A chromaticity compensation method for a display panel

Abstract

The application belongs to the technical field of image processing and display control, and discloses a chromaticity compensation method for a display panel, comprising the following steps: acquiring a color temperature curve of a panel gray scale picture; acquiring a color temperature curve of an R / G / B picture; matching the color temperature curve of the panel gray scale picture with the color temperature curve of the R / G / B picture; confirming the closest color temperature corresponding to each gray scale color temperature of the panel gray scale picture on the color temperature curve of the R / G / B picture; and confirming a compensation matrix of each gray scale picture of the panel based on the color temperature. The application fuses panel gray scale picture data, more accurately establishes a chromaticity model of the full gray scale of the panel, improves the chromaticity compensation effect, is helpful for performing panel chromaticity Inline compensation on a factory production line, reduces the difference between panel pieces, and improves the picture quality performance.

Description

Technical Field

[0001] This application belongs to the field of image processing and display control technology, and in particular relates to a color compensation method for display panels. Background Technology

[0002] In the field of TFT LCD displays, because liquid crystals have different transmittance for different wavelengths of light, there can be abrupt changes in the chromaticity of various gray levels on the panel, resulting in chromaticity shift. To improve the display quality, the panel's white balance is usually compensated to ensure a smooth transition of chromaticity across different gray levels, with no noticeable color cast subjectively.

[0003] Currently, due to differences between individual panels, the same set of compensation data cannot accurately compensate for each panel. Therefore, panel colorimetric inline compensation is required on the production line. First, it is necessary to obtain the initial colorimetric characteristics of each panel. Furthermore, considering production efficiency and T / T (Tact Time), the panel colorimetric characteristics need to be fitted as accurately as possible with as few sampling points as possible.

[0004] like Figure 1 As shown, the chromaticity characteristic matrix Mn with n binding points is obtained by using the tristimulus values ​​X, Y, and Z of n sets of R / G / B images. Then, the chromaticity characteristic matrix of the full grayscale from 0 to 255 is interpolated and fitted to perform chromaticity compensation.

[0005] However, the full grayscale chromaticity characteristics obtained in this way deviate somewhat from the measured values. Because the chromaticity characteristic matrix obtained by fitting the nth grayscale R / G / B image does not perfectly match the chromaticity characteristics of the nth grayscale white image, especially with larger deviations in lower grayscales, and the transition at the binding points is not smooth enough, color cast occurs in lower grayscales after chromatic coordinate compensation. Summary of the Invention

[0006] Purpose of the invention: This application provides a colorimetric compensation method for display panels. By performing grayscale matching on an established panel colorimetric characteristic matrix model, a more accurate panel colorimetric characteristic model is established, and colorimetric compensation is performed to improve the color coordinate compensation effect.

[0007] Summary of the Invention: This application proposes a color compensation method for a display panel, comprising the following steps:

[0008] Obtain the color temperature curve of the panel's grayscale image;

[0009] Obtain the color temperature curve of the R / G / B image;

[0010] The color temperature curve of the panel gray scale picture is matched with the color temperature curve of the R / G / B picture, a color temperature corresponding to each gray scale color temperature of the panel gray scale picture is confirmed on the color temperature curve of the R / G / B picture, and a chromaticity characteristic matrix of each gray scale picture of the panel is confirmed based on the color temperature.

[0011] In some embodiments, the color temperature curve of the panel gray scale picture is obtained by collecting three-stimulus values of multiple groups of gray scale binding point pictures, fitting the three-stimulus values of the gray scale binding point pictures, and obtaining three-stimulus value curves of full gray scales of the panel.

[0012] The color temperature curve of the panel gray scale picture is obtained based on the color temperature formula.

[0013] In some embodiments, the color temperature curve of the R / G / B picture is obtained by constructing a chromaticity characteristic matrix model Mn of full gray scales of the R / G / B picture, obtaining three-stimulus values of a gray scale corresponding to each chromaticity characteristic matrix, and obtaining the color temperature curve of the R / G / B picture based on the color temperature formula.

[0014] In some embodiments, the chromaticity characteristic model Mn of full gray scales of the R / G / B picture is constructed by collecting three-stimulus value data of multiple groups of R / G / B pictures, obtaining a chromaticity characteristic matrix corresponding to a gray scale, and interpolating and fitting the chromaticity characteristic matrix to obtain the chromaticity characteristic model Mn of full gray scales of the R / G / B picture.

