A display dynamic contrast adjustment method and system

Abstract

The present application relates to the technical field of image enhancement, in particular to a display dynamic contrast adjustment method and system, comprising the following steps: obtaining the to-be-displayed gray data of the current display picture of the display, counting the dark field area proportion, the bright field area proportion and the gray concentration degree according to the preset gray interval, respectively calculating the dark field gray level promotion parameter and the bright field gray level suppression parameter, generating the dynamic contrast adjustment parameter group within the global contrast constraint range and combining the intermediate gray level maintaining condition, comparing the current display picture with the historical frame picture features, updating the display driving parameter according to the scene switching condition or the update step length, and writing into the display driving link. In the present application, the display driving parameter is formed into a corresponding relationship with the picture content change through the light and dark area separation calculation, global constraint fusion and inter-frame update control, so that the influence degree of the dark gray level compression and the bright gray level saturation on the picture level is reduced.

Description

Technical Field

[0001] This invention relates to the field of image enhancement technology, and in particular to a method and system for adjusting the dynamic contrast of a display. Background Technology

[0002] Image enhancement technology focuses on the acquisition, analysis, calculation, and display control of brightness, grayscale, color, and detail levels of digital images or video frames. The processing targets can originate from display driver chips, image processors, video memory buffers, or external video interfaces. Programs map, limit, look up tables, perform gamma correction, or call backlight control commands on image data based on pixel grayscale values, histogram distribution, regional brightness / darkness ratios, inter-frame variations, and preset display parameters. This data is then transmitted to the LCD panel, OLED panel, or their driver circuits via the display control link. Traditional dynamic contrast adjustment methods and systems for displays refer to techniques that process contrast parameters based on the brightness / darkness distribution of the currently input or displayed image. Typically, a display control board or image processing chip reads video frame data, statistically analyzes the full-frame or zone grayscale histogram, average brightness, peak brightness, and dark area ratio, compares the statistical results with preset thresholds, lookup tables, or display mode parameters, and generates control parameters such as contrast gain, grayscale mapping, gamma curves, or backlight brightness, which are then written to the display driver register or driver configuration items.

[0003] Traditional monitor contrast adjustment relies on average brightness, peak brightness, grayscale histogram, etc., with preset thresholds or display modes to generate uniform contrast parameters. When dark and bright areas coexist in the actual image, a single grayscale mapping is difficult to meet the display needs of different grayscale ranges. Dark details are easily compressed, and bright grayscale is easily close to saturation. When the content of the image changes in consecutive frames, the parameter refresh lacks a control basis corresponding to the magnitude of the image change, and the display driving parameters are difficult to keep matched between scene switching and slowly changing images. Summary of the Invention

[0004] The purpose of this invention is to provide a dynamic contrast adjustment method and system for a display, which enables the contrast adjustment of the display to be determined based on the grayscale distribution, the proportion of bright and dark areas, the grayscale span of the dark field, the continuity of the pixel distribution in the dark field, the saturation proximity of the bright field, the grayscale concentration, and the changes in the image between frames. This reduces the situation where a uniform contrast parameter cannot meet the display requirements of both dark and bright areas, and enables the display driving parameters to be updated accordingly with scene switching or continuous image changes.

[0005] To achieve the above objectives, this invention employs a dynamic contrast adjustment method for a display, comprising the following steps: acquiring grayscale data to be displayed from the current display screen; performing statistical analysis and feature extraction on the grayscale data to be displayed according to a preset grayscale range to obtain the proportion of dark areas, the proportion of bright areas, the grayscale span of dark areas, the continuity of pixel distribution in dark areas, the saturation proximity of bright areas, and the grayscale concentration; calculating dark area grayscale enhancement parameters based on the proportion of dark areas, the grayscale span of dark areas, and the continuity of pixel distribution in dark areas; calculating bright area grayscale suppression parameters based on the proportion of bright areas, the saturation proximity of bright areas, and the grayscale concentration of bright areas; and combining the dark area grayscale enhancement parameters with the grayscale concentration of bright areas. Bright field grayscale suppression parameters are fused within the global contrast constraint range and combined with midtone grayscale preservation conditions to generate a dynamic contrast adjustment parameter group. The image features of the current display screen are compared with the image features of historical frames. When the change in image features meets the scene switching conditions, the display driving parameters are updated according to the dynamic contrast adjustment parameter group. When the change in image features does not meet the scene switching conditions, the display driving parameters are updated according to the update step size of the historical adjustment parameters and the dynamic contrast adjustment parameter group. The display driving parameters are converted into contrast gain, grayscale mapping table or gamma curve and written into the display driving link, and the display driving link drives the display panel to output the image according to the written parameters.

[0006] Furthermore, the grayscale data to be displayed is read from the display's video frame buffer and extracted from the luminance component of the currently displayed image. When statistically analyzing the grayscale data to be displayed according to the preset grayscale range, the preset grayscale range is divided into a low grayscale range, a middle grayscale range, and a high grayscale range, and the number of pixels in the low grayscale range, the number of pixels in the high grayscale range, and the total number of pixels in the entire frame are counted respectively. The proportion of the dark area is determined based on the ratio of the number of pixels in the low grayscale range to the total number of pixels in the entire frame, and the proportion of the bright area is determined based on the ratio of the number of pixels in the high grayscale range to the total number of pixels in the entire frame.

