Method and driving device for grayscale display of electronic ink screen

Abstract

A method and apparatus for grayscale display on an e-ink screen includes: decomposing a grayscale image into one or more grayscale display areas, wherein the pixel array size of the grayscale display area is less than or equal to the size of a grayscale scattering table; comparing the grayscale display area with the grayscale scattering table pixel by pixel, if the grayscale value is less than the value in the grayscale scattering table, it is displayed as white; if the grayscale display area with the grayscale scattering table pixel by pixel, if the grayscale value is greater than the value in the grayscale scattering table, it is displayed as black; the values ​​within the grayscale scattering table are randomly distributed according to a set grayscale level, wherein the set grayscale level is 64, 16, 8, or 4. This allows for a more uniform brightness across the entire image while maintaining clear and undistorted texture display.

Description

Technical Field

[0001] This application belongs to the field of display technology, specifically relating to an image data processing method and apparatus suitable for electronic ink screens. Background Technology

[0002] Electronic paper features ultra-low power consumption, paper-like texture, and sunlight visibility, and is widely used in industries such as retail, education, healthcare, and advertising. It improves the level of intelligence in these industries while saving various resources. For example, in the retail industry, using electronic price tags to replace traditional paper labels can effectively save labor costs.

[0003] Currently, common e-ink displays can be categorized into monochrome, monochrome-yellow, monochrome-red, monochrome-yellow-red, and seven-color displays. Images need to be processed and converted into fewer colors for better display on e-ink screens. End users have increasingly higher demands for the display quality of e-paper, hoping for more realistic results.

[0004] Therefore, how to process images to achieve a more realistic effect with fewer colors is particularly important in the e-paper industry. Currently, the number of gray levels in e-paper monochrome screens is very limited. Typically, there are only 16 gray levels, with some having as few as 8 or 4 gray levels.

[0005] The grayscale implementation uses a point-based grayscale algorithm, which represents grayscale using the density of white and black dots. The density distribution of white and black dots has a significant impact on the display effect.

[0006] This algorithm uses symmetric energy to determine grayscale levels. This results in a much more uniform distribution of points across the entire image, making it appear more balanced when viewed up close.

[0007] It is a point grayscale algorithm that ensures uniform image brightness. It can make the brightness of the entire image more even. Summary of the Invention

[0008] To address the issues of uneven display effects, excessive energy concentration on the right side, and uneven brightness across the entire image caused by existing pixel dithering algorithms, this paper proposes an electronic ink screen grayscale display method that can achieve more uniform brightness across the entire image.

[0009] It can further solve the problem of distorted texture display after the brightness of the whole picture is uniform, and provide an electronic ink screen grayscale display method that can make the brightness of the whole picture more uniform while the texture display is clear and not distorted.

[0010] The technical solution of this application to solve the above technical problems is an electronic ink screen grayscale display method, including: decomposing a grayscale image into more than one grayscale display area, where the pixel array size of the grayscale display area is less than or equal to the size of the gray scale scattering table; comparing the pixels of the grayscale display area with the gray scale scattering table, if the gray value is less than the value of the gray scale scattering table, display white; comparing the pixels of the grayscale display area with the gray scale scattering table, if the gray value is greater than the value of the gray scale scattering table, display black; the values inside the gray scale scattering table are randomly distributed according to the set gray scale, and the set gray scale is 64, 16, 8 or 4.

[0011] The grayscale image is obtained by converting a color picture.

[0012] The gray scale scattering table is a 64-gray scale table, which is 8 rows and 8 columns, and has 64 pixel points.

[0013] The gray scale scattering table is divided into 4 gray scale scattering sub-tables, and each gray scale scattering sub-table has 16 pixel points.

[0014] The pixel values inside the gray scale scattering sub-table are distributed randomly in terms of size.

[0015] The pixel values inside the gray scale scattering sub-table are distributed in a "cross" shape.

[0016] The value of the gray scale scattering sub-table is calculated according to pixel number × 4 + sub-table number.

[0017] The technical solution of this application to solve the above technical problems can also be an electronic ink screen driving device, and the driving device displays the gray value according to the above electronic ink screen grayscale display method.

[0018] The technical solution of this application to solve the above technical problems can also be a data storage device, and the data storage device stores the gray scale scattering table in the above electronic ink screen grayscale display method.

[0019] One of the beneficial effects of the technical solution in this application is that the values inside the gray scale scattering table are randomly distributed according to the set gray scale, which can make the display more uniform.

