Display screen brightness compensation method, device and system and storage medium

Abstract

The invention discloses a display screen brightness compensation method, device and system and a storage medium, and is used for realizing high-precision screen calibration and image registration, and the method comprises the steps: obtaining feature images of a to-be-detected screen under different gray scales, and extracting a coordinate corresponding relation between a standard screen and the to-be-detected screen based on the feature images; generating a homography matrix according to the coordinate corresponding relation, wherein the homography matrix is used for describing a mapping relation between a standard screen coordinate system and a to-be-tested screen coordinate system; standard sub-pixel position data in a reference coordinate library are input into the homography matrix, actual sub-pixel positions of the to-be-detected screen are obtained through calculation, and the reference coordinate library comprises position coordinates of standard sub-pixels in a standard coordinate system and the relative geometrical relationship of the standard sub-pixels; and acquiring brightness data of the to-be-detected screen under different gray scales according to the actual sub-pixel position, and performing brightness compensation on the to-be-detected screen based on the brightness data.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of display screen detection, and particularly to a display screen brightness compensation method, device, system and storage medium. Background Art

[0002] With the update and iteration of electronic products, display screens are used more frequently, and consumers have higher requirements for product quality. In the field of display screen production, the brightness uniformity and accuracy of display screens directly determine the visual effect of display devices and are one of the core indicators affecting user experience. For various display devices such as mobile phones, TVs, and computer monitors, uneven picture brightness will cause image distortion and color deviation. In severe cases, it may even cause visual fatigue and reduce the market competitiveness of products. As sub-pixels are the smallest light-emitting units that make up the display screen, their positioning accuracy directly affects the accuracy of brightness compensation. Therefore, the precise positioning of sub-pixels has become a basic technology for achieving precise brightness compensation.

[0003] Currently, traditional display panel brightness compensation methods generally adopt a screen-by-screen positioning strategy, that is, sub-pixel positioning of the RGB / W positioning screen needs to be performed on each display screen. In the specific implementation process, first, high-precision image acquisition devices such as industrial cameras are required to capture the RGB / W positioning screens of each screen. Since the cooperative emission of the three primary colors of red, green, and blue and white sub-pixels determines the final display color and brightness, complex image processing algorithms are required to identify and calculate the coordinates of sub-pixels in the positioning screen one by one to determine the actual positions of sub-pixels, and then perform brightness compensation.

[0004] Although traditional brightness compensation methods can ensure a certain degree of accuracy, since repeated sub-pixel positioning operations need to be performed on each screen, it not only consumes a large amount of time and labor costs, reduces production efficiency, but also increases the complexity and uncertainty in the production process, which is not conducive to large-scale production. With the continuous growth of the market demand for display screens and the increasing requirements for production efficiency, there is an urgent need for a display screen brightness compensation solution that can simplify the production process and improve production efficiency. Summary of the Invention

[0005] The present application discloses a display screen brightness compensation method, device, system and storage medium for achieving high-precision screen calibration and image registration.

[0006] The first aspect of the present application discloses a display screen brightness compensation method, including: Obtaining characteristic images of a screen to be measured at different gray levels, and extracting the coordinate correspondence between a standard screen and the screen to be measured based on the characteristic images; Generating a homography matrix according to the coordinate correspondence, where the homography matrix is used to describe the mapping relationship between the standard screen coordinate system and the screen to be measured coordinate system; Inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix to calculate the actual sub-pixel position of the screen to be tested, wherein the reference coordinate library contains the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationship; The brightness data of the screen to be tested at different grayscales are collected according to the actual sub-pixel positions, and brightness compensation is performed on the screen to be tested based on the brightness data.

[0007] Optionally, generating a homography matrix according to the coordinate correspondence includes: Extracting the coordinates of four corner points of the characteristic image at different grayscales of the screen to be tested; Based on the correspondence between the coordinates of the four corner points of the standard screen and the coordinates of the four corner points of the screen to be tested, a homography matrix is calculated and generated.