[0007] Furthermore, the grayscale concentration includes dark-field grayscale concentration and bright-field grayscale concentration. When calculating the dark-field grayscale concentration, the proportion of pixel grayscale values ​​falling into consecutive grayscale sub-intervals within the low grayscale range is counted; when calculating the bright-field grayscale concentration, the proportion of pixel grayscale values ​​falling into consecutive grayscale sub-intervals within the high grayscale range is counted; when the proportion of consecutive grayscale sub-intervals meets the concentration determination condition, the corresponding grayscale range is marked as a concentrated distribution state; when the proportion of consecutive grayscale sub-intervals does not meet the concentration determination condition, the corresponding grayscale range is marked as a discrete distribution state.

[0008] Furthermore, when calculating the dark field grayscale enhancement parameter, the dark field adjustment weight is first determined based on the proportion of the dark field region, and then the dark field enhancement magnitude is determined based on the dark field grayscale span. The continuity of the dark field pixel distribution is used as the basis for correcting the dark field enhancement magnitude. When the proportion of the dark field region meets the dark field proportion trigger condition and the dark field grayscale span is less than the dark field span judgment threshold, the dark field grayscale enhancement parameter is increased; when the proportion of the dark field region does not meet the dark field proportion trigger condition or the dark field grayscale span is not less than the dark field span judgment threshold, the adjustment magnitude of the dark field grayscale enhancement parameter is limited.

[0009] Furthermore, when calculating the bright field grayscale suppression parameter, the bright field adjustment weight is first determined based on the proportion of the bright field region, and then the bright field suppression amplitude is determined based on the degree of brightness field saturation proximity. The concentrated or discrete distribution state of the bright field grayscale concentration is used as the basis for correcting the bright field suppression amplitude. When the proportion of the bright field region meets the bright field proportion trigger condition and the degree of brightness field saturation proximity meets the saturation proximity judgment condition, the bright field grayscale suppression parameter is increased; when the proportion of the bright field region does not meet the bright field proportion trigger condition or the degree of brightness field saturation proximity does not meet the saturation proximity judgment condition, the adjustment amplitude of the bright field grayscale suppression parameter is limited.

[0010] Furthermore, when fusing the dark-field grayscale enhancement parameter and the bright-field grayscale suppression parameter within the global contrast constraint range, the parameter fusion priority is first determined based on the relative size of the dark-field region proportion and the bright-field region proportion. When the dark-field region proportion is greater than the bright-field region proportion, the dark-field grayscale enhancement parameter is used as the main adjustment parameter, and the bright-field grayscale suppression parameter is used as the limiting parameter; when the bright-field region proportion is greater than the dark-field region proportion, the bright-field grayscale suppression parameter is used as the main adjustment parameter, and the dark-field grayscale enhancement parameter is used as the limiting parameter; when the dark-field region proportion and the bright-field region proportion meet the equalization judgment condition, the dark-field grayscale enhancement parameter and the bright-field grayscale suppression parameter are weighted and fused according to the midtone grayscale preservation condition.

[0011] Furthermore, the midtone grayscale preservation condition includes grayscale offset limits and grayscale mapping continuity limits for the midtone grayscale intervals. When generating the dynamic contrast adjustment parameter set, the upper and lower limits of the merged parameters are first defined according to the global contrast constraint range. Then, the mapping slope corresponding to the midtone grayscale interval is corrected according to the grayscale offset limit. When the corrected mapping slope satisfies the grayscale mapping continuity limit, the dynamic contrast adjustment parameter set is output. When the corrected mapping slope does not satisfy the grayscale mapping continuity limit, the fusion weights of the dark field grayscale enhancement parameter or the bright field grayscale suppression parameter are adjusted until the corrected mapping slope satisfies the grayscale mapping continuity limit.

[0012] Furthermore, when comparing the image features of the current display with the image features of the historical frames, the current frame image features are first constructed using the proportion of dark areas, the proportion of bright areas, and the grayscale concentration. Then, the historical frame image features are read from the historical parameter storage area. When the difference between the current frame image features and the historical frame image features meets the scene switching condition, the updated display driving parameters are directly generated according to the dynamic contrast adjustment parameter group. When the difference between the current frame image features and the historical frame image features does not meet the scene switching condition, the parameter difference between the historical adjustment parameters and the dynamic contrast adjustment parameter group is calculated. The update step size is dynamically matched according to the parameter difference, and the historical adjustment parameters are used as a benchmark to perform step adjustments according to the matched update step size, thereby generating the updated display driving parameters.

[0013] Furthermore, when writing the display driving parameters into the display driving link, the updated display driving parameters are first converted into contrast gain, grayscale map, or gamma curve, and then the contrast gain, grayscale map, or gamma curve is written into the display driving register. When the display driving register completes the write confirmation, the display driving link is controlled to drive the display panel to output the image according to the contrast gain, grayscale map, or gamma curve; when the display driving register does not complete the write confirmation, the display driving parameters before writing are retained as the display parameters for this frame.

