WO2021218410A1 - 动态局部调光显示控制方法及装置、显示装置 - Google Patents

动态局部调光显示控制方法及装置、显示装置 Download PDF

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Publication number
WO2021218410A1
WO2021218410A1 PCT/CN2021/079851 CN2021079851W WO2021218410A1 WO 2021218410 A1 WO2021218410 A1 WO 2021218410A1 CN 2021079851 W CN2021079851 W CN 2021079851W WO 2021218410 A1 WO2021218410 A1 WO 2021218410A1
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backlight
display
grayscale
value
subarea
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PCT/CN2021/079851
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English (en)
French (fr)
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石炳川
马希通
饶天珉
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京东方科技集团股份有限公司
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Priority to US17/762,010 priority Critical patent/US20220335907A1/en
Publication of WO2021218410A1 publication Critical patent/WO2021218410A1/zh

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/2007—Display of intermediate tones
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0233—Improving the luminance or brightness uniformity across the screen
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0242—Compensation of deficiencies in the appearance of colours
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0285—Improving the quality of display appearance using tables for spatial correction of display data
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/16—Calculation or use of calculated indices related to luminance levels in display data

Definitions

  • the embodiments of the present disclosure relate to the field of display technology, and in particular, to a dynamic local dimming display control method and device, and a display device.
  • dynamic local dimming technology In the field of high-brightness display, the liquid crystal display panel will cause a decrease in the contrast of the display picture due to its inherent light leakage phenomenon.
  • dynamic local dimming technology is widely used in the field of high-quality display. Unlike traditional LCD panel lighting that uses uniform backlighting, dynamic local dimming technology uses a partitioned backlight scheme, which divides the LCD panel into M*N (row*column) partitions, each of which is independently controllable When displaying a dark screen, you can lower the brightness of the backlight to reduce light leakage and increase the contrast of the screen. At the same time, the reduction of the backlight can effectively reduce the power consumption of the whole machine, which is of special significance for mobile devices and large-size display devices.
  • the early dynamic local dimming technology divided the liquid crystal display panel into several partitions in the row and column direction, providing a total of dozens of partitions. With the miniaturization of LED (Light Emitting Diode) backlights and the development of control technology, it is possible to provide more partitions for the display panel. Now there have been dynamic local dimming display products that are divided into hundreds of rows and columns, with a total of 10,000 backlight partitions.
  • LED Light Emitting Diode
  • the dynamic local dimming technology reduces the brightness of the backlight on the basis of the existing backlight.
  • it is necessary to increase the gray level of the corresponding pixel in the display panel (increase the transmittance of the panel) as compensation.
  • the gray level of the display panel cannot be increased indefinitely.
  • the highest gray level is only 255. Once the compensation gray level is greater than 255, it will cause overflow. Grayscale overflow will cause the color cast of the display. Therefore, how to determine the appropriate area backlight brightness and limit the grayscale overflow becomes the core of the dynamic local dimming technology.
  • the embodiments of the present disclosure provide a dynamic local dimming display control method and device, and a display device, which are used to solve the problem of grayscale overflow caused by the existing dynamic local dimming technology.
  • embodiments of the present disclosure provide a dynamic local dimming display control method, including:
  • the image is displayed according to the compensated grayscale value.
  • the calculating the backlight control signal of each backlight subarea according to the gray level control parameter and the gray level statistical function of each display subarea includes:
  • the target backlight control signal of each backlight subarea is determined, wherein the target backlight control signal of each backlight subarea is the maximum value of the initial backlight control signal in the neighborhood where it is located ,
  • the neighborhood of the backlight subarea is composed of the backlight subarea and a plurality of backlight subarea around it.
  • the determining the compensated grayscale value according to the backlight control signal and the backlight diffusion model of each backlight zone includes:
  • the grayscale statistical function is a grayscale-cumulative distribution function
  • determining the grayscale statistical function of each display partition according to the grayscale of the image to be displayed includes:
  • the grayscale-cumulative distribution function of the grayscale image of the display partition is obtained.