[0020] One of the beneficial effects of the technical solution in this application is that the grayscale image is obtained by converting a color picture, which is applicable to various grayscale images.

[0021] One of the beneficial effects of the technical solution in this application is that the gray scale scattering table is a 64-gray scale table, which is 8 rows and 8 columns, and has 64 pixel points, so it can display more gray scales than the prior art and has richer gray levels.

[0022] One of the beneficial effects of the technical solution in this application is that the pixel values ​​inside the grayscale scattering sub-table are distributed according to random size, which makes the grayscale image display more uniform.

[0023] One of the beneficial effects of the technical solution in this application is that the value of the grayscale scattering sub-table is calculated by pixel number × 4 + sub-table number, which reduces the amount of calculation and makes the grayscale display more uniform.

[0024] One of the beneficial effects of the technical solution in this application is that the pixel values ​​inside the grayscale scattering sub-table are distributed in a "rice" shape, which can better display the grayscale image with texture. It can maintain the display uniformity while also maintaining the display effect of texture, and will not be distorted due to uniformity.

[0025] One of the beneficial effects of the technical solution in this application is that the electronic ink screen driver displays grayscale values ​​using the above method, resulting in a uniform effect and preventing texture distortion. Attached Figure Description

[0026] Figure 1 This is a grayscale image display illustration on an e-ink screen. Figure 1 ;

[0027] Figure 2 This is a grayscale image display illustration on an e-ink screen. Figure 2 ;

[0028] Figure 3 This is a grayscale image display illustration on an e-ink screen. Figure 3 ;

[0029] Figure 4 This is a diagram of a grayscale scattering table. Figure 1 ;

[0030] Figure 5 This is a diagram of a grayscale scattering table. Figure 2 ;

[0031] Figure 6 This is a diagram of a grayscale scattering table. Figure 3 ;

[0032] Figure 7 It is a partial encoding of the image to be displayed;

[0033] Figure 8 This is the calculated code number of the image to be displayed;

[0034] Figure 9 It is a black and white image encoding after random shuffling;

[0035] Figure 10 This is a flowchart illustrating the grayscale display method for e-ink screens. Figure 1 ;

[0036] Figure 11This is a grayscale image display illustration on an e-ink screen. Figure 4 ;

[0037] Figure 12 This is a grayscale image display illustration on an e-ink screen. Figure 5 ;

[0038] Figure 13 This is a grayscale image display illustration on an e-ink screen. Figure 6 ;

[0039] Figure 14 This is a diagram of a grayscale scattering table. Figure 4 ;

[0040] Figure 15 yes Figure 14 A schematic diagram illustrating the calculation process of the local grayscale dispersion table;

[0041] Figure 16 yes Figure 15 A schematic diagram illustrating the calculation process of obtaining the black-and-white image code from the local grayscale scattering table;

[0042] Figure 17 This is a diagram illustrating the grayscale display method of e-ink screens. Figure 1 ;

[0043] Figure 18 This is a diagram illustrating the grayscale display method of e-ink screens. Figure 2 ;

[0044] Figure 19 This is a diagram illustrating the grayscale display method of e-ink screens. Figure 3 ;

[0045] Figure 20 This is a diagram illustrating the grayscale display method of e-ink screens. Figure 4 . Detailed Implementation

[0046] The embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0047] It should be noted that the following description of preferred embodiments of this application does not constitute any limitation on this application. The description of preferred embodiments is merely an illustration of the general principles of this application. The embodiments described in this application are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and technical features numbered with Arabic numerals 1, 2, 3, etc., and designations such as "A" and "B," are used for descriptive purposes only, for ease of explanation, and do not represent a temporal or spatial order; they should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first," "second," and numbered with Arabic numerals 1, 2, 3, etc., may explicitly or implicitly include one or more of that feature. In the description of this application, "several" means two or more, unless otherwise expressly and specifically defined.

[0049] like Figure 17 As shown, an electronic ink screen grayscale display method includes decomposing a grayscale image into one or more grayscale display areas, wherein the pixel array size of the grayscale display area is less than or equal to the size of a grayscale scattering table; the grayscale display area is compared with the grayscale scattering table by pixel, and if the grayscale value is less than the value of the grayscale scattering table, it is displayed as white; if the grayscale display area is compared with the grayscale scattering table by pixel, and the grayscale value is greater than the value of the grayscale scattering table, it is displayed as black; the values ​​within the grayscale scattering table are randomly distributed according to a set grayscale, wherein the set grayscale is 64, 16, 8, or 4.

