White balance adjustment method, spliced screen, storage medium and computer program product

Abstract

The present disclosure provides a white balance adjustment method, a spliced screen, a storage medium and a computer program product. The method comprises the following steps: determining a reference sub-display from each sub-display of a spliced screen, taking the display brightness of the reference sub-display when displaying a target white picture as a target display brightness, and taking the display chroma of the reference sub-display when displaying the target white picture as a target display chroma; the sub-displays other than the reference sub-display in the spliced screen are regarded as to-be-adjusted sub-displays; obtaining the brightness characteristic parameters of each to-be-adjusted sub-display, wherein the brightness characteristic parameters comprise first coefficients corresponding to each color channel of the to-be-adjusted sub-display; for any to-be-adjusted sub-display, according to the target display brightness, the target display chroma and the brightness characteristic parameters, an adjustment value meeting a first brightness condition and a first constraint condition is searched from a pre-stored lookup table as a target adjustment value; and a first adjustment layer of each to-be-adjusted sub-display is set according to the target adjustment value.

Description

Technical Field

[0001] This disclosure relates to the field of computer technology. More specifically, it relates to a white balance adjustment method, a video wall, a storage medium, and a computer program product. Background Technology

[0002] A video wall is a display device that combines multiple independent displays into a unified whole. It can achieve ultra-large display screens by seamlessly splicing multiple high-definition displays and is widely used in shopping malls, airports, entertainment and leisure venues, education, medical care, government and other scenarios.

[0003] White balance is one of the important indicators affecting the display properties of video wall displays. The relevant technology discloses a solution to add a mask layer above the UI layer of the video wall display and adjust the white balance by setting the mask layer parameters. However, this solution has problems of low efficiency and poor accuracy. Summary of the Invention

[0004] The purpose of this disclosure is to provide a white balance adjustment method, a video wall, a storage medium, and a computer program product to solve the problems of low efficiency and poor accuracy in white balance adjustment of video walls in related technologies.

[0005] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0006] The first aspect of this disclosure provides a white balance adjustment method applicable to video wall displays, wherein the video wall displays include at least two sub-displays, each of the sub-displays is provided with a first adjustment layer, the first adjustment layer having color channels that correspond one-to-one with each color channel of the sub-display; the white balance adjustment method includes the following steps:

[0007] A reference sub-display screen is determined from each sub-display screen of the splicing screen. The display brightness of the reference sub-display screen when displaying the target white image is taken as the target display brightness, and the display chromaticity of the reference sub-display screen when displaying the target white image is taken as the target display chromaticity. The sub-display screens other than the reference sub-display screen in the splicing screen are the sub-display screens to be adjusted.

[0008] Obtain the brightness characteristic parameters of each sub-display screen to be adjusted. The brightness characteristic parameters include the first coefficient corresponding to each color channel of the sub-display screen to be adjusted. The first coefficient is used to represent the influence weight of the brightness of the corresponding color channel on the display brightness of the sub-display screen to be adjusted.

[0009] For any sub-display screen to be adjusted, an adjustment value that satisfies the first brightness condition and the first constraint condition is searched from a pre-stored lookup table based on the target display brightness, target display chromaticity, and brightness characteristic parameters as the target adjustment value. The lookup table includes luminance and chromaticity data, which includes the luminance and chromaticity of each color channel of the sub-display screen to be adjusted when the target monochrome image is displayed and the first adjustment layer is set to different adjustment values. The target monochrome image is the sub-image of the target white image on the corresponding color channel. The first brightness condition includes that when the first adjustment layer is set to the target adjustment value, the weighted sum of the luminance of each color channel of the sub-display screen to be adjusted and the first coefficient is equal to the target display brightness. The first constraint condition includes that the chromaticity offset between the display chromaticity corresponding to the target adjustment value and the target display chromaticity is less than the first chromaticity offset threshold.

[0010] The first adjustment layer of each sub-display screen to be adjusted is set according to the target adjustment value.

[0011] Optionally, the step of determining the reference sub-display screen from each sub-display screen of the splicing screen includes:

[0012] Obtain the display brightness of each sub-display screen when the splicing screen displays the target white image;

[0013] The sub-display with the lowest brightness will be identified as the reference sub-display.

[0014] Optionally, the first adjustment layer includes multiple transparency levels, and the lookup table includes multiple sets of brightness and chromaticity data, with each set of brightness and chromaticity data corresponding to a transparency level;

[0015] Based on the target display brightness, target display chromaticity, and brightness characteristic parameters, the adjustment value that satisfies the first brightness condition and the first constraint condition is searched from a pre-stored lookup table as the target adjustment value. Specifically, this includes:

[0016] Based on the target display brightness, target display chromaticity, and brightness characteristic parameters, the transparency and adjustment values ​​of each color channel that satisfy the first brightness condition and the first constraint condition are searched from the multiple sets of brightness and chromaticity data as the target transparency and target adjustment values;

[0017] The step of setting the first adjustment layer of each sub-display screen to be adjusted according to the target adjustment value specifically includes: setting the first adjustment layer of each sub-display screen to be adjusted according to the target adjustment value and the target transparency.

[0018] Optionally, the step of obtaining the brightness characteristic parameters of each sub-display to be adjusted may include:

[0019] For any sub-display to be adjusted, measure the transparency of the first adjustment layer corresponding to the sub-display to be adjusted to a first value, and the display brightness and the brightness of each color channel when the sub-display to be adjusted displays multiple reference grayscale white images;

[0020] The first coefficient corresponding to each color channel is calculated based on the measured multiple sets of display brightness and individual brightness. The weighted sum of the first coefficient and the individual brightness of the corresponding color channel is the display brightness.