[0014] The present invention also provides a display dynamic contrast adjustment system, which supports the above method and includes a screen feature extraction unit, a contrast parameter calculation unit, a parameter fusion unit, an inter-frame update control unit, and a drive parameter writing unit. The image feature extraction unit is connected to the video frame buffer and is used to read the grayscale data to be displayed in the current display image, and extract the proportion of dark area, proportion of bright area, grayscale span of dark area, continuity of dark area pixel distribution, saturation closeness of bright area, and grayscale concentration. The contrast parameter calculation unit is used to calculate the dark area grayscale enhancement parameter and the bright area grayscale suppression parameter according to the extracted image feature data. The parameter fusion unit is used to fuse the dark area grayscale enhancement parameter and the bright area grayscale suppression parameter within the global contrast constraint range, and generate a dynamic contrast adjustment parameter group in combination with the midtone grayscale preservation condition. The inter-frame update control unit is connected to the historical parameter storage area and is used to compare the image features of the current display image with the image features of historical frames, and output direct update instructions or smooth update instructions according to the scene switching conditions. The drive parameter writing unit is used to convert the display drive parameters into contrast gain, grayscale mapping table or gamma curve according to the direct update instruction or the smooth update instruction, and write them into the display drive register.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0016] In this invention, by statistically analyzing the grayscale data to be displayed in the current screen according to preset grayscale intervals, the proportion of dark areas, the proportion of bright areas, and the grayscale concentration are formed, giving the contrast parameters a basis for calculation oriented towards the screen content. The dark area grayscale enhancement parameter is obtained by combining the dark area grayscale span and the continuity of dark area pixel distribution, while the bright area grayscale suppression parameter is obtained by combining the brightness saturation proximity and the concentration of high grayscale levels. These parameters are then fused within the global contrast constraint range and combined with midtone grayscale preservation conditions, ensuring that dark and bright grayscale levels are controlled separately. After comparing the screen feature change amplitude with the screen features of historical frames, the display driving parameters are updated according to scene switching conditions or update step size, allowing continuous and switched screens to correspond to different parameter update methods. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the accompanying drawings without creative effort.

[0018] Figure 1 This is a complete flowchart of the display dynamic contrast adjustment method of the present invention;

[0019] Figure 2 This is a flowchart of the grayscale data statistics and feature extraction process to be displayed in this invention;

[0020] Figure 3 This is a logic diagram for calculating the dark field grayscale enhancement parameters and bright field grayscale suppression parameters of this invention;

[0021] Figure 4 This is a flowchart of the driver parameter generation and inter-frame update control process of the present invention;

[0022] Figure 5 This is a data flow diagram of the display dynamic contrast adjustment system of the present invention. Detailed Implementation

[0023] The technical solution described in this invention will be explained below with reference to the newly added accompanying drawings. Subsequent embodiments will focus on the dynamic contrast adjustment method for a display, and a dynamic contrast adjustment system for a display will be used as a supporting implementation corresponding to the method. The grayscale data to be displayed used in this description refers to the grayscale data read from the display's video frame buffer and extracted from the luminance component of the currently displayed image; the proportion of dark areas, the proportion of bright areas, the grayscale span of dark areas, the continuity of dark area pixel distribution, the saturation proximity of bright areas, and the grayscale concentration are all image feature data obtained by statistically analyzing and extracting features from the grayscale data to be displayed according to a preset grayscale range; the dynamic contrast adjustment parameter group refers to the display adjustment data formed by fusing dark area grayscale enhancement parameters and bright area grayscale suppression parameters within a global contrast constraint range, and capable of being converted into contrast gain, grayscale mapping tables, or gamma curves.

[0024] Example 1

[0025] Please see Figures 1 to 4 This embodiment provides a method for dynamic contrast adjustment of a display. In this embodiment, after receiving video frame data, the display does not directly output uniform contrast parameters according to a fixed display mode. Instead, it first obtains the grayscale data to be displayed from the current display screen, and then performs grayscale interval division, area proportion statistics, grayscale span extraction, pixel distribution continuity judgment, saturation proximity judgment, and grayscale concentration statistics on the grayscale data to be displayed. The resulting image feature data enters the subsequent parameter calculation and fusion process, and participates in inter-frame update control through historical frame image features, so that the display driving parameters can be written according to the current frame content and inter-frame change state.

[0026] S1. Obtain the grayscale data to be displayed in the current display screen, and perform statistics and feature extraction on the grayscale data to be displayed according to the preset grayscale range to obtain the proportion of dark area, proportion of bright area, grayscale span of dark area, continuity of pixel distribution in dark area, saturation proximity of bright area and grayscale concentration.

[0027] During the execution of S1, the display's video frame buffer stores the video frame data corresponding to the currently displayed screen. The image processing program or display control program extracts the luminance component from the video frame data and converts the luminance component into grayscale data to be displayed. The statistical object of the grayscale data to be displayed is the pixel grayscale value of the currently displayed screen, and the statistical scope corresponds to the current frame and does not cross the next frame. If the current displayed screen is a color video frame, the extraction process uses the luminance component as the source of grayscale statistics; if the current displayed screen is already a grayscale frame, the read grayscale value is directly used as the grayscale data to be displayed and entered into the interval statistics.

[0028] S11. Divide the preset grayscale range into a low grayscale range, a middle grayscale range, and a high grayscale range. The low grayscale range represents the grayscale value range corresponding to the dark area, the middle grayscale range represents the grayscale value range corresponding to the mid-tone area, and the high grayscale range represents the grayscale value range corresponding to the bright area. The preset grayscale range is predetermined by the display control program or display driver configuration and remains unchanged during the statistical process within the same frame.

[0029] S12. Count the number of pixels in the low grayscale range, the number of pixels in the high grayscale range, and the total number of pixels in the entire frame. The number of pixels in the low grayscale range refers to the number of pixels whose grayscale values ​​fall within the low grayscale range; the number of pixels in the high grayscale range refers to the number of pixels whose grayscale values ​​fall within the high grayscale range; and the total number of pixels in the entire frame refers to the total number of pixels in the currently displayed image that are included in the statistics. Determine the proportion of dark areas based on the ratio of the number of pixels in the low grayscale range to the total number of pixels in the entire frame, and determine the proportion of bright areas based on the ratio of the number of pixels in the high grayscale range to the total number of pixels in the entire frame.

