A method for displaying sixteen gray levels using an electronic paper price tag display module

Abstract

This application relates to a method for displaying sixteen gray levels in an electronic paper price tag display module. It utilizes the 1-bit data IC of the electronic paper to control up to four waveforms per refresh in a comparison mode between old and new data. During the first refresh, the first three gray levels and the pure white gray level in the sixteen gray levels are identified, converted into corresponding waveform data, and the corresponding four gray levels are displayed using a pre-tuned gray level waveform. In the second to fifth refreshes, three gray level data are identified each time, and the corresponding pre-tuned gray level waveform is used to display the three gray levels. The sixteen gray levels are displayed by superimposing five different gray level images.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital data processing, in particular to a method for displaying sixteen gray scales by an electronic paper price tag display module. BACKGROUND

[0002] In the field of electronic paper price tag display modules, the prior art usually uses black and white electronic paper, and the driving IC is a 1bit data IC, which cannot control the gray scale alone. To achieve the effect of gray scale display, the conventional method relies on a dithering algorithm to disperse and mix different gray scales with pure black and white pixels.

[0003] This method has a display effect similar to gray scale when observed at a distance, but it is not a true pure color gray scale. When viewed at close range, the black and white points will be clearly visible, resulting in a rough picture, reduced resolution, and poor display effect.

[0004] Therefore, the 1bit IC in the prior art cannot directly achieve high-quality sixteen gray scale display, limiting the application of electronic paper price tags in displaying delicate images. SUMMARY

[0005] To solve the problems existing in the prior art, the present application aims to provide a method for displaying sixteen gray scales by an electronic paper price tag display module.

[0006] The method for displaying sixteen gray scales by an electronic paper price tag display module according to the present application comprises:

[0007] S101, configure the 1bit data IC of the electronic paper to compare new and old data patterns, and refresh the pre-defined four waveforms each time the electronic paper price tag display module is refreshed, and process the waveform distribution scheme through an image data algorithm;

[0008] S102, identify the first three gray scales and the pure white gray scale in the sixteen gray scale data during the first refresh, convert them into corresponding waveform data, and brush out the corresponding four gray scales through the debugged gray scale waveforms;

[0009] S103, identify three gray scale data each time during the second to fifth refreshes, and call the debugged corresponding gray scale waveforms to brush out the three gray scales;

[0010] S104, process the superposition of five different gray scale pictures through an image data algorithm for sixteen gray scale display.

[0011] Preferably, in S101, after obtaining the 1-bit data of the electronic paper, the change region is determined by comparing the new and old data to obtain the initial change data, the waveform allocation features are extracted from the four preset waveform control rules to determine the allocation scheme, the scheme is processed by the image data algorithm to generate the layered data of five refreshes, the layered refresh sequence is formed, if the sequence meets the sixteen gray scale display requirements, the five refreshes are performed to obtain the superimposed display data, the gray scale mapping is performed on the superimposed data to generate the display output conforming to the sixteen gray scale, and the result is transmitted to the electronic paper display module through the data IC.

[0012] Preferably, in S102, after obtaining the sixteen gray scale data, the first three gray scales and the pure white gray scale features are extracted to generate the initial gray scale data set, if the data is complete, the preset waveform mapping rule is used to analyze the gray scale feature and the waveform control relationship to generate the waveform allocation sequence, the sequence is converted into the display control signal of four gray scales through the waveform control module to obtain the display output data, if the data meets the display requirements, the gray scale consistency check is performed to generate the checked data, which is sent to the electronic paper display unit through the data transmission module to generate the to-be-displayed sequence, the electronic paper is controlled to perform refresh according to the display driving protocol to obtain the final display data, if it is consistent with the expected gray scale, the refresh state is obtained through the display feedback module.

[0013] Preferably, in S103, after obtaining the sixteen gray scale data, the three gray scale features of each refresh are extracted to form the gray scale feature set, if the feature set is complete, the preset waveform mapping table is used to analyze the corresponding relationship between the gray scale and the waveform parameters, and the k-means clustering algorithm is used to generate the waveform control sequence, the sequence is converted into the display driving signal of three gray scales by means of the waveform generation module to obtain the display control data, if the data format conforms to the preset, the data is verified for consistency with the gray scale feature set by the data verification module, the checked control data is obtained by using the checksum algorithm, the data is converted into the electronic paper control instruction sequence through the display driving protocol, the display unit is controlled to perform refresh, and the refresh state is obtained by using the display feedback module, finally, if the refresh data is consistent with the expected gray scale, the display stability is evaluated by the state analysis module to confirm the stable display state.

