A method and device for correcting a digital drive display panel

Abstract

The present invention relates to the field of image correction technology, and discloses a correction method and device for a digital drive display panel, which utilizes the visual persistence characteristics of the human eye and the characteristics of the digital drive mode, and realizes the adjustment of brightness and grayscale levels through time control. When correcting the brightness of different grayscales that are completely linear, the brightness information of the display screen at a preset grayscale is obtained, a compensation coefficient is generated, and Mura is corrected. The present invention provides a special DeMura correction method for a digital drive display panel, and saves a lot of storage space while recording the brightness information of the display screen at different grayscales.

Description

Technical Field

[0001] The present invention relates to the technical field of image correction, and in particular to a correction method and device for a digital drive display panel. Background Art

[0002] Mura refers to the uneven brightness of the display screen caused by materials and processes during the production process. This unevenness will show various obvious traces on the display screen, such as bright spots, dark spots, stripes, etc., affecting the visual experience and display quality. In order to improve the visual discomfort caused by this uneven brightness, panel manufacturers usually use DeMura processing technology. DeMura obtains sub-pixel optical imaging data through industrial cameras and uses a specific DeMura algorithm for compensation, thereby improving brightness uniformity, improving display quality, meeting shipping standards, and improving mass production yield. The DeMura algorithms of different manufacturers have their own characteristics, but generally they are corrected by shooting the brightness information of the display screen at different grayscales, such as 32, 64, 128, 192, 255, generating compensation parameters or grayscale compensation tables. The currently used DeMura algorithm needs to take up a lot of storage space because it needs to record the brightness information of the display screen at different grayscales, and there is no DeMura correction method specifically for digital drive display panels. This has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above problems existing in the prior art, the present invention proposes a correction method and device for a digital drive display panel. The technical solution adopted by the present invention is as follows:

[0004] A correction method for a digital drive display panel, the method comprising:

[0005] Step S1, obtaining correction data of a complete data frame from a first memory, and sequentially and associatively storing the correction data of each pixel in the digital drive display panel in a second memory;

[0006] Step S2, obtaining input video data, and obtaining correction data of corresponding addresses from the second memory according to the position of each pixel in the current video data frame;

[0007] Step S3: Correct the brightness information of the corresponding pixel according to the correction data, and output the corrected brightness information of the pixel.

[0008] Furthermore, before the above step S1, the method further comprises the following steps:

[0009] Step 101, obtaining pixel brightness information of each pixel of a digital drive display panel at a preset gray scale;

[0010] Step 102: Count the pixel brightness information of each pixel and determine the compensation interval according to a preset maximum compensation ratio;

[0011] Step 103, comparing the pixel brightness information of each pixel with the determined brightness information of the pixels within the compensation interval, and determining the correction data of each pixel according to the comparison result;

[0012] Step 104: normalize the calculated correction data, and associate the normalized data with the brightness information of each pixel and store them in the first memory.

[0013] Furthermore, the pixel brightness information is the correction data, and the correction data of each pixel is determined according to the comparison result, specifically including:

[0014] If the pixel brightness information is greater than the brightness information of the pixel in the compensation interval, the correction data of the pixel is the maximum value of the brightness information in the compensation interval;

[0015] If the brightness information of each pixel is within the range of the brightness information of the pixel in the compensation interval, the correction data of the pixel is its own brightness information;

[0016] If the brightness information of each pixel is less than the brightness information of the pixel in the compensation interval, the correction data of the pixel is the minimum value of the brightness information in the compensation interval.

[0017] Furthermore, in the above step 104, normalization processing is performed, specifically including: dividing the pixel brightness information of each pixel by the maximum value of all pixel brightness information and then multiplying by 255, and converting the calculated result into an 8-bit hexadecimal integer.

[0018] Furthermore, in the above step S3, the brightness information of the corresponding pixel is corrected, specifically including:

[0019] Step S301, determining a calibration reference brightness;

[0020] Step S302, calculating the ratio of the calibration reference brightness to the calibration data;

[0021] Step S303, correcting the brightness information of the pixel according to the ratio;

[0022] Step S304: output the corrected pixel brightness information.