  • the grayscale control parameter is a preset overflow rate value
  • the grayscale statistical function is a grayscale-cumulative distribution function
  • the determining the critical overflow gray level of each display area according to the gray level statistical function and the gray level control parameter of the gray level image of each display area includes:
  • the gray scale corresponding to the cumulative distribution probability k is determined as the critical overflow gray scale, where k is equal to 1-p, and the p is the overflow rate value.
  • the determining the critical backlight brightness of each backlight subarea according to the critical overflow gray scale of each display subarea includes:
  • Lmax is the original brightness value of the backlight
  • gamma is the gamma value of the display panel
  • ⁇ is the power exponent operation
  • Gt is the critical overflow gray scale
  • Gmax is the maximum gray scale value.
  • the size of the neighborhood is 3 ⁇ 3 backlight partitions or 5 ⁇ 5 backlight partitions.
  • the determining the compensated grayscale value of each pixel according to the backlight brightness information of each pixel includes:
  • the compensation rate S (Lmax/Lnew) ⁇ (1/gamma), where Lmax is the original backlight brightness value of the pixel, and Lnew is the calculated backlight of the pixel Brightness information, gamma is the gamma value of the display panel, and ⁇ is a power exponent operation;
  • the compensated grayscale value Gnew Gori*S, where Gori is the original grayscale value of the pixel.
  • the method further includes:
  • the compensated grayscale value is greater than the maximum grayscale value, lower the compensation rate so that the compensated grayscale value is equal to the maximum grayscale value.
  • the method before determining the gray-scale statistical function of each display partition according to the gray-scale of the image to be displayed, the method further includes:
  • the image to be displayed is converted from a color image to a grayscale image.
  • a dynamic local dimming display control device including:
  • the first determining module is configured to determine the gray-scale statistical function of each display partition according to the gray-scale of the image to be displayed;
  • An obtaining module configured to obtain gray scale control parameters of each display zone, where the gray scale control parameters are related to an overflow rate
  • a calculation module configured to calculate the backlight control signal of each backlight subarea according to the gray level control parameter and the gray level statistical function of each display subarea;
  • the second determining module is configured to determine the compensated gray scale value according to the backlight control signal and the backlight diffusion model of each backlight zone;
  • the display module is used to display the image according to the compensated grayscale value.
  • embodiments of the present disclosure provide a display device, including the above-mentioned dynamic local dimming display control device.
  • embodiments of the present disclosure provide a display device, including a processor, a memory, and a computer program stored on the memory and running on the processor, the computer program being executed by the processor When realizing the steps of the above-mentioned dynamic local dimming display control method.
  • embodiments of the present disclosure provide a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned dynamic local dimming display control method are implemented .
  • the backlight control signal of each backlight subarea is determined by the gray level control parameter related to the overflow rate and the gray level statistical function of each display subarea, and then the gray level value of the pixel that needs to be compensated is determined to ensure The pixel overflow rate in pixel compensation is not higher than the preset value.
  • FIG. 1 is an example diagram of crosstalk between backlights of different partitions of a display panel to form a uniform backlight
  • Figure 2 is a comparison diagram of the measured backlight brightness versus distance (pixel) distribution and the backlight brightness versus distance (pixel) distribution using double Gaussian fitting;
  • Figure 3 is an example diagram of the backlight brightness reduction caused by backlight crosstalk exceeding expectations
  • FIG. 4 is a schematic flowchart of a dynamic local dimming display control method according to an embodiment of the disclosure
  • FIG. 5 is a schematic diagram of a gray scale-probability density function in an embodiment of the disclosure.