[0050] like Figure 17 As shown, the grayscale image and the grayscale scattering table are compared and calculated to obtain the black-and-white image code, which then drives the display. Figure 18 The grayscale image is obtained by converting a color image.

[0051] like Figures 4 to 9 ,as well as Figures 14 to 16 The grayscale scattering table has 64 grayscale levels, and the grayscale scattering table has 8 rows and 8 columns, with 64 pixels.

[0052] like Figures 4 to 9 ,as well as Figures 14 to 16 The grayscale scattering table is divided into four grayscale scattering sub-tables, each containing 16 pixels. The value of each grayscale scattering sub-table is calculated as pixel number × 4 + sub-table number.

[0053] like Figure 19, the pixel values inside the gray-scale scattering sub-table are distributed randomly in terms of size.

[0054] Such as Figure 20 , the pixel values inside the gray-scale scattering sub-table are distributed in a "rice" shape.

[0055] Such as Figure 1 As shown, it is a normal screen for electronic paper display testing. In electronic paper display, the number of gray scales is very limited. Usually, there are 16 gray scales; in some cases, there are only 8 gray scales or 4 gray scales. In the implementation of gray scales, the dot gray-scale algorithm is usually adopted. The dot gray-scale algorithm represents gray scales by the density of white dots and black dots.

[0056] Such as Figure 2 As shown is a black-and-white dot matrix displayed by the conventional dot gray-scale algorithm in the prior art. The conventional dot gray-scale algorithm in the prior art is the dithering dot algorithm. The dithering dot algorithm sacrifices resolution to increase the number of colors. The gray scale is displayed by the density of black dots. If the screen can only display black and white, a part of the area matrix can be sampled, such as a 2×2 matrix, to display 5 levels of gray scale. Regarding 4 pixels as one pixel, there will be 5 levels of gray scale. Such as Figure 2 As shown, for the dithering dot algorithm, the display effect is not uniform. The main reason is that the energy is too concentrated on the right side. Therefore, the dot matrix on the relative right side is concentrated.

[0057] How to make the display effect better and make the layout of dots on the entire screen more uniform, especially when viewed closely, the display effect can be relatively uniform is a technical problem to be solved.

[0058] Such as Figure 3 As shown, it is a black-and-white dot matrix displayed by the dot gray-scale algorithm in this application. In this application, a random gray-scale scattering table is adopted to complete the dot gray-scale algorithm. It can not only achieve the effect of dot gray scale but also greatly simplify the calculation.

[0059] In this application, first, it is set how many gray scales the dot gray-scale algorithm is to represent. For example: representing 64 gray scales. Other gray scales are also possible. Usually, it is 64, 128 gray scales, or 256 gray scales. Such as [[ID=**29**]] Figure 4 [[ID=**30**]]And [[ID=**31**]] Figure 5 [[ID=**32**]], it is a random gray-scale scattering table set for representing 64 gray scales. [[ID=**33**]] [[ID=**3-4**]]

[0060] [[ID=**35**]]Such as [[ID=**36**]] Figure 4 [[ID=**37**]]And [[ID=**38**]] Figure 5The grayscale table is divided into four zones: the top left (16 dots) is zone one; the top right (16 dots) is zone two; the bottom left (16 dots) is zone four; and the bottom right (16 dots) is zone three. An 8x8 or 16x4 grayscale table is acceptable. Rectangular and square frames are generally better choices. This solution uses four zones (16x4). More zones are also possible, such as eight or six. Data is filled within the zones, and the state shown in this example is not limited; relatively uniform filling is sufficient.

[0061] like Figure 5 The data to be filled in the first section are: 1, 1×4+1=5, 2×4+1=9, 3×4+1=13, 4×4+1=17, 5×4+1=21, 6×4+1=25, 7×4+1=29, 8×4+1=33, 9×4+1=37, 10×4+1=41, 11×4+1=45, 12×4+1=49, 13×4+1=53, 14×4+1=57, 15×4+1=61.

[0062] like Figure 5 The second section is filled with the following data: 2, 1×4+2, 2×4+2, 3×4+2, 4×4+2, ... 15×4+2=62.

[0063] like Figure 5 The data to be filled in the third section is: 3, 1×4+3, 2×4+3, 3×4+3, 4×4+3, ... 15×4+3=63.

[0064] like Figure 5 The fourth section is filled with the following data: 4, 1×4+4, 2×4+4, 3×4+4, 4×4+4, ... 15×4+4=64.