[0015] In some embodiments, the chromaticity characteristic matrix model Mn of full gray scales of the R / G / B picture is represented as:

[0016]

[0017] wherein, are respectively three-stimulus values of the R channel fitted, are respectively three-stimulus values of the G channel fitted, are respectively three-stimulus values of the B channel fitted.

[0018] In some embodiments, the three-stimulus value of the gray scale picture corresponding to each chromaticity characteristic matrix is represented as:

[0019]

[0020]

[0021]

[0022] The color temperature curve of the R / G / B picture is obtained based on the color temperature formula.

[0023] In some embodiments, the color temperature formula is used to obtain a color temperature curve of the panel gray scale picture, wherein the color temperature formula is:

[0024]

[0025] wherein (x, y) is the chromaticity coordinate of each gray scale:

[0026] x = X / (X+Y+Z);

[0027] y = Y / (X+Y+Z);

[0028] X, Y, and Z represent tristimulus values.

[0029] In some embodiments, the color temperature is used to determine the chromaticity characteristic matrix of each gray scale picture of the panel, specifically comprising:

[0030] The color temperature corresponding to each gray scale of the panel gray scale picture is determined using the color temperature corresponding to each gray scale of the panel gray scale picture and the chromaticity characteristic matrix model Mn, and the chromaticity characteristic matrix is used as the initial chromaticity characteristic matrix of the panel corresponding to the gray scale picture.

[0031] The initial chromaticity characteristic matrix is subtracted from the pre-determined target chromaticity characteristic matrix to obtain a compensation matrix, and the initial chromaticity characteristic matrix is compensated using the compensation matrix.

[0032] In some embodiments, the color temperature corresponding to the white point on the color temperature curve of the R / G / B picture is determined, and the chromaticity characteristic matrix corresponding to the color temperature is determined using the chromaticity characteristic matrix model Mn, which is used as the target chromaticity characteristic matrix. In some embodiments, the target chromaticity characteristic matrix is pre-determined by the following steps:

[0033] The color temperature corresponding to the white point on the color temperature curve of the R / G / B picture is determined, and the chromaticity characteristic matrix corresponding to the color temperature is determined using the chromaticity characteristic matrix model Mn, which is used as the target chromaticity characteristic matrix.

[0034] In some embodiments, the present application also discloses a display panel, which uses the chromaticity compensation method of the panel color temperature matching of the present application to perform panel chromaticity Inline compensation on the production line.

[0035] The color temperature curve of the panel gray scale picture is obtained, specifically comprising: collecting tristimulus values of multiple groups of gray scale binding point pictures, interpolating and fitting the tristimulus values of the picture to obtain a tristimulus value curve of the panel full gray scale; and then using a color temperature formula to obtain a color temperature curve of the panel gray scale picture.

[0036] The color temperature curve of the panel gray scale picture is matched with the color temperature curve of the R / G / B picture, the color temperature corresponding to each gray scale color temperature of the panel gray scale picture is confirmed on the color temperature curve of the R / G / B picture, and the colorimetric characteristic matrix of each gray scale picture of the panel is confirmed based on the color temperature.

[0037] The color temperature curve of the panel gray scale picture is matched with the color temperature curve of the R / G / B picture, the color temperature corresponding to each gray scale color temperature of the panel gray scale picture is confirmed on the color temperature curve of the R / G / B picture, and the colorimetric characteristic matrix of each gray scale picture of the panel is confirmed based on the color temperature.

[0038] Beneficial effects: compared with the colorimetric compensation process in the prior art, the color temperature curve of the panel gray scale picture is matched with the color temperature curve of the R / G / B picture in the present application, the color temperature corresponding to each gray scale color temperature of the panel gray scale picture is confirmed, the colorimetric characteristic matrix of each gray scale picture of the panel is confirmed based on the color temperature, the panel gray scale picture data is fused, the colorimetric model of the panel full gray scale is more accurately established, the colorimetric compensation effect is improved, the panel colorimetric Inline compensation is helpful in the factory production line, the panel sheet difference is reduced, and the picture quality performance is improved. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0040] Figure 1 is the colorimetric compensation process diagram in the prior art;

[0041] Figure 2 is the flowchart of the colorimetric compensation method in the embodiment of the present application;

[0042] Figure 3 is the comparison diagram before and after the colorimetric compensation by using the method in the embodiment of the present application. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0044] Since the human eye is more sensitive to the color of the gray scale picture (White), the gray scale picture is usually compensated when the panel chroma compensation is performed. A chroma compensation method for a display panel according to the present application is based on the established R / G / B picture 0~255 full gray scale chroma characteristic matrix, which is matched with the gray scale picture to confirm the most accurate chroma characteristic matrix of each gray scale picture, thereby improving the accuracy of chroma compensation.