  • Fig. 6 is a schematic diagram of a gray scale-cumulative distribution function in an embodiment of the present disclosure
  • FIG. 7 is a schematic diagram of a method for converting an initial backlight control signal array Lt(m,n) into a backlight signal control array Lc(m,n);
  • FIG. 8 is an exemplary diagram of backlight brightness in an embodiment of the disclosure.
  • FIG. 9 is a schematic flowchart of a dynamic local dimming display control method according to another embodiment of the present disclosure.
  • FIG. 10 is a schematic structural diagram of a dynamic local dimming display control device according to an embodiment of the disclosure.
  • the earlier adopted average method, square root method, maximum value method and other methods adopt simple methods to determine the backlight control signal.
  • the disadvantage is that the overflow rate is completely uncontrollable.
  • the backlight determination algorithm based on pixel statistics has improved the control of the overflow rate to a certain extent.
  • the calculation of the overflow rate is based on the uniformity of the backlight brightness in the backlight zone, that is, the backlight control signal Directly used as a backlight
  • this method is suitable when there are fewer partitions and the backlight crosstalk between partitions is small.
  • the illumination area of the light source has a certain range, within which the brightness of the backlight gradually decreases from the middle to the periphery; in addition, the mutual crosstalk (light mixing) between the backlights is also an important condition for the formation of a uniform backlight.
  • Figure 1 is an example of the crosstalk between the backlights of different partitions of the display panel to form a uniform backlight.
  • Figure 1 shows a total of 11 partitions of the backlight, and the backlight distribution is Gaussian.
  • L is the brightness
  • d is the distance
  • the unit is pixel (pix)
  • ⁇ n is the mean value
  • ⁇ is the variance.
  • Figure 1 only shows the beam spread in one-dimensional space, and the actual beam spread is two-dimensional.
  • Figure 2 is a comparison diagram of the measured backlight brightness versus distance (pixel) distribution and the backlight brightness versus distance (pixel) distribution using double Gaussian fitting; the real curve is the measured data (data), the imaginary The curve is the double Gaussian fitting data (fit). It can be seen from Fig. 2 that the double Gaussian fitting can fit the measurement results well.
  • the backlight crosstalk in the area causes the brightness of the backlight in the area to not strictly correspond to the backlight control signal, which will lead to if the backlight reduction ratio of the adjacent zone is higher than the backlight reduction ratio of the zone, the actual backlight of the area The brightness will be lower than the brightness level corresponding to the backlight control signal.
  • Figure 3 shows an example of the reduction in backlight brightness caused by backlight crosstalk that exceeds expectations.
  • the brightness corresponding to the backlight control signal of the partition 6 is maintained at 1, and the brightness corresponding to the backlight control signal of the peripheral partition is reduced to 0.8.
  • the area 6 should maintain the expected brightness (see Figure 3, the expected brightness corresponding to the area 6 is about 1.65).
  • the backlight component of the peripheral light source radiated to the area 6 is reduced, the contribution of the peripheral partition to the partition 6 is reduced, and the partition 6 can no longer maintain the original backlight brightness (see Figure 3, the actual brightness corresponding to the area 6 is about 1.5) .
  • the brightness reduction caused by this situation is not considered in the calculation of the overflow rate. Since the calculation of the overflow rate is based on the backlight control signal of the zone, and the actual backlight brightness in the zone is lower than the expected brightness corresponding to the backlight control signal, this will cause the number of pixels to be compensated and the degree of compensation to be higher than expected, resulting in an overflow rate Exceeded.
  • an embodiment of the present disclosure provides a dynamic local dimming display control method, including:
  • Step 41 Determine the gray-scale statistical function of each display area according to the gray-scale of the image to be displayed;
  • the display panel is divided into multiple display partitions.
  • the display area of the display panel can be divided into M*N (row*column) display partitions.
  • M and N are positive integers greater than 1.
  • Step 42 Obtain the gray-scale control parameters of each display zone, where the gray-scale control parameters are related to the overflow rate;
  • Step 43 Calculate the backlight control signal of each backlight subarea according to the gray level control parameter and the gray level statistical function of each display subarea;
  • the backlight source is divided into a plurality of backlight zones.