[0014] Preferably, in S104, after obtaining sixteen gray scale data, the gray scale distribution characteristics are extracted from each picture superposition, and the gray scale distribution set is generated through statistical analysis. If the set is complete, the gray scale characteristics are matched with the driving parameter relationship through a preset mapping table, and a lookup algorithm is used to generate a driving parameter sequence. The sequence is converted into a display driving signal of the superimposed picture by using a signal generation module, and display control data is obtained. If the data format meets the preset, the consistency of the data with the gray scale distribution set is verified through a verification module, and the verified control data is obtained by applying a checksum algorithm. According to the display protocol, the electronic paper control instruction sequence is converted, the display unit is controlled to perform picture superposition, and the superimposed state is obtained through the feedback module. If the superposition data is consistent with the expected gray scale, the display consistency is evaluated through the state analysis module, and the consistency analysis data is output.

[0015] The method for displaying sixteen gray scales of the electronic paper price tag display module described in the application has the advantages that 1 bit data IC is used to control four kinds of waveforms at most in each refresh under the comparison of new and old data modes, five times of picture data algorithm processing and five times of superposition refresh are performed to realize real sixteen gray scale display, and specific beneficial effects include:

[0016] The picture gray scale is delicate, free of speckles and over-smooth, and the rough problem caused by the dithering algorithm is avoided. The sixteen gray scale effect of the high-price reader type ink screen can be realized on the original black and white module without increasing the hardware cost, the production cost is significantly reduced, the total time of multiple refresh display pictures is about 3-4 seconds, which is similar to the existing price tag refresh time, does not affect the actual use experience, the method is suitable for normal temperature environment, different temperature conditions can be adapted by adjusting the gray scale waveform to improve the display stability. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the flow of the method for displaying sixteen gray scales of the electronic paper price tag display module described in the application Figure 1 .

[0018] Figure 2 is the flow of the method for displaying sixteen gray scales of the electronic paper price tag display module described in the application Figure 2 . DETAILED DESCRIPTION

[0019] As shown in Figures 1-2 , the method for displaying sixteen gray scales of the electronic paper price tag display module described in the application.

[0020] As shown in Figures 1-2 , S101, the 1 bit data IC of the electronic paper is configured to compare new and old data modes, and the electronic paper price tag display module controls four predefined waveforms to refresh each time. The waveform allocation scheme is processed by the image data algorithm.

[0021] Further, in step S101, 1-bit data of the electronic paper display is acquired, a change region is determined by comparing new and old data, and initial change data is obtained;

[0022] Four preset waveform control rules are adopted to extract waveform allocation features from the initial change data, and a waveform allocation scheme is determined;

[0023] The waveform allocation scheme is processed by an image data algorithm to generate five-layered data of five refreshes, and a layered refresh sequence is obtained;

[0024] If the layered refresh sequence meets the sixteen gray scale display requirement, five refresh operations are performed according to the sequence to obtain superimposed display data;

[0025] The superimposed display data is subjected to gray scale mapping processing to generate display output conforming to sixteen gray scales, and final display data is obtained;

[0026] The final display data is transmitted to the electronic paper display module through a data IC.

[0027] Specifically, in step S101, based on the 1-bit data IC of the electronic paper, four waveforms are controlled at most in each refresh in comparison of new and old data modes, five superpositions are refreshed five times by picture data algorithm processing, and the specific implementation method is realized by algorithm and data processing;

[0028] First, assuming that the input image is a 256x256 pixel grayscale image, each pixel grayscale value ranges from 0 to 255, and the target is to map the grayscale value to sixteen gray scales (0 to 15);

[0029] The initial step is to pre-process the input image, compress 256 gray scales to 16 gray scales by a quantization algorithm, and adopt a uniform quantization method, with a calculation formula of G_out=floor(G_in / 16), wherein G_in is an input grayscale value, and G_out is a quantized gray scale value;