[0008] Optionally, the calculation to generate a homography matrix includes: Constructing a linear equation system based on at least four non-collinear corner point coordinates of the standard screen and the screen to be tested; The RANSA algorithm is used to obtain the optimal parameter set through iterative calculation; An inlier threshold is set to remove abnormal matching points in the optimal parameter set, matrix parameters of the homography matrix are obtained, and a homography matrix is generated.

[0009] Optionally, the formula for mapping the standard sub-pixel position to the screen to be tested through the homography matrix is:

[0010] Among them, h11, h12, …, h33 are matrix parameters solved by the least squares method or RANSAC algorithm. is the coordinate position of the standard screen, is the coordinate position of the screen to be tested.

[0011] Optionally, inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix to calculate the actual sub-pixel position of the screen to be tested includes: Performing homogeneous coordinate conversion on the standard sub-pixel position data to expand the two-dimensional coordinates into a three-dimensional homogeneous coordinate form; Linearly transforming the standard sub-pixel position data in the form of three-dimensional homogeneous coordinates by using the homography matrix; The transformed coordinates are normalized to obtain the two-dimensional actual sub-pixel position coordinates of the screen to be tested.

[0012] Optionally, the transformed coordinates are normalized to obtain the two-dimensional actual sub-pixel position coordinates of the screen to be tested using the following formula:

[0013] Similarly, for the pixels of the screen to be measured and the coordinate positions are calculated by the same formula:

[0014]

[0015] where h11, h12, …, h33 are the matrix parameters of the homography matrix, , , are the coordinate positions of different colors of the standard screen respectively, , , are the coordinate positions of different colors of the screen to be measured.

[0016] Optionally, before inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix, it further includes: Calculating the error between the coordinates of the standard screen sub-pixels after being transformed by the homography matrix and the actual coordinates of the screen to be measured, and when the error exceeds a preset threshold, recalibrating the homography matrix.

[0017] The second aspect of the present application provides a display screen brightness compensation device, including: An acquisition unit, configured to acquire the characteristic images of the screen to be measured at different gray levels, and extract the coordinate correspondence between the standard screen and the screen to be measured based on the characteristic images; A generation unit, configured to generate a homography matrix according to the coordinate correspondence, and the homography matrix is used to describe the mapping relationship between the standard screen coordinate system and the screen to be measured coordinate system; A calculation unit, configured to input the standard sub-pixel position data in the reference coordinate library into the homography matrix, and calculate the actual sub-pixel positions of the screen to be measured, where the reference coordinate library includes the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationships; A compensation unit, configured to collect the brightness data of the screen to be measured at different gray levels according to the actual sub-pixel positions, and perform brightness compensation on the screen to be measured based on the brightness data.

[0018] The third aspect of the present application provides a display screen brightness compensation system, including: A processor, a memory, an input / output unit, and a bus; The processor is connected to the memory, the input / output unit, and the bus; The memory stores a program, and the processor calls the program to execute the method as described in the first aspect and any optional method of the first aspect.

[0019] A fourth aspect of the present application provides a computer-readable storage medium, on which a program is stored. When the program is executed on a computer, it executes the methods described in the first aspect and any optional methods of the first aspect.

[0020] As can be seen from the above technical solutions, the embodiments of the present application have the following advantages: The present invention first performs a high-precision sub-pixel positioning on a standard screen to construct a reference coordinate library containing the position coordinates of standard sub-pixels in the standard coordinate system and their relative geometric relationships. Then, it obtains the characteristic images of the screen to be measured at different gray levels, quickly extracts the coordinate correspondence between the standard screen and the screen to be measured through edge detection, and then generates a homography matrix. Subsequently, by inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix, the actual sub-pixel positions of the screen to be measured can be calculated, without the need for cumbersome sub-pixel positioning calculations for each screen to be measured. This reduces the time and labor costs of industrial camera acquisition and complex processing, simplifies the production process, effectively improves production efficiency, reduces production complexity and uncertainty, shortens the production line cycle, and is applicable to large-scale production scenarios.

