Luminance and chrominance calibration method and device, and computer-readable storage medium

Abstract

Provided in the embodiments of the present disclosure are a luminance and chrominance calibration method and device, and a storage medium. The method comprises: controlling a display screen to display a preset test image, and controlling a colorimeter to collect luminance and chrominance data of the display screen; on the basis of the luminance and chrominance data, generating a smooth gamma table, and iteratively calculating red, green and blue calibration coefficients for each grayscale, so as to obtain a grayscale expansion mapping table; and on the basis of the grayscale expansion mapping table, performing full-grayscale expansion mapping processing on an input image, and controlling the display screen to display an output image that has been subjected to mapping processing. The embodiments of the present disclosure improve the smoothness of grayscale gradients and the color accuracy across all grayscale levels of display, meet both luminance and chrominance calibration requirements and full‑grayscale smoothness requirements, and reduce the calibration time, thereby improving the production efficiency.

Description

A bright chroma calibration method, device and computer readable storage medium

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202411083188.0, filed on August 7, 2024, and entitled "A bright chroma calibration method, device and computer readable storage medium", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to, but is not limited to, the technical field of display testing, for example, to a bright chroma calibration method, device and computer readable storage medium. BACKGROUND

[0004] Due to the influence of display driving chips, the LED display screen has low display precision and insufficient smoothness when displaying full gray scale, that is, there is a "striped" display phenomenon in the transition area of full gray scale, and the change range of low gray scale is large and the precision is low. As a result, the image details are not sufficient and the color is biased, the image has color banding and color halo, and it cannot meet the requirements of market customers on image quality.

[0005] DISCLOSURE

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] In order to solve the technical defects that the gradual transition smoothness and full gray scale color accuracy are poor in the LED display technology, the corresponding calibration scheme cannot simultaneously meet the requirements of bright chroma calibration and full gray scale smoothness, the calibration time is high, and the calibration efficiency is low, the present application embodiment proposes a bright chroma calibration method, device and computer readable storage medium.

[0008] The present application embodiment proposes a bright chroma calibration method, which comprises:

[0009] controlling the display screen to display a preset test picture, and controlling a colorimeter to collect bright chroma data of the display screen;

[0010] generating a smooth gamma table according to the bright chroma data, iteratively calculating red, green and blue calibration coefficients of each gray scale to obtain a gray scale expansion mapping table;

[0011] performing full gray scale expansion mapping processing on an input image according to the gray scale expansion mapping table, and controlling the display screen to display an output image after the mapping processing.

[0012] Optionally, the generating a smooth gamma table according to the bright chroma data comprises:

[0013] generate full gray scale X, Y, Z theoretical values according to the maximum white gray scale X, Y, Z acquisition values in the bright colorimetric data;

[0014] generate the smooth gamma table according to the red, green, and blue full gray scale X, Y, Z acquisition values in the bright colorimetric data and the full gray scale X, Y, Z theoretical values.

[0015] Optionally, the method further comprises:

[0016] calculate full gray scale theoretical Y values according to the red, green, and blue Y values in the bright colorimetric data;

[0017] generate a full gray scale extended smooth gamma table according to the smooth gamma table;

[0018] The iterative calculation of the red, green, and blue calibration coefficients of each gray scale to obtain the gray scale extended mapping table comprises:

[0019] In combination with the full gray scale theoretical Y values, search for the gray scale mapping values closest to the theoretical Y values of each order in the full gray scale extended smooth gamma table to obtain a first gray scale extended mapping table;

[0020] calculate the full gray scale theoretical X, Y, Z values of each order according to the maximum original white X, Y, Z values in the bright colorimetric data to obtain a white theoretical gray scale extended mapping table;

[0021] Based on the first gray scale extended mapping table and the white theoretical gray scale extended table, and in combination with a preset coefficient iterative algorithm, calculate the gray scale extended mapping table containing the extended mapping values of each gray scale.

[0022] Optionally, the maximum gray scale value of an input source is M, and the maximum display output gray scale value of a display screen is M1;

[0023] The maximum display output gray scale of the display screen after the gray scale extension is M2, and the maximum gray scale white Y value and the original full gray scale Y value acquired include:

[0024] Control the display screen to display the white gray scale as the maximum value M1, acquire the corresponding color coordinates X, Y, Z values, and display red, green, and blue, and acquire the color coordinates X, Y, Z values of each gray scale from 0 to M1;

[0025] The generation of the full gray scale extended smooth gamma table according to the smooth gamma table comprises:

[0026] According to the maximum brightness Y Max and the preset brightness threshold values K1 and K2, segment the gray scales;

[0027] Segment the original full gray scale gamma table into low brightness 0 to K1, medium brightness K1 to K2, and high brightness K2 to YMax Three segments, wherein, assuming monochrome full gray scale linearly increasing brightness, and according to the pre-designated empirical value to determine the segmented said brightness threshold K1 and K2.