[0023] Further, correcting the brightness information of the pixel according to the ratio specifically includes:

[0024] If the ratio of the calibration reference brightness to the calibration data is less than 1, the output data of the calibrated brightness information is the input data of the brightness information multiplied by the ratio of the calibration reference brightness to the calibration data;

[0025] If the ratio of the correction reference brightness to the correction data is greater than or equal to 1, no correction is performed, and the input data of the brightness information is directly output as output data.

[0026] Furthermore, when determining the correction reference brightness, an independent correction reference brightness is set for each gray scale.

[0027] Furthermore, when determining the correction reference brightness, a uniform correction reference brightness is set for each gray scale.

[0028] Furthermore, in the above step 101 , the grayscale value is preset to be 255.

[0029] A correction device for a digital drive display panel, the device is used to implement the above method, the device comprises:

[0030] An associated storage module, used to obtain the correction data of a complete data frame from the first memory, and sequentially associate and store the correction data of each pixel in the digital drive display panel into the second memory;

[0031] A data acquisition module, used to acquire input video data, and acquire correction data of corresponding addresses from the second memory according to the position of each pixel in the current video data frame;

[0032] The brightness correction module is used to correct the brightness information of the corresponding pixels according to the correction data and output the brightness information of the corrected pixels.

[0033] Through the embodiments of the present invention, the following technical effects can be achieved: the correction method and device of the present invention provide a special DeMura correction method for a digital drive display panel, and save a lot of storage space while recording the brightness information of the display screen at different grayscales. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a flow chart of the calibration method;

[0036] Figure 2 This is a schematic diagram of the output duty cycle when the correction data (DeMura data) is 255;

[0037] Figure 3This is a schematic diagram of the output duty cycle when the correction data (DeMura data) is 64;

[0038] Figure 4 is a schematic diagram showing the comparison of the first example screen at different calibration reference brightnesses;

[0039] Figure 5 is a schematic diagram showing the comparison of the second example screen at different calibration reference brightnesses;

[0040] Figure 6 is a schematic diagram showing comparison of the third example screen at different calibration reference brightnesses;

[0041] Figure 7 A schematic diagram of display effects with inconsistent grayscale correction effects;

[0042] Figure 8 Schematic diagram of the display effect after separate calibration of different grayscales. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Before introducing the technical solution of this application, the technical terms involved in the technical solution are explained as follows:

[0045] Mura: refers to various traces caused by uneven brightness of LCD / OLED / microLED display;

[0046] DeMura: A technology that eliminates display Mura and makes the screen brightness uniform. By adjusting the grayscale value or voltage of the pixels in the Mura area, the dark areas become brighter and the bright areas become darker, thereby achieving a uniform display effect.

[0047] Digital drive: Digital drive is based on the visual persistence characteristics of the human eye, which controls the light-emitting time of the display unit in time to change the brightness perceived by the human eye to achieve grayscale control;

[0048] Digital pulse width modulation: Pulse width modulation (PWM) is a method of digitally encoding analog signal levels by using a high-resolution counter to generate a square wave and encoding the analog signal level by adjusting the duty cycle of the square wave.

[0049] Grayscale compensation: A compensation technology designed to improve the image quality of display devices. It adjusts the brightness of the display panel at different grayscales to reduce display unevenness and improve the visual experience.

[0050] The driving principle of digital drive display panels utilizes the visual persistence characteristics of the human eye and adjusts the brightness and grayscale levels through time control. Due to the characteristics of the digital drive method, the brightness values ​​of different grayscales are completely linear. When doing DeMura processing, you only need to capture the brightness information of the display at 255 grayscale, generate compensation parameters, and correct Mura.

[0051] In a first aspect, the present application provides a calibration method for a digitally driven display panel, such as Figure 1 As shown, the method comprises the following steps:

[0052] Step S1, obtaining correction data (DeMura data) of a complete data frame from a first memory, and sequentially and associatively storing the DeMura data of each pixel in the digital drive display panel in a second memory;

[0053] The DeMura data of the complete data frame includes DeMura data of each pixel in the digital drive display panel;

[0054] In the above steps, the memory may be a FLASH memory. After the system is powered on, a read request is sent to a memory read controller, such as a FLASH read controller, and the memory read controller reads DeMura data of a complete data frame from the memory according to the read request. After that, the read operation on the memory is stopped. The DeMura data of the first pixel to the last pixel in the digital drive display panel are sequentially stored in a second memory, and the second memory may be an SRAM memory.