[0021] Secondly, by constructing an accurate reference coordinate library and a scientific mapping mechanism, the positioning accuracy is improved. On the one hand, the reference coordinate library details the position coordinates of standard sub-pixels in the standard coordinate system and their relative geometric relationships, providing a high-precision reference benchmark for subsequent positioning of the screen to be measured. On the other hand, the coordinate correspondence between the standard screen and the screen to be measured is extracted using the characteristic images at different gray levels, and a homography matrix is generated. This matrix can accurately describe the mapping relationship between the two coordinate systems. When calculating the actual sub-pixel positions of the screen to be measured, based on the accurate reference coordinate library data and the reliable homography matrix mapping, factors such as substrate deformation and process errors that may exist during the production process of the display panel can be fully considered, accurately determining the sub-pixel positions, improving the positioning accuracy, and reducing the complexity of the sub-pixel positioning algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of an embodiment of the display screen brightness compensation method of the present application; Figure 2 It is a schematic diagram of an embodiment of the method for generating a homography matrix according to the coordinate correspondence of the present application; Figure 3 It is a schematic diagram of an embodiment of the method for calculating and generating a homography matrix of the present application; Figure 4 Schematic diagram of an embodiment of the method for calculating the actual sub-pixel position of the screen to be measured in this application; Figure 5 Schematic diagram of an embodiment of the method for determining whether to recalibrate the homography matrix in this application; Figure 6 Schematic diagram of an embodiment of the device for compensating the brightness of the display screen in this application; Figure 7 Schematic diagram of an embodiment of the system for compensating the brightness of the display screen in this application. Detailed implementation manners

[0024] In the following description, specific details such as specific system architectures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of this application. However, those skilled in the art should clearly understand that this application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of this application.

[0025] It should be understood that when used in the specification and appended claims of this application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0026] It should also be understood that the term "and / or" as used in the specification and appended claims of this application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0027] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when", "once", "in response to determining", or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if detecting [the described condition or event]" can be interpreted as meaning "once determined", "in response to determining", "once detecting [the described condition or event]", or "in response to detecting [the described condition or event]" depending on the context.

[0028] In addition, in the description of the specification and appended claims of this application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that specific features, structures or characteristics described in connection with that embodiment are included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments" etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized.

[0030] Based on this, the present application discloses a display screen brightness compensation method, device, system and storage medium for realizing high-precision screen calibration and image registration.

[0031] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0032] The method of the present application can be applied to a server, a device, a terminal or other devices with logical processing capabilities, and the present application makes no limitation thereto. For the convenience of description, the following description will be made by taking the execution subject as a system as an example.

[0033] Please refer to Figure 1 , an embodiment of a display screen brightness compensation method provided by the present application includes: 101. Obtain characteristic images of the screen to be measured at different gray levels, and extract the coordinate correspondence between the standard screen and the screen to be measured based on the characteristic images; 102. Generate a homography matrix according to the coordinate correspondence, and the homography matrix is used to describe the mapping relationship between the standard screen coordinate system and the screen to be measured coordinate system; 103. Input the standard sub-pixel position data in the reference coordinate library into the homography matrix, and calculate the actual sub-pixel positions of the screen to be measured. The reference coordinate library includes the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationships; 104. Collect the brightness data of the screen to be measured at different gray levels according to the actual sub-pixel positions, and perform brightness compensation on the screen to be measured based on the brightness data.

[0034] In step 101, first, perform multi - gray - scale testing on the screen under test to obtain its characteristic images at different gray - scale levels. These characteristic images contain the display characteristics of the screen under test under different driving conditions. Through image - processing algorithms, extract the geometric feature points of the screen under test from the characteristic images, and match them with the corresponding feature points of the standard screen to establish the coordinate correspondence relationship between the two. Specifically, input 0 - gray - scale, 128 - gray - scale, and 255 - gray - scale signals to the screen under test in sequence, and use an industrial camera to vertically capture three characteristic images. Perform Gaussian blur denoising on the all - black image, perform histogram equalization on the all - white image to enhance the edge contrast, and crop to retain the effective display area. Then perform Canny edge detection on the pre - processed image, set the low threshold to 50 and the high threshold to 150, and extract the rectangular edge contour of the screen body. Use the Douglas - Peucker algorithm to approximate the contour, determine the coordinates of the four corner points, and improve the coordinate accuracy to the sub - pixel level through cubic spline interpolation. Use the BRIEF feature descriptor to match the same - named corner points in different gray - scale images, calculate the Hamming distance to screen out the matching pairs. Take the average value of the coordinates of the same corner point at different gray - scale levels. Verify the geometric relationship of the four corner points, calculate the side - length error and interior - angle degrees, and eliminate the out - of - tolerance matching points. Finally, establish a coordinate correspondence table between the standard screen and the screen under test.

