Gamma table generation method and display control parameter generation method

Abstract

The present application relates to a method and device for generating a Gamma table, a method and device for generating display control parameters, a display processing device, and a display system. The method comprises: obtaining video source data and video source display parameters related to a color gamut standard, as well as test video data and device display parameters of a display device; determining target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters; performing grayscale stretching on the test video data according to the target display parameters to obtain actual display parameters of the display device; performing source data color recoding on the video source data based on the target display parameters, performing test color recoding on the test video data based on the actual display parameters, and generating a Gamma table according to the source data color recoding results and the test color recoding results. The Gamma table generated by the present method is used to adjust the display parameters of the display device, so as to ensure the display effect of low grayscale in the color gamut standard.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a gamma table generating method, a gamma table generating device, a display control parameter generating method, a display control parameter generating device, a display processing device and a display system. Background Art

[0002] HDR mode, namely high-dynamic range image (HDR for short), can provide a wider dynamic range than ordinary images, retain more highlight and shadow details, and use the different exposure of each image to synthesize the final HDR image. It is widely used in the display field.

[0003] When the LED (Light Emitting Diode) display turns on the HDR mode, in order to ensure the display effect, the LED display needs to have a high low-gray display capability. At present, the low-gray display range of general LED displays is generally around 1nit, and the low-gray display of the P3 color gamut of LED theater screens can reach 0.01nit. However, the DCI (Digital Cinema Initiatives) 2022 color gamut standard requires support for HDR (High Dynamic Range Imaging) to reach 0.005nit. At present, LED displays are difficult to meet the normal display of grayscale in this low gray segment. Summary of the invention

[0004] Based on this, it is necessary to provide a gamma table generation method and device that can support improving the display capability of the display device for low gray segment grayscale, as well as a display control parameter generation method and device that can improve the display quality of the display device, as well as a display processing device and a display system to address the above technical problems.

[0005] In a first aspect, the present application provides a method for generating a gamma table. The method for generating a gamma table comprises:

[0006] Acquire video source data and video source display parameters related to the color gamut standard, as well as test video data and device display parameters of the display device;

[0007] Determining target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters;

[0008] Performing grayscale stretching on the test video data according to the target display parameters to obtain actual display parameters of the display device;

[0009] The video source data is color-recoded based on the target display parameters, the test video data is color-recoded based on the actual display parameters, and a gamma table is generated according to the source data color-recoding result and the test color-recoding result.

[0010] In one embodiment, the gamma table generation method further includes:

[0011] Determining whether the actual display parameter matches the target display parameter;

[0012] If not, obtaining the updated test video data of the display device, and performing grayscale stretching again on the updated test video data according to the target display parameters to obtain updated actual display parameters; returning to the step of determining whether the actual display parameters match the target display parameters;

[0013] If they match, the process proceeds to the step of recoding the source data color of the video source data based on the target display parameters, recoding the test color of the test video data based on the actual display parameters, and generating a gamma table according to the source data color recoding result and the test color recoding result.

[0014] In one of the embodiments, determining the target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters includes:

[0015] Determining a minimum target brightness value in the video source display parameters, and a minimum display brightness value and grayscale bit width in the device display parameters;

[0016] Perform unit brightness grading according to the minimum target brightness value and the minimum display brightness value to obtain a minimum brightness level;

[0017] Determine the minimum brightness value of each classification based on the minimum brightness level, and determine the number of data bits required to represent the minimum brightness value in the storage space;

[0018] The minimum brightness value of each classification, the number of data bits and the grayscale bit width are collected to obtain target display parameters.

[0019] In one embodiment, the grayscale stretching of the test video data according to the target display parameter to obtain the actual display parameter of the display device includes:

[0020] Acquire each pixel of the whole frame image in the test video data;

[0021] Processing each of the pixels one by one according to the target display parameter to obtain a grayscale parameter of each of the pixels, wherein the grayscale parameter includes an integer grayscale parameter and a decimal grayscale parameter, the number of bits of the integer grayscale parameter corresponds to the grayscale bit width, and the number of bits of the decimal grayscale parameter corresponds to the number of data bits;

[0022] The grayscale parameters are subjected to dithering processing to obtain actual display parameters of the display device.

[0023] In a second aspect, the present application further provides a display control parameter generation method, the display control parameter generation method comprising:

[0024] Get video source data;

[0025] Determine corresponding target display parameters according to the color gamut standard of the video source data, wherein the target display parameters are determined according to the video source display parameters corresponding to the color gamut standard and the display parameters of the display device;

[0026] Performing grayscale expansion processing on the video source data according to the target display parameter to obtain corresponding video source grayscale parameters;

[0027] Generate display control parameters according to the video source grayscale parameters and the gamma table corresponding to the color gamut standard;

[0028] The Gamma table corresponding to the color gamut standard is generated using the above method.

[0029] In one of the embodiments, the field synchronization frame data of the video source data includes color gamut standard parameters, and different parameter values ​​of the color gamut standard parameters correspond to different color gamut standards.