[0028] Optionally, the display screen full gray scale number M1 linearly extended PlusBit times to get the gray scale number M2, the maximum gray scale X, Y, Z of red, green, blue collected respectively with F maxr X, Y, Z value of red, F maxg X, Y, Z value of green, F maxb X, Y, Z value of blue, respectively generate M2 order of each order x1 theoretical X, Y, Z value table, red, green, blue respectively Ftr(x1), Ftg(x1), Ftb(x1);

[0029] The combination of the original full gray scale Y value, in the full gray scale expansion smooth gamma table, search for each order the closest gray scale mapping value of the full gray scale theoretical Y value, get the first gray scale expansion mapping table, including:

[0030] According to the collected M1 gray scale of the original red, green, blue each order of the actual X, Y, Z value table Facr(x1), Facg(x1), Facb(x1) linear expansion, expansion multiple is M2 / M1, get M2 expansion gray scale each order x1 actual X, Y, Z value table, red, green, blue respectively Far(x1), Fag(x1), Fab(x1);

[0031] According to the M2 order theoretical Y value table, search for the index that satisfies the actual Y value equal to the theoretical Y value in the actual Y value table as the current mapping value;

[0032] Traverse all M2 gray scales to get all corresponding current mapping values as the first gray scale mapping table G1r(x1), G1g(x1), G1b(x1).

[0033] Optionally, the display screen full gray scale number M1 linearly extended PlusBit times to get the gray scale number M2;

[0034] The maximum original white X, Y, Z value in the said light color data is calculated to get the white theoretical gray scale expansion mapping table, including:

[0035] The collected white maximum gray scale M1 X maxw , Y maxw , Z maxw value linearly expanded to M2 gray scale;

[0036] According to the formula,

[0037] The white color theoretical gray scale extension mapping table Xw(x1), Yw(x1), Zw(x1) is calculated.

[0038] Optionally, the number of red, green, blue and white gray scales is M, and the maximum value of the full gray scale extension smoothing gamma table GmEx(x) is M2.

[0039] The method further comprises:

[0040] The mapping gray scale value is determined as x1.

[0041] According to the X, Y and Z theoretical extension mapping table, the smoothed M-order white color theoretical X, Y and Z values Xw(x1), Yw(x1) and Zw(x1) are obtained, and the smoothed theoretical white color X, Y and Z values of x gray scale are determined.

[0042] In the M2-order extension measurement table obtained by actual measurement, the X, Y and Z measured values Far(x1), Fag(x1) and Fab(x1) are searched, the red, green and blue are summed, and the white color extension X, Y and Z measured values Faw(x1) are obtained.

[0043] Optionally, the final gray scale extension mapping table red, green and blue is Gmr(x), Gmg(x) and Gmb(x) respectively.

[0044] The gray scale extension mapping table containing each gray scale extension mapping value is calculated based on the first gray scale extension mapping table and the white color theoretical gray scale extension table, and combined with a preset coefficient iterative algorithm, comprising:

[0045] It is judged whether the error of the measured value Faw(x1) and the theoretical value Xw(x1), Yw(x1) and Zw(x1) is within a preset range. In the case that the error is within the preset range, x1 is the final mapping gray scale value of x, recorded as Gmr(x)=x1, Gmg(x)=x1, Gmb(x)=x1, and in the case that the error is not within the preset range, calibration is performed.

[0046] Optionally, the calculation of the gray scale extension mapping table containing each gray scale extension mapping value comprises:

[0047] The derivation formula is determined,

[0048] Wherein, xr, xg and xb are the adjusted gray scale mapping values, and Coefr, Coefg and Coefb are the calibration coefficients of red, green and blue respectively.

[0049] The iterative formula is obtained,

[0050] Each gray scale extension mapping value is calculated according to the iterative formula.

[0051] Optionally, the calculation of the gray scale expansion mapping table containing each gray scale expansion mapping value further comprises:

[0052] Setting the current gray scale x=0 for calibration;

[0053] For the current gray scale x in the M-order gamma, using GmEx(x) to obtain a mapping value x1;

[0054] Substituting x1 into G1r(x1), G1g(x1), G1b(x1) to obtain xr, xg, xb;

[0055] Substituting x1 and xr, xg, xb into the iterative formula to obtain Coefr, Coefg, Coefb;

[0056] Calculating and judging whether Coefr, Coefg, Coefb satisfy the following conditions,

[0057] Repeating the steps of calculating Coefr, Coefg, Coefb until a set of xr, xg, xb is found, which makes Coefr, Coefg, Coefb closest to 1, and recording the final mapping gray scale values Gmr(x)=xr, Gmg(x)=xg, Gmb(x)=xb at this time, wherein the preset enumeration range is,

[0058] Wherein, SRs(xr) represents the red color x r gray scale retrieval starting gray scale, SRe(xr) represents the red color x r gray scale retrieval ending gray scale, SGs(xg) represents the green color x g gray scale retrieval starting gray scale, SGe(xg) represents the green color x g gray scale retrieval ending gray scale, SBs(xb) represents the blue color x b gray scale retrieval starting gray scale, and SBe(xb) represents the blue color x b gray scale retrieval ending gray scale.

[0059] In the case of determining the current gray scale expansion mapping value, setting the current gray scale x to be incremented by 1, repeating the determination operation of the gray scale expansion mapping value until the calibration operation for all gray scales is completed.

[0060] The embodiments of the present disclosure further provide a bright chroma calibration device, which comprises a memory, a processor, and computer instructions stored in the memory and executable on the processor, and the computer instructions are executed by the processor to implement the steps of the bright chroma calibration method according to any one of the above embodiments.

[0061] The present disclosure further provides a computer readable storage medium having stored thereon a bright chroma calibration instruction, which, when executed by a processor, implements the steps of the bright chroma calibration method according to any one of the preceding embodiments.