[0055] Before the above step S1, the method further comprises the following steps:

[0056] Step 101, obtaining pixel brightness information of each pixel of a digital drive display panel at a preset gray scale;

[0057] In the above step 101, the grayscale value is preset to be 255;

[0058] Step 102: Count the pixel brightness information of each pixel and determine the compensation interval according to a preset maximum compensation ratio;

[0059] In the above step 102, the maximum compensation ratio = the maximum value of the brightness information within the compensation interval / the minimum value of the brightness information within the compensation interval;

[0060] The larger the compensation interval, the better the compensation effect. The larger the maximum compensation ratio, the greater the brightness loss after compensation. When the maximum compensation ratio is fixed, the better the screen consistency, the larger the compensation interval. The compensation interval is selected according to the preset maximum compensation ratio so that the pixel brightness information of as many pixels of the digital drive display panel as possible can be located in the compensation interval, and the adjustment of the pixel brightness information is achieved by performing subsequent correction.

[0061] Step 103: Compare the pixel brightness information of each pixel with the determined brightness information of the pixels within the compensation interval, and determine the DeMura data of each pixel according to the comparison result;

[0062] In the above step 103, the pixel brightness information is the DeMura data, and the DeMura data of each pixel is determined according to the comparison result, specifically including:

[0063] If the pixel brightness information is greater than the brightness information of the pixel in the compensation interval, the DeMura data of the pixel is the maximum value of the brightness information in the compensation interval;

[0064] If the brightness information of each pixel is within the range of the brightness information of the pixel in the compensation interval, the DeMura data of the pixel is its own brightness information;

[0065] If the brightness information of each pixel is less than the brightness information of the pixel in the compensation interval, the DeMura data of the pixel is the minimum value of the brightness information in the compensation interval;

[0066] Step 104: normalize the calculated DeMura data, associate it with the brightness information of each pixel and store it in the first memory;

[0067] In the above step 104, a normalization process is performed, specifically including: dividing the pixel brightness information of each pixel by the maximum value of all pixel brightness information and then multiplying by 255, and converting the calculated result into an 8-bit hexadecimal integer;

[0068] In the above method, the first memory is preferably a non-volatile memory FLASH. Since the data stored in FLASH is an 8-bit hexadecimal integer, all pixel brightness information needs to be normalized first. The data stored in FLASH has the characteristic of not being lost when power is off, but the reading speed is slow. In order to ensure the data processing speed, the data stored in FLASH needs to be read into the second memory. The second memory usually uses SRAM. The characteristic of SRAM is that the data will be lost when power is off, but the reading speed is fast and can meet the data processing speed requirements.

[0069] Step S2, obtaining input video data, and obtaining DeMura data of corresponding addresses from the second memory according to the position of each pixel in the current video data frame;

[0070] In the above steps, the input video data frame is acquired by detecting the frame start signal, and after completing the reading of the associated DeMura data of each pixel in the current frame, the frame start signal of the next video data frame is waited;

[0071] Step S3, correcting the brightness information of the corresponding pixel according to the DeMura data, and outputting the corrected brightness information of the pixel;

[0072] In the above steps, the brightness information of the corresponding pixels is corrected, specifically including:

[0073] Step S301, determining a DeMura correction reference brightness;

[0074] The DeMura correction reference brightness = 255 / maximum compensation magnification;

[0075] Step S302, calculating the ratio of the DeMura correction reference brightness to the DeMura data;

[0076] Step S303, correcting the brightness information of the pixel according to the ratio;

[0077] In the above step S303, the brightness information of the pixel is corrected according to the ratio, specifically including:

[0078] If the ratio of the DeMura correction reference brightness to the DeMura data is less than 1, the output data (data_out) of the corrected brightness information is the input data (data_in) of the brightness information multiplied by the ratio of the DeMura correction reference brightness to the DeMura data;

[0079] If the ratio of the DeMura correction reference brightness to the DeMura data is greater than or equal to 1, no correction is performed, and the input data (data_in) of the brightness information is directly output as the output data (data_out);

[0080] Step S304: output the corrected pixel brightness information.