[0030] In a third aspect, the present application further provides a gamma table generation device. The gamma table generation device comprises:

[0031] A parameter acquisition module, used to acquire video source data and video source display parameters related to the color gamut standard, as well as test video data and device display parameters of the display device;

[0032] A target parameter determination module, configured to determine a target display parameter corresponding to the color gamut standard according to the video source display parameter and the device display parameter;

[0033] A grayscale stretching module, used for performing grayscale stretching on the test video data according to the target display parameters to obtain actual display parameters of the display device;

[0034] A gamma generation module is used to perform source data color recoding on the video source data based on the target display parameters, perform test color recoding on the test video data based on the actual display parameters, and generate a gamma table according to the source data color recoding result and the test color recoding result.

[0035] In a fourth aspect, the present application further provides a display control parameter generation device. The display control parameter generation device comprises:

[0036] Video acquisition module, used to acquire video source data;

[0037] A display parameter determination module, configured to determine corresponding target display parameters according to the color gamut standard of the video source data, wherein the target display parameters are determined according to the video source display parameters corresponding to the color gamut standard and the display parameters of the display device;

[0038] A grayscale expansion module, used for performing grayscale expansion processing on the video source data according to the target display parameter to obtain corresponding video source grayscale parameters;

[0039] A parameter generation module is used to generate display control parameters according to the grayscale parameters of the video source and the Gamma table corresponding to the color gamut standard; wherein the Gamma table corresponding to the color gamut standard is generated using the Gamma table generation method as described above.

[0040] In a fifth aspect, the present application also provides a display processing device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the steps of the gamma table generation method as described above, or implements the steps of the display control parameter generation method as described above.

[0041] In a sixth aspect, the present application also provides a display system, comprising a connected display device and a display processing device as described above.

[0042] The above-mentioned Gamma table generation method, Gamma table generation device, display control parameter generation method, display control parameter generation device, display processing device and display system. The Gamma table generation method determines the target display parameters corresponding to the color gamut standard based on the video source display parameters related to the color gamut standard and the device display parameters of the display device, and grayscale stretches the test video data according to the target display parameters to obtain the actual display parameters of the display device, and generates the Gamma table according to the result of color recoding processing of the video source data and the test video data respectively according to the target display parameters and the actual display parameters. In this way, it is ensured that the Gamma table can meet the display requirements of the color gamut standard. When the display device displays the video source data of the color gamut standard, the display parameters of the display device are adjusted according to the Gamma table to meet the requirements of the color gamut standard, ensuring the display effect of the low gray grayscale in the color gamut standard. The above-mentioned display control parameter generation method can determine the corresponding Gamma table according to the color gamut standard of the video source data, ensure the low gray display effect of the display device on the video source data of the color gamut standard, and improve the display quality of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 An application environment diagram of a method for generating a gamma table in one embodiment;

[0044] Figure 2 A schematic diagram of a process for generating a Gamma table in one embodiment;

[0045] Figure 3 A schematic diagram of a process for determining target display parameters corresponding to a color gamut standard according to video source display parameters and device display parameters in one embodiment;

[0046] Figure 4 It is a flowchart of a method for generating a Gamma table in another embodiment;

[0047] Figure 5 A partial flow chart of a method for generating a gamma table in one embodiment;

[0048] Figure 6 A schematic diagram of three-pixel error transmission in one embodiment;

[0049] Figure 7 A diagram comparing display effects of using a gamma table generation method and not using the method in an embodiment;

[0050] Figure 8 A schematic diagram of a module of a display system in one embodiment;

[0051] Fig. 9 A schematic diagram showing a flow chart of a method for generating control parameters in one embodiment;

[0052] Fig.10 A schematic diagram of a module of a display system in another embodiment;

[0053] Fig.11 A schematic diagram showing the working process of a system in one embodiment;

[0054] Fig.12 This is a schematic diagram of the functional modules of a sending card in one embodiment;

[0055] Fig.13 A schematic diagram of the functional modules of a receiving card in one embodiment;

[0056] Fig.14 is a structural block diagram of a Gamma table generating device in one embodiment;

[0057] Fig.15 FIG. 1 is a structural block diagram showing a control parameter generating device in an embodiment. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0059] The gamma table generation method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the display processing device 100 is connected to the display device 200, and the display processing device 100 obtains the video source data and video source display parameters related to the color gamut standard, as well as the test video data and device display parameters of the display device; according to the video source display parameters and the device display parameters, the target display parameters corresponding to the color gamut standard are determined; according to the target display parameters, the test video data is gray-scale stretched to obtain the actual display parameters of the display device; based on the target display parameters, the source data color of the video source data is re-encoded, and based on the actual display parameters, the test video data is test-colored re-encoded, and a gamma table is generated according to the source data color re-encoding result and the test color re-encoding result. Among them, the display device 200 can be, but is not limited to, a display screen such as an LED screen, and the display processing device 100 can be a processor device such as a sending card for processing video data. For the sake of convenience, the following examples all take the display device 200 as an LED display screen and the display processing device 100 as a sending card as an example.

[0060] In one embodiment, Figure 2 As shown, a method for generating a Gamma table is provided, which is applied to Figure 1 The display processing device in is taken as an example to illustrate, including steps S100-S400.

[0061] S100, acquiring video source data and video source display parameters related to a color gamut standard, and test video data and device display parameters of a display device.