[0021] Optionally, the plurality of reference grayscale white images include at least a low grayscale white image, a medium grayscale white image, and a high grayscale white image.

[0022] Optionally, for any sub-display screen to be adjusted, the measurement method for any set of luminance and chromaticity data includes:

[0023] Set the transparency of the first adjustment layer corresponding to the sub-display to be adjusted to a first transparency, where the first transparency is one of the plurality of transparencyes;

[0024] For any color channel, the adjustment value of that color channel in the first adjustment layer is set to one of the preset adjustment value ranges in sequence. The sub-display to be adjusted is controlled to display the target monochrome image of that color channel, and the current display brightness and display chromaticity of the sub-display to be adjusted are measured. The display brightness is taken as the sub-brightness corresponding to that color channel, and the display chromaticity is taken as the display chromaticity corresponding to that color channel. The sub-brightness and display chromaticity corresponding to each color channel constitute a set of brightness and chromaticity data.

[0025] Optionally, the first adjustment layer corresponds to a first transparency range, and the plurality of transparency layers are arranged at equal intervals within the first transparency range.

[0026] Optionally, the first constraint further includes:

[0027] The sum of the target adjustment values ​​corresponding to each color channel in the first adjustment layer is minimized; and / or

[0028] In the first adjustment layer, the first color channel has the highest brightness among the target adjustment values ​​corresponding to each color channel, and the first color channel is the color channel with the largest first coefficient.

[0029] Optionally, the color channels of the first adjustment layer include a red color channel, a green color channel, and a blue color channel, wherein the first color channel is the green color channel; the first constraint condition further includes:

[0030] In the first adjustment layer, the brightness of the target adjustment value corresponding to the red and blue color channels is not 0.

[0031] A second aspect of this disclosure provides a video wall, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the white balance adjustment method described above.

[0032] A third aspect of this disclosure provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the white balance adjustment method as described above.

[0033] The fourth aspect of this disclosure provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the white balance adjustment method as described above.

[0034] The beneficial effects of this disclosure are as follows:

[0035] The white balance adjustment method of this disclosure determines a reference sub-display and a sub-display to be adjusted from the sub-displays of the splicing screen by pre-measuring the brightness characteristic parameters of each sub-display and using a lookup table of the first adjustment layer under different parameter values. The display brightness of the reference sub-display is used as the target display brightness, and the display chromaticity is used as the target display chromaticity. When adjusting the white balance, for each sub-display to be adjusted, the target display brightness, target display chromaticity, and brightness characteristic parameters are directly used to find the adjustment value that satisfies the first brightness condition and the first constraint condition from the pre-stored lookup table as the target adjustment value. Compared with manual adjustment, this setting can improve the adjustment efficiency of the target adjustment value, save time, and find the target adjustment value with high accuracy. It can make the brightness and chromaticity of each sub-display in the splicing screen highly consistent and have a better white balance effect. Attached Figure Description

[0036] The specific embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of the splicing screen provided in the embodiments of this disclosure;

[0038] Figure 2 A schematic diagram of the mask parameter setting interface provided in an embodiment of this disclosure;

[0039] Figure 3 A flowchart of a white balance adjustment method provided in an embodiment of this disclosure. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0041] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0042] In related technologies, when adding a mask layer above the UI layer and adjusting the white balance of the splicing screen by adjusting the mask layer parameters, repeated adjustments are required due to the large differences between the various sub-displays in the splicing screen, which is very time-consuming and has poor accuracy.

[0043] To address the aforementioned technical problems, this disclosure provides a white balance adjustment method applicable to video wall displays. Please refer to the following embodiments first. Figure 1 , Figure 1 This is a schematic diagram of the structure of the splicing screen provided in the embodiments of this disclosure, such as... Figure 1 As shown, the video wall includes at least two sub-display screens (such as...). Figure 1 In the diagram, A11, A12, A21, and A22 each represent a sub-display screen. Each sub-display screen is provided with a first adjustment layer, which is used to adjust the brightness, color, and other characteristics of the sub-display screen. By setting different parameter values ​​for the first adjustment layer of each sub-display screen, the brightness and color of the entire splicing screen can be adjusted, so that the white balance of the entire splicing screen is as uniform as possible, so that the splicing screen as a whole can obtain a better display effect.

[0044] In one implementation, the first adjustment layer is a mask layer, which is overlaid on the UI layer via a floating window. This mask layer has the same color channels as the sub-display. The mask layer adjusts the brightness, chroma, and other characteristics of the sub-display. This can be understood as adjusting the pixel values ​​of different color channels of the white screen. For example, for a sub-display with RGB color channels, the mask layer adjusts the white balance of that sub-display. Specifically, the adjustment values ​​of the mask layer's R, G, and B color channels are used to adjust the R, G, and B values ​​of the white screen displayed on the sub-display. Essentially, an adjustment screen composed of adjustment values ​​is overlaid on the white screen; this adjustment screen is the mask layer. For example, as shown... Figure 1 As shown, for sub-display A22, assuming the RGB values ​​of the white screen are (R1, G1, B1) and the adjustment value on the mask is (R2, G2, B2), the white screen after white balance adjustment can be understood as the effect of (R1, G1, B1) and (R2, G2, B2) superimposed. Furthermore, the mask settings also include transparency, which indicates the degree of mask layering. When the mask transparency is 0, it's equivalent to the mask not being active, meaning no mask is superimposed on the UI layer of the sub-display. The higher the mask transparency, the greater the impact of the mask on the sub-display, and the lower the brightness of the sub-display. For example... Figure 2 As shown, when adjusting the white balance, you need to set parameters such as the mask transparency, R gain, G gain, and B gain in the mask parameter settings interface. R gain is the adjustment value of the R color channel, G gain is the adjustment value of the G color channel, and B gain is the adjustment value of the B color channel.