[0062] The bright chroma calibration method, device and computer readable storage medium according to the present disclosure can display a preset test picture on a display screen, and control a colorimeter to collect bright chroma data of the display screen; generate a smooth gamma table according to the bright chroma data, iteratively calculate red, green and blue calibration coefficients of each gray scale, and obtain a gray scale expansion mapping table; perform full gray scale expansion mapping processing on an input image according to the gray scale expansion mapping table, and control the display screen to display an output image after the mapping processing. A more efficient bright chroma calibration scheme is implemented, the gray scale gradient smoothness and full gray scale colorimetric accuracy of the display are improved, the requirements of bright chroma calibration and full gray scale smoothness are met, the calibration time is reduced, and the production efficiency is improved.

[0063] Other aspects can become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0064] The present disclosure will be described with respect to the following drawings in which:

[0065] FIG. 1 is a first flowchart of the bright chroma calibration method according to the present disclosure;

[0066] FIG. 2 is a scene building schematic diagram of the bright chroma calibration method according to the present disclosure;

[0067] FIG. 3 is a control schematic diagram of the bright chroma calibration method according to the present disclosure;

[0068] FIG. 4 is a second flowchart of the bright chroma calibration method according to the present disclosure;

[0069] FIG. 5 is a third flowchart of the bright chroma calibration method according to the present disclosure. DETAILED DESCRIPTION

[0070] The embodiments described herein are merely intended to explain the present disclosure and are not intended to limit the present disclosure.

[0071] In the following description, the suffixes such as "module", "part", or "unit" used for an element are merely intended for facilitating explanation of the present disclosure and do not have specific meanings or roles. Therefore, "module", "part", or "unit" can be mixedly used.

[0072] In the process of implementing the embodiments of the present disclosure, the applicant finds that the existing brightness calibration and color temperature calibration are performed by original gray scale expansion and actual brightness of red, green, blue and white is collected, but the dual goals of brightness accuracy and colorimetric accuracy cannot be achieved. Or, the full gray scale is corrected by mapping the gamma curve, but due to the limitation of the preset gamma value and the preset difference threshold accuracy, the color difference cannot be corrected, and the calibration result is not good. Moreover, the calibration of the above two schemes takes a long time.

[0073] Therefore, how to improve the gray scale gradient smoothness and full gray scale colorimetric accuracy, while meeting the requirements of bright colorimetric calibration and full gray scale smoothness, reducing the calibration time, and improving the calibration efficiency, has become a matter to be solved at present.

[0074] FIG. 1 is a first flowchart of a bright colorimetric calibration method according to an embodiment of the present disclosure. The embodiment proposes a bright colorimetric calibration method, which comprises:

[0075] S1, controlling a display screen to display a preset test picture, and controlling a colorimeter to collect bright colorimetric data of the display screen;

[0076] S2, generating a smooth gamma table according to the bright colorimetric data, iteratively calculating red, green and blue calibration coefficients of each gray scale to obtain a gray scale expansion mapping table;

[0077] S3, performing full gray scale expansion mapping processing on an input image according to the gray scale expansion mapping table, and controlling the display screen to display an output image after the mapping processing.

[0078] Optionally, in the embodiment, the full gray scale X, Y, Z theoretical values are generated according to the maximum white gray scale X, Y, Z collection values in the bright colorimetric data; then, the smooth gamma table is generated according to the red, green and blue full gray scale X, Y, Z collection values in the bright colorimetric data and the full gray scale X, Y, Z theoretical values. Optionally, in the embodiment, the full gray scale theoretical Y value is calculated according to the red, green and blue Y values in the bright colorimetric data; the full gray scale expansion smooth gamma table is generated according to the smooth gamma table. Based on this, in combination with the full gray scale theoretical Y value, the gray scale mapping value closest to the theoretical Y value is searched in the full gray scale expansion smooth gamma table to obtain a first gray scale expansion mapping table; the theoretical X, Y, Z values of each expansion gray scale are calculated according to the maximum original white X, Y, Z values in the bright colorimetric data to obtain a white theoretical gray scale expansion mapping table; based on the first gray scale expansion mapping table and the white theoretical gray scale expansion table, and in combination with a preset coefficient iterative algorithm, the gray scale expansion mapping table containing each gray scale expansion mapping value is calculated.

[0079] In the embodiment, please refer to the scene building schematic diagram shown in FIG. 2, the test scene includes the LED display screen 100, the acquisition device 200, the calibration station 300 and the control system 400, wherein: when calibrating the LED display screen 100, by controlling the preset control system 400, on one hand, the LED display screen 100 is controlled to display the acquisition picture, on the other hand, the acquisition device is controlled to acquire the bright chrominance data of the LED display screen 100, based on which, the full gray scale gamma table is calculated by the calibration station 300 according to the acquired data; after calibrating the LED display screen 100, the video source of the LED display screen 100 is outputted and displayed after gray scale mapping according to the full gray scale gamma table calculated above.

[0080] In the embodiment, please refer to the control schematic diagram shown in FIG. 3, wherein: the chroma meter acquisition part 10 is configured to connect / disconnect the chroma meter, and calibrate before acquisition and implement acquisition; the host computer control automatic acquisition part 20 is configured to control the chroma meter automatic acquisition, receive and transmit the acquisition data, and control the LED screen display test picture; the data distribution part 30 is configured to distribute the data acquired by the host computer to the related calculation part; the first calculation part 40 is configured to save the red, green and blue full gray scale X, Y and Z acquisition values, and provide to the second calculation part 50; the third calculation part 60 is configured to generate the full gray scale X, Y and Z theoretical values according to the maximum white gray scale X, Y and Z acquisition values; the fourth calculation part 70 is configured to generate the smooth gamma table according to the full gray scale acquisition values and the full gray scale theoretical values in cooperation with the brightness smoothing algorithm; the second calculation part 50 is configured to iterative search, that is, calculate the red, green and blue calibration coefficients of each gray scale and perform iterative calibration; the fifth calculation part 80 is configured to obtain the gray scale smooth and calibrated output image by the gray scale mapping processing of the input image through the smooth gamma table; the LED screen display control part 90 is configured to control the LED screen display test picture, or display the result picture of the mapping output.