[0035] Based on the coordinate correspondence relationship obtained in step 101, in step 102, use an optimization algorithm such as the least - squares method to calculate the homography matrix. This 3×3 homography matrix completely describes the projective transformation relationship between the standard - screen coordinate system and the screen - under - test coordinate system, including geometric transformations such as rotation, translation, scaling, and perspective distortion.

[0036] In step 103, input the standard sub - pixel position data in the pre - established reference coordinate library into the homography matrix, and obtain the corresponding actual sub - pixel positions on the screen under test through matrix operations. The reference coordinate library contains the precise coordinates of each sub - pixel on the standard screen and their relative geometric relationships, and these data are obtained in advance through high - precision measurement equipment.

[0037] In step 104, according to the calculated actual sub - pixel positions, use a high - precision photometer to collect the brightness data of the screen under test at different gray - scale levels. Compare these brightness data with the reference brightness of the standard screen, calculate the brightness compensation value for each sub - pixel, and generate a brightness compensation look - up table. The brightness compensation process includes: measuring the actual brightness at multiple gray - scale levels (such as 0 - 255), establishing a brightness - gray - scale response curve, calculating the compensation coefficient to match the response curve with the standard curve, and writing the compensation coefficient into the display - screen driving chip.

[0038] In this embodiment, first, a high-precision sub-pixel positioning is performed on the standard screen to construct a reference coordinate library containing the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationships. Then, the characteristic images of the screen to be measured at different gray levels are obtained, and the coordinate correspondence between the standard screen and the screen to be measured is quickly extracted through edge detection, and then a homography matrix is generated. Subsequently, the position data of the standard sub-pixels in the reference coordinate library is input into the homography matrix, and the actual sub-pixel positions of the screen to be measured can be calculated without performing cumbersome sub-pixel positioning calculations for each screen to be measured. This reduces the time and labor costs of industrial camera acquisition and complex processing, simplifies the production process, effectively improves production efficiency, reduces production complexity and uncertainty, shortens the production line cycle, and is applicable to large-scale production scenarios.

[0039] Secondly, by constructing an accurate reference coordinate library and a scientific mapping mechanism, the positioning accuracy is improved. On the one hand, the reference coordinate library details the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationships, providing a high-precision reference benchmark for the subsequent positioning of the screen to be measured. On the other hand, the coordinate correspondence between the standard screen and the screen to be measured is extracted using the characteristic images at different gray levels, and a homography matrix is generated, which can accurately describe the mapping relationship between the two coordinate systems. When calculating the actual sub-pixel positions of the screen to be measured, based on the accurate reference coordinate library data and the reliable homography matrix mapping, factors such as substrate deformation and process errors that may exist in the display panel production process can be fully considered, accurately determining the sub-pixel positions, improving the positioning accuracy, and reducing the complexity of the sub-pixel positioning algorithm.

[0040] Please refer to Figure 2 , an embodiment of a method for generating a homography matrix according to coordinate correspondence provided by this application includes: 201. Extract the four corner coordinates of the characteristic images of the screen to be measured at different gray levels; 202. Calculate and generate a homography matrix based on the correspondence between the four corner coordinates of the standard screen and the four corner coordinates of the screen to be measured.

[0041] In step 201, Canny edge detection or Hough transform is performed on the gray level image of the screen to be measured to extract the four corner coordinates of the characteristic images of the screen to be measured at different gray levels , , , .