[0062] The video source data may be video data in HDR format, and the color gamut standards include DCI standards, BT2020 and other color gamut standards of the display industry. Generally, when the color gamut standard of the video source data is determined, the video source display parameters related to the color gamut standard can also be determined. The video source display parameters may include minimum target brightness, maximum target brightness, color temperature, color coordinates, grayscale bits, etc. according to actual needs.

[0063] The display parameters of the display device are the maximum display brightness, minimum display brightness, color temperature, color coordinates, grayscale bits, etc. that the LED screen can achieve. The test video data of the display device is the video data output to the display device during the testing and adjustment of the display device. During the testing and adjustment process, the display device receives and displays the test video data, and detects optical parameters such as brightness and chromaticity at the screen end of the display device through the optical testing equipment. The specific testing and adjustment process does not need to be limited.

[0064] S200, determining target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters.

[0065] The minimum target brightness in the video source display parameters of the HDR video source is generally much lower than the minimum display brightness of the display device. Therefore, it is necessary to determine the target display parameters corresponding to the display device and the color gamut standard based on the video source display parameters and the device display parameters.

[0066] Assume that the color gamut standard is the DCI standard, and the wide dynamic video source data corresponding to the standard is low gray 0.005nit, 6500K color temperature (color coordinates: x=0.312, y=0.329), maximum brightness 300nit, 6500K color temperature (color coordinates: x=0.312, y=0.329), and grayscale bit width 12bit (the above parameter values ​​are only examples, and they need to be determined according to specific standards in actual applications). Assume that the grayscale bit width of the LED screen is 16bit, the minimum display brightness is 0.018nit, and the color temperature is 6500K (color coordinates: x=0.312, y=0.329). In order to improve the low grayscale display effect of the display device for the wide dynamic video source data, it is necessary to determine the target display parameters of the display device based on the minimum target brightness of the video source display parameters of 0.005nit and the minimum display brightness of the LED screen of 0.018nit.

[0067] Specifically, Figure 3 As shown, S200 may include S201 - S204 .

[0068] S201, determining a minimum target brightness value in a video source display parameter, and a minimum display brightness value and a number of grayscale bits in a device display parameter.

[0069] Still taking the above parameters as an example, the minimum target brightness value is determined to be 0.005nit, the minimum display brightness value is 0.018nit, and the grayscale bit number is 16bit.

[0070] S202, performing unit brightness classification according to the minimum target brightness value and the minimum display brightness value to obtain a minimum brightness level.

[0071] Unit brightness grading is to re-quantize the unit brightness (1 nit) into multiple gradings, and generally select 2, 4, 8, 16, 32, etc. (integer powers of 2) grading. Exemplarily, S202 includes calculating the ratio between the minimum display brightness value and the minimum target brightness value; obtaining the minimum brightness level according to the ratio; determining the lower limit brightness value lower than the minimum target brightness value; and determining the minimum brightness level according to the lower limit brightness value and the minimum brightness level.

[0072] As for the above parameters, the minimum display brightness value is 0.018nit, and the minimum target brightness value is 0.005nit, which means that the display brightness needs to be extended from 0.018nit to 0.005nit. Then the number of levels should first calculate the ratio between the minimum display brightness value and the minimum target brightness value, 0.018nit / 0.005nit=3.6, the ratio is 3.6, and the level is an integer, so it must be greater than or equal to 4, that is, the minimum brightness level is 4. After obtaining the minimum brightness level, on the one hand, when the minimum target brightness value is expected to be achieved, it is also necessary to consider reserving enough margin. Therefore, the lower limit brightness value below the minimum target brightness value can be determined based on experience or test data. Taking 0.001nit as an example, the minimum brightness level is determined based on the lower limit brightness value and the minimum brightness level, 0.018nit / 0.001nit=18, and thus the minimum brightness level can be determined as 16, which is close to 18. On the other hand, in actual application, in order to consider the acquisition of the Gamma table during HDR display, it is generally necessary to select a larger grading level according to the LED screen, so 16 is more suitable for the needs. Then 0.018nit needs to be re-quantized and graded into 16 levels, and the minimum brightness level is 16.

[0073] S203, determining the minimum brightness value of each classification based on the minimum brightness level, and determining the number of data bits required to represent the minimum brightness value in the storage space.

[0074] When the minimum brightness level is determined, the unit brightness is re-quantized and graded according to the minimum brightness level, and the minimum brightness value of each level and the number of data bits required for the minimum brightness value in the storage space (that is, the number of data bits required when expressed in binary) are calculated. If the minimum brightness level is 16, the minimum brightness of each level is 0.018nit / 16=0.001125nit, thereby achieving the stretching of unit brightness and obtaining a more delicate brightness value in the low-gray display range. At the same time, the brightness of 0.001125nit requires 4 bits in binary, so the number of stored data bits is 4 bits.

[0075] S204, collecting the minimum brightness value, data bit number and grayscale bit width of each classification to obtain target display parameters.

[0076] The target display parameters include the minimum brightness value and grayscale bit number of each level. The grayscale bit number is equal to the sum of the grayscale bit width and the number of data bits. For example, if the minimum brightness value is 0.001125nit, the grayscale bit number is 20bit=16bit+4bit, 16bit is the integer part, and 4bit is the decimal part.

[0077] S300, grayscale stretching is performed on the test video data according to the target display parameters to obtain actual display parameters of the display device.