[0081] In the embodiment, please refer to the second flow chart shown in Fig. 4, wherein: in an operation step (step S10), the color coordinates X, Y, Z of all gray-scale red, green and blue, and the color coordinates X, Y, Z of the maximum gray-scale white are collected, on one hand, the full gray-scale smooth gamma table and the full gray-scale extended smooth gamma table are generated according to the collected maximum gray-scale white Y value, on the other hand, the full gray-scale theoretical Y value is calculated according to the collected red, green and blue Y values; then (step S20), according to the collected original red, green and blue full gray-scale Y values, the gray-scale mapping value closest to the theoretical Y value of each step is searched on the full gray-scale extended smooth gamma table to obtain the first gray-scale extended mapping table, and the extended gray-scale theoretical X, Y, Z value of each step is calculated according to the collected maximum original white X, Y, Z value to obtain the white theoretical gray-scale extended mapping table; after that (step S30), based on the first gray-scale extended mapping table and the white theoretical gray-scale extended table, the gray-scale extended mapping value of each gray-scale is obtained by using the coefficient iteration algorithm, so that the lightness calibration of each gray-scale is completed, and the final gray-scale extended mapping table is obtained.

[0082] In the embodiment, please refer to the third flow chart shown in Fig. 5, wherein: after the calibration starts, the initial collection color is set (step S100), and the initial collection gray-scale is set (step S200), based on which, the host computer controls the LED screen to display the test picture (step S300), and meanwhile, the host computer controls the colorimeter to perform the collection (step S400); in the process, it is judged whether the collection operation for the current gray-scale is ended (step S500), in the case of not ended, the host computer controls the LED screen to update and display the test picture of the next gray-scale of the current color (step S310) again, in the case of ended, it is determined that the collection operation for all gray-scales of the current color is ended; the gray-scale collection operation state for other colors is detected (step S600), in the case of not ended for the gray-scale collection operation of other colors, the next color is set (step S210), and the initial collection gray-scale of the color is set (step S200), until the collection of all gray-scales of the color is ended, in the case of ended for the gray-scale collection operation of all other colors, the calibration calculation as described in the above flow is performed (step S700), until the gray-scale extended mapping value of each gray-scale of each color is obtained, so that the lightness calibration of each gray-scale of each color is completed.

[0083] The beneficial effects of this embodiment are as follows: by controlling the display screen to show a preset test image and controlling the colorimeter to collect luminance and chromaticity data of the display screen; generating a smooth gamma table based on the luminance and chromaticity data, iteratively calculating the red, green, and blue calibration coefficients for each grayscale level to obtain a grayscale extended mapping table; performing full grayscale extended mapping processing on the input image based on the grayscale extended mapping table, and controlling the display screen to display the output image after mapping processing. This achieves a more efficient luminance and chromaticity calibration scheme, improves the smoothness of grayscale gradients and full grayscale color accuracy, simultaneously meets the requirements of luminance and chromaticity calibration and full grayscale smoothness, and reduces calibration time, thereby improving production efficiency.

[0084] In this embodiment, the maximum grayscale value of the input source is set to M, the maximum grayscale value of the display output is set to M1, and the maximum grayscale value of the display output after grayscale expansion is set to M2. The steps of collecting the maximum grayscale white Y value and the original full grayscale Y value include: controlling the display to show the white grayscale as the maximum value M1, collecting the corresponding color coordinates X, Y, and Z values; and displaying red, green, and blue, collecting the color coordinates X, Y, and Z values ​​for each grayscale from 0 to M1. Optionally:

[0085] ① The host computer sets the current display color to red and the current grayscale value to 0;

[0086] ②The host computer sends the current grayscale value to the control system for display;

[0087] ③ The host computer controls the colorimeter to collect and record the color coordinates X, Y, and Z of the current grayscale;

[0088] ④ Determine whether the current gray level is the end gray level M1. If it is the end gray level M1, then end the acquisition. If it is not the end gray level M1, then set the current gray level as the next gray level and repeat ②③④ until the end.

[0089] ⑤ Set the current display color to green and the current grayscale value to 0 in the host computer, and then repeat steps ②③④ until the end;

[0090] ⑥ Set the current display color to blue and the current grayscale value to 0 in the host computer, and then repeat steps ②③④ until the end;

[0091] ⑦ Set the current display color to white and the current grayscale value to the maximum grayscale M1 on the host computer, then execute ② and ③ to finish.

[0092] Thus, through the above data collection, the recording of the data required by the host computer has been completed.