[0042] In step 202, a homography matrix describing the geometric transformation between the two is calculated based on the four intersection coordinates. Specifically, a one-to-one correspondence is established between the corner coordinates of the screen to be measured and the corner coordinates of the standard screen measured in advance. The corner coordinates of the standard screen are obtained through a high-precision measuring device and stored in the reference database. The homography matrix is calculated through the following formula:

[0043] Among them, $(1\leq i\leq4)$ is the set of row coordinates of the four corner points corresponding to the standard screen area, $(1\leq j\leq4)$ is the set of column coordinates of the four corner points corresponding to the standard screen area; $(1\leq i\leq4)$ is the set of row coordinates for positioning the four corner points of the screen area to be measured, $(1\leq j\leq4)$ is the set of column coordinates for positioning the four corner points of the screen area to be measured; Matrix is a $3\times3$ homography matrix, specifically: .

[0044] In this embodiment, through precise four-corner point matching and homography matrix calculation, the following technical advantages are achieved: High-precision geometric correction: It can accurately compensate for the translation, rotation, scaling, and perspective distortion of the screen to be measured; High calculation efficiency: Only four feature points are required to complete the calculation, which is suitable for rapid detection on the production line; Strong robustness: Insensitive to slight illumination changes and image noise; Good compatibility: Applicable to various types of display screens, including LCD, OLED, etc.

[0045] Please refer to Figure 3 , this application provides an embodiment of a method for calculating and generating a homography matrix, including: 301. Based on the at least four non-collinear corner point coordinates of the standard screen and the screen to be measured, construct a system of linear equations; 302. Use the RANSAC algorithm to obtain the optimal parameter set through iterative calculation; 303. Set an inlier threshold to eliminate the abnormal matching points in the optimal parameter set, obtain the matrix parameters of the homography matrix, and generate the homography matrix.

[0046] In step 301, it is first necessary to obtain the at least four non-collinear corner point coordinates of the standard screen and the screen to be measured. Corner points are points with obvious features in the image, usually located at the intersections of edges. In the screen calibration scenario, these corner points can be the four vertices of the screen or other known feature points. The non-collinearity requirement is to ensure that the problem has a unique solution because three collinear points cannot determine a plane. After obtaining these corner point coordinates, a system of linear equations is constructed to describe the mapping relationship between the point coordinates.

[0047] In step 302, the RANSAC (Random Sample Consensus) algorithm is used to estimate the homography matrix. This algorithm is very robust to outliers. Specifically, by randomly selecting a small number of sample points to estimate the model parameters, then evaluating the support degree of other points for this model, and finally selecting the model with the most support as the optimal model. The specific steps are as follows: Randomly select 4 pairs of non - collinear corner points from all matching point pairs; Use these 4 pairs of corner points to solve the linear equation system to obtain a homography matrix estimate; Calculate the projection error of all point pairs under this homography matrix; Mark the point pairs with errors less than a certain threshold as inliers; If the number of inliers exceeds the preset minimum value, re - estimate the homography matrix using all inliers; Repeat the above process multiple times, and select the model with the largest number of inliers as the final result.

[0048] After the iteration of the RANSAC algorithm based on step 302, a homography matrix estimate with the most inlier support is obtained. However, there may still be some points with large errors among these inliers, so further screening is required.

[0049] In step 303, by setting a suitable inlier threshold, the points with projection errors exceeding this threshold are excluded again. The selection of this threshold is usually based on the specific application scenario and data characteristics, and a trade - off between accuracy and robustness is required.

[0050] After excluding the outlier points, use the remaining high - quality inliers to re - estimate the homography matrix to obtain the final matrix parameters. The homography matrix can accurately describe the geometric transformation relationship between the standard screen and the screen to be measured.

[0051] In this embodiment, a linear equation system is constructed through at least four non - collinear corner points to ensure a unique solution for the homography matrix parameters, avoid the problem of solution degradation caused by collinear points, and improve the mapping accuracy. Iteratively excluding the outlier matching points can effectively resist the corner detection errors (such as edge blurring, noise interference) and incorrect matches, making the homography matrix closer to the real geometric transformation. The random sampling strategy of RANSAC reduces the dependence on the full - volume data, quickly converges to the optimal solution through a limited number of iterations, transforms the homography matrix solution into a linear equation system problem, avoids the complex iterative process of non - linear optimization, and reduces the computational complexity.

