Programmable Read Only Memory, Electrically Erasable Programmable Read-Only Memory), CD-ROM (Compact DiscRead Only Memory, CD-ROM) or other CD storage, CD storage (including compact CD, 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.

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

Wherein, the electronic equipment includes, but is not limited to: mobile terminals such as mobile phones, notebook computers, PADs, etc., and fixed terminals such as digital TVs, desktop computers, etc.

Based on the same inventive concept, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps and corresponding contents of the aforementioned method embodiments can be realized.

An embodiment of the present application provides a computer program product or computer program, where the computer program product or computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device realizes the following when executing:

Obtain initial pixel data of multiple pixel points of the image to be displayed;

Based on the display lookup table and the saturation difference between the pixel point and the reference vertex, determine the corrected pixel value of the reference vertex, where the reference vertex is a vertex of a color space formed based on the reference color;

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 a display image.

The terms "first", "second", "third", "fourth", "1", "2", etc. (if any) in the description and claims of this application and the above drawings are used for Distinguishes between similar objects and does not necessarily describe a particular order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described in writing.

It should be understood that although arrows indicate various operation steps in the flow chart of the embodiment of the present application, the execution order of these steps is not limited to the order indicated by the arrows. Unless otherwise specified herein, in some implementation scenarios of the embodiments of the present application, the implementation steps in each flowchart may be performed in other orders as required. In addition, part or all of the steps in each flow chart may include multiple sub-steps or multiple stages based on actual implementation scenarios. Some or all of these sub-steps or stages may be executed at the same time, and each of these sub-steps or stages may also be executed at different times. In scenarios where execution times are different, the execution order of these sub-steps or stages can be flexibly configured according to requirements, which is not limited in this embodiment of the present application.

The above are only optional implementations of some implementation scenarios of this application. It should be pointed out that for those of ordinary skill in the art, on the premise of not departing from the technical concept of this application, other similar methods based on the technical ideas of this application can be adopted. The means of implementation also belong to the scope of protection of the embodiments of the present application.

Claims (10)

1. A color correction method, comprising:

acquiring initial pixel data of a plurality of pixel points of an image to be displayed;

determining 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, wherein the reference vertex is a vertex of a color space formed based on a reference color;

performing linear interpolation processing on the initial pixel data based on the correction pixel value of the reference vertex to obtain correction pixel data corresponding to the pixel point;

the corrected pixel data is used to output a display image.

2. The method of claim 1, wherein determining the corrected pixel value for the reference vertex based on the display lookup table and the saturation difference between the pixel point and the reference vertex comprises:

determining a first saturation of the pixel point based on the initial pixel data, determining a second saturation of the reference vertex based on an input value of the reference vertex, the input value of the reference vertex being a pixel value of the reference vertex in an original color space;

determining a saturation gap between the pixel point and the reference vertex based on the first saturation and the second saturation;

determining a corrected pixel value for the reference vertex based on the display lookup table and the saturation gap.

3. The method of claim 2, wherein determining the corrected pixel value for the reference vertex based on the display lookup table and the saturation gap comprises:

inputting the input value of the reference vertex into the display lookup table to obtain the output value of the reference vertex;

determining a corrected pixel value for the reference vertex based on the input value for the reference vertex, the output value for the reference vertex, and the saturation gap.

4. The method of claim 3, wherein determining the corrected pixel value for the reference vertex based on the input value for the reference vertex, the output value for the reference vertex, and the saturation gap comprises:

weighting the saturation differences;

and determining a correction 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.

5. The method of claim 4, wherein weighting the saturation gaps comprises:

weighting the saturation gap based on display characteristics of the display panel.

6. The method of claim 1, wherein the image to be displayed comprises three color channels; the display lookup table is a three-dimensional display lookup table;

the 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:

and performing cubic linear interpolation processing on the initial pixel data based on the correction pixel value of the reference vertex to obtain correction pixel data corresponding to the pixel point.

7. A color correction apparatus, characterized by comprising:

the acquisition module is used for acquiring initial pixel data of a plurality of pixel points contained in an image to be displayed;

a determining module, configured to 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, where the reference vertex is a vertex of a color space formed based on a reference color; performing linear interpolation processing on the initial pixel data based on the correction pixel value of the reference vertex to obtain correction pixel data corresponding to the pixel point; the corrected pixel data is used to output a display image.

8. An electronic device comprising a processor and a memory, the processor and the memory being interconnected;

the memory is used for storing a computer program;

the processor is configured to perform the method of any of claims 1 to 6 when the computer program is invoked.

9. The electronic device of claim 8, further comprising a display panel;

the display panel is electrically connected with the processor and used for receiving the corrected pixel data of the image to be displayed output by the processor so as to output the display image.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which is executed by a processor to implement the method of any one of claims 1 to 6.

Images