[0093] In this embodiment, the step of generating a full grayscale extended smooth gamma table based on the smooth gamma table includes: based on the currently measured maximum brightness Y... Maxand preset luminance threshold K1 and K2 segment the gray scale; the original full gray scale gamma table is divided into low brightness 0 to K1, medium brightness K1 to K2, and high brightness K2 to Y Max three segments, wherein it is assumed that monochrome full gray scale luminance linearly increases, and the segmented luminance threshold K1 and K2 are determined according to pre-specified empirical values. Optionally:

[0094] ① low brightness 0 to K1 segment:

[0095] Assuming that the current fitting gamma coefficient is Gm1, the gamma single gray scale increment step is Step, the maximum gray scale number after expansion mapping is not more than GE, and the minimum gray scale number after expansion mapping is not less than GS, and the gray scale value corresponding to the initial K1 luminance is Gray1=M / 2, the linear expansion value is Gray1ps=Gray1*PlusBit, wherein PlusBit is the expansion bit number, and the expansion mapping formula is Gm1Ex(x);

[0096] In order to ensure the smoothness of the gray scale curve, Gm1 needs to be iteratively adjusted, and the iterative adjustment formula is:

[0097] wherein N1 is the iteration round, and C(i) is a group of empirical coefficient values, and the iteration round N1 satisfies:

[0098] In order to ensure the 1st order gray after expansion, Gm1 also needs to be iteratively adjusted according to the following formula:

[0099] So that Gm1 satisfies:

[0100] wherein P1 is an empirical value, and the coefficient gcr1 obtained by iterative search is different according to the different iteration ranges of gray scale GS.

[0101] After the above iteration, Gm1 can effectively avoid the problem that the low gray scale number is small and the gray start luminance is too high due to the excessively high peak luminance.

[0102] Then, the first segment low brightness gamma table is obtained according to the obtained Gm1 substituted into the standard gamma formula, and the expansion mapping formula of the original gray scale x to the mapping value is:

[0103] ② medium brightness K1 to K2 segment:

[0104] Assuming that the current fitting gamma coefficient is Gm2=1 / Gm1, the gray scale value corresponding to the initial K2 luminance is Gray2=M*7 / 8, the linear expansion value is Gray2ps=Gray2*PlusBit, and the expansion mapping formula is Gm2Ex(x);

[0105] Similarly, to ensure the smoothness of the curve, the iteration adjustment formula for Gm2 is:

[0106] where N2 is the iteration round, D(i) is a set of empirical coefficient values, and the iteration round N2 satisfies:

[0107] To ensure smoothness, the mapping value variation amplitude of the gray scale Gm1Ex(Gray1-1) to Gm1Ex(Gray1) to Gm2Ex(Gray1+1) is close to consistent, therefore, the following formula iteration is required:

[0108] so that Gm2 satisfies:

[0109] where P2 is an empirical value, and the coefficient gcr2 obtained by iteration search is different according to the selection of the gray scale iteration range GS.

[0110] Then, the first segment low-brightness gamma table is obtained according to the obtained Gm2 by substituting the standard gamma formula, and the expansion mapping formula of the original gray scale x to the mapping value y is:

[0111] ③High K2 to Y Max Segment:

[0112] Due to the non-linear visual characteristics of the human eye, the human eye is not sensitive to the change of brightness in the high-light part, therefore, the embodiment adopts a simple linear mapping mode.

[0113] The expansion mapping formula Gm3Ex(x) of the original gray scale x to the mapping value is: Gm3Ex(x) = x*PlusBit, (Gray2 < x <= M);

[0114] ④Integrate the three segment formulas:

[0115] In the embodiment, the full gray scale number M1 of the display screen is linearly expanded by PlusBit times to obtain the gray scale number M2, and the maximum gray scale X, Y, Z of the collected red, green and blue colors are respectively represented by F maxr X, Y, Z values of red, F maxg X, Y, Z values of green, and F maxbX, Y, Z values representing blue, respectively generate M2 order of each order x1 Theoretical X, Y, Z value table of x1, red, green, blue are Ftr(x1), Ftg(x1), Ftb(x1) respectively;In the full gray scale expansion smoothing gamma table, combined with the original full gray scale Y value, search for the gray scale mapping value closest to the full gray scale theoretical Y value of each order, get the first gray scale expansion mapping table, comprising: according to the linear expansion of the actual X, Y, Z value table Facr(x1), Facg(x1), Facb(x1) of each order x1 of the original red, green, blue of M1 gray scale, the expansion multiple is M2 / M1, get the actual X, Y, Z value table of each order x1 of M2 expansion gray scale, red, green, blue are Far(x1), Fag(x1), Fab(x1) respectively;According to the M2 order theoretical Y value table, search for the index that satisfies the actual Y value equal to the theoretical Y value in the actual Y value table as the current mapping value;Traverse all M2 gray scales to get all corresponding current mapping values as the first gray scale mapping table G1r(x1), G1g(x1), G1b(x1). Optionally:

[0116] ①Generate theoretical expansion X, Y, Z value table:

[0117] ②Generate actual expansion X, Y, Z value table:

[0118] The original gray scale value x0 corresponding to the current expansion gray scale x1 is:

[0119] Where, INT(*) represents the down rounding operation of the arithmetic * in the parentheses;

[0120] Then the actual X, Y, Z value of the current expansion gray scale x1 satisfies the formula:

[0121] Where, LS(*) represents the remainder operation of the arithmetic * in the parentheses;

[0122] ③Generate the first gray scale mapping table:

[0123] For a given to be mapped gray scale value x1, its theoretical Y value can be obtained from the theoretical gray scale table, and the Y value of the actual mapping gray scale x2 satisfies the following formula operation: G1r(x1)=x2=TH(0,M2,abs(Ftr(x1).Y-Far(x2).Y)),(0<=x1<=M2); G1g(x1)=x2=TH(0,M2,abs(Ftg(x1).Y-Fag(x2).Y)),(0<=x1<=M2); G1b(x1)=x2=TH(0,M2,abs(Ftb(x1).Y-Fab(x2).Y)),(0<=x1<=M2);

[0124] wherein the function TH(*,*,*) represents the result of the x2 value that is the minimum of abs(*) in the search range (0<=x2<=M2), and abs(*) represents an absolute value operation on the arithmetic * in the parentheses.