[0045] For the convenience of matching, the chroma characteristics of the R / G / B picture and the gray scale picture are described by color temperature CCT, and the matching of three values is converted into a single value, so that the chroma model matching can be performed more quickly. The gray scale picture data used is the data that needs to be collected when the production line performs Gamma compensation, and no additional data is required, so that the T / T is not increased.

[0046] Embodiment one

[0047] A chroma compensation method for a display panel according to the present application includes the following steps:

[0048] Obtain the color temperature curve of the panel gray scale picture.

[0049] Obtain the color temperature curve of the R / G / B picture.

[0050] Match the color temperature curve of the panel gray scale picture with the color temperature curve of the R / G / B picture, confirm the color temperature closest to each gray scale color temperature of the panel gray scale picture on the color temperature curve of the R / G / B picture, and confirm the chroma characteristic matrix of each gray scale picture of the panel based on the color temperature.

[0051] Embodiment two

[0052] A chroma compensation method for a display panel according to the present application includes the following steps:

[0053] Obtain the color temperature curve of the panel gray scale picture, specifically including: collecting three stimulus values of multiple groups of gray scale binding point pictures, interpolating and fitting the three stimulus values of the picture to obtain the three stimulus value curve of the full gray scale of the panel; and then obtaining the color temperature curve of the panel gray scale picture based on the color temperature formula.

[0054] Obtain the color temperature curve of the R / G / B picture, specifically including: constructing the chroma characteristic model Mn of the full gray scale of the R / G / B picture to obtain the three stimulus values of the gray scale corresponding to each chroma characteristic matrix, and then obtaining the color temperature curve of the R / G / B picture based on the color temperature formula.

[0055] In color matching, the three colors used for color mixing to produce any color are called three primary colors. In general additive color mixing, red, green, and blue three color lights are used as three primary colors to obtain the most mixed colors.

[0056] The number of primary colors required to achieve color matching with the color to be measured in a color matching experiment is referred to as tristimulus value.

[0057] The color temperature curve of the panel gray scale picture is matched with the color temperature curve of the R / G / B picture, the closest color temperature corresponding to the color temperature of each gray scale of the panel gray scale picture is confirmed on the color temperature curve of the R / G / B picture, and the chromaticity characteristic matrix of each gray scale picture of the panel is confirmed based on the color temperature.

[0058] Example Three

[0059] A chromaticity compensation method for a display panel according to the present application, as shown in the accompanying drawings, comprises the following steps: Figure 2

[0060] Step 1: The chromaticity characteristics of the gray scale picture are described by color temperature CCT, which specifically comprises the following steps.

[0061] Step 1.1: The CIE spectral tristimulus values X, Y and Z of m1 groups of gray scale binding point pictures are collected, the CIE spectral tristimulus values are used to describe the brightness and color of the panel, in this embodiment, m1 takes a value less than or equal to 255, of course, m1 can also take a value not limited to the range less than or equal to 255.

[0062] The m1 groups of tristimulus values X, Y and Z are respectively interpolated and fitted to obtain the X, Y and Z curves of the panel 0-255 full gray scale, and a chromaticity model of the panel full gray scale is established.

[0063] In this embodiment, the interpolation fitting method is selected because if the panel is directly sampled at 0-255 full gray scale, a relatively long time is required, while the interpolation fitting method takes less time and the accuracy can also meet the requirements.

[0064] Step 1.2: The color temperature curve of the panel is calculated based on the color temperature CCT formula to obtain the color temperature curve CCT_ORI of the panel gray scale picture.

[0065]

[0066] Wherein (x, y) is the chromaticity coordinate of each gray scale:

[0067] x = X / (X+Y+Z);

[0068] y = Y / (X+Y+Z);

[0069] Step 2: The chromaticity characteristics X, Y and Z of the RGB picture are described by color temperature CCT, which specifically comprises the following steps.

[0070] Step 2.1: The tristimulus values X, Y and Z data of m2 groups of R / G / B pictures are collected, m2 is less than or equal to 256, the tristimulus values of the R channel are represented as X​R , Y R , Z R , the tristimulus values of the G channel are represented as X G , Y G , Z G , the tristimulus values of the Z channel are represented as X Z , Y Z , Z Z ;

[0071] Therefore, the tristimulus values X, Y, Z of a single gray scale R / G / B channel have nine values, which form the colorimetric characteristic matrix of the gray scale. The tristimulus values X, Y, Z of the mth group of R / G / B pictures collected can be represented as Xm, Ym, Zm, wherein m = (1 ~ m2). The tristimulus values X, Y, Z of the first group of R / G / B pictures collected can be represented as X1, Y1, Z1. The colorimetric characteristic matrix is as follows.