[0045] The following is combined with Figure 3 This invention discloses a white balance adjustment method provided in embodiments thereof, such as... Figure 3 As shown, the white balance adjustment method includes the following steps:

[0046] Step S101: Determine a reference sub-display screen from each sub-display screen of the splicing screen, take the display brightness of the reference sub-display screen when displaying the target white image as the target display brightness, take the display chromaticity of the reference sub-display screen when displaying the target white image as the target display chromaticity, and take the sub-display screens other than the reference sub-display screen in the splicing screen as the sub-display screens to be adjusted.

[0047] In one possible implementation, the step of determining the reference sub-display screen from each sub-display screen of the splicing screen includes: (1) obtaining the display brightness of each sub-display screen when the splicing screen displays the target white image; and (2) determining the sub-display screen with the lowest display brightness as the reference sub-display screen.

[0048] In this embodiment, the splicing screen is first controlled to display the target white image, that is, each sub-display screen displays the target white image. Then, the display brightness of each sub-display screen is measured by a measuring instrument, and the sub-display screen with the lowest display brightness is determined as the reference sub-display screen. The remaining sub-display screens are determined as sub-display screens to be adjusted. For example, for... Figure 1 In the splicing screen shown, when all sub-displays display the target white image, sub-display A22 has the lowest display brightness. Therefore, sub-display A22 can be set as the reference sub-display, and the remaining sub-displays A11, A12, and A21 are identified as sub-displays to be adjusted. During white balance adjustment, the display brightness of the reference sub-display is used as the target display brightness, and the display chromaticity of the reference sub-display is used as the target display chromaticity. By setting the parameters of the first adjustment layer in the sub-displays to be adjusted, the display brightness of each sub-display to be adjusted is adjusted to the target display brightness, and the offset between the display chromaticity of each sub-display to be adjusted and the target display chromaticity is kept within a certain range.

[0049] The target display chromaticity includes the display chromaticity of each color channel when the reference sub-display displays the target white image. For example, for an RGB display, the target display chromaticity includes the display chromaticity of the R, G, and B color channels when the reference sub-display displays the target white image. The display chromaticity includes two parameters: chromaticity x and chromaticity y, which represent the hue and chromaticity (or saturation) of the color, respectively. In specific measurements, for the R color channel, the reference sub-display can be controlled to display a red image (255,0,0), and then the current display chromaticity is measured as the chromaticity x(r) and y(r) of the R color channel. Similarly, for the G color channel, the reference sub-display can be controlled to display a green image (0,255,0), and then the current display chromaticity is measured as the chromaticity x(g) and y(g) of the G color channel. For the B color channel, the reference sub-display can be controlled to display a blue image (0,0,255), and then the current display chromaticity is measured as the chromaticity x(b) and y(b) of the B color channel. The x(r), y(r), x(g), y(g), x(b), and y(b) obtained through the above steps are used as the target display chromaticity. In this embodiment, the target white image is formed by superimposing the monochrome images (i.e., the target monochrome images) of each color channel. The display chromaticity of each color channel when the reference sub-display displays the target white image specifically refers to the display chromaticity of each color channel of the reference sub-display when displaying the corresponding monochrome image.

[0050] Optionally, the target white image is a white image with a grayscale value of 255, meaning the RGB value of the target white image is (255, 255, 255). In digital image processing, grayscale 255 represents the maximum grayscale level of brightness. At this grayscale, because the image brightness is at its highest, any slight color deviation may become noticeable. Therefore, adjusting the white balance at this grayscale ensures the white balance effect at other grayscale levels. Furthermore, when the target white image is a grayscale 255 image, since the display brightness of each sub-display is at its maximum and cannot be increased further, when adjusting the white balance of the entire splicing screen, the sub-display with the lowest display brightness needs to be set as the reference sub-display. Then, the display brightness of other sub-displays is adjusted to approach this lowest display brightness. If a larger display brightness is set as the target display brightness, the sub-display with the lowest display brightness will not be able to reach the target display brightness, resulting in poor adjustment effects.

[0051] Step S102: Obtain the brightness characteristic parameters of each sub-display screen to be adjusted. The brightness characteristic parameters include the first coefficient corresponding to each color channel of the sub-display screen to be adjusted. The first coefficient is used to represent the influence weight of the brightness of the corresponding color channel on the display brightness of the sub-display screen to be adjusted.

[0052] In this embodiment of the disclosure, each sub-display screen to be adjusted has a corresponding brightness characteristic parameter, which can be obtained by pre-measurement.

[0053] For any sub-display, taking an RGB display as an example, the relationship between its display brightness Y and the brightness of each color channel can be expressed as: Y = a * Y r +b*Y g +c*Y b , where Y r Y g Y b These represent the display brightness of the R, G, and B color channels, i.e., the individual brightness values, with a, b, and c being the first coefficients. For different sub-displays, the values ​​of a, b, and c will differ to some extent. In this embodiment, the a, b, and c values ​​of each sub-display are pre-measured and stored as brightness characteristic parameters.

[0054] Step S103: For any sub-display screen to be adjusted, an adjustment value that satisfies the first brightness condition and the first constraint condition is searched from a pre-stored lookup table according to the target display brightness, target display chromaticity, and brightness characteristic parameters as the target adjustment value. The lookup table includes luminance and chromaticity data, which includes the luminance and chromaticity of each color channel of the sub-display screen to be adjusted when the target monochrome image is displayed and the first adjustment layer is set to different adjustment values. The target monochrome image is the sub-image of the target white image on the corresponding color channel. The first brightness condition includes that when the first adjustment layer is set to the target adjustment value, the weighted sum of the luminance of each color channel of the sub-display screen to be adjusted and the first coefficient is equal to the target display brightness. The first constraint condition includes that the chromaticity offset between the display chromaticity corresponding to the target adjustment value and the target display chromaticity is less than the first chromaticity offset threshold.