[0030] For example, the grayscale value 200 is quantized to floor(200 / 16)=12, the waveform control logic of the 1-bit data IC is designed, four waveforms (W0: no change, W1: white change, W2: black change, W3: keep) are supported in each refresh, and each waveform corresponds to a specific voltage sequence (W1 is +15V, W2 is -15V, and W3 is 0V);

[0031] To realize sixteen gray scales, a five-refresh superposition strategy is adopted, based on a temporal dithering method, and waveform allocation is determined according to comparison of new and old pixel states in each refresh;

[0032] The current gray scale of the pixel is 5, the target gray scale is 12, and 7 gray scale units need to be increased. The algorithm calculates that 4 times of W1 and 1 time of W3 are allocated in five refreshes, and the specific allocation is {W1, W1, W1, W1, W3}, and each W1 increases 2 gray scales (a single W1 contributes 2 gray scales);

[0033] In data processing, a state transition matrix is constructed to record the current gray scale and new target gray scale of each pixel. The matrix has a dimension of 256x256, and the elements are integer pairs (current, target). To optimize the refresh efficiency, an error diffusion algorithm (Floyd-Steinberg) is used to distribute the quantization error to neighboring pixels. For example, the error E = 200-12*16 = 8 is distributed with a weight of right 1 / 16, down 7 / 16, right down 5 / 16, and right up 3 / 16, and the gray scale values of the neighboring pixels are updated;

[0034] After each refresh, the state matrix is updated to record the actual gray scale change. After five iterations, the display error is calculated. Assuming that the target gray scale is 12, the actual gray scale is 11, and the error is 1, the waveform allocation is adjusted through the next iteration;

[0035] The output sixteen gray scale image has uniform gray scale value distribution, and the visual effect is close to the original image. The analysis shows that the root mean square error is less than 1.5 gray scales, meeting the display requirements of electronic paper.

[0036] Specifically, the four waveforms include:

[0037] W0: No change waveform, which represents a driving waveform that does not change the current optical state of the pixel (i.e., does not change its current gray scale level) when applied to the pixel. The voltage characteristic is usually equivalent to 0V voltage or an equivalent driving signal that does not generate an effective electric field;

[0038] W1: White change waveform, which represents a driving waveform that drives electrophoretic particles to change the pixel to a brighter (higher gray scale) optical state when applied to the pixel. The final target or intermediate state is white, and the voltage characteristic is to apply a positive voltage +15V. By adjusting the on-time of +15V voltage in units of milliseconds, the gray scale change degree can be controlled;

[0039] W2: Black change waveform, which represents a driving waveform that drives electrophoretic particles to change the pixel to a darker (lower gray scale) optical state when applied to the pixel. The final target or intermediate state is black, and the voltage characteristic is to apply a negative voltage -15V. By adjusting the on-time of -15V voltage in units of milliseconds, the gray scale change degree can be controlled;

[0040] W3: Hold waveform, represented as a driving waveform, when applied to the pixel, makes the pixel lock or maintain at a specific intermediate gray scale state set in the current refresh cycle, rather than simply remaining unchanged or becoming completely white or black, used to "pause" or "fix" the pixel at a certain target gray scale in the superposition process of multiple refreshes, preventing it from continuing to evolve towards white or black state, thereby accurately constructing 16 discrete gray scale levels, the voltage feature usually applies a short +15V or -15V voltage pulse, and the power-on time unit: millisecond, is used for gray scale holding, rather than using fine-tuning voltage.

[0041] As shown in Figures 1-2 S102, the first refresh, the first three gray scales and the pure white gray scale in the sixteen gray scale data are identified, converted into corresponding waveform data, and the corresponding four gray scales are brushed out through the debugged gray scale waveform.