[0078] It can be understood that the grayscale parameters of the test video data only include integer values, not decimal values, while the grayscale digits in the target display parameters include decimal parts. Therefore, the grayscale of the test video data needs to be expanded and stretched according to the target display parameters so that it includes integer and decimal parts, corresponding to the digits of the target display parameters. It is still assumed that the LED display screen is a 16-bit grayscale display and considering the correction effect, the debugging brightness is 350nit and the color temperature starts at 6500K. After debugging, it is found that the minimum display brightness value can only reach 0.018nit during the grayscale adjustment process. Then, the input RGB value needs to be scattered to obtain a 16-bit integer part and a 4-bit decimal part.

[0079] Since the LED screen has a good display effect in medium and high grayscale, basically no adjustment is required. The main adjustment is on the display of the low gray area. Therefore, the integer part does not require complex processing, and the decimal part is mainly processed. Specifically, an error transfer algorithm can be selected to perform error transfer calculation on the decimal part, and the actual display parameters of the display device are obtained by combining the error transfer calculation results and the integer part, thereby achieving spatial dispersion of the brightness at the display end.

[0080] S400, performing source data color recoding on the video source data based on the target display parameters, performing test color recoding on the test video data based on the actual display parameters, and performing source data color recoding on the test video data based on the source data color recoding result and the test color recoding result.

[0081] The video source data is color-recoded based on the target display parameters, and the obtained source data color recoding result is the theoretical color gamut coding value; the test video data is color-recoded based on the actual display parameters, and the obtained test color recoding result is the actual color gamut coding value. Ideally, the actual color gamut coding value exactly matches the theoretical color gamut coding value, thereby generating a gamma table corresponding to the color gamut standard. The source data color recoding and the test color recoding can both be RGB (color gamut space) recoding to obtain theoretical RGB values ​​and actual RGB values. The specific method of RGB recoding can be selected according to the actual situation, for example, referring to the following embodiment, using EOTF conversion and other methods.

[0082] The above-mentioned Gamma table generation method obtains the video source display parameters related to the color gamut standard of the video source data (such as the DCI color gamut standard) and the device display parameters and test video data of the display device; determines the target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters; performs grayscale stretching on the test video data according to the target display parameters to obtain the actual display parameters of the display device; and generates the Gamma table based on the target display parameters and the actual display parameters. This ensures that the Gamma table can meet the display requirements of the color gamut standard. When the display device displays the video source data of the color gamut standard, the display parameters of the display device are adjusted according to the Gamma table to meet the requirements of the color gamut standard, thereby ensuring the display effect of low grayscale in the color gamut standard.

[0083] Furthermore, multiple Gamma tables can be pre-generated in the sending card according to different color gamut standards. When the display device displays HDR video data, if the color gamut standard is switched to other standards, such as BT2020, it is only necessary to adjust the display parameters of the display device according to the Gamma table corresponding to the BT2020 standard to display the HDR video data, which greatly improves the display flexibility of the display processing device.

[0084] In one embodiment, Figure 4 As shown, the Gamma table generation method also includes S310 and S320.

[0085] S310, determining whether the actual display parameters match the target display parameters.

[0086] If not, then proceed to S320 to obtain updated test video data of the display device, perform grayscale stretching on the updated test video data again according to the target display parameters, and obtain updated actual display parameters. Return to S310 to determine whether the actual display parameters match the target display parameters.

[0087] If they match, the process proceeds to S400.

[0088] Since the actual physical display is unlikely to have an ideal realization condition, the actual color gamut encoding value obtained for the first time is likely to be mismatched with the theoretical color gamut encoding value, so it is necessary to make a judgment. If there is a mismatch, the updated test video data of the display device is re-acquired, and the updated actual display parameters are generated again. It is judged again whether the two match. If there is still a mismatch, the test video data needs to be updated again until the two match. For example, Figure 5 As shown in the figure, after obtaining the actual RGB value and the theoretical RGB value, a comparison is made to determine whether the two match. If they do not match, the input RGB needs to be adjusted. At this time, the test video data is obtained again to obtain the test RGB value, and the grayscale is stretched again to obtain the actual RGB value, and the comparison is made again until the two match to generate a Gamma table. In this way, it can be ensured that the obtained Gamma table can meet the display needs of the corresponding color gamut standard.

[0089] In one embodiment, S300 includes obtaining each pixel of the entire frame image in the test video data; processing each pixel one by one according to the target display parameter to obtain the grayscale parameter of each pixel, wherein the grayscale parameter includes an integer grayscale parameter and a decimal grayscale parameter, the number of bits of the integer grayscale parameter corresponds to the grayscale bit width, and the number of bits of the decimal grayscale parameter corresponds to the number of data bits; performing dithering processing on the grayscale parameter to obtain the actual display parameters of the display device.

[0090] Grayscale stretching of the test video data is also to break up the brightness in space. Assuming that the low gray uniformity of the LED display is ideal, and still assuming that the LED display is a 16-bit grayscale display and considering the correction effect, the debugging brightness is 350nit and the color temperature starts at 6500K. After debugging, it is found that the minimum display brightness value can only reach 0.018nit during the grayscale adjustment process. In this case, the input RGB value needs to be broken up to obtain the required decimal part.