[0125] In the embodiment, the full gray scale number M1 of the display screen is linearly extended by PlusBit times to obtain a gray scale number M2; the step of calculating the theoretical X, Y, Z values of each extended gray scale according to the maximum original white X, Y, Z values in the light chroma data to obtain a white theoretical gray scale extension mapping table comprises: linearly extending the collected X maxw , Y maxw , and Z maxw values of the maximum gray scale M1 of the white color to M2 gray scales;

[0126] According to the formula,

[0127] the white theoretical gray scale extension mapping table Xw(x1), Yw(x1), and Zw(x1) are calculated.

[0128] In the embodiment, it is assumed that the red, green, blue, and white gray scale numbers are M, and the maximum value of the full gray scale extension smooth gamma table GmEx(x) is M2; the method further comprises: determining a mapping gray scale value x1; obtaining the smooth M-order theoretical X, Y, and Z values of the white color Xw(x1), Yw(x1), and Zw(x1) according to the X, Y, and Z theoretical extension mapping tables; searching for the measured values Far(x1), Fag(x1), and Fab(x1) of the X, Y, and Z in the M2-order extension measured table obtained by actual measurement; summing the red, green, and blue to obtain the measured values Faw(x1) of the X, Y, and Z of the white color.

[0129] In the embodiment, it is assumed that the final gray scale extension mapping tables of the red, green, and blue are Gmr(x), Gmg(x), and Gmb(x) respectively; based on the first gray scale extension mapping table and the white theoretical gray scale extension table, and in combination with a preset coefficient iteration algorithm, the step of calculating the gray scale extension mapping table containing each gray scale extension mapping value comprises: judging whether the error of the measured value Faw(x1) and the theoretical values Xw(x1), Yw(x1), and Zw(x1) is within a preset range; in the case that the error is within the preset range, x1 is the final mapping gray scale value of x, and is recorded as Gmr(x)=x1, Gmg(x)=x1, and Gmb(x)=x1; and in the case that the error is not within the preset range, calibration is performed.

[0130] In the embodiment, the step of performing calibration comprises:

[0131] determining a derivation formula,

[0132] wherein xr, xg, xb are the adjusted gray scale mapping values, Coefr, Coefg, Coefb represent the calibration coefficients of red, green, and blue respectively;

[0133] The iteration formula is obtained as follows,

[0134] Each gray scale extension mapping value is calculated according to the iteration formula.

[0135] In the embodiment, the step of calculating each gray scale extension mapping value according to the iteration formula comprises:

[0136] Setting the current gray scale x of calibration as 0;

[0137] For the current gray scale x in the M-order gamma, the mapping value x1 is obtained by using GmEx(x);

[0138] The x1 is substituted into G1r(x1), G1g(x1), and G1b(x1) to obtain xr, xg, and xb;

[0139] The x1, xr, xg, and xb are substituted into the iteration formula to calculate Coefr, Coefg, and Coefb;

[0140] The Coefr, Coefg, and Coefb are calculated and determined whether they satisfy the following conditions,

[0141] The step of calculating Coefr, Coefg, and Coefb is repeatedly executed in a preset enumeration range until a set of xr, xg, and xb is found, which makes Coefr, Coefg, and Coefb closest to 1, and the final mapping gray scale values Gmr(x) = xr, Gmg(x) = xg, and Gmb(x) = xb at this time are recorded, wherein the preset enumeration range is,

[0142] wherein SRs(xr) represents the red color x r gray scale retrieval starting gray scale, SRe(xr) represents the red color x r gray scale retrieval ending gray scale, SGs(xg) represents the green color x g gray scale retrieval starting gray scale, SGe(xg) represents the green color x g gray scale retrieval ending gray scale, SBs(xb) represents the blue color x b gray scale retrieval starting gray scale, and SBe(xb) represents the blue color x b gray scale retrieval ending gray scale;

[0143] In the case of determining the current gray scale extension mapping value, the current gray scale x is set to be incremented by 1, and the determination operation of the gray scale extension mapping value is repeatedly executed until the calibration operation for all gray scales is completed.

[0144] In the embodiment, the starting gray scale of the above-mentioned retrieval is generally obtained by experience, and can also be calculated. One calculation method is as follows:

[0145] Let the retrieval starting gray scale of the red gray scale x and the smoothed and expanded mapping gray scale xr be SRs and SRe, and be expressed as follows: SRs(xr)=G1r(x-1)+(G1r(x)-G1r(x-1))*RT; SRe(xr)=G1r(x)+(G1r(x+1)-G1r(x))*RT;

[0146] Wherein, RT represents the gray scale fault tolerance width ratio, the value range of RT is [0, 1], SRs(xr) represents the interval in which the retrieval starting gray scale value falls, and SRe(xr) represents the interval in which the retrieval ending gray scale value falls.

[0147] It can be seen that, in the embodiment, the calibration method using the acquisition and addition algorithm correction can effectively improve and solve the problem that the calibration technology cannot simultaneously well meet the requirements of bright chroma calibration and full gray scale smoothness. The processing strategy of the acquisition and addition algorithm used in the embodiment reduces the repeated verification and repeated acquisition process in the acquisition, reduces the overall time consumption, thereby improving the efficiency, reduces the acquisition times to about half of the original acquisition times, and reduces the overall calibration scheme time consumption by about 20%, which is beneficial to improving the production capacity in the production process.