[0065] like Figure 6 It is Figure 5 The data distribution was based on a random shuffling of data within each partition. For example... Figure 7 Yes, a 256-grayscale (8 gray levels) grayscale image to be displayed is a 4×4 unit grayscale structure. The corresponding positional relationships are as follows: Figure 8 As shown.

[0066] use Figure 6 The data in the corresponding position in the table ×4 and Figure 7 The data at the corresponding positions is compared, and based on the comparison results, grayscale values ​​are assigned to each point; the assignment results are output to the calculated values. Figure 8 , used for display. If Figure 6 Data × 4 is greater than Figure 7 The data at the corresponding position is assigned a grayscale value of 255. If Figure 6 Data × 4 is less than Figure 7The data at the corresponding position is assigned a value of 0. A result of 0 is displayed in white; a result of 255 is displayed in black.

[0067] like Figures 6 to 8 The calculation process is shown below:

[0068] Since 0 < 61 × 4 for the point N[x][y], the calculated value of N[x][y] is 0.

[0069] For the point N[x+1][y], 120 > 21 × 4, so N[x+1][y] is 255 after calculation.

[0070] For the point N[x+2][y], 65 < 53 × 4, so N[x+2][y] is 0 after calculation.

[0071] For the point N[x+3][y], 129 > 13×4, so N[x+3][y] is 255 after calculation.

[0072] like Figure 9 It is based on Figure 6 and Figure 7 The calculation results. For example... Figure 3 The image shows the display effect using the algorithm described above. This algorithm is a point grayscale algorithm based on region probability statistics. The calculation rule of this algorithm is to compare the value of a pixel in the image with the points in the random grayscale scattering table to determine whether it is 0 or 255, that is, a black point or a white point.

[0073] Take any point in the pixel, say a brightness of 100. The probability that this brightness of 100 is 0 is 39 / 64, and the probability that it is 255 is 25 / 64. If the entire image shows a brightness value of 100 64 times, then among these 64 brightness values ​​of 100, there are likely 39 that are 0 and 25 that are 255. This is the same result as the dithering algorithm. Perceptually, the dithering algorithm increases the probability of 0 in darker areas and increases the probability of 255 in brighter areas. This creates grayscale. The same function can be accomplished using a matrix probability table.

[0074] The algorithm in this application uses a random grayscale scrambling table to scan the entire image once. This forms a black and white dot map of 0s and 255s. The random grayscale scrambling table needs to be re-scrambled after several iterations. The uniformity of the image depends on the random grayscale scrambling table. Because the dots in the random grayscale scrambling table are uniformly distributed, the image itself is also uniformly distributed.

[0075] When the start command is clicked, the initialization process is completed, such as reading relevant data from the electronic paper and resetting basic parameters. Then, the image is input and stored in the DDR. After an image is stored, the grayscale algorithm is performed. The result is then stored back in the DDR. Once the calculation for an image is complete, the grayscale image is read out and output to the electronic paper for display. The front-end image data is processed into a grayscale image, and then the grayscale image is stored in DDR3 (memory). The algorithm is then performed again, and the calculated values ​​are saved. When ready to display, the appropriate waveform is found based on the read brightness values ​​to complete the illumination.

[0076] This algorithm uses a randomized grayscale table to perform the point grayscale algorithm. It can achieve the effect of point grayscale while greatly simplifying the calculation.

[0077] like Figure 3 As shown, the algorithm described above can make the layout of points across the entire image much more symmetrical. This results in a significantly more symmetrical appearance when viewed up close. In areas with a relatively large number of pixels, this uniformity will look more comfortable.

[0078] However, in the display as shown Figure 11 When displaying images containing text, tables, or other elements with many prominent edges, a uniform algorithm can disrupt these edges, resulting in a distorted display. Figure 13 The display shown is incorrect; the vertical orientation of the image is not correct. Figure 12 Then it's symmetrical, much more balanced. But... Figure 13 The presence of sharp, jagged lines in the image can also disrupt their display, resulting in a less than ideal effect. For example, in an image of a rectangular table, the lines become skewed after homogenization. Figure 12 As shown, although the display effect of the ridge lines is not destroyed, the display effect is uneven. The main reason is that the energy is too concentrated on the right side. Therefore, it causes a relative concentration of dots on the right side. How can we make the display both uniform and balanced, while protecting the display effect of the ridge lines?