[0055] In this embodiment of the disclosure, for any sub-display screen to be adjusted, a lookup table (i.e., LUT table) is pre-measured, and subsequently, the lookup table is used to automatically find the adjustment value that meets the conditions as the target adjustment value. Optionally, the first adjustment layer includes multiple transparency values, and the lookup table includes multiple sets of luminance and chrominance data. Each set of luminance and chrominance data corresponds to a transparency value, and each set of luminance and chrominance data includes the luminance and chrominance of each color channel of the sub-display screen to be adjusted when displaying a target monochrome image and the first adjustment layer is set to different adjustment values. Here, different adjustment values ​​for the first adjustment layer mean that the R gain, B gain, and G gain in the first adjustment layer are different adjustment values. For example, for the R color channel, the luminance and chrominance data includes the luminance Y of the sub-display screen to be adjusted when displaying an R monochrome image and the R gain (i.e., R-adjustment value) in the first adjustment layer is set to different adjustment values ​​(e.g., 0-255). r And display chromaticity; similarly, for the G color channel, luminance and chromaticity data include the luminance Y of the sub-display to be adjusted when the sub-display to be adjusted displays a G monochrome image and the G gain (i.e., the G-adjustment value) in the first adjustment layer is set to different adjustment values ​​(e.g., 0-255). g And display chromaticity; for the B color channel, luminance and chromaticity data include the luminance Y of the sub-display to be adjusted when the sub-display to be adjusted displays a B monochrome image and the B gain (i.e., the B-adjustment value) in the first adjustment layer is set to different adjustment values ​​(e.g., 0-255). b And the displayed color gradation. Please refer to Table 1, which is the lookup table for transparency T1.

[0056] Table 1 - Lookup table for Transparency TI

[0057]

[0058] As shown in Table 1, the range of adjustment values ​​for each color channel of the first adjustment layer in the lookup table is [0, 255]. For transparency T1, the corresponding luminance and chrominance data includes a total of 256*3=768 records. Each record includes at least the transparency T1 of the first adjustment layer, the adjustment value of the R color channel, the adjustment value of the G color channel, the adjustment value of the B color channel, luminance Y, chrominance x, and chrominance y.

[0059] In this context, luminance Y represents the spectral tristimulus values ​​X, Y, and Z. Specifically, the spectral tristimulus values ​​are based on the theory of three primary colors and are used to quantify the three basic stimuli of color. In the CIEXYZ color space, the Y value represents the stimulus amount of the green primary color, which, together with the stimulus amounts of the red primary color X and the blue primary color Z, constitutes the tristimulus values ​​of the color. However, since the Y value is related to the spectral luminous efficiency function V(λ) of human photopic vision, it can intuitively represent the luminance characteristics of the color. Therefore, the Y value can represent not only the quantity of the green primary color but also the luminance. In practice, the spectral tristimulus values ​​of the sub-display can be measured using a colorimeter (or color difference meter).

[0060] Chromaticity x and chromaticity y represent the hue and chromaticity (or saturation) of a color, respectively. x and y can be obtained by normalizing the three stimulus values ​​X, Y, and Z. Specifically, chromaticity x can be expressed as: x = X / (X + Y + Z), and chromaticity y can be expressed as: y = Y / (X + Y + Z).

[0061] In Table 1, for the R color channel, the sub-display to be adjusted displays an R monochrome image, i.e., a (255,0,0) monochrome image. During the process of the adjustment value of the R color channel in the first adjustment layer changing from 0 to 255, since the values ​​of the G and B color channels are both 0, the brightness Y measured at this time can also represent the brightness Y of the R color channel. r At this point, the measured chromaticity x and chromaticity y can also represent the display chromaticity of the R color channel; similarly, for the G color channel, the sub-display to be adjusted displays a G monochrome image, that is, a (0,255,0) monochrome image. During the process of the adjustment value of the G color channel in the first adjustment layer changing from 0 to 255, since the values ​​of the R color channel and the B color channel are both 0, the measured brightness Y can also represent the luminance Y of the G color channel. g At this point, the measured chromaticity x and chromaticity y can also represent the display chromaticity of the G color channel. For the B color channel, the sub-display to be adjusted displays a B monochrome image, that is, a (0,0,255) monochrome image. During the process of the adjustment value of the B color channel changing from 0 to 255, since the values ​​of the R and G color channels are both 0, the measured luminance Y can also represent the luminance Y of the B color channel. bAt this point, the measured chromaticity x and chromaticity y can also represent the display chromaticity of the B color channel.

[0062] In this embodiment of the disclosure, the first brightness condition includes the weighted sum of the brightness of each color channel of the sub-display to be adjusted and the first coefficient when the first adjustment layer is set to the target adjustment value, which equals the target display brightness. That is, the target adjustment value found in the lookup table satisfies the following: when the R gain, B gain, and G gain in the first adjustment layer are set to the target adjustment value, the weighted sum of the brightness of the R, G, and B color channels when the sub-display to be adjusted displays the target white image equals the target display brightness. This can be expressed by the formula: Y = a * Y r +b*Y g +c*Y b For any sub-display screen to be adjusted, the known variables in this formula are a, b, c, and Y, where Y is the target display brightness determined in step S101. Then, the formula is searched for a Y value that satisfies the given formula. r Y g Y b Typically, multiple sets of Y can be obtained. r Y g Y b Each group of Y r Y g Y b The adjustment values ​​for each color channel in the first adjustment layer correspond to a set of adjustment values, which means that multiple sets of adjustment values ​​for each color channel can be obtained. Therefore, the search results are further constrained by the first constraint condition.