[0081] Figure 2 and Figure 3 is the compensation curve of different pixels of a screen during compensation, where Figure 2 For the case where the DeMura correction reference brightness is less than the DeMura data, Figure 3In the case where the DeMura correction reference brightness is greater than the DeMura data, in digital drive display, grayscale is achieved by adjusting the duty cycle. In the above figure, ref is the DeMura correction reference brightness, demura_in is the DeMura data of the pixel, the horizontal axis is the input grayscale of the pixel, and the vertical axis is the output duty cycle of the pixel. Figure 2 In , the DeMura data is 255, and the DeMura correction reference brightness is less than the DeMura data. At this time, there is a compensation effect, and the compensation effect of all grayscales is consistent; Figure 3 In the example, the DeMura data is 64, and the DeMura correction reference brightness is greater than the DeMura data. At this time, there is no compensation effect.

[0082] As an example, assuming that the DeMura correction reference brightness ref = 128, when the DeMura data of pixel 1 (Pixel_1) is 255, that is, demura_in(demura_data) = 255, the output duty cycle is Figure 2 As another example, assuming that the DeMura correction reference brightness ref = 128, when the DeMura data of pixel 1 (Pixel_1) is 64, that is, demura_in(demura_data) = 64, the output duty cycle is Figure 3 shown.

[0083] Figures 4 to 6 The following are comparison diagrams of three different sample screens at different calibration reference brightness. It can be seen from the figure that with the continuous adjustment of the calibration reference brightness, the screen display effect is also continuously improved synchronously.

[0084] In actual applications, the quality and performance of screens vary. The IV characteristics of a screen refer to the current changes of the screen under different voltages, which is directly related to the visual performance of the screen, such as brightness and contrast. The IV characteristics of a screen mainly involve the current-voltage characteristics of the screen, which is an important indicator for evaluating screen performance. For screens with poor IV characteristics, if a unified demura correction is performed, the correction effects of different grayscales will be inconsistent, such as Figure 7 For this case, in one embodiment, an independent DeMura correction reference brightness ref is set for each gray scale, and the display effect after the individual correction of different gray scales is as follows: Figure 8 As shown, the problem of inconsistent correction effects of different grayscales can be solved. Figure 7 The nonlinear relationship between screen duty cycle and brightness is caused by process reasons. If the above method is used to compensate, Figure 7 In the case of grayscale, the compensation effect is good only when the grayscale is 255, and the compensation effects of other grayscales are poor; Figure 8 for Figure 7 When compensating, the screen sets different DeMura correction reference brightness ref for different grayscales, which can achieve better compensation effects at different grayscales.

[0085] In a second aspect, the present application provides a correction device for a digital drive display panel, the device being used to implement the method of the first aspect, the device comprising:

[0086] An associated storage module, used for acquiring DeMura data of a complete data frame from the first memory, and sequentially associatively storing the DeMura data of each pixel in the digital drive display panel in the second memory;

[0087] A data acquisition module, used to acquire input video data, and acquire DeMura data of corresponding addresses from the second memory according to the position of each pixel in the current video data frame;

[0088] The brightness correction module is used to correct the brightness information of the corresponding pixels according to the DeMura data and output the corrected brightness information of the pixels.

[0089] The first memory from which the above-mentioned associated storage module obtains data may be a FLASH memory. After the system is powered on, a read request is sent to a memory read controller, such as a FLASH read controller, and the memory read controller reads the DeMura data of a complete data frame from the memory according to the read request; thereafter, the read operation on the memory is stopped; and the DeMura data from the first pixel to the last pixel in the digital drive display panel are sequentially stored in the second memory, which may be an SRAM memory.

[0090] The data acquisition module acquires the input video data frame by detecting the frame start signal, and waits for the frame start signal of the next video data frame after completing the reading of the associated DeMura data of each pixel in the current frame.

[0091] The brightness correction module determines the DeMura correction reference brightness, calculates the ratio of the DeMura correction reference brightness to the DeMura data, and corrects the brightness information of the pixel according to the ratio. If the ratio of the DeMura correction reference brightness to the DeMura data is less than 1, the output data (data_out) of the corrected brightness information is the input data (data_in) of the brightness information multiplied by the ratio of the DeMura correction reference brightness to the DeMura data; if the ratio of the DeMura correction reference brightness to the DeMura data is greater than or equal to 1, no correction is performed, and the input data (data_in) of the brightness information is directly output as the output data (data_out); the brightness information of the corrected pixel is output.