[0091] Optionally, during the grayscale stretching process, select the entire frame image of the test video data, process it pixel by pixel, and split the grayscale of each pixel into integers and decimals, such as 16-bit integer + 4-bit decimal. The integer part does not require complex processing, and the decimal part is mainly jittered. For example, you can select an error propagation algorithm and only perform error propagation calculations on the decimal part. Since the error can be positive or negative, a sign bit can be added to the 4-bit basis, and finally the 4-bit error propagation result of the decimal part is judged. If the accumulated error value is greater than 7, the high bit is increased by 1. If the value is less than 7, but greater than or equal to 0, the high bit remains unchanged. If the sign bit is 1, it indicates a negative number, and the high bit is reduced by 1. In the specific calculation process, the number of jitter bits can be 4, that is, the association operation of one bit requires 4 adjacent bits to participate in the error propagation operation. You can also select three strongly correlated points for simplified operations. The relationship diagram is as follows Figure 6 shown.

[0092] After the error transfer processing, when the test video data is input into the low gray range value RGB again, the actual RGB values ​​are: R high 16bit value 6, low value 7, G high 16bit value 7, low value 8, B high 16bit value 5, low value 12, which can achieve 0.005nit, 6500K color temperature color point. The theoretical RGB values ​​are: R high 16 bits are 0000_0000_0000_0001 (1), and the low 4 bits are 0001 (0.001125), G high 16 bits are 0000_0000_0000_0001 (decimal 1), and the low 4 bits are 0010 (0.125), B high 16 bits are 0000_0000_0000_0001 (decimal 1), and the low 4 bits are 0010 (0.125). In this way, the theoretical RGB value and the actual RGB value can be matched on the Gamma table, and there is a corresponding point on the Gamma table. By analogy, more points can be obtained, and the Gamma curve drawn based on more points will be more accurate, which is not limited in this embodiment.

[0093] Therefore, by stretching the low-gray display part of the LED display screen to expand the low-gray display area, HDR ultra-low-gray display is realized in the LED display screen control system, and the low-gray element is expanded from the content domain of the video source data and the display domain of the display device end, so that Gamma is more accurate and the Gamma value index in the range of 0-1 is realized. Figure 7As shown in the figure, the original low-gray display brightness can only reach about 0.01nit. After the low-gray stretching, the display brightness can be as low as 0.005nit. This stretching is very beneficial to HDR display, which improves the brightness difference of high and low gray displays of HDR, and the brightness of the medium and high gray parts remains unchanged (although the medium and high gray parts are adjusted, the impact on the medium and high gray scales is negligible and within the allowable error range, so it can be ignored), maintaining the color coordinates of the medium and high gray display, thereby maintaining the display color gamut space.

[0094] In one embodiment, a display control parameter generation method is provided, which can be applied to Figure 8 In the display system shown in the figure, the display processing device 100 in the display system is connected to the display device 200 and the video playback device 300 respectively, and the display processing device 100 obtains the video source data output by the video playback device 300; according to the color gamut standard of the video source data, the corresponding target display parameters are determined, wherein the target display parameters are determined according to the video source display parameters corresponding to the color gamut standard and the display parameters of the display device; according to the target display parameters, the video source data is subjected to grayscale expansion processing to obtain the corresponding video source grayscale parameters; according to the video source grayscale parameters and the Gamma table corresponding to the color gamut standard, the display control parameters are generated, and the display control parameters are output to the display device 200, and the display processing device 100 also outputs the video content data in the video source data, and the display device 100 displays the video content data according to the display control parameters, thereby realizing the display of the video source data.

[0095] In one embodiment, Fig. 9 As shown, a method for generating display control parameters is provided, and the method is applied to Figure 8 The display processing device in is used as an example for explanation, including S500-S800.

[0096] S500, obtaining video source data.

[0097] S600, determining corresponding target display parameters according to a color gamut standard of the video source data, wherein the target display parameters are determined according to video source display parameters corresponding to the color gamut standard and display parameters of a display device.

[0098] S700, performing grayscale expansion processing on the video source data according to the target display parameter to obtain corresponding video source grayscale parameters.

[0099] S800: Generate display control parameters according to the grayscale parameters of the video source and a gamma table corresponding to the color gamut standard.

[0100] The video source data may be HDR video data. After receiving the video source data, the corresponding color gamut standard may be determined based on the video source data, thereby determining the target display parameters corresponding to the color gamut standard. The specific method for determining the target display parameters may be determined with reference to the above embodiments. The gamma table corresponding to the color gamut standard may be generated using the method of the above embodiments, which will not be described in detail in this embodiment.

[0101] The process of grayscale expansion of video source data according to the target display parameters needs to be specifically processed according to the specific format and bit width of the video source data. If the bit width is smaller than the system requirement, it is necessary to expand the bit width first, and finally obtain the RGB value of RGB re-quantization, that is, the grayscale parameter of the video source.

[0102] For example, if the system requirement is 12 bits, and the current input video source data is in RGB format less than 12 bits, the RGB re-encoding process is:

[0103] (1) Normalize the RGB values ​​so that the integer value (range 0-4095) is converted into a floating point value (range 0.0-1.0). The processing formula is:

[0104] CVR'=(R / 4096)*4096; CVG'=(G / 4096)*4096; CVB'=(B / 4096)*4096.