  • the backlight area of the backlight source can be divided into M*N (row*column) backlight partitions.
  • M and N are positive integers greater than 1.
  • Step 44 Determine the compensated gray scale value according to the backlight control signal of each backlight zone and the backlight diffusion model
  • Step 45 Perform image display according to the compensated grayscale value.
  • the backlight control signal of each backlight subarea is determined by the gray level control parameter related to the overflow rate and the gray level statistical function of each display subarea, and then the gray level value of the pixel that needs to be compensated is determined to ensure the pixel The pixel overflow rate during compensation is not higher than the preset value.
  • the method before determining the grayscale statistical function of each display partition according to the grayscale of the image to be displayed, the method further includes: converting the image to be displayed from a color image to a grayscale image.
  • the image to be displayed to be input to the display panel is converted from a color image to a grayscale image
  • the largest of the RGB (red, green, and blue) components of each pixel of the color image may be converted The value is used as the grayscale value of the corresponding pixel in the grayscale image, because the maximum value in the RGB component is directly related to the overflow rate.
  • the grayscale statistical function is a grayscale-cumulative distribution function (CDF).
  • CDF grayscale-cumulative distribution function
  • the cumulative distribution function (CDF) is the integral of the probability density function (Probability Density Function, PDF), which can completely describe the probability distribution of a real random variable X.
  • PDF Probabilistic Density Function
  • the real random variable X is a gray scale.
  • the grayscale statistical function may also be other types of functions.
  • the determination of the grayscale statistical function of each display partition according to the grayscale of the image to be displayed includes:
  • Step 411 For each display partition, obtain the grayscale value of each pixel in the grayscale image of the display partition;
  • Step 412 Obtain the probability density distribution function of each grayscale value
  • Step 413 Obtain the grayscale-cumulative distribution function of the grayscale image of the display partition according to the probability density distribution function of all the grayscale values in the display partition.
  • FIG. 5 is a schematic diagram of a gray scale-probability density function in an embodiment of the disclosure
  • FIG. 6 is a schematic diagram of a gray scale-cumulative distribution function in an embodiment of the disclosure.
  • PDF and CDF is a relatively simple method of statistical gray-scale probability information.
  • the calculation of the backlight control signal of each backlight subarea according to the gray level control parameter and the gray level statistical function of each display subarea includes:
  • Step 431 Determine the critical overflow gray level of each display area according to the gray level statistical function and gray level control parameters of the gray level image of each display area;
  • the grayscale control parameter is a preset overflow rate value.
  • the overflow rate is the ratio of the number of pixels with grayscale overflow to the total pixel data.
  • the so-called overflow for example, for an 8-bit image, if the grayscale exceeds 255, it is overflow.
  • the overflow rate value is a preset value, and the preset value can be set according to an empirical value. In the embodiment of the present disclosure, the overflow rate of each display partition is the same.
  • the critical overflow gray scale of each display partition may be determined in the following manner: according to the gray scale-cumulative distribution function, the gray scale corresponding to the cumulative distribution probability k is determined as the critical overflow gray scale, wherein: k is equal to 1-p, and the p is the overflow rate.
  • the significance of the critical overflow gray scale is: when the critical overflow gray scale Gt happens to overflow, the pixels with a gray scale higher than Gt have overflowed, and the proportion is p, and the part with a proportion k will not overflow because the gray scale is lower than Gt.
  • the grayscale control parameter is another parameter, such as the overflow rate multiplied by a specified coefficient.
  • Step 432 Determine the critical backlight brightness of each backlight subarea according to the critical overflow gray scale of each display subarea
  • the following formula is used to determine the critical backlight brightness Lt of each backlight zone:
  • Lmax is the original brightness value of the backlight
  • gamma is the gamma value of the display panel
  • ⁇ is the power exponent operation
  • Gt is the critical overflow gray scale
  • Gmax is the maximum gray scale value. For example, for an 8-bit image, Gmax Is 255.