[0030] S13. Extract the dark field grayscale span. Perform range statistics on the grayscale values ​​of pixels falling into the low grayscale range, and use the span between the upper and lower grayscale boundaries of the dark field pixels as the dark field grayscale span. If there are no pixels in the low grayscale range to participate in the statistics, set the proportion of the dark field region to the state corresponding to the region without dark field, and put the subsequent calculation of the dark field grayscale enhancement parameters into the limiting processing path.

[0031] S14. Extract the continuity of dark field pixel distribution. The adjacency relationship of pixels in the low grayscale range within the current display screen is determined, based on the adjacency connection status of pixels in the row or column direction and the pixel clustering status of continuous dark field areas. If adjacent low grayscale pixels form a continuous area, the corresponding area is included in the continuous dark field distribution; if low grayscale pixels are scattered, the corresponding area is included in the discrete dark field distribution. The continuity of dark field pixel distribution serves as the basis for correcting the dark field enhancement magnitude and is subsequently used in the calculation of dark field grayscale enhancement parameters.

[0032] S15. Extract the brightness saturation proximity. Statistically analyze the grayscale values ​​of pixels falling within the high grayscale range to determine how close these values ​​are to the upper boundary of the high grayscale range. Brightness saturation proximity can be determined by the grayscale distance between high grayscale pixels and the upper boundary of the high grayscale range, the proportion of pixels close to the upper boundary, or the grayscale distribution within the high grayscale range. Brightness saturation proximity does not directly replace the proportion of the bright area; instead, it is included in the calculation of the bright area grayscale suppression parameters along with the proportion of the bright area.

[0033] S16. Calculate grayscale concentration. Grayscale concentration includes dark-field grayscale concentration and bright-field grayscale concentration. When calculating dark-field grayscale concentration, the low-grayscale range is divided into continuous grayscale sub-ranges, and the proportion of pixel grayscale values ​​within the low-grayscale range falling into the same or adjacent continuous grayscale sub-ranges is calculated. When calculating bright-field grayscale concentration, the high-grayscale range is divided into continuous grayscale sub-ranges, and the proportion of pixel grayscale values ​​within the high-grayscale range falling into the same or adjacent continuous grayscale sub-ranges is calculated. When the proportion of continuous grayscale sub-ranges meets the concentration criteria, the corresponding grayscale range is marked as a concentrated distribution state; when the proportion of continuous grayscale sub-ranges does not meet the concentration criteria, the corresponding grayscale range is marked as a discrete distribution state. The concentrated and discrete distribution states are called by subsequent parameter calculation steps.

[0034] S2. Calculate the dark field grayscale enhancement parameters based on the proportion of dark field areas, the grayscale span of dark field areas, and the continuity of dark field pixel distribution. Calculate the bright field grayscale suppression parameters based on the proportion of bright field areas, the degree of brightness saturation proximity, and the brightness grayscale concentration in the grayscale concentration.

[0035] During S2 execution, the dark-field grayscale enhancement parameter and the bright-field grayscale suppression parameter are calculated separately and are not directly merged in the same calculation entry. The dark-field grayscale enhancement parameter represents the adjustment amount for grayscale enhancement in low-grayscale areas, while the bright-field grayscale suppression parameter represents the adjustment amount for grayscale suppression in high-grayscale areas. Both the dark-field grayscale enhancement parameter and the bright-field grayscale suppression parameter use the current frame's image feature data as input and are subject to global contrast constraint range limitations in subsequent fusion steps.

[0036] S21. When calculating the dark field grayscale enhancement parameters, first determine the dark field adjustment weight based on the proportion of the dark field area, then determine the dark field enhancement magnitude based on the dark field grayscale span, and use the continuity of the dark field pixel distribution as the basis for correcting the dark field enhancement magnitude. When the proportion of the dark field area meets the dark field proportion trigger condition and the dark field grayscale span is less than the dark field span judgment threshold, it indicates that the low grayscale pixels in the current display have reached the dark field adjustment entry condition, and the grayscale levels inside the dark field area are compressed, so increase the dark field grayscale enhancement parameters. When the proportion of the dark field area does not meet the dark field proportion trigger condition or the dark field grayscale span is not less than the dark field span judgment threshold, limit the adjustment magnitude of the dark field grayscale enhancement parameters so that the dark field adjustment will not produce excessive enhancement due to a small number of local low grayscale pixels or dark areas that already have a span.

[0037] S22. When the continuity of dark-field pixel distribution is involved in the correction, if low-grayscale pixels form a continuous dark-field region, the dark-field enhancement magnitude is adjusted according to the correction path corresponding to the continuous dark-field region; if low-grayscale pixels exhibit a discrete dark-field distribution, the dark-field enhancement magnitude is adjusted according to the correction path corresponding to the discrete dark-field region. The adjustment result corresponding to the continuous dark-field region is entered into the dark-field grayscale enhancement parameter, while the adjustment result corresponding to the discrete dark-field distribution is used to limit the influence of local dark points on the overall dark-field adjustment. After the dark-field grayscale enhancement parameter is output, it is sent to the subsequent parameter fusion step and serves as a parameter to be fused within the global contrast constraint range.

[0038] S23. When calculating the bright field grayscale suppression parameter, first determine the bright field adjustment weight based on the proportion of the bright field area, then determine the bright field suppression amplitude based on the brightness field saturation proximity, and use the concentrated or discrete distribution of the bright field grayscale concentration as the basis for correcting the bright field suppression amplitude. When the proportion of the bright field area meets the bright field proportion trigger condition and the brightness field saturation proximity meets the saturation proximity judgment condition, it indicates that high grayscale pixels have reached the bright field adjustment entry condition in the current display screen, and the bright grayscale is close to saturation, so increase the bright field grayscale suppression parameter. When the proportion of the bright field area does not meet the bright field proportion trigger condition or the brightness field saturation proximity does not meet the saturation proximity judgment condition, limit the adjustment amplitude of the bright field grayscale suppression parameter so that the bright field adjustment will not produce excessive suppression due to high grayscale pixels that have not reached the saturation proximity state.