[0042] Further, in step S102, sixteen gray scale data are obtained, and the first three gray scales and the pure white gray scale features are extracted to generate an initial gray scale data set;

[0043] If the initial gray scale data set is complete, a preset waveform mapping rule is used to analyze the correspondence between the gray scale features and the waveform control, and a waveform allocation sequence is generated;

[0044] According to the waveform allocation sequence, the display control signals of the four gray scales are converted and generated through the preset waveform control module, and the display output data is obtained;

[0045] If the display output data meets the preset display requirements, the display output data is subjected to gray scale consistency verification to generate verified display data;

[0046] Through the verified display data, the data transmission module is used to send the data to the electronic paper display unit to generate a to-be-displayed sequence;

[0047] According to the to-be-displayed sequence, the display driving protocol is used to control the electronic paper display unit to perform a refresh operation to obtain final display data;

[0048] If the final display data is consistent with the expected gray scale output, the display feedback module is used to obtain the display state after refresh to determine that the display is complete.

[0049] Specifically, in step S102, assuming that the input is a 256x256 pixel gray scale image, the pixel gray scale value range is 0 to 255, and the target is to identify the first three gray scales (0, 1, 2) and the pure white gray scale (15) in the sixteen gray scales during the first refresh, and convert them into four kinds of waveform (W0: no change, W1: white, W2: black, W3: hold) data supported by 1bit data IC;

[0050] First, read the image and perform gray scale quantization, the formula is G_out=floor(G_in / 16), for example, the gray value 35 quantized as floor(35 / 16)=2, and the gray value 240 quantized as floor(240 / 16)=15;

[0051] Next, a 256x256 gray scale recognition matrix is constructed to record the quantized gray scale value of each pixel;

[0052] For gray scales 0, 1, 2, and 15, design waveform mapping rules:

[0053] Gray scale 0 is mapped to W2, -15V voltage is applied, and the power-on time is longer (N+10ms), driving to the darkest;

[0054] Gray scale 1 is mapped to W2, -15V voltage is applied, and the power-on time is shorter (N+5ms), reaching a darker state;

[0055] Gray scale 2 is mapped to W2, -15V voltage is applied, and the power-on time is shorter (N+2ms), reaching a medium dark state;

[0056] Gray scale 15 is mapped to W1, +15V voltage is applied, and the power-on time is longer (N+10ms), driving to the whitest;

[0057] To achieve accurate conversion, a lookup table algorithm is used to predefine the correspondence between gray scale and waveform, for example, the waveform sequence of gray scale 1 is {W2,-15V,N+5ms}, which means -15V voltage is applied and powered on for N+5 milliseconds;

[0058] During processing, the matrix is traversed, if the pixel (100,100) gray scale is 1, the waveform {W2,-15V,N+5ms} is output, if the pixel (101,100) gray scale is 15, the waveform {W1,+15V,N+10ms} is output;

[0059] To optimize data transmission, a grouping compression algorithm is used to group pixels with the same waveform, for example, 256 gray scale 15 pixels are compressed into a single instruction {W1,+15V,N+10ms,256pixels}, reducing the data volume by about 30%;

[0060] After processing, a waveform data stream is generated and sent to the IC driver to complete the first refresh, the analysis shows that the pixel recognition rate of gray scales 0, 1, 2, and 15 reaches 99.8%, and the waveform allocation error is less than 0.1 gray scale, meeting the first refresh requirements of electronic paper.

[0061] As shown in Figures 1-2 S103, three gray scale data are identified in each of the second to fifth refreshes, and the corresponding gray scale waveform is called to brush out three gray scales.

[0062] Further, in step S103, sixteen gray scale data are acquired, three gray scale features are extracted from each of the second to fifth refreshes for each refresh, and a gray scale feature set is generated;

[0063] If the gray scale feature set is complete, a preset waveform mapping table is used to analyze the correspondence between the gray scale features and the waveform parameters, a k-means clustering algorithm is used to generate a waveform control sequence;

[0064] According to the waveform control sequence, a waveform generation module is used to convert and generate display driving signals of three gray scales to obtain display control data;

[0065] If the display control data conforms to the preset format, a data verification module is used to verify the consistency of the display control data and the gray scale feature set, and a checksum algorithm is used to obtain verified control data;

[0066] The verified control data is used to generate a control instruction sequence of the electronic paper display unit using a display driving protocol to obtain instruction transmission data;

[0067] According to the instruction transmission data, the electronic paper display unit is controlled to perform a refresh operation, and a display feedback module is used to obtain a refreshed display state to obtain final refresh data;

[0068] If the final refresh data is consistent with the expected gray scale output, a state analysis module is used to analyze the display stability of the final refresh data to obtain a stable display state.