[0063] Optionally, the first constraint condition includes a chromaticity constraint condition, that is, the chromaticity offset between the display chromaticity corresponding to the target adjustment value and the target display chromaticity is less than a first chromaticity offset threshold. In other words, for each color channel, under each color channel, the chromaticity offset between the display chromaticity corresponding to the target adjustment value and the target display chromaticity of that color channel is less than the first chromaticity offset threshold.

[0064] Assuming the target display chromaticity is represented as x(r), y(r), x(g), y(g), x(b), y(b), for any set of adjustment values ​​found, the corresponding display chromaticity is represented as x1(r), y1(r), x1(g), y1(g), x1(b), y1(b). Then, the following conditions must be met: the absolute value of the difference between x(r) and x1(r) is less than Δx, and the absolute value of the difference between y(r) and y1(r) is less than Δy; and the absolute value of the difference between x(g) and x1(g) is less than Δx, and the absolute value of the difference between y(g) and y1(r) is less than Δy. The absolute value of the difference between 1(g) and x1(b) is less than Δy; and the absolute value of the difference between x(b) and x1(b) is less than Δx, and the absolute value of the difference between y(b) and y1(b) is less than Δy. Here, Δx and Δy are the first chromaticity offset thresholds. For example, the value of the first chromaticity offset threshold is 0.003, that is, the chromaticity offset is within ±0.003 when adjusting the white balance. This can ensure that the difference between the chromaticity of each sub-display after adjustment and the target chromaticity is within a certain range, so that the chromaticity of each sub-display after adjustment is relatively consistent.

[0065] Step S104: Set the first adjustment layer of each sub-display screen to be adjusted according to the target adjustment value. This process of setting the first adjustment layer of each sub-display screen is the process of adjusting the white balance of the splicing screen. For example, for sub-display screen A11, the adjustment values ​​for the R, G, and B color channels found in the LUT table are R11, G11, and B11, respectively. Then, the R gain, G gain, and B gain in the first adjustment layer of sub-display screen A11 are set to R11, G11, and B11, respectively. Similarly, other sub-display screens are set. The resulting splicing screen achieves highly consistent display brightness and color, with good white balance. Furthermore, after finding the target adjustment value for each sub-display screen, these values ​​can be stored in the splicing screen's SoC module. This data can then be directly used to set the first adjustment layer of each sub-display screen.

[0066] Compared with related technologies, the white balance adjustment method of this disclosure determines the reference sub-display and the sub-display to be adjusted from the sub-displays of the splicing screen by pre-measuring the brightness characteristic parameters of each sub-display and the lookup table of the first adjustment layer under different parameter values. The display brightness of the reference sub-display is used as the target display brightness and the display chromaticity is used as the target display chromaticity. Then, when adjusting the white balance, for each sub-display to be adjusted, the target display brightness, target display chromaticity and brightness characteristic parameters are directly used to find the adjustment value that meets the first brightness condition and the first constraint condition from the pre-stored lookup table as the target adjustment value. Compared with manual adjustment, this setting can improve the adjustment efficiency of the target adjustment value, save time, and find the target adjustment value with high accuracy. It can make the brightness and chromaticity of each sub-display in the splicing screen highly consistent and have a better white balance effect.

[0067] In one possible implementation, the transparency of the mask layer ranges from 0 to 128. When the transparency of the mask layer is greater than 0, the mask layer is active, and the R gain, G gain, and B gain in the mask layer take effect. However, the transparency of the mask layer affects the display brightness of the sub-display screen. Specifically, the display brightness of the sub-display screen decreases as the transparency of the mask layer increases. For example, when the transparency of the mask layer reaches its maximum value of 128, the display brightness of the sub-display screen decreases to 50% of its original value. Therefore, considering the impact of transparency on brightness, when adjusting the white balance of the splicing screen in this embodiment, a transparency range (denoted as the first transparency range) needs to be set, and the transparency of the first adjustment layer needs to be selected within this range.

[0068] Optionally, the first transparency range is [0, 30]. If 128 is taken as the maximum transparency, then the first transparency range expressed as a percentage is 0-23%. Correspondingly, the pre-measured lookup table also needs to include luminance data under different transparency levels, as shown in Table 1. Table 1 only illustrates the format of luminance data corresponding to any transparency T1, while the luminance data for other transparency levels is the same as in Table 1.

[0069] To simplify the measurement process, in one possible implementation, multiple transparency values ​​are uniformly selected from a first transparency range as typical values, and then the luminance and chrominance data corresponding to the typical values ​​are measured. That is, multiple transparency values ​​are arranged at equal intervals within the first transparency range. For example, with an interval of 3, 10 transparency values ​​are selected from the first transparency range [0, 30] for measurement, resulting in 10 sets of luminance and chrominance data. For instance, transparency values ​​1, 4, 7, 10, 13, 16, 19, 21, 24, and 27 are selected as typical values, and the luminance and chrominance data corresponding to these 10 transparency values ​​are measured, as shown in Table 1. In this case, for each transparency value, the luminance and chrominance data includes 256 * 3 = 768 data points. It is understood that the transparency interval can also be other values. A smaller interval results in higher precision but also a larger data volume. Therefore, the transparency interval can be reasonably set according to data volume limitations and precision requirements. For example, the transparency interval can be 3, 4, or 5.