[0039] S24. When the brightness field grayscale concentration is involved in the correction, if the high grayscale range is marked as a concentrated distribution, the brightness field suppression amplitude is adjusted according to the correction path corresponding to the concentrated brightness field; if the high grayscale range is marked as a discrete distribution, the brightness field suppression amplitude is adjusted according to the correction path corresponding to the discrete brightness field. After the brightness field grayscale suppression parameter is output, it enters the subsequent fusion step together with the dark field grayscale enhancement parameter.

[0040] S3. The dark field grayscale enhancement parameter and the bright field grayscale suppression parameter are fused within the global contrast constraint range, and combined with the midtone grayscale preservation condition to generate a dynamic contrast adjustment parameter group.

[0041] When S3 is executed, the parameter blending priority is first determined based on the relative proportions of the dark and bright areas. The parameter blending priority is used to determine whether to prioritize dark area adjustment, bright area adjustment, or perform balanced blending according to midtone grayscale preservation conditions within the same frame. The global contrast constraint range is used to limit the upper and lower limits of the blended parameters, preventing dark area grayscale enhancement parameters or bright area grayscale suppression parameters from independently dominating the display driver parameters.

[0042] S31. When the proportion of dark areas is greater than that of bright areas, the dark area grayscale enhancement parameter is used as the main adjustment parameter, and the bright area grayscale suppression parameter is used as the limiting parameter. In this case, the parameter fusion process prioritizes preserving the dark area grayscale enhancement direction, while using the bright area grayscale suppression parameter to limit excessive changes in high grayscale areas. After the fusion result is determined by the global contrast constraint range, candidate adjustment parameters corresponding to the current frame are formed.

[0043] S32. When the proportion of bright areas is greater than that of dark areas, the bright area grayscale suppression parameter is used as the main adjustment parameter, and the dark area grayscale enhancement parameter is used as the limiting parameter. In this case, the parameter fusion process prioritizes preserving the bright area grayscale suppression direction, while using the dark area grayscale enhancement parameter to maintain the grayscale distinguishability of low grayscale areas. After the fusion result is determined by the global contrast constraint range, it forms the candidate adjustment parameters corresponding to the current frame.

[0044] S33. When the proportions of dark and bright areas meet the balance criteria, the dark area grayscale enhancement parameters and bright area grayscale suppression parameters are weighted and fused according to the midtone grayscale preservation condition. The midtone grayscale preservation condition includes grayscale offset limits and grayscale mapping continuity limits for the midtone grayscale intervals. When generating the dynamic contrast adjustment parameter group, the upper and lower limits of the fused parameters are first limited according to the global contrast constraint range, and then the mapping slope corresponding to the midtone grayscale interval is corrected according to the grayscale offset limit.

[0045] S34. When the corrected mapping slope meets the grayscale mapping continuity constraint, output the dynamic contrast adjustment parameter group. When the corrected mapping slope does not meet the grayscale mapping continuity constraint, adjust the fusion weight of the dark field grayscale enhancement parameter or the bright field grayscale suppression parameter until the corrected mapping slope meets the grayscale mapping continuity constraint. After the dynamic contrast adjustment parameter group is output, it serves as both a candidate parameter for updating the display driving parameters of the current frame and a comparison object in subsequent inter-frame update control steps.

[0046] S4. Compare the image features of the currently displayed image with the image features of historical frames. When the change in image features meets the scene switching conditions, update the display driving parameters according to the dynamic contrast adjustment parameter group. When the change in image features does not meet the scene switching conditions, update the display driving parameters according to the update step size of the historical adjustment parameters and the dynamic contrast adjustment parameter group.

[0047] During S4 execution, the current frame's image features are first constructed from the proportion of dark areas, the proportion of bright areas, and the grayscale concentration. Then, historical frame image features are read from the historical parameter storage area. Historical frame image features originate from image feature data already written to the historical parameter storage area in the previous frame or within the historical window; historical adjustment parameters originate from adjustment parameters already used in the display driver chain in the previous frame or within the historical window. The difference between the current frame's image features and the historical frame's image features is used to determine whether the image content meets the scene switching conditions.

[0048] S41. When the difference between the current frame's image features and the historical frame's image features meets the scene switching conditions, the updated display driver parameters are directly generated according to the dynamic contrast adjustment parameter group. "Direct generation" indicates that the current frame's display driver parameters primarily use the dynamic contrast adjustment parameter group as their source, and then proceeds to the driver writing step. This branch is suitable for situations where the change in image features reaches the scene switching conditions, ensuring that the current frame's display driver parameters match the new image features.

[0049] S42. When the difference between the current frame's image features and the historical frame's image features does not meet the scene switching conditions, calculate the parameter difference between the historical adjustment parameters and the dynamic contrast adjustment parameter group. Dynamically match the update step size based on the parameter difference, and adjust the parameters stepwise according to the matched update step size, using the historical adjustment parameters as a benchmark, thereby generating the updated display driving parameters. The input to the update step size is the parameter difference, and the output is the single-frame update amplitude. This stepwise adjustment causes the display driving parameters in consecutive frames to update along the historical adjustment parameters towards the dynamic contrast adjustment parameter group, rather than jumping directly when the image feature change amplitude is low.