[0052] Please refer to Figure 4 , this application provides an embodiment of a method for calculating the actual sub - pixel position of the screen to be measured, including: 401. Perform homogeneous coordinate transformation on the standard sub - pixel position data to expand the two - dimensional coordinates into a three - dimensional homogeneous coordinate form; 402. Perform a linear transformation on the standard sub - pixel position data in the three - dimensional homogeneous coordinate form through the homography matrix; 403. Normalize the transformed coordinates to obtain the two - dimensional actual sub - pixel position coordinates of the screen to be measured.

[0053] The formula for expanding matrix multiplication and normalizing homogeneous coordinates, and mapping the offline standard sub-pixel positions to the online screen to be measured through the homography matrix Matrix is as follows:

[0054] Among them, h11, h12, …, h33 are the matrix parameters solved by the least squares method or the RANSAC algorithm, is the coordinate position of the standard screen, is the coordinate position of the screen to be measured.

[0055] Assume that the coordinate position of the offline standard sub-pixel Rstd is , then the coordinate position of the sub-pixel of the screen to be measured is:

[0056] Similarly, the coordinate positions of the sub-pixels and of the screen to be measured are calculated by the same formula:

[0057]

[0058] Among them, h11, h12, …, h33 are the matrix parameters of the homography matrix, , , are the coordinate positions of different colors of the standard screen respectively, , , are the coordinate positions of different colors of the screen to be measured.

[0059] In this embodiment, the normalization process ensures the consistency and interpretability of the coordinates, converts the representation in the homogeneous coordinate system into actual physical coordinates, and the normalization process also avoids the singularity problem of the denominator being zero in the homogeneous coordinates, ensuring the reliability of the algorithm in various scenarios. Through the homography matrix and the normalization process, an accurate coordinate mapping from the standard screen to the screen to be measured is achieved.

[0060] Please refer to Figure 5 , this application provides an embodiment of a method for determining whether to recalibrate the homography matrix, including: 501. Calculate the error between the coordinates of the standard screen sub-pixels after being transformed by the homography matrix and the actual coordinates of the screen to be measured. When the error exceeds the preset threshold, recalibrate the homography matrix.

[0061] By real-time monitoring of the coordinate mapping error between the standard screen and the screen to be measured, when the error exceeds the acceptable range, the recalibration process is automatically triggered to ensure that the system maintains a high-precision coordinate mapping relationship for a long time.

[0062] Specifically, reasonable and different error thresholds are set to trigger the recalibration process: Global threshold: Set a fixed error threshold, and when the error at any detection point exceeds this threshold, calibration is triggered.

[0063] Statistical threshold: Calculate the average error or root mean square error of all detection points, and when the statistical error exceeds the threshold, calibration is triggered.

[0064] Adaptive threshold: Dynamically adjust the threshold according to the system operating environment. For example, relax the threshold appropriately in a high-temperature environment or tighten the threshold during precise operations.

[0065] When it is detected that the error exceeds the threshold, the system automatically starts recalibration, re-acquires the coordinates of at least four non-collinear corner points of the standard screen and the screen to be measured, and uses the RANSAC algorithm to re-estimate the homography matrix parameters to generate a new homography matrix.

[0066] After generating the new homography matrix, an error level coefficient is generated according to the previous homography matrix global threshold, statistical threshold, and adaptive threshold , and the formula is as follows:

[0067] Among them, , and are the global error, statistical error, and adaptive error respectively, , and are the global threshold, statistical threshold, and adaptive threshold respectively. Calculate the matrix element adjustment value according to the two homography matrices , and the formula is as follows:

[0068] Among them, M is the number of row elements of the homography matrix, N is the number of column elements of the homography matrix, is the element value at the coordinate (i, j) in the original homography matrix, is the element value at the coordinate (i, j) in the calibrated homography matrix.

[0069] Next, calculate the abnormal element adjustment value of the abnormal point position and the corner element adjustment value of the corner point , is the k-th abnormal element value in the original homography matrix, is the element value corresponding to the k-th abnormal element in the calibrated homography matrix, and T is the number of abnormal point positions. is the s-th corner point element value in the original homography matrix, is the element value corresponding to the s-th corner point element in the rectified homography matrix, where S is the number of corner points.