[0070] Correspondingly, step S103 involves searching for target adjustment values ​​for each color channel that satisfy the first brightness condition and the first constraint condition from a pre-stored lookup table based on the target display brightness, target display chromaticity, and brightness characteristic parameters. This includes searching for the transparency and adjustment values ​​for each color channel that satisfy the first brightness condition and the first constraint condition from the multiple sets of luminance and chromaticity data based on the target display brightness, target display chromaticity, and brightness characteristic parameters as the target transparency and target adjustment values.

[0071] Correspondingly, adjusting the white balance of the splicing screen according to the target adjustment value specifically involves adjusting the white balance of the splicing screen according to the target adjustment value and the target transparency, that is, setting the R gain, G gain, and B gain of the first adjustment layer to the target adjustment value, and setting the transparency of the first adjustment layer to the target transparency.

[0072] In one possible implementation, the method for measuring any set of luminance and chromaticity data for any sub-display to be adjusted includes:

[0073] Step S201: Set the transparency of the first adjustment layer corresponding to the sub-display to be adjusted to a first transparency, where the first transparency is one of the plurality of transparencyes.

[0074] Step S202: For any color channel, sequentially set the adjustment value of that color channel in the first adjustment layer to one of the preset adjustment value ranges. Control the sub-display to be adjusted to display the target monochrome image of that color channel and measure the current display brightness and display chromaticity of the sub-display to be adjusted. Use the display brightness as the luminance of the color channel and the display chromaticity as the chromaticity of the color channel. The luminance and chromaticity of each color channel constitute a set of luminance and chromaticity data. The preset adjustment value range is the range of adjustment values. For example, for an 8-bit image, the adjustment value range is [0, 255].

[0075] The measurement of luminance and chromaticity data for any transparency can be achieved through the above steps S201 and S202. For example, taking transparency T1 as an example, the process of measuring the luminance and chromaticity data corresponding to transparency T1 may include the following steps (1) to (4).

[0076] (1) Set the transparency of the first adjustment layer to T1.

[0077] (2) For the R color channel, the adjustment value of the R color channel in the first adjustment layer is set to one of 0-255 in sequence, and the adjustment values ​​of the G color channel and B color channel in the first adjustment layer are set to 0. The sub-display to be adjusted is controlled to display the target monochrome image (i.e. R monochrome image) corresponding to the R color channel and the display brightness and display chromaticity of the sub-display to be adjusted are measured. A total of 256 records are obtained. The measured display brightness and display chromaticity can also be understood as the brightness and display chromaticity of the R color channel. The R monochrome image is the sub-image (255,0,0) of the target white image (255,255,255) on the R color channel.

[0078] (3) For the G color channel, the adjustment value of the G color channel in the first adjustment layer is set to one of 0-255 in sequence, and the adjustment values ​​of the R color channel and B color channel in the first adjustment layer are set to 0. The sub-display to be adjusted is controlled to display the target monochrome image corresponding to the G color channel (i.e., the G monochrome image), and the display brightness and display chromaticity of the sub-display to be adjusted are measured. A total of 256 records are obtained. The measured display brightness and display chromaticity can also be understood as the brightness and display chromaticity of the G color channel. Among them, the G monochrome image is the sub-image (0,255,0) of the target white image (255,255,255) on the G color channel.

[0079] (4) For the B color channel, the adjustment value of the B color channel in the first adjustment layer is set to one of 0-255 in sequence. The adjustment values ​​of the R color channel and G color channel in the first adjustment layer are set to 0. The sub-display to be adjusted is controlled to display the target monochrome image corresponding to the B color channel (i.e., the B monochrome image), and the display brightness and display chromaticity of the sub-display to be adjusted are measured. A total of 256 records are obtained. The measured display brightness and display chromaticity can also be understood as the brightness and display chromaticity of the B color channel. Among them, the B monochrome image is the sub-image (0,0,255) of the target white image (255,255,255) on the B color channel.

[0080] In one possible implementation, the step of obtaining the brightness characteristic parameters of each sub-display to be adjusted further includes: measuring the brightness characteristic parameters corresponding to each sub-display to be adjusted.

[0081] For any sub-display screen to be adjusted, the measurement process of the brightness characteristic parameters includes:

[0082] (1) Measure the display brightness and the brightness of each color channel when the transparency of the first adjustment layer corresponding to the sub-display to be adjusted is a first value and the sub-display to be adjusted displays multiple reference grayscale white images. That is, measure the display brightness and the brightness of each color channel of the sub-display to be adjusted under multiple specific display scenarios. The specific display scenario is when the transparency of the first adjustment layer corresponding to the sub-display to be adjusted is a first value and the sub-display to be adjusted displays a reference grayscale white image.

[0083] Optionally, the multiple reference grayscale white images include at least a low grayscale white image, a medium grayscale white image, and a high grayscale white image.

[0084] When the first value is 0, the transparency of the first adjustment layer is set to 0, indicating that the first adjustment layer is not in effect. In this case, the measured display brightness and individual brightness are not affected by the first adjustment layer, and the measurement results can be used to calculate the brightness characteristics of the sub-display. If the transparency of the first adjustment layer is not 0, the measured display brightness and individual brightness are not only related to the sub-display itself but also affected by the first adjustment layer, resulting in significant deviations in the measurement results.