[0050] S43. If no usable historical frame image features are formed in the first frame or the historical parameter storage area, the current frame image features are used as the historical comparison entry point, and display driving parameters are generated using the current dynamic contrast adjustment parameter group. This process is only used to establish the basis for subsequent inter-frame comparisons and does not change the execution relationship of scene switching conditions and update step sizes in subsequent steps. After the display driving parameters are written, the historical parameter storage area updates the corresponding historical frame image features and historical adjustment parameters to provide a data source for the next frame comparison.

[0051] S5 converts the display driving parameters into contrast gain, grayscale mapping table or gamma curve and writes them into the display driving link, and makes the display driving link drive the display panel to output the image according to the written parameters.

[0052] When S5 is executed, the updated display driver parameters first enter the parameter conversion process. If the display driver link uses contrast gain control, the display driver parameters are converted to contrast gain; if the display driver link uses grayscale mapping control, the display driver parameters are converted to a grayscale mapping table; if the display driver link uses gamma curve control, the display driver parameters are converted to a gamma curve. The converted parameters are written to the display driver register, which serves as the hardware or program configuration entry point for the display driver link to receive adjustment parameters.

[0053] S51. When the display driver register completes the write confirmation, the control display driver link drives the display panel to output the image according to the contrast gain, grayscale map table, or gamma curve. The write confirmation can be reflected by the register write return status, driver configuration status, or parameter receiving status of the display control program. The display panel outputs the image according to the written parameters, forming the display result of the current frame.

[0054] S52. When the display driver register has not been confirmed for writing, the display driver parameters before writing are retained as the display parameters for this frame. The state of incomplete write confirmation does not enter a new parameter driving path, preventing parameters not confirmed by the display driver register from directly affecting the display panel. After the display parameters for this frame are output, the historical parameter storage area still retains the historical adjustment parameters before writing, and subsequent frames continue to be processed according to the comparison and update logic in S4.

[0055] Through the execution of S1 to S5 above, the grayscale data to be displayed corresponding to the current display screen is statistically analyzed to form screen feature data. The screen feature data is then used to calculate dark field grayscale enhancement parameters and bright field grayscale suppression parameters. After being processed by global contrast constraint range, midtone grayscale preservation conditions, and inter-frame update control, display driving parameters are formed. After being confirmed by the display driving register, the display driving parameters enter the display driving link, forming a closed loop of data processing and driving execution from the video frame buffer to the output screen of the display panel.

[0056] Example 2

[0057] Please see Figure 5 This embodiment provides a dynamic contrast adjustment system for a display. The difference between this embodiment and Embodiment 1 is that this embodiment describes the support method for the method of Embodiment 1 in terms of system structure and unit collaboration relationship, while its input objects, parameter names, judgment conditions and output results are consistent with those of Embodiment 1.

[0058] The display's dynamic contrast adjustment system includes an image feature extraction unit, a contrast parameter calculation unit, a parameter fusion unit, an inter-frame update control unit, and a drive parameter writing unit. The image feature extraction unit is connected to the video frame buffer, which provides the image feature extraction unit with the grayscale data of the currently displayed image. The image feature extraction unit performs statistical analysis and feature extraction on the grayscale data, and outputs the proportion of dark areas, the proportion of bright areas, the grayscale span of dark areas, the continuity of dark area pixel distribution, the saturation proximity of bright areas, and the grayscale concentration. The grayscale concentration includes dark area grayscale concentration and bright area grayscale concentration; the bright area grayscale concentration can be used as a correction basis in the calculation of bright area grayscale suppression parameters.

[0059] The contrast parameter calculation unit receives image feature data output by the image feature extraction unit and calculates dark field grayscale enhancement parameters and bright field grayscale suppression parameters respectively. For the dark field grayscale enhancement parameter, the contrast parameter calculation unit determines the dark field adjustment weight based on the proportion of the dark field area, determines the dark field enhancement magnitude based on the dark field grayscale span, and corrects the dark field enhancement magnitude based on the continuity of the dark field pixel distribution. For the bright field grayscale suppression parameter, the contrast parameter calculation unit determines the bright field adjustment weight based on the proportion of the bright field area, determines the bright field suppression magnitude based on the proximity of bright field saturation, and corrects the bright field suppression magnitude based on the concentrated or discrete distribution of bright field grayscale concentration. The dark field grayscale enhancement parameters and bright field grayscale suppression parameters are output to the parameter fusion unit respectively.

[0060] The parameter fusion unit receives dark field grayscale enhancement parameters and bright field grayscale suppression parameters, and performs fusion within the global contrast constraint range. The parameter fusion unit determines the parameter fusion priority based on the relative proportions of the dark and bright field regions. When the dark field region proportion is greater than the bright field region proportion, the dark field grayscale enhancement parameter is used as the primary adjustment parameter, and the bright field grayscale suppression parameter is used as the limiting parameter. When the bright field region proportion is greater than the dark field region proportion, the bright field grayscale suppression parameter is used as the primary adjustment parameter, and the dark field grayscale enhancement parameter is used as the limiting parameter. When the dark and bright field regions meet the equalization criteria, the dark field grayscale enhancement parameters and bright field grayscale suppression parameters are weighted and fused according to the midtone grayscale preservation condition. The parameter fusion unit outputs a dynamic contrast adjustment parameter set and transmits the dynamic contrast adjustment parameter set to the inter-frame update control unit.