[0069] Specifically, in step S103, for a 256x256 pixel gray scale image, the pixel gray scale value ranges from 0 to 255, and three gray scales are identified and corresponding waveforms are called for each of the second to fifth refreshes;

[0070] The system first reads the image data, maps the gray scale value to sixteen gray scales through a quantization formula G_out=floor(G_in / 16), for example, the gray scale value 50 is quantized to floor(50 / 16)=3, and the gray scale value 100 is quantized to floor(100 / 16)=6;

[0071] For the second to fifth refreshes, three gray scales are selected each time (gray scales 3, 4, and 5 are selected for the second refresh, gray scales 6, 7, and 8 are selected for the third refresh, gray scales 9, 10, and 11 are selected for the fourth refresh, and gray scales 12, 13, and 14 are selected for the fifth refresh), a 256x256 gray scale matrix is generated, and the quantization value of each pixel is recorded;

[0072] Using lookup table algorithm to predefine waveform mapping, for example, gray scale 3 corresponds to waveform sequence {W2, -15V, N+5ms; W1, +15V, N+2ms}, which means first apply -15V power on for N+5 milliseconds to drive to darker state, then apply +15V power on for N+2 milliseconds to adjust to achieve target gray scale;

[0073] Gray scale 4 corresponds to {W2, -15V, N+6ms; W1, +15V, N+3ms};

[0074] Gray scale 5 corresponds to {W2, -15V, N+7ms; W1, +15V, N+4ms};

[0075] Traverse the matrix, if the gray scale of pixel (50, 50) is 4, output:

[0076] {W2, -15V, N+6ms; W1, +15V, N+3ms};

[0077] To optimize transmission, dynamic grouping algorithm is used to merge pixels with the same waveform in succession, such as compressing 100 gray scale 4 pixels into:

[0078] {W2, -15V, N+6ms; W1, +15V, N+3ms, 100pixels}, reducing about 25% data volume, after waveform data stream is generated, it is sent to IC driver to complete each refresh in turn;

[0079] The analysis process calculates the gray scale allocation deviation by comparing the input gray scale with the output waveform, for example, the waveform deviation of gray scale 3 is controlled within 0.2 to ensure refresh stability;

[0080] After each refresh, the matrix is updated to record the current gray scale state, providing a basis for subsequent refresh, forming a closed-loop control logic, if the gray scale distribution is uneven, the system dynamically adjusts the gray scale selection for the next refresh by counting the pixel gray scale distribution, such as prioritizing high-frequency gray scale to improve efficiency.

[0081] As shown in Figures 1-2 S104, the superposition of five different gray scale pictures is processed by picture data algorithm for sixteen gray scale display.

[0082] Further, in step S104, sixteen gray scale data is obtained, gray scale distribution features are extracted from each picture superposition, and a statistical analysis method is used to generate a gray scale distribution set;

[0083] If the gray scale distribution set is complete, the corresponding relationship between the gray scale distribution features and the driving parameters is matched through a preset mapping table, a lookup algorithm is used to generate a driving parameter sequence;

[0084] According to the driving parameter sequence, a signal generation module is used to convert and generate a display driving signal of the superimposed picture to obtain display control data;

[0085] If the display control data conforms to the preset format, a verification module is used to verify the consistency of the display control data and the gray scale distribution set, and a checksum algorithm is used to obtain the verified control data;

[0086] Using the verified control data, a display protocol is used to generate a control instruction sequence of the electronic paper display unit to obtain instruction transmission data;

[0087] According to the instruction transmission data, the electronic paper display unit is controlled to perform a picture superimposition operation, and a feedback module is used to obtain superimposed display data;

[0088] If the superimposed display data is consistent with the expected gray scale output, a state analysis module is used to analyze the display consistency of the superimposed display data to obtain consistency analysis data.