[0085] For example, for an 8-bit white screen, its grayscale range is [0, 255]. In this case, grayscale levels 64, 128, and 192 can be selected as representatives of low, medium, and high grayscale levels, respectively. The RGB values ​​of the low grayscale white screen are (64, 64, 64), the RGB values ​​of the medium grayscale white screen are (128, 128, 128), and the RGB values ​​of the high grayscale white screen are (192, 192, 192). For a 10-bit white screen, its grayscale range is [0, 1023]. In this case, grayscale levels 256, 512, and 768 can be selected as representatives of low, medium, and high grayscale levels, respectively. The RGB values ​​of the low grayscale white screen are (256, 256, 256), the RGB values ​​of the medium grayscale white screen are (512, 512, 512), and the RGB values ​​of the high grayscale white screen are (768, 768, 768). In this implementation, taking an 8-bit white screen as an example, during the measurement of brightness characteristic parameters, it is necessary to measure the display brightness and the individual brightness of each color channel when the sub-display to be adjusted displays the reference grayscale white screen (64,64,64), (128,128,128), and (192,192,192). The measurement data are shown in Table 2, where Y w1、 Y w2、 Y w3 These represent the display brightness of the sub-display screen to be adjusted when displaying low grayscale white images, medium grayscale white images, and high grayscale white images, respectively. r1 Y r2 Y r3 These represent the luminance of the R color channel when the sub-display to be adjusted displays a low grayscale white image, a medium grayscale white image, and a high grayscale white image, respectively. g1 Y g2 Y g3 These represent the brightness of the G color channel when the sub-display to be adjusted displays a low grayscale white image, a medium grayscale white image, and a high grayscale white image, respectively. b1 Y b2 Y b3 These represent the luminance of the B color channel when the sub-display to be adjusted displays a low-grayscale white image, a medium-grayscale white image, and a high-grayscale white image, respectively. For example, for any one of these luminance values ​​Y... r1 The measurement process is as follows: Control the sub-display screen to be adjusted to display a low grayscale monochrome image, for example (64,0,0), and measure the display brightness of the sub-display screen to be adjusted at this time as the luminance Y of the R color channel. r1 Similarly, the brightness of other gray levels and other color channels in Table 2 can be measured.

[0086] Table 2 Measurement Data

[0087] Baseline grayscale white image Y <![CDATA[Y r ]]> <![CDATA[Y g ]]> <![CDATA[Y b ]]> (64,64,64) <![CDATA[Y w1 ]]> <![CDATA[Y r1 ]]> <![CDATA[Y g1 ]]> <![CDATA[Y b1 ]]> (128,128,128) <![CDATA[Y w2 ]]> <![CDATA[Y r2 ]]> <![CDATA[Y g2 ]]> <![CDATA[Y b2 ]]> (192,192,192) <![CDATA[Y w3 ]]> <![CDATA[Y r3 ]]> <![CDATA[Y g3 ]]> <![CDATA[Y b3 ]]>

[0088] (2) The first coefficient corresponding to each color channel is obtained by fitting multiple sets of display brightness and sub-brightness obtained by measurement, and the weighted sum of the first coefficient and the sub-brightness of the corresponding color channel is the display brightness.

[0089] Specifically, using the three sets of data obtained from Table 2, according to the formula Y = a * Y r +b*Y g +c*Y b Establish a system of equations, as follows:

[0090] Y w1 =a*Y r1 +b*Y g1 +c*Y b1 ;

[0091] Y w2 =a*Y r2 +b*Y g2 +c*Y b2 ;

[0092] Y w3 =a*Y r3 +b*Y g3 +c*Y b3 .

[0093] Solving the above system of equations yields the values ​​of a, b, and c. Specifically, the values ​​of a, b, and c can be represented by matrices as follows:

[0094]

[0095] Because different sub-displays have certain differences, the brightness characteristic parameters calculated for different sub-displays may be different.

[0096] In one possible implementation, the first constraint further includes:

[0097] (1) The sum of the target adjustment values ​​corresponding to each color channel in the first adjustment layer is the smallest; and / or

[0098] (2) Among the target adjustment values ​​of each color channel in the first adjustment layer, the first color channel has the largest brightness and is the color channel with the largest first coefficient.

[0099] Optionally, the color channels of the first adjustment layer include a red color channel (R channel), a green color channel (G channel), and a blue color channel (B channel), with the first color channel being the green color channel. In an RGB display panel, the luminance Y of the green color channel... gThe white light component accounts for the largest proportion of the overall display brightness (i.e., white brightness), approximately 60%. Therefore, given the existence of multiple adjustment values ​​that meet the first brightness condition, the individual brightness value Y is selected first. g The largest set of adjustment values ​​ensures the maximum brightness of the adjusted display.

[0100] In this embodiment of the disclosure, the first constraint condition includes not only the chromaticity constraint condition (i.e., the chromaticity offset between the display chromaticity corresponding to the target adjustment value and the target display chromaticity is less than the first chromaticity offset threshold), but also the constraint conditions shown in (1) and (2) above. Wherein, the sum of the target adjustment values ​​corresponding to each color channel in the first adjustment layer is the smallest, that is, the sum of R gain, G gain, and B gain in the first adjustment layer is the smallest, which corresponds to the case of the smallest adjustment amount during white balance adjustment, i.e., white balance is achieved through minimal adjustment.

[0101] In addition, the first constraint may also include: the luminance of the target adjustment value corresponding to the red and blue color channels in the first adjustment layer is not 0.

[0102] Based on the same inventive concept, a second aspect of this disclosure provides a video wall, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the white balance adjustment method as described above.

[0103] Based on the same inventive concept, a third aspect of this disclosure provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the white balance adjustment method as described above.

[0104] In specific implementation, computer storage media can include: Universal Serial Bus Flash Drive (USB), portable hard drive, Read-Only Memory (ROM), Random Access Memory (RAM), magnetic disk or optical disk, and other storage media that can store program code.

[0105] Based on the same inventive concept, the fourth aspect of this disclosure provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the white balance adjustment method as described above. Since the principle by which the computer program solves the problem is similar to the principle of the white balance adjustment method, the implementation of the computer program can be referred to the implementation of the white balance adjustment method, and repeated details will not be elaborated further.