[0079] exist Figure 6 Based on, according to Figure 14 As shown, the grayscale table is randomly scattered in a star-shaped pattern. There are some rules governing this randomness. The standard texture pattern can be called a "star" shape. Therefore, the scattering rule follows the direction of the star shape. Thus, the scattering rules appear quite strict. The current distribution rule in this case is the sequential layout of "\", " / ", "—", and "|".

[0080] To display Figure 7 Taking a partial image as an example, first perform... Figure 15 The calculation is shown. (As shown in the image.) Figure 16 ,Will Figure 15 The calculated results and Figure 7 Comparative calculations are performed to obtain the dot matrix data used for displaying black and white images, i.e., the black and white image encoded dot matrix data. Based on... Figure 16 The black and white image encoding in the image is used for display driving.

[0081] Compared to the previous embodiment, the rules in this embodiment are different. The principle of random scattering is to disperse all similar elements. Therefore, the grayscale scattering table is completely random and requires multiple scattering operations during runtime. For different textures, the goal is to ensure similar elements appear along the texture direction. Therefore, the grayscale scattering table is laid out according to the texture direction. The texture grayscale scattering table does not need to be updated; only one is needed. The grayscale scattering table does not need to be partitioned. Random scattering is uniformly distributed, while texture scattering is uneven. Random scattering is uniformly distributed across the image, resulting in distinct grayscale levels. Texture scattering, on the other hand, is distributed across scenes with more textures, resulting in fewer grayscale levels. Therefore, the random grayscale scattering table can contain multiple 1s, multiple 60s, etc., or it can omit 20s, 23s, etc. Based on texture characteristics, grayscale levels in the image will be concentrated in black and white, with fewer intermediate grayscale levels.

[0082] When the start command is clicked, the initialization process is completed, such as reading relevant data from the electronic paper and resetting basic parameters. Then, the image is input and stored in the DDR memory. After an image is stored, the grayscale algorithm is performed. The result is then stored back in the DDR memory. Once the calculation for an image is complete, the grayscale image is read out and output to the electronic paper for display. The front-end image data is processed into a grayscale image, and then the grayscale image is stored in DDR3 memory. The algorithm is then performed again, and the calculated values ​​are saved. When ready to display, the appropriate waveform is found based on the read brightness values ​​to complete the lighting process.

[0083] An electronic ink screen driving device, wherein the driving device displays grayscale values ​​according to the above-described electronic ink screen grayscale display method.

[0084] A data storage device, wherein the data storage device stores the grayscale scattering table in the above-mentioned electronic ink screen grayscale display method.

[0085] As shown in the accompanying drawings, the above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of the invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An electronic ink screen gray-scale display method, characterized in that, It includes: Decompose a grayscale image into more than one grayscale display area, and the pixel array size of the grayscale display area is less than or equal to the size of the gray-scale scatter table; Compare the grayscale display area with the gray-scale scatter table pixel by pixel. If the grayscale value is less than the value in the gray-scale scatter table, display white; Compare the grayscale display area with the gray-scale scatter table pixel by pixel. If the grayscale value is greater than the value in the gray-scale scatter table, display black; The values inside the gray-scale scatter table are randomly distributed according to the set gray scale, and the set gray scale is 64, 16, 8 or 4.

2. The grayscale display method for electronic ink screen according to claim 1, characterized in that, The grayscale image is obtained by converting a color picture.

3. The electronic ink screen gray-scale display method according to claim 1, characterized in that, The gray-scale scatter table is a 64-gray-scale table, with 8 rows and 8 columns, and �4 pixel points.

4. The electronic ink screen gray-scale display method according to claim 3, characterized in that, The gray-scale scatter table is divided into 4 gray-scale scatter sub-tables, and each gray-scale scatter sub-table has 16 pixel points.

5. The electronic ink screen grayscale display method according to claim 4, characterized in that, The pixel values inside the gray-scale scatter sub-table are distributed according to random sizes.

6. The grayscale display method for electronic ink screen according to claim 4, characterized in that, The pixel values inside the gray-scale scatter sub-table are distributed in a "cross" shape.

7. The grayscale display method for electronic ink screen according to claim 4, characterized in that, The value of the gray-scale scatter sub-table is calculated according to pixel number × 4 + sub-table number.

8. An electronic ink screen driving device, characterized in that, The driving device displays the grayscale value according to the electronic ink screen gray-scale display method described in any one of claims 1 to 7.

9. A data storage device, characterized in that, The data storage device stores the gray-scale scatter table in the electronic ink screen gray-scale display method described in any one of claims 1 to 7.

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