  • Step 433 Determine the initial backlight control signal of each backlight subarea according to the critical backlight brightness of each backlight subarea
  • the backlight brightness and the backlight control signal have a mapping relationship, and the mapping relationship may be predetermined.
  • the initial backlight control signals of each backlight subarea can form an initial backlight control signal array Lt(m,n).
  • Step 434 Determine the target backlight control signal of each backlight subarea according to the initial backlight control signal of each backlight subarea, wherein the target backlight control signal of each backlight subarea is the initial backlight control signal in the neighborhood where it is located
  • the neighborhood of the backlight subarea is composed of the backlight subarea and a plurality of backlight subarea around it;
  • the size of the neighborhood is 3 ⁇ 3 backlight partitions (3 rows and 3 columns backlight partitions) or 5 ⁇ 5 backlight partitions (5 rows and 5 columns backlight partitions), or other larger neighborhoods .
  • the specific size is determined according to the degree of influence of the backlight partition by the surrounding backlight partition.
  • the backlight zone is located in the center of the neighborhood.
  • the target backlight control signal of each backlight zone composes the target backlight signal control array Lc(m,n).
  • FIG. 7 is a schematic diagram of a method of converting the initial backlight control signal array Lt(m,n) into the target backlight signal control array Lc(m,n).
  • the size of the neighborhood is 3 ⁇ 3 backlight partitions.
  • the target backlight control signal of each backlight subarea is the maximum value of the initial backlight control signal in the neighborhood where it is located, which can ensure that after the backlight of the surrounding backlight subarea of the backlight subarea is turned down, the backlight of the backlight subarea The brightness of the light is not lower than the theoretical value calculated by the backlight zone (ie the expected brightness).
  • FIG. 8 a schematic diagram of the backlight obtained by the above method.
  • the neighborhood of the 3 ⁇ 3 backlight partition is adopted.
  • the actual brightness of the area 6 is about 1.65, which basically reaches Expected brightness.
  • the crosstalk of the backlight between each backlight partition is considered, and the maximum value in the neighborhood is used to determine the backlight control signal of the partition before the backlight control signal of each backlight partition is determined, so as to ensure that the backlight of the partition is not lower than the theoretical value. Value to ensure that the pixel overflow rate in pixel compensation is not higher than the preset value.
  • the determining the compensated grayscale value according to the backlight control signal and the backlight diffusion model of each backlight zone includes:
  • Step 441 Determine the backlight brightness information of each pixel on the display panel according to the backlight control signal of each backlight zone and the backlight diffusion model; the backlight diffusion model is that when a single group of backlights is lit, the backlight on the back of the display panel Dimensional distribution status can be measured by the imaging luminance meter to obtain the data, and then the mathematical model obtained by data denoising and fitting.
  • the backlight diffusion model is established using a multi-Gaussian fitting method.
  • the multi-Gaussian fitting method can well establish the backlight diffusion model.
  • the measurement data shown in Fig. 1 can be well fitted using a double Gaussian distribution.
  • the backlight signal is a discrete array of backlight points, and the light emitted by each backlight point is diffused on the display panel by the diffuser to appear as a planar light source.
  • this process can be achieved by convolution of the backlight signal at each point with the backlight diffusion model.
  • the backlight control signal of each backlight point and the backlight diffusion model can be convoluted to obtain the backlight brightness information of each pixel on the display panel.
  • Step 442 Determine the compensated grayscale value of each pixel according to the backlight brightness information of each pixel.