[0092] Various embodiments of the systems and techniques described above in the present invention can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: being implemented in one or more computer programs, which can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a dedicated or general programmable processor, which can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0093] The program code for implementing the method disclosed in the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0094] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0095] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0096] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0097] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0098] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and the present invention is not limited here.

[0099] The above specific implementations do not constitute a limitation on the scope of protection disclosed by the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle disclosed by the present invention shall be included in the scope of protection disclosed by the present invention.

Claims

1. A calibration method for a digital drive display panel, characterized in that: The method includes: Step S1, obtaining correction data of a complete data frame from the first memory, and sequentially and associatively storing the correction data of each pixel in the digital drive display panel in the second memory; Step S2, obtaining input video data, and obtaining correction data of corresponding addresses from the second memory according to the position of each pixel in the current video data frame; Step S3, correcting the brightness information of the corresponding pixel according to the correction data, and outputting the corrected brightness information of the pixel; Before the above step S1, the method further comprises the following steps: Step 101, obtaining pixel brightness information of each pixel of a digital drive display panel at a preset gray scale; Step 102: Count the pixel brightness information of each pixel and determine the compensation interval according to a preset maximum compensation ratio; Step 103, comparing the pixel brightness information of each pixel with the determined brightness information of the pixels within the compensation interval, and determining the correction data of each pixel according to the comparison result; Step 104: normalize the calculated correction data, associate it with the brightness information of each pixel and store it in the first memory; In the above step 102, the maximum compensation ratio = the maximum value of the brightness information within the compensation interval / the minimum value of the brightness information within the compensation interval.

2. The method according to claim 1, characterized in that The pixel brightness information is the correction data. The correction data of each pixel is determined according to the comparison result, including: If the pixel brightness information is greater than the brightness information of the pixel in the compensation interval, the correction data of the pixel is the maximum value of the brightness information in the compensation interval; If the brightness information of each pixel is within the range of the brightness information of the pixel in the compensation interval, the correction data of the pixel is its own brightness information; If the brightness information of each pixel is less than the brightness information of the pixel in the compensation interval, the correction data of the pixel is the minimum value of the brightness information in the compensation interval.

3. The method according to claim 1 or 2, characterized in that: In the above step 104, normalization processing is performed, specifically including: dividing the pixel brightness information of each pixel by the maximum value of all pixel brightness information and then multiplying by 255, and converting the calculated result into an 8-bit hexadecimal integer.

4. The method according to claim 1, characterized in that In the above step S3, the brightness information of the corresponding pixel is corrected, specifically including: Step S301, determining a calibration reference brightness; Step S302, calculating the ratio of the calibration reference brightness to the calibration data; Step S303, correcting the brightness information of the pixel according to the ratio; Step S304: output the corrected pixel brightness information.

5. The method according to claim 4, characterized in that Correcting the brightness information of the pixel according to the ratio specifically includes: If the ratio of the calibration reference brightness to the calibration data is less than 1, the output data of the calibrated brightness information is the input data of the brightness information multiplied by the ratio of the calibration reference brightness to the calibration data; If the ratio of the correction reference brightness to the correction data is greater than or equal to 1, no correction is performed, and the input data of the brightness information is directly output as output data.

6. The method according to claim 4, characterized in that When determining the correction reference brightness, an independent correction reference brightness is set for each gray scale.

7. The method according to claim 4, characterized in that When determining the correction reference brightness, a uniform correction reference brightness is set for each gray scale.

8. The method according to claim 1, characterized in that In the above step 101 , the grayscale value is preset to be 255.

9. A correction device for a digital drive display panel, the device being used to implement the method according to any one of claims 1 to 8, characterized in that: The device includes: An associated storage module, used for acquiring data of a complete data frame from the first memory, and sequentially and associatedly storing the data of each pixel in the digital drive display panel in the second memory; A data acquisition module, used to acquire input video data, and acquire data of corresponding addresses from the second memory according to the position of each pixel in the current video data frame; The brightness correction module is used to correct the brightness information of the corresponding pixels according to the data and output the corrected brightness information of the pixels.

Images