[0105] (2) The nonlinear R'G'B' at the video source data end is converted into the linear RGB in the display domain through the EOTF function. For example, [SMPTE ST 2084] is selected here. The selection of EOTF is related to the color gamut to be presented by the LED screen. For example, the HDR video source data is the HDR of the DCI standard, and the recommended EOTF is selected accordingly. The formula is:

[0106]

[0107]

[0108]

[0109] Among them, K0 = 10000, K1 = 4095; m1 = (2610*1) / (4096*4); m2 = (2523*128) / 4096; c2 = (2413*32) / 4096; c3 = (2392*32) / 4096; c1 = c3-c2+1. The value of K0 determines the range of RGB value from 0.0 to 10000.0.

[0110] (3) To convert the color space to a colorimetric system XYZ that is more in line with human eye standards, a linear coordinate conversion is required, and the formula is:

[0111]

[0112] (4) Then, after inverse EOTF and 12-bit quantization (the maximum brightness in this example is about 300 nit, with a value range of 0-4095), the input stimulus values ​​CVX", CVY" and CVZ" for the display domain are obtained. The formula is:

[0113]

[0114] Among them, K0=10000; K1=4095; m1=(2610*1) / (4096*4); m2=(2523*128) / 4096; c2=(2413*32) / 4096; c3=(2392*32) / 4096; c1=c3-c2+1.

[0115] In this way, after RGB re-encoding, the display domain input CVX", CVY" and CVZ" are obtained, which are quantized at 12 bits, enriching the low-gray range of the original RGB at the content end.

[0116] (5) Finally, the EOTF of input excitation is performed. The EOTF is used to obtain the RGB of the display domain, and then the color is adjusted through the display module Gamma to obtain the correct brightness and color gamut display. The EOTF formula of input excitation is:

[0117]

[0118] Among them, K0=10000; K1=4095; m1=(2610*1) / (4096*4); m2=(2523*128) / 4096; c2=(2413*32) / 4096; c3=(2392*32) / 4096; c1=c3-c2+1.

[0119] Then convert the XYZ colorimetry system to the RGB colorimetry system, the formula is:

[0120]

[0121] This value range needs to be consistent with the display module of the LED display screen. In this example, the parameter value in the above embodiment is still taken as an example. The target display parameter is a 16-bit integer + 4-bit decimal. Then after quantization, it also corresponds to a 16-bit integer + 4-bit decimal, thereby obtaining a 20-bit video source grayscale parameter.

[0122] If the current input video source data is in 12-bit RGB format, normalization, EOTF conversion and inverse EOTF are not required in the RGB re-encoding process. Only the input excitation EOTF needs to be processed to obtain 20-bit grayscale parameters. If the current input video source data is in 12-bit XYZ format, only inverse EOTF and input excitation EOTF processing are required.

[0123] The above-mentioned display control parameter generation method can determine the corresponding Gamma table according to the color gamut standard of the video source data, ensure the low-gray display effect of the display device for the video source data of the color gamut standard, and improve the display flexibility of the display device. At the same time, the grayscale of the video source data is expanded according to the format and bit number of the video source data, so that the video source data is more matched with the display capability of the display device, thereby improving the display capability of the display system.

[0124] In one embodiment, the video playback device outputs wide dynamic data in a video frame format, including field synchronization signals, video data signals, HDR wide dynamic and other related information, and HDR wide dynamic related information includes HDR maximum and minimum brightness, and color temperature. After receiving the data in the above video frame format, the sending card parses the field synchronization signal, HDR wide dynamic related information, video frame data, etc.

[0125] For example, the video playback device outputs 12-bit wide dynamic data in RGB format, which is output in video frame format and includes field synchronization signal, video data signal, and HDR wide dynamic related information. After receiving the above data, the display processing device parses the field synchronization signal, HDR wide dynamic related information, video frame data, etc. The wide dynamic video input is low gray 0.005nit, 6500K color temperature (color coordinates: x=0.312, y=0.329), maximum brightness 300nit, 6500K color temperature (color coordinates: x=0.312, y=0.329), data bit width 12bit, etc., and synchronizes each field synchronization signal to output HDR field synchronization frame as shown in Table 4:

[0126] symbol name describe Code coding Values ​​correspond to the color gamut standard LTC Linear time code Frame Count HACT Valid line length Number of pixels per row VACT Column effective length Number of pixels per column FMT Format Color space and sampling rate information MAXL HDR Brightness Description Maximum brightness MINL HDR Brightness Description Minimum brightness Temp HDR color temperature description Color Temperature CRC reserve CRC16 checksum

[0127] Table 4 HDR field synchronization frame has a total of 16 bytes, as shown in Table 5:

[0128]

[0129] Table 5

[0130] The coded values ​​can be 0x00, 0x01, etc., respectively. When the value is 00, it indicates an HDR video based on the DCI standard, and when the value is 01, it indicates an HDR video based on the BT2020 standard. Thus, the display processing device can accurately determine the color gamut standard of the received video source data according to the HDR field synchronization frame signal.

[0131] Furthermore, the display processing device outputs the HDR field synchronization frame to the display device, and the display device parses the HDR field synchronization frame to obtain its frame header information, thereby performing drive configuration according to different color gamut standards, thereby improving the processing capability of the display device.