[0070]

[0071]

[0072] According to the matrix element adjustment value , the abnormal element adjustment value and the corner point element adjustment value of the corner point perform analysis and calculation to generate an equilibrium adjustment value ;

[0073] When the equilibrium adjustment value is compared with the error level coefficient to determine whether the equilibrium adjustment value and the error level coefficient are comparable, that is, to determine whether the degree of adjustment and the degree of the original error are appropriate. If not, the equilibrium adjustment value needs to be used to calculate new micro-adjustment parameters with the error level coefficient , and then the new homography matrix is adjusted as a whole.

[0074] In this embodiment, through continuous monitoring and dynamic calibration, parameter drift caused by factors such as screen aging and temperature change is compensated to ensure that the system maintains high precision for a long time. Combining with the anti-noise ability of the RANSAC algorithm, reliable coordinate mapping can still be maintained in the presence of environmental interference. Calibration can be completed without manual intervention, which is suitable for unattended devices.

[0075] Please refer to Figure 6 , this application provides an embodiment of a device for compensating the brightness of a display screen, including: An acquisition unit 601, configured to acquire characteristic images of the screen to be measured at different gray levels, and extract the coordinate correspondence between the standard screen and the screen to be measured based on the characteristic images; A generation unit 602, configured to generate a homography matrix according to the coordinate correspondence, and the homography matrix is used to describe the mapping relationship between the standard screen coordinate system and the screen to be measured coordinate system; Optionally, the generation unit 602 includes: Extract the four corner point coordinates of the characteristic images of the screen to be measured at different gray levels; Calculate and generate a homography matrix based on the correspondence between the four corner point coordinates of the standard screen and the four corner point coordinates of the screen to be measured.

[0076] Optionally, the generation unit 602 further includes: Construct a system of linear equations based on at least four non-collinear corner point coordinates of the standard screen and the screen to be measured; The RANSA algorithm is adopted to obtain the optimal parameter set through iterative calculation; An inlier threshold is set to eliminate abnormal matching points in the optimal parameter set, obtain the matrix parameters of the homography matrix, and generate the homography matrix.

[0077] Optionally, it further includes a calibration unit 603: Calculate the error between the coordinates of the standard screen sub-pixels after being transformed by the homography matrix and the actual coordinates of the screen to be measured. When the error exceeds the preset threshold, recalibrate the homography matrix.

[0078] A calculation unit 604 is used to input the standard sub-pixel position data in the reference coordinate library into the homography matrix, and calculate the actual sub-pixel position of the screen to be measured. The reference coordinate library includes the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationships; Optionally, the calculation unit 604 includes: Perform homogeneous coordinate transformation on the standard sub-pixel position data to expand the two-dimensional coordinates into a three-dimensional homogeneous coordinate form; Perform a linear transformation on the standard sub-pixel position data in the three-dimensional homogeneous coordinate form through the homography matrix; Normalize the transformed coordinates to obtain the two-dimensional actual sub-pixel position coordinates of the screen to be measured.

[0079] A compensation unit 605 is used to collect the brightness data of the screen to be measured at different gray levels according to the actual sub-pixel positions, and perform brightness compensation on the screen to be measured based on the brightness data.

[0080] For the specific implementation manners, refer to Figures 1 - 5 the embodiments, which will not be elaborated here.

[0081] Please refer to Figure 7 , this application provides a display screen brightness compensation system, including: A processor 701, a memory 702, an input / output unit 703, and a bus 704.

[0082] The processor 701 is connected to the memory 702, the input / output unit 703, and the bus 704.

[0083] The memory 702 stores a program, and the processor 701 calls the program to execute the methods as described in Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 above.

[0084] This application provides a computer-readable storage medium, on which a program is stored. When the program is executed on a computer, it executes the methods as described in Figure 1 , Figure 2, Figure 3 , Figure 4 , and Figure 5 the methods in.

[0085] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0086] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0087] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] In addition, the functional units in each embodiment of the present application can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0089] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. And the foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, read-only memory), random access memories (RAM, random access memory), magnetic disks, or optical discs that can store program codes.