[0061] The inter-frame update control unit is connected to the historical parameter storage area. The historical parameter storage area stores historical frame image features and historical adjustment parameters. The inter-frame update control unit receives the image features and dynamic contrast adjustment parameter set of the currently displayed image, and reads the historical frame image features and historical adjustment parameters from the historical parameter storage area. The inter-frame update control unit compares the difference between the current frame image features and the historical frame image features; when the difference meets the scene switching conditions, it outputs a direct update command; when the difference does not meet the scene switching conditions, it matches the update step size according to the parameter difference between the historical adjustment parameters and the dynamic contrast adjustment parameter set, and outputs a smooth update command. Both the direct update command and the smooth update command are sent to the drive parameter writing unit.

[0062] The drive parameter writing unit receives either a direct update command or a smooth update command, and determines the writing method for the display drive parameters based on the corresponding command. When receiving a direct update command, the drive parameter writing unit generates display drive parameters according to the dynamic contrast adjustment parameter group; when receiving a smooth update command, the drive parameter writing unit generates display drive parameters based on historical adjustment parameters and according to the update step size. The drive parameter writing unit converts the display drive parameters into contrast gain, grayscale mapping table, or gamma curve, and writes them to the display drive register. After the display drive register completes the write confirmation, the display drive link drives the display panel to output the image according to the written parameters; if the display drive register has not completed the write confirmation, the drive parameter writing unit retains the display drive parameters before writing as the display parameters for the current frame.

[0063] Through the aforementioned system collaboration, the image feature extraction unit, contrast parameter calculation unit, parameter fusion unit, inter-frame update control unit, and drive parameter writing unit form a signal and data processing chain consisting of input of grayscale data to be displayed, output of image feature data, parameter calculation, parameter fusion, inter-frame judgment, drive writing, and output of the display panel. The display dynamic contrast adjustment system can support the above units through a display control board, image processing chip, display driver, or a combination thereof, and work in conjunction with the display's video frame buffer, historical parameter storage area, display driver register, display driver link, and display panel.

[0064] The specific processes, field states, parameter sources, judgment conditions, unit collaboration relationships, and driver writing methods described in the above embodiments are used to illustrate the feasible implementation methods of the technical solutions recorded in this invention, and should not limit this invention to the specific embodiments listed. Without departing from the scope of the technical solutions recorded in this invention, any equivalent substitutions, equivalent modifications, equivalent combinations, order adjustments, corresponding unit substitutions, equivalent transformations of field names, equivalent inheritance of execution subjects, or equivalent changes in carrier forms that can be conceived by those skilled in the art should fall within the scope of protection of this patent; however, they should not be extended to unclaimed topics, nor should the substantive correspondence of technical objects be changed through name changes.

Claims

1. A method for adjusting the dynamic contrast of a display, characterized in that, The grayscale data to be displayed in the current display screen is obtained, and the grayscale data to be displayed is statistically analyzed and feature extracted according to the preset grayscale range to obtain the proportion of dark area, proportion of bright area, grayscale range of dark area, continuity of pixel distribution in dark area, saturation closeness of bright area and grayscale concentration. The dark field grayscale enhancement parameters are calculated based on the dark field region ratio, the dark field grayscale span, and the dark field pixel distribution continuity. The bright field grayscale suppression parameters are calculated based on the bright field region ratio, the bright field saturation proximity, and the bright field grayscale concentration in the grayscale concentration. The dark field grayscale enhancement parameter and the bright field grayscale suppression parameter are fused within the global contrast constraint range, and combined with the midtone grayscale preservation condition to generate a dynamic contrast adjustment parameter group. The screen features of the currently displayed screen are compared with the screen features of historical frames. When the change in screen features meets the scene switching conditions, the display driving parameters are updated according to the dynamic contrast adjustment parameter group. When the change in screen features does not meet the scene switching conditions, the display driving parameters are updated according to the update step size of the historical adjustment parameters and the dynamic contrast adjustment parameter group. The display driving parameters are converted into contrast gain, grayscale mapping table or gamma curve and written into the display driving link, and the display driving link drives the display panel to output the image according to the written parameters.

2. The display dynamic contrast adjustment method according to claim 1, characterized in that, The grayscale data to be displayed is read from the video frame buffer of the display and extracted from the luminance component of the currently displayed image; When the grayscale data to be displayed is statistically analyzed according to the preset grayscale range, the preset grayscale range is divided into a low grayscale range, a middle grayscale range and a high grayscale range, and the number of pixels in the low grayscale range, the number of pixels in the high grayscale range and the total number of pixels in the whole frame are counted respectively. The proportion of the dark area is determined by the ratio of the number of pixels in the low grayscale range to the total number of pixels in the frame, and the proportion of the bright area is determined by the ratio of the number of pixels in the high grayscale range to the total number of pixels in the frame.

3. The display dynamic contrast adjustment method according to claim 2, characterized in that, The grayscale concentration includes dark field grayscale concentration and bright field grayscale concentration; When calculating the dark field grayscale concentration, the proportion of pixel grayscale values ​​falling into consecutive grayscale sub-intervals within the low grayscale range is statistically analyzed. When calculating the brightness field grayscale concentration, the proportion of pixel grayscale values ​​falling into consecutive grayscale sub-intervals within the high grayscale range is statistically analyzed. When the proportion of consecutive grayscale sub-intervals meets the centralization judgment condition, the corresponding grayscale interval is marked as a central distribution state; when the proportion of consecutive grayscale sub-intervals does not meet the centralization judgment condition, the corresponding grayscale interval is marked as a discrete distribution state.