[0132] In one embodiment, Fig.10 As shown, the display processing device 100 is a sending card, the display device 200 includes a receiving card 21 and an LED display module 22 connected to each other, and the receiving card 21 is connected to the sending card; the video playback device 300 is a player. The workflow of the player, the sending card, the receiving card and the LED display module is as follows: Fig.11 As shown, the player outputs HDR video source data in YUV, RGB or XYZ format. For more information about the sending card function, refer to Fig.12 After receiving the video source data, the sending card increases the low grayscale bit width through RGB re-encoding, Gamma table conversion, grayscale stretching and other processing to obtain grayscale data, and sends the display data including grayscale data and HDR field synchronization frame to the receiving card. The receiving card functions are as follows: Fig.13 As shown, after receiving the display data, the receiving card extracts relevant information according to the HDR synchronization frame and loads the corresponding pre-stored driver IC configuration parameters, so that the optical parameters of the light board of the LED display module meet the display requirements and the display effect is good.

[0133] The display control parameter generation method can ensure the low-gray display effect of the display device for the video source data of the color gamut standard, thereby improving the display quality and display flexibility of the display device.

[0134] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0135] Based on the same inventive concept, the embodiment of the present application also provides a gamma table generation device for implementing the gamma table generation method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more gamma table generation device embodiments provided below can refer to the limitations of the gamma table generation method above, and will not be repeated here.

[0136] In one embodiment, Fig.14 As shown, a Gamma table generation device is provided, including a parameter acquisition module 901, a target parameter determination module 902, a grayscale stretching module 903 and a Gamma generation module 904, wherein:

[0137] The parameter acquisition module 901 is used to acquire video source display parameters related to the color gamut standard of the video source data, as well as test video data and device display parameters of the display device.

[0138] The target parameter determination module 902 is used to determine the target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters.

[0139] The grayscale stretching module 903 is used to perform grayscale stretching on the test video data according to the target display parameters to obtain the actual display parameters of the display device.

[0140] The gamma generation module 904 is used to perform source data color recoding on the video source data based on the target display parameters, perform test color recoding on the test video data based on the actual display parameters, and generate a gamma table according to the source data color recoding results and the test color recoding results.

[0141] In one embodiment, the Gamma generation module 904 is also used to determine whether the actual display parameters match the target display parameters; if not, then obtain the test video data of the updated display device, and grayscale stretch the updated test video data again according to the target display parameters to obtain the updated actual display parameters; return to the step of determining whether the actual display parameters match the target display parameters; if they do match, then enter the step of performing source data color recoding on the video source data based on the target display parameters, perform test color recoding on the test video data based on the actual display parameters, and generate a Gamma table according to the source data color recoding result and the test color recoding result.

[0142] The target parameter determination module 902 is also used to determine the minimum target brightness value in the video source display parameters, as well as the minimum display brightness value and grayscale bit width in the device display parameters; perform unit brightness grading according to the minimum target brightness value and the minimum display brightness value to obtain the minimum brightness level; determine the minimum brightness value of each level based on the minimum brightness level, and determine the number of data bits required to represent the minimum brightness value in the storage space; and collect the minimum brightness value, data bit number and grayscale bit width of each level to obtain the target display parameters.

[0143] The grayscale stretching module 903 is also used to obtain each pixel of the entire frame image in the test video data; each pixel is processed successively according to the target display parameter to obtain the grayscale parameter of each pixel, wherein the grayscale parameter includes an integer grayscale parameter and a decimal grayscale parameter, the number of bits of the integer grayscale parameter corresponds to the grayscale bit width, and the number of bits of the decimal grayscale parameter corresponds to the number of data bits; the grayscale parameter is jittered to obtain the actual display parameters of the display device.

[0144] Each module in the above-mentioned Gamma table generation device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the display processing device in the form of hardware, or can be stored in the memory in the display processing device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0145] In one embodiment, Fig.15 As shown, a display control parameter generation device is provided, including: a video acquisition module 905, a display parameter determination module 906, a grayscale expansion module 907 and a parameter generation module 908. Among them:

[0146] The video acquisition module 905 is used to acquire video source data.

[0147] The display parameter determination module 906 is used to determine corresponding target display parameters according to the color gamut standard of the video source data, wherein the target display parameters are determined according to the video source display parameters corresponding to the color gamut standard and the display parameters of the display device.

[0148] The grayscale expansion module 907 is used to perform grayscale expansion processing on the video source data according to the target display parameters to obtain corresponding video source grayscale parameters.

[0149] The parameter generation module 908 is used to generate display control parameters according to the grayscale parameters of the video source and the Gamma table corresponding to the color gamut standard; wherein the Gamma table corresponding to the color gamut standard is generated using the Gamma table generation method of the above embodiment.

[0150] Each module in the above display control parameter generation device can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor in the display processing device in the form of hardware, or can be stored in the memory in the display processing device in the form of software, so that the processor can call and execute the operations corresponding to each module.

[0151] In one embodiment, a display device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0152] In one embodiment, a display system is further provided, including a display device and a display processing device connected to each other. The display device can be configured according to the parameters of the above embodiments, which will not be described in detail.