[0106] Computer program products may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0107] Obviously, the above embodiments of this disclosure are merely examples for clearly illustrating this disclosure, and are not intended to limit the implementation of this disclosure. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. Any obvious variations or modifications derived from the technical solutions of this disclosure are still within the protection scope of this disclosure.

Claims

1. A white balance adjustment method, characterized in that, The white balance adjustment method is applicable to video wall displays, which include at least two sub-displays, each of which has a first adjustment layer. The white balance adjustment method includes the following steps: A reference sub-display screen is determined from each sub-display screen of the splicing screen. The display brightness of the reference sub-display screen when displaying the target white image is taken as the target display brightness, and the display chromaticity of the reference sub-display screen when displaying the target white image is taken as the target display chromaticity. The sub-display screens other than the reference sub-display screen in the splicing screen are the sub-display screens to be adjusted. Obtain the brightness characteristic parameters of each sub-display screen to be adjusted. The brightness characteristic parameters include the first coefficient corresponding to each color channel of the sub-display screen to be adjusted. The first coefficient is used to represent the influence weight of the brightness of the corresponding color channel on the display brightness of the sub-display screen to be adjusted. For any sub-display screen to be adjusted, an adjustment value that satisfies the first brightness condition and the first constraint condition is searched from a pre-stored lookup table according to the target display brightness, target display chromaticity, and brightness characteristic parameters as the target adjustment value. The lookup table includes luminance and chromaticity data, which includes the luminance and chromaticity of each color channel of the sub-display screen to be adjusted when the target monochrome image is displayed and the first adjustment layer is set to different adjustment values. The target monochrome image is the image of the target white image on the corresponding color channel. The first brightness condition includes that when the first adjustment layer is set to the target adjustment value, the weighted sum of the luminance of each color channel of the sub-display screen to be adjusted and the first coefficient is equal to the target display brightness. The first constraint condition includes that the chromaticity offset between the display chromaticity corresponding to the target adjustment value and the target display chromaticity is less than the first chromaticity offset threshold. The first adjustment layer of each sub-display screen to be adjusted is set according to the target adjustment value; The first adjustment layer includes multiple transparency levels, and the lookup table includes multiple sets of brightness and chromaticity data, with each set of brightness and chromaticity data corresponding to a transparency level. Based on the target display brightness, target display chromaticity, and brightness characteristic parameters, the adjustment value that satisfies the first brightness condition and the first constraint condition is searched from a pre-stored lookup table as the target adjustment value. Specifically, this includes: Based on the target display brightness, target display chromaticity, and brightness characteristic parameters, the transparency and adjustment values ​​of each color channel that satisfy the first brightness condition and the first constraint condition are searched from the multiple sets of brightness and chromaticity data as the target transparency and target adjustment values; The step of setting the first adjustment layer of each sub-display screen to be adjusted according to the target adjustment value specifically includes: setting the first adjustment layer of each sub-display screen to be adjusted according to the target adjustment value and the target transparency.

2. The white balance adjustment method according to claim 1, characterized in that, The steps for determining the reference sub-display screen from each sub-display screen of the splicing screen include: Obtain the display brightness of each sub-display screen when the splicing screen displays the target white image; The sub-display with the lowest brightness will be identified as the reference sub-display.

3. The white balance adjustment method according to claim 1, characterized in that, The steps preceding the acquisition of the brightness characteristic parameters of each sub-display to be adjusted also include: For any sub-display to be adjusted, measure the transparency of the first adjustment layer corresponding to the sub-display to be adjusted to a first value, and the display brightness and the brightness of each color channel when the sub-display to be adjusted displays multiple reference grayscale white images; The first coefficient corresponding to each color channel is calculated based on the measured multiple sets of display brightness and individual brightness. The weighted sum of the first coefficient and the individual brightness of the corresponding color channel is the display brightness.

4. The white balance adjustment method according to claim 3, characterized in that, The plurality of reference grayscale white images include at least a low grayscale white image, a medium grayscale white image, and a high grayscale white image.

5. The white balance adjustment method according to claim 1, characterized in that, For any sub-display screen to be adjusted, the measurement methods for any set of luminance and chromaticity data include: Set the transparency of the first adjustment layer corresponding to the sub-display to be adjusted to a first transparency, where the first transparency is one of the plurality of transparencyes; For any color channel, the adjustment value of that color channel in the first adjustment layer is set to one of the preset adjustment value ranges in sequence. The sub-display to be adjusted is controlled to display the target monochrome image of that color channel, and the current display brightness and display chromaticity of the sub-display to be adjusted are measured. The display brightness is taken as the sub-brightness corresponding to that color channel, and the display chromaticity is taken as the display chromaticity corresponding to that color channel. The sub-brightness and display chromaticity corresponding to each color channel constitute a set of brightness and chromaticity data.

6. The white balance adjustment method according to claim 5, characterized in that, The first adjustment layer corresponds to a first transparency range, and the plurality of transparency layers are arranged at equal intervals within the first transparency range.

7. The white balance adjustment method according to claim 1, characterized in that, The first constraint also includes: The sum of the target adjustment values ​​corresponding to each color channel in the first adjustment layer is minimized; and / or In the first adjustment layer, the first color channel has the highest brightness among the target adjustment values ​​corresponding to each color channel, and the first color channel is the color channel with the largest first coefficient.

8. The white balance adjustment method according to claim 7, characterized in that, The first adjustment layer's color channels include a red channel, a green channel, and a blue channel, with the first color channel being the green channel; the first constraint also includes: In the first adjustment layer, the brightness of the target adjustment value corresponding to the red and blue color channels is not 0.

9. A video wall, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the white balance adjustment method as described in any one of claims 1-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the white balance adjustment method as described in any one of claims 1-8.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the white balance adjustment method as described in any one of claims 1 to 8.

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