[0072]

[0073] The tristimulus values X, Y, Z of the mth group of R / G / B pictures collected can be represented as Xm, Ym, Zm, wherein m = (1 ~ m2). The colorimetric characteristic matrix is as follows.

[0074]

[0075] The colorimetric characteristic model Mn of the panel 0 ~ 255 full gray scale is obtained by interpolating and fitting the colorimetric characteristic matrices of m2 gray scales, wherein n = (0 ~ 255).

[0076]

[0077] wherein, are the tristimulus values of the R channel fitted respectively, are the tristimulus values of the G channel fitted respectively, are the tristimulus values of the B channel fitted respectively.

[0078] The tristimulus values X, Y, Z of the gray scale pictures corresponding to the 256 colorimetric characteristic matrices can be obtained from the colorimetric characteristic model Mn. n

[0079]

[0080]

[0081]

[0082] The color temperature curve CCT_FIT of the R / G / B pictures is obtained based on the tristimulus values X, Y, Z.

[0083] ​​

[0084] wherein, is a chromaticity coordinate value;

[0085]

[0086]

[0087] Step 3, match the color temperature curve CCT_ORI of the gray scale picture with the color temperature curve CCT_FIT of the R / G / B picture, and confirm the color temperature that each gray scale needs to reach on the color temperature curve CCT_FIT of the R / G / B picture. The color temperature refers to the color temperature that is closest to the color temperature coordinate of the gray scale.

[0088] Then, based on the color temperature on the color temperature curve CCT_FIT of the R / G / B picture and in combination with the chromaticity characteristic model Mn, confirm the corresponding chromaticity characteristic matrix as the initial chromaticity characteristic matrix M of the gray scale picture corresponding panel. i , which is expressed as:

[0089]

[0090] Step 4, confirm the corresponding chromaticity characteristic matrix based on the color temperature of the white point (W255) on the color temperature curve CCT_FIT of the R / G / B picture and in combination with the chromaticity characteristic model Mn, as the target chromaticity characteristic matrix, which is expressed as:

[0091]

[0092] Step 5, based on the difference between the initial chromaticity characteristic matrix M i and the target chromaticity characteristic matrix M 255 , obtain the compensation gray scale value to compensate the initial chromaticity characteristic matrix of the gray scale picture corresponding panel.

[0093] Embodiment Four

[0094] The application also discloses a display panel, which adopts the chromaticity compensation method for panel color temperature matching of the application to perform panel chromaticity Inline compensation on a production line.

[0095] Obtain the color temperature curve of the gray scale picture of the panel, specifically including: collect three stimulus values of multiple groups of gray scale binding point pictures, perform interpolation fitting on the three stimulus values of the picture to obtain the three stimulus value curve of the full gray scale of the panel, and then obtain the color temperature curve of the gray scale picture of the panel based on the color temperature formula. In view of production efficiency and T / T (Tact Time), it is necessary to fit the color temperature curve of the gray scale picture of the panel as accurately as possible with as few gray scale binding points as possible.

[0096] Obtaining the color temperature curve of the R / G / B image specifically includes: acquiring the CIE spectral tristimulus values ​​X, Y, and Z of multiple sets of grayscale bound-point images. The CIE spectral tristimulus values ​​are used to describe the brightness and color of the panel. Interpolation fitting is performed on the tristimulus values ​​X, Y, and Z respectively to obtain the X, Y, and Z curves of the panel's full grayscale from 0 to 255, and a chromaticity model of the panel's full grayscale is established. Based on the color temperature formula, the panel's color temperature curve is calculated to obtain the color temperature curve of the panel's grayscale image. Similarly, for production efficiency and T / T (Tact Time) considerations, the color temperature curve of the panel's grayscale image needs to be fitted as accurately as possible with as few grayscale bound points as possible.

[0097] Match the color temperature curve of the grayscale image on the panel with the color temperature curve of the R / G / B image. On the color temperature curve of the R / G / B image, identify the closest color temperature corresponding to each grayscale color temperature of the panel grayscale image. Based on the color temperature, determine the chromaticity characteristic matrix of each grayscale image on the panel.