[0153] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0154] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0155] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0156] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0157] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for generating a gamma table, characterized in that: The method comprises: Acquire video source data and video source display parameters related to the color gamut standard, as well as test video data and device display parameters of the display device; Determining target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters; Performing grayscale stretching on the test video data according to the target display parameters to obtain actual display parameters of the display device; Re-encode the source data color of the video source data based on the target display parameter, re-encode the test color of the test video data based on the actual display parameter, and generate a gamma table according to the source data color re-encoding result and the test color re-encoding result; Wherein, determining the target display parameters corresponding to the color gamut standard according to the video source display parameters and the device display parameters includes: determining the minimum target brightness value in the video source display parameters, and the minimum display brightness value and grayscale bit width in the device display parameters; performing unit brightness grading according to the minimum target brightness value and the minimum display brightness value to obtain a minimum brightness level; determining the minimum brightness value of each grading based on the minimum brightness level, and determining the number of data bits required to represent the minimum brightness value in the storage space; and collecting the minimum brightness value of each grading, the number of data bits and the grayscale bit width to obtain the target display parameters; The grayscale stretching of the test video data according to the target display parameter to obtain the actual display parameter of the display device includes: obtaining each pixel of the whole frame image in the test video data; processing each pixel one by one according to the target display parameter to obtain the grayscale parameter of each pixel, wherein the grayscale parameter includes an integer grayscale parameter and a decimal grayscale parameter, the number of bits of the integer grayscale parameter corresponds to the grayscale bit width, and the number of bits of the decimal grayscale parameter corresponds to the number of data bits; The grayscale parameters are subjected to dithering processing to obtain actual display parameters of the display device.

2. The method according to claim 1, characterized in that Also includes: Determining whether the actual display parameter matches the target display parameter; If there is no match, obtaining updated test video data of the display device, and performing grayscale stretching again on the updated test video data according to the target display parameters to obtain updated actual display parameters; Returning to the step of determining whether the actual display parameters match the target display parameters; If they match, the process proceeds to the step of recoding the source data color of the video source data based on the target display parameters, recoding the test color of the test video data based on the actual display parameters, and generating a gamma table according to the source data color recoding result and the test color recoding result.

3. A method for generating display control parameters, characterized in that: The method comprises: Get video source data; Determine corresponding target display parameters according to the color gamut standard of the video source data, wherein the target display parameters are determined according to the video source display parameters corresponding to the color gamut standard and the display parameters of the display device; Performing grayscale expansion processing on the video source data according to the target display parameter to obtain corresponding video source grayscale parameters; Generate display control parameters according to the video source grayscale parameters and the gamma table corresponding to the color gamut standard; Wherein, the gamma table corresponding to the color gamut standard is generated using the method described in claim 1 or 2.

4. The method according to claim 3, characterized in that The field synchronization frame data of the video source data includes color gamut standard parameters, and different parameter values ​​of the color gamut standard parameters correspond to different color gamut standards.

5. A gamma table generating device, characterized in that: The device comprises: A parameter acquisition module, used to acquire video source data and video source display parameters related to the color gamut standard, as well as test video data and device display parameters of the display device; A target parameter determination module, configured to determine a target display parameter corresponding to the color gamut standard according to the video source display parameter and the device display parameter; A grayscale stretching module, used for performing grayscale stretching on the test video data according to the target display parameters to obtain actual display parameters of the display device; A gamma generation module, configured to perform source data color recoding on the video source data based on the target display parameter, perform test color recoding on the test video data based on the actual display parameter, and generate a gamma table according to the source data color recoding result and the test color recoding result; The target parameter determination module is further used to determine the minimum target brightness value in the video source display parameters, and the minimum display brightness value and grayscale bit width in the device display parameters; perform unit brightness grading according to the minimum target brightness value and the minimum display brightness value to obtain the minimum brightness level; determine the minimum brightness value of each grading based on the minimum brightness level, and determine the number of data bits required to represent the minimum brightness value in the storage space; collect the minimum brightness value of each grading, the number of data bits and the grayscale bit width to obtain the target display parameters; The grayscale stretching module is further used to obtain each pixel of the entire frame image in the test video data; process each pixel one by one according to the target display parameter to obtain the grayscale parameter of each pixel, wherein the grayscale parameter includes an integer grayscale parameter and a decimal grayscale parameter, the number of bits of the integer grayscale parameter corresponds to the grayscale bit width, and the number of bits of the decimal grayscale parameter corresponds to the number of data bits; The grayscale parameters are subjected to dithering processing to obtain actual display parameters of the display device.

6. A display control parameter generating device, characterized in that: The device comprises: Video acquisition module, used to acquire video source data; A display parameter determination module, configured to determine corresponding target display parameters according to the color gamut standard of the video source data, wherein the target display parameters are determined according to the video source display parameters corresponding to the color gamut standard and the display parameters of the display device; A grayscale expansion module, used for performing grayscale expansion processing on the video source data according to the target display parameter to obtain corresponding video source grayscale parameters; A parameter generation module is used to generate display control parameters according to the video source grayscale parameters and the Gamma table corresponding to the color gamut standard; wherein the Gamma table corresponding to the color gamut standard is generated using the method described in claim 1 or 2.

7. A display processing device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the processor implements the steps of the method according to any one of claims 1 to 2, or implements the steps of the method according to any one of claims 3 to 4.

8. A display system comprising a display device and the display processing device according to claim 7 connected to each other.

Images