Claims

1. A method for compensating the brightness of a display screen, characterized in that, include: Acquire characteristic images of the screen to be tested at different grayscales, and extract the coordinate correspondence between the standard screen and the screen to be tested based on the characteristic images; Generate a homography matrix according to the coordinate correspondence, wherein the homography matrix is used to describe the mapping relationship between the standard screen coordinate system and the screen coordinate system to be measured; Inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix to calculate the actual sub-pixel position of the screen to be tested, wherein the reference coordinate library contains the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationship; The brightness data of the screen to be tested at different grayscales are collected according to the actual sub-pixel positions, and brightness compensation is performed on the screen to be tested based on the brightness data.

2. The display screen brightness compensation method according to claim 1, wherein The generating a homography matrix according to the coordinate correspondence relationship comprises: Extracting the coordinates of four corner points of the characteristic image at different grayscales of the screen to be tested; Based on the correspondence between the coordinates of the four corner points of the standard screen and the coordinates of the four corner points of the screen to be tested, a homography matrix is calculated and generated.

3. The display brightness compensation method according to claim 2, wherein The calculation generates a homography matrix, including: Constructing a linear equation system based on at least four non-collinear corner point coordinates of the standard screen and the screen to be tested; The RANSA algorithm is used to obtain the optimal parameter set through iterative calculation; An inlier threshold is set to remove abnormal matching points in the optimal parameter set, matrix parameters of the homography matrix are obtained, and a homography matrix is generated.

4. The display screen brightness compensation method according to claim 1, characterized in that, The formula for mapping the standard sub-pixel position to the screen to be tested through the homography matrix is: Among them, h11, h12, …, h33 are matrix parameters solved by the least squares method or the RANSAC algorithm, which is the coordinate position of the standard screen, and which is the coordinate position of the screen to be measured.

5. The display brightness compensation method according to claim 1, wherein, Inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix to calculate the actual sub-pixel position of the screen to be tested, including: Performing homogeneous coordinate conversion on the standard sub-pixel position data to expand the two-dimensional coordinates into a three-dimensional homogeneous coordinate form; Linearly transforming the standard sub-pixel position data in the form of three-dimensional homogeneous coordinates by using the homography matrix; The transformed coordinates are normalized to obtain the two-dimensional actual sub-pixel position coordinates of the screen to be tested.

6. The display screen brightness compensation method according to claim 5, wherein The transformed coordinates are normalized to obtain the formula for the two-dimensional actual sub-pixel position coordinates of the screen to be tested as follows: Similarly, the coordinate positions of the pixels of the screen to be measured and are calculated by the same formula: Among them, h11, h12, …, h33 are the matrix parameters of the homography matrix, , , are the coordinate positions of different colors of the standard screen respectively, , , are the coordinate positions of different colors of the screen to be measured.

7. The method for compensating the brightness of a display screen according to any one of claims 1 to 6, characterized in that, Before inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix, the method further includes: Calculate the error between the coordinates of the sub-pixels of the standard screen after transformation by the homography matrix and the actual coordinates of the screen to be tested. When the error exceeds the preset threshold, recalibrate the homography matrix.

8. A display screen brightness compensation device, characterized in that, include: An acquisition unit, used for acquiring characteristic images of the screen to be tested at different grayscales, and extracting the coordinate correspondence between the standard screen and the screen to be tested based on the characteristic images; A generating unit, used for generating a homography matrix according to the coordinate correspondence, wherein the homography matrix is used for describing the mapping relationship between the standard screen coordinate system and the screen coordinate system to be measured; A calculation unit, used for inputting the standard sub-pixel position data in the reference coordinate library into the homography matrix to calculate the actual sub-pixel position of the screen to be measured, wherein the reference coordinate library contains the position coordinates of the standard sub-pixels in the standard coordinate system and their relative geometric relationship; A compensation unit is used to collect brightness data of the screen to be tested at different grayscales according to the actual sub-pixel positions, and perform brightness compensation on the screen to be tested based on the brightness data.

9. A display screen brightness compensation system, characterized in that, include: A processor, a memory, an input / output unit, and a bus, where the processor is connected to the memory, the input / output unit, and the bus, the memory stores a program, and the processor calls the program to execute the display screen brightness compensation method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, A program is stored on the computer-readable storage medium, and when the program is executed on a computer, it executes the display screen brightness compensation method according to any one of claims 1 to 7.

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