[0148] Based on the above-mentioned embodiments, the embodiment of the present disclosure further proposes a bright chroma calibration device, which comprises a memory, a processor, and computer instructions stored on the memory and executable on the processor, and the computer instructions are executed by the processor to implement the steps of the bright chroma calibration method according to any one of the above-mentioned embodiments.

[0149] The above-mentioned device embodiment and method embodiment belong to the same concept, the implementation process is detailed in the method embodiment, and the technical features in the method embodiment are all applicable in the device embodiment, which will not be repeated here.

[0150] Based on the above-mentioned embodiments, the embodiment of the present disclosure further proposes a computer readable storage medium, which stores a bright chroma calibration instruction, and the bright chroma calibration instruction is executed by a processor to implement the steps of the bright chroma calibration method according to any one of the above-mentioned embodiments.

[0151] The above-mentioned medium embodiment and method embodiment belong to the same concept, the implementation process is detailed in the method embodiment, and the technical features in the method embodiment are all applicable in the medium embodiment, which will not be repeated here.

[0152] Those skilled in the art can clearly understand the method of the above-mentioned embodiments can be realized by means of software plus a general hardware platform, and of course can also be realized by hardware. Based on such understanding, the technical solutions of the embodiments of the present disclosure can be embodied in the form of a software product, and the computer software product is stored in a storage medium (such as a ROM / RAM, a magnetic disk, or an optical disk), and includes a plurality of instructions to make a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device) execute the method described in the embodiments of the present disclosure.

[0153] In this document, the terms "comprise", "contain", or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article, or device that includes a list of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent in such a process, method, article, or device. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of additional identical elements in the process, method, article, or device that includes the element.

[0154] The embodiments of the present disclosure are described above in conjunction with the drawings, but the embodiments of the present disclosure are not limited to the above-described embodiments, and the above-described embodiments are merely illustrative rather than limiting. Those skilled in the art can make many forms under the inspiration of the embodiments of the present disclosure without departing from the scope of the embodiments of the present disclosure and the scope of protection of the claims, and all these belong to the protection of the embodiments of the present disclosure.

Claims

1. A bright color calibration method, comprising: controlling a display screen to display a preset test picture, and controlling a colorimeter to collect bright color data of the display screen; generating a smooth gamma table according to the bright color data, iteratively calculating red, green and blue calibration coefficients of each gray scale to obtain a gray scale expansion mapping table; performing full gray scale expansion mapping processing on an input image according to the gray scale expansion mapping table, and controlling the display screen to display an output image after the mapping processing.

2. The bright chrominance calibration method of claim 1, wherein, The generating of the smooth gamma table according to the bright color data comprises: generating full gray scale X, Y and Z theoretical values according to maximum white gray scale X, Y and Z acquisition values in the bright color data; generating the smooth gamma table according to red, green and blue full gray scale X, Y and Z acquisition values in the bright color data and the full gray scale X, Y and Z theoretical values. 3.The bright color calibration method according to claim 1, further comprising: calculating full gray scale theoretical Y values according to red, green and blue Y values in the bright color data; generating a full gray scale expansion smooth gamma table according to the smooth gamma table; The iteratively calculating of the red, green and blue calibration coefficients of each gray scale to obtain the gray scale expansion mapping table comprises: searching for a gray scale mapping value closest to the theoretical Y value of each order in the full gray scale expansion smooth gamma table in combination with the full gray scale theoretical Y values to obtain a first gray scale expansion mapping table; calculating each order expansion gray scale theoretical X, Y and Z values according to maximum original white X, Y and Z values in the bright color data to obtain a white theoretical gray scale expansion mapping table; calculating the gray scale expansion mapping table containing each gray scale expansion mapping value based on the first gray scale expansion mapping table and the white theoretical gray scale expansion table in combination with a preset coefficient iterative algorithm.

4. The bright chrominance calibration method of claim 3, wherein, Supposing that a maximum gray scale value of an input source is M and a display output maximum gray scale value of the display screen is M1; A display output maximum gray scale of the display screen after the gray scale expansion is M2, and the collected maximum gray scale white Y value and original full gray scale Y value comprise: controlling the display screen to display a white gray scale as the maximum value M1, collecting corresponding color coordinates X, Y and Z values, and displaying red, green and blue, and collecting color coordinates X, Y and Z values of each gray scale from 0 to M1; The generating of the full gray scale expansion smooth gamma table according to the smooth gamma table comprises: According to the current measured maximum brightness Y Max And the preset brightness threshold K1 and K2 will gray scale segmentation; Splitting the original full gray scale gamma table into low light 0 to K1, mid light K1 to K2, high light K2 to Y Max Three segments, wherein, assuming monochrome full gray scale luminance linearly increasing, and according to pre-designated empirical values, determining the luminance threshold K1 and K2 of the segments.