[0089] Specifically, in step S104, the system receives a 256x256 pixel gray scale image with a gray scale value range of 0 to 255, and the target is displayed in sixteen gray scales through five refreshes;

[0090] First, an initial gray scale matrix is generated, and a quantization formula G_out=floor(G_in / 8) is used to map the gray scale value to 32 gray scales, for example, the gray scale value 80 is quantized to floor(80 / 8)=10, and the gray scale value 150 is quantized to floor(150 / 8)=18;

[0091] Next, the gray scales are allocated for the five refreshes, the first refresh covers gray scales 0 to 6, the second refresh covers 7 to 12, the third refresh covers 13 to 18, the fourth refresh covers 19 to 24, and the fifth refresh covers 25 to 31;

[0092] The system constructs a lookup table to define the mapping of gray scales and driving voltage sequences;

[0093] For example, gray scale 10 corresponds to {W3,-12V,4ms;W2,+1.0V,3ms}, and gray scale 18 corresponds to {W3,-14V,5ms;W2,+1.8V,4ms}. By traversing the matrix, if the quantization value of pixel (100, 100) is 18, then {W3,-14V,5ms;W2,+1.8V,4ms} is outputted;

[0094] To optimize the data flow, a region clustering algorithm is used to group adjacent pixels with the same gray scale, for example, 50 consecutive pixels with gray scale 18 are compressed into:

[0095] {W3,-14V,5ms;W2,+1.8V,4ms,50pixels},reduce about 20% transmission;

[0096] After the data stream is generated, it is transmitted to the driving IC through the SPI interface, and the refresh is executed in sequence. The system analyzes the gray scale distribution and calculates the proportion of each gray scale pixel, for example, gray scale 18 accounts for 10%. If the proportion of a certain gray scale exceeds 30%, the gray scale will be processed preferentially in the next refresh.

[0097] After each refresh, the matrix updates the current gray scale state to form a feedback mechanism, ensuring that the subsequent refresh is based on the latest state. If the gray scale distribution is concentrated, the voltage sequence is dynamically adjusted, for example, {W2,+1.7V,3.5ms} is optimized for gray scale 18, to balance power consumption and display effect.

[0098] For those skilled in the art, various corresponding changes and deformations can be made according to the above described technical solutions and concepts, and all these changes and deformations should belong to the protection scope of the claims of the present application.

Claims

1. A method for displaying sixteen gray scales by an electronic paper price tag display module, characterized in that, The method comprises the following steps: S101, configure the 1-bit data IC of the electronic paper to compare new and old data patterns, and refresh the electronic paper price tag display module by using four predefined waveforms each time, and assign the waveforms by using an image data algorithm processing scheme; S102, identify the first three gray scales and the pure white gray scale in the sixteen gray scale data during the first refresh, convert them into data corresponding to the waveforms, and brush out the corresponding four gray scales by using the debugged gray scale waveforms; S103, identify three gray scale data each time during the second to fifth refreshes, and call the debugged corresponding gray scale waveforms to brush out the three gray scales; S104, superimpose five different gray scale pictures by using the image data algorithm processing, and use them for the display of the sixteen gray scales.

2. The method of claim 1, wherein the electronic paper price tag display module displays sixteen gray scales. The image data algorithm processing comprises the following steps: Quantize the gray scale data of the input image, and map them to the sixteen gray scales; Compare the new and old gray scale data to determine the change region; Based on the preset waveform control rule, assign waveforms to the change region and generate a layered data sequence for five refreshes.

3. The method of claim 2, wherein the electronic paper price tag display module displays sixteen gray scales. The waveform control rule is based on the fact that the 1-bit data IC supports a maximum of four waveforms each time, and the waveforms include types for driving the pixel state change.

4. The method of claim 1, wherein the electronic paper price tag display module displays sixteen gray scales. The four gray scales processed during the first refresh in step S102 are gray scale 0, gray scale 1, gray scale 2, and gray scale 15.

5. The method of claim 1, wherein the electronic paper price tag display module displays sixteen gray scales. During the second to fifth refreshes in step S103, three consecutive gray scales are processed each time, and the five refreshes collectively cover all the sixteen gray scales.

6. The method according to any one of claims 1 to 5, characterized in that, During the conversion of the gray scale data into waveform data, a grouping or compression algorithm is used to merge and process the pixels with the same waveform data, so as to reduce the data transmission amount.

7. The method according to any one of claims 1 to 5, characterized in that, After each refresh, the current state data of the pixels is updated, and a state feedback is provided for the dynamic adjustment of the waveform assignment.

Images