[0098] like Figure 3 As shown, a comparison diagram is presented before and after compensation using the method described in this application. Figure 3 (a) in the figure is a comparison of the chromaticity coordinates y in the full grayscale before and after compensation using the method of this application. Figure 3 Figure (b) shows a comparison of the chromaticity coordinates x in the full grayscale before and after compensation using the method of this application. It can be seen that the chromaticity curve of the panel is smoother and closer to the white point (W255). Especially in the low grayscale area, the deviation before compensation is larger, the chromaticity curve fluctuates more, and the transition at the binding point is not smooth enough, which also leads to color cast in the low grayscale after chromaticity coordinate compensation. For the chromaticity curve after compensation using the method of this application, the chromaticity curve becomes smoother in the low grayscale area.

[0099] In summary, although the embodiments of this application have been described in detail above, the above embodiments are not intended to limit this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A chromaticity compensation method for a display panel, comprising: obtaining a color temperature curve of a panel grayscale image; obtaining a color temperature curve of an R / G / B image; matching the color temperature curve of the panel grayscale image with the color temperature curve of the R / G / B image, identifying a color temperature corresponding to each grayscale color temperature of the panel grayscale image on the color temperature curve of the R / G / B image, and identifying a chromaticity characteristic matrix of each grayscale image of the panel based on the color temperature; wherein the identification of the chromaticity characteristic matrix of each grayscale image of the panel based on the color temperature comprises: identifying a chromaticity characteristic matrix corresponding to the color temperature using the color temperature corresponding to each grayscale color temperature of the panel grayscale image and a chromaticity characteristic matrix model Mn, and taking the chromaticity characteristic matrix as an initial chromaticity characteristic matrix of the panel corresponding to the grayscale image; and subtracting the initial chromaticity characteristic matrix from a target chromaticity characteristic matrix identified in advance to obtain a compensation matrix, and using the compensation matrix to compensate the initial chromaticity characteristic matrix. The obtaining of the color temperature curve of the panel grayscale image comprises: collecting three stimulus values of multiple sets of grayscale binding point images, fitting the three stimulus values of the grayscale binding point images to obtain three stimulus value curves of all grayscale images of the panel; and obtaining the color temperature curve of the panel grayscale image based on a color temperature formula. The obtaining of the color temperature curve of the R / G / B image comprises: constructing a chromaticity characteristic matrix model Mn of all grayscale images of the R / G / B image, obtaining three stimulus values of a grayscale corresponding to each chromaticity characteristic matrix, and obtaining the color temperature curve of the R / G / B image based on a color temperature formula. The construction of the chromaticity characteristic matrix model Mn of all grayscale images of the R / G / B image comprises: collecting three stimulus value data of multiple sets of R / G / B images to obtain a chromaticity characteristic matrix of a grayscale corresponding to the three stimulus values of the R / G / B image, fitting the chromaticity characteristic matrix to obtain the chromaticity characteristic matrix model Mn of all grayscale images of the R / G / B image. The chromaticity characteristic matrix model Mn of all grayscale images of the R / G / B image is represented as: The obtaining of the color temperature curve of the R / G / B image based on the color temperature formula. The color temperature formula is: wherein (x, y) is a chromaticity coordinate of each grayscale image: x = X / (X+Y+Z); y = Y / (X+Y+Z); and X, Y, and Z represent three stimulus values. 2.The method for chromaticity compensation of a display panel according to claim 1, wherein: The target chromaticity characteristic matrix is identified in advance by: identifying a color temperature corresponding to a white point on the color temperature curve of the R / G / B image, identifying a chromaticity characteristic matrix corresponding to the color temperature based on a chromaticity characteristic matrix model Mn, and taking the chromaticity characteristic matrix corresponding to the color temperature as the target chromaticity characteristic matrix. The display panel chromaticity compensation method for display panel color temperature matching according to any one of claims 1-8 is used for display panel chromaticity compensation. 3.The method for chromaticity compensation of a display panel according to claim 1, wherein: ​ 4. The method of claim 3, wherein the color compensation method for a display panel is characterized by: ​ ​ 5. The method of claim 3, wherein the color compensation method for a display panel is characterized by: ​ wherein, respectively refer to the fitted tristimulus values of the R channel, respectively refer to the fitted tristimulus values of the G channel, respectively refer to the fitted tristimulus values of the B channel.

6. The method of claim 3, wherein the color compensation method for a display panel is characterized by: The three stimulus values of the gray scale picture corresponding to each chromaticity characteristic matrix are expressed as: ​ 7. The method for chromaticity compensation of a display panel according to claim 2 or 3, wherein: ​ ​ ​ ​ ​ 8.The method for chromaticity compensation of a display panel according to claim 1, wherein: ​ ​ 9. A display panel, characterized by, ​

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