5. The lightness calibration method of claim 4, wherein, The full gray scale number M1 of the display screen is linearly extended by PlusBit times to obtain a gray scale number M2. The maximum gray scales X, Y and Z of the collected red, green and blue colors are respectively represented by F maxr X, Y and Z values of red, F maxg X, Y and Z values of green, F maxb X, Y and Z values of blue, and the theoretical X, Y and Z value tables of each order x1 of M2 orders are respectively generated, and the red, green and blue are respectively Ftr(x1), Ftg(x1) and Ftb(x1). The searching for the gray scale mapping value closest to the full gray scale theoretical Y value of each order in the full gray scale expansion smooth gamma table in combination with the original full gray scale Y values to obtain the first gray scale expansion mapping table comprises: performing linear expansion on original red, green and blue actual X, Y and Z value tables Facr(x1), Facg(x1) and Facb(x1) of each order of M1 gray scales according to the collected M1 gray scales, with an expansion multiple of M2 / M1 to obtain actual X, Y and Z value tables of M2 expansion gray scales, red, green and blue being Far(x1), Fag(x1) and Fab(x1) respectively; searching for an index satisfying actual Y value equal to theoretical Y value in the actual Y value table as a current mapping value according to the M2 order theoretical Y value table. All the corresponding current mapping values are obtained as first gray scale mapping table G1r(x1), G1g(x1), G1b(x1) by traversing all M2 gray scales.

6. The bright chrominance calibration method of claim 3, wherein, The full gray scale number M1 of the display screen is linearly extended by PlusBit times to obtain a gray scale number M2; The white color theoretical gray scale extension mapping table is calculated according to the maximum original white X, Y, Z values in the light color data, and the white color theoretical gray scale extension mapping table is obtained, It comprises: The X maxw , Y maxw , Z maxw values of the collected white maximum gray scale M1 are linearly extended to M2 gray scales; According to the formula, The white color theoretical gray scale extension mapping table Xw(x1), Yw(x1), Zw(x1) is calculated.

7. The bright chrominance calibration method of claim 3, wherein, Supposing that the red, green, blue and white gray scale numbers are M, and the maximum value of the full gray scale extension smooth gamma table GmEx(x) is M2; The method further comprises: The mapping gray scale value is determined as x1; According to the X, Y, Z theoretical extension mapping table, the smooth M-order white color theoretical X, Y, Z values Xw(x1), Yw(x1), Zw(x1) are obtained, and the theoretical white color X, Y, Z values after x gray scale smoothing are determined; In the M2-order extension measurement table obtained by actual measurement extension, the X, Y, Z measured values Far(x1), Fag(x1), Fab(x1) are searched, the red, green and blue are summed, and the white color extension X, Y, Z measured values Faw(x1) are obtained.

8. The lightness calibration method of claim 7, wherein, Supposing that the final gray scale extension mapping table red, green and blue are Gmr(x), Gmg(x), Gmb(x) respectively; The gray scale extension mapping table containing each gray scale extension mapping value is calculated based on the first gray scale extension mapping table and the white color theoretical gray scale extension table, and combined with a preset coefficient iterative algorithm, comprising: It is judged whether the error of the measured value Faw(x1) and the theoretical value Xw(x1), Yw(x1), Zw(x1) is within a preset range, in the case that the error is within the preset range, x1 is the final mapping gray scale value of x, recorded as Gmr(x)=x1, Gmg(x)=x1, Gmb(x)=x1, and in the case that the error is not within the preset range, calibration is performed.

9. The lightness calibration method of claim 8, wherein, The gray scale extension mapping table containing each gray scale extension mapping value is calculated, comprising: determining a derivation formula, Wherein, xr, xg, xb are the adjusted gray scale mapping values respectively, and Coefr, Coefg, Coefb represent the calibration coefficients of red, green and blue respectively; The iteration formula is obtained, Each gray scale extension mapping value is calculated according to the iterative formula.

10. The lightness calibration method of claim 9, wherein, The gray scale extension mapping table containing each gray scale extension mapping value is further calculated, comprising: The calibrated current gray scale x is set to 0; For the current gray scale x in the M-order gamma, the mapping value x1 is obtained by using GmEx(x); x1 is substituted into G1r(x1), G1g(x1), G1b(x1) to obtain xr, xg, xb; x1 and xr, xg, xb are substituted into the iterative formula to calculate Coefr, Coefg, Coefb; Coefr, Coefg, Coefb are calculated and determined whether they satisfy the following conditions, The steps of calculating Coefr, Coefg and Coefb are repeatedly performed within a preset enumeration range until a set of xr, xg and xb is found, such that Coefr, Coefg and Coefb are closest to 1, and the final mapping gray scale values Gmr(x) = xr, Gmg(x) = xg and Gmb(x) = xb at this time are recorded, wherein the preset enumeration range is, wherein SRs(xr) represents a red color xr gray scale searching start gray scale, SRe(xr) represents a red color xr gray scale searching end gray scale, SGs(xg) represents a green color xg gray scale searching start gray scale, SGe(xg) represents a green color xg gray scale searching end gray scale, SBs(xb) represents a blue color xb gray scale searching start gray scale, and SBe(xb) represents a blue color xb gray scale searching end gray scale; In a case where the current gray scale expansion mapping value is determined, the current gray scale x is increased by 1, and the determination operation of the gray scale expansion mapping value is repeatedly executed until the calibration operation for all the gray scales is completed. 11.A bright chrominance calibration device, comprising a memory, a processor, and computer instructions stored on the memory and executable on the processor, wherein the computer instructions, when executed by the processor, implement the steps of the bright chrominance calibration method according to any one of claims 1 to 10. 12.A computer readable storage medium storing bright chrominance calibration instructions, wherein the bright chrominance calibration instructions, when executed by a processor, implement the steps of the bright chrominance calibration method according to any one of claims 1 to 10.

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