4. The display dynamic contrast adjustment method according to claim 1, characterized in that, When calculating the dark field grayscale enhancement parameters, the dark field adjustment weight is first determined based on the proportion of the dark field region, and then the dark field enhancement range is determined based on the dark field grayscale span. The continuity of the dark field pixel distribution is used as the basis for correcting the dark field enhancement range. When the proportion of the dark field area meets the dark field proportion triggering condition and the dark field grayscale span is less than the dark field span judgment threshold, the dark field grayscale enhancement parameter is increased. When the proportion of the dark field area does not meet the triggering condition of the dark field proportion or the grayscale span of the dark field is not less than the dark field span judgment threshold, the adjustment range of the dark field grayscale enhancement parameter is restricted.

5. The display dynamic contrast adjustment method according to claim 3, characterized in that, When calculating the bright field grayscale suppression parameters, the bright field adjustment weight is first determined based on the proportion of the bright field region, and then the bright field suppression amplitude is determined based on the degree of closeness of the bright field saturation. The concentrated or discrete distribution state of the bright field grayscale concentration is used as the basis for correcting the bright field suppression amplitude. When the proportion of the bright field area meets the bright field proportion triggering condition and the brightness field saturation closeness meets the saturation closeness judgment condition, the bright field grayscale suppression parameter is increased. When the proportion of the bright field area does not meet the triggering condition of the bright field proportion or the saturation proximity of the bright field does not meet the saturation proximity judgment condition, the adjustment range of the bright field grayscale suppression parameter is limited.

6. The display dynamic contrast adjustment method according to claim 1, characterized in that, When fusing the dark field grayscale enhancement parameter and the bright field grayscale suppression parameter within the global contrast constraint range, the parameter fusion priority is first determined based on the relative size of the dark field area proportion and the bright field area proportion. When the proportion of the dark field region is greater than the proportion of the bright field region, the dark field grayscale enhancement parameter is used as the main adjustment parameter, and the bright field grayscale suppression parameter is used as the limiting parameter. When the proportion of the bright field area is greater than the proportion of the dark field area, the bright field grayscale suppression parameter is used as the main adjustment parameter, and the dark field grayscale enhancement parameter is used as the limiting parameter. When the proportion of the dark area and the proportion of the bright area meet the balance judgment condition, the dark area grayscale enhancement parameter and the bright area grayscale suppression parameter are weighted and fused according to the midtone grayscale preservation condition.

7. The display dynamic contrast adjustment method according to claim 6, characterized in that, The mid-tone grayscale preservation conditions include grayscale offset restrictions and grayscale mapping continuity restrictions for the mid-tone grayscale range. When generating the dynamic contrast adjustment parameter group, the upper and lower limits of the parameters after fusion are first limited according to the global contrast constraint range, and then the mapping slope corresponding to the intermediate gray level interval is corrected according to the gray level offset limit. When the corrected mapping slope meets the grayscale mapping continuity constraint, the dynamic contrast adjustment parameter group is output. When the corrected mapping slope does not meet the grayscale mapping continuity constraint, the fusion weight of the dark field grayscale enhancement parameter or the bright field grayscale suppression parameter is adjusted until the corrected mapping slope meets the grayscale mapping continuity constraint.

8. The display dynamic contrast adjustment method according to claim 1, characterized in that, When comparing the image features of the currently displayed image with the image features of the historical frames, the current frame image features are first constructed from the proportion of the dark area, the proportion of the bright area, and the grayscale concentration, and then the historical frame image features are read from the historical parameter storage area. When the difference between the current frame image features and the historical frame image features meets the scene switching conditions, the updated display driving parameters are directly generated according to the dynamic contrast adjustment parameter group. When the difference between the current frame image features and the historical frame image features does not meet the scene switching conditions, the parameter difference between the historical adjustment parameters and the dynamic contrast adjustment parameter group is calculated, the update step size is dynamically matched according to the parameter difference, and the historical adjustment parameters are used as a reference to perform step adjustment according to the matched update step size, thereby generating updated display driving parameters.

9. The display dynamic contrast adjustment method according to claim 1, characterized in that, When writing the display driver parameters into the display driver link, the updated display driver parameters are first converted into contrast gain, grayscale mapping table or gamma curve, and then the contrast gain, grayscale mapping table or gamma curve is written into the display driver register. When the display driver register completes the write confirmation, the display driver link is controlled to drive the display panel to output the image according to the contrast gain, the grayscale mapping table or the gamma curve. If the display driver register has not been confirmed for writing, the display driver parameters before writing are retained as the display parameters for this frame.

10. A display dynamic contrast adjustment system for supporting the method of any one of claims 1 to 9, characterized in that, It includes a picture feature extraction unit, a contrast parameter calculation unit, a parameter fusion unit, an inter-frame update control unit, and a drive parameter writing unit; The image feature extraction unit is connected to the video frame buffer and is used to read the grayscale data to be displayed in the current display image and extract the proportion of dark area, proportion of bright area, grayscale span of dark area, continuity of dark area pixel distribution, saturation proximity of bright area and grayscale concentration. The contrast parameter calculation unit is used to calculate the dark field grayscale enhancement parameter and the bright field grayscale suppression parameter respectively based on the extracted image feature data. The parameter fusion unit is used to fuse the dark field grayscale enhancement parameter and the bright field grayscale suppression parameter within the global contrast constraint range, and generate a dynamic contrast adjustment parameter group in combination with the midtone grayscale preservation condition. The inter-frame update control unit is connected to the historical parameter storage area and is used to compare the screen features of the currently displayed screen with the screen features of historical frames, and output direct update instructions or smooth update instructions according to the scene switching conditions. The drive parameter writing unit is used to convert the display drive parameters into contrast gain, grayscale mapping table or gamma curve according to the direct update instruction or the smooth update instruction, and write them into the display drive register.

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