  • the compensated grayscale value of each pixel may be determined in the following manner including:
  • Lmax is the original backlight brightness value of the pixel
  • Lnew is the calculated value
  • gamma is the gamma value of the display panel
  • ⁇ is the power exponent operation
  • the overflow rate S for example, the compensation rate can be multiplied by the RGB components separately, if the maximum value of the three products is greater than The maximum gray scale value (such as 255), it is judged that there is an overflow
  • the compensated grayscale value of each pixel it also includes: if the compensated grayscale value is greater than the maximum grayscale value (overflow), adjusting The compensation rate is low, so that the compensated gray scale value is equal to the maximum gray scale value.
  • the dynamic local dimming display control method in the embodiment of the present disclosure is applicable to the situation where the display panel is divided into super-multiple display partitions, and the backlight between the display partitions has crosstalk.
  • the present disclosure also provides a dynamic local dimming display control device 100, including:
  • the first determining module 101 is configured to determine the gray scale statistical function of each display partition according to the gray scale of the image to be displayed;
  • the obtaining module 102 is configured to obtain the gray-scale control parameters of each display partition, where the gray-scale control parameters are related to the overflow rate;
  • the calculation module 103 is configured to calculate the backlight control signal of each backlight subarea according to the gray level control parameter and the gray level statistical function of each display subarea;
  • the second determining module 104 is configured to determine the compensated gray scale value according to the backlight control signal and the backlight diffusion model of each backlight zone;
  • the display module 105 is configured to display an image according to the compensated grayscale value.
  • the calculation module 103 includes:
  • the first determining sub-module is configured to determine the critical overflow gray scale of each display zone according to the gray scale statistical function and the gray scale control parameter of the gray scale image of each display zone;
  • the second determining sub-module is configured to determine the critical backlight brightness of each backlight partition according to the critical overflow gray scale of each display partition;
  • the third determining sub-module is configured to determine the initial backlight control signal of each backlight subarea according to the critical backlight brightness of each backlight subarea;
  • the fourth determining sub-module is used to determine the target backlight control signal of each backlight subarea according to the initial backlight control signal of each backlight subarea, wherein the target backlight control signal of each backlight subarea is in the neighborhood where it is located.
  • the maximum value of the initial backlight control signal, the neighborhood of the backlight subarea is composed of the backlight subarea and a plurality of backlight subarea around it.
  • the second determining module 104 includes:
  • a fifth determining sub-module configured to determine the backlight brightness information of each pixel on the display panel according to the backlight control signal and the backlight diffusion model of each of the backlight zones;
  • the sixth determining sub-module is configured to determine the compensated grayscale value of each pixel according to the backlight brightness information of each pixel.
  • the grayscale statistical function is a grayscale-cumulative distribution function
  • the first determining module 101 includes:
  • the first obtaining sub-module is configured to obtain the grayscale value of each pixel in the grayscale image of the display subarea for each of the display subarea;
  • the second obtaining sub-module is used to obtain the probability density distribution function of each gray scale value
  • the third acquisition sub-module is configured to obtain the grayscale-cumulative distribution function of the grayscale image of the display partition according to the probability density distribution function of all the grayscale values in the display partition.
  • the grayscale control parameter is a preset overflow rate value
  • the grayscale statistical function is a grayscale-cumulative distribution function
  • the first determining sub-module is configured to determine the gray level corresponding to the cumulative distribution probability k as the critical overflow gray level according to the gray level-cumulative distribution function, where k is equal to 1-p, and the p is the gray level.
  • the overflow rate value is configured to determine the gray level corresponding to the cumulative distribution probability k as the critical overflow gray level according to the gray level-cumulative distribution function, where k is equal to 1-p, and the p is the gray level.
  • the overflow rate value is configured to determine the gray level corresponding to the cumulative distribution probability k as the critical overflow gray level according to the gray level-cumulative distribution function, where k is equal to 1-p, and the p is the gray level.
  • the overflow rate value is configured to determine the gray level corresponding to the cumulative distribution probability k as the critical overflow gray level according to the gray level-cumulative distribution function, where k is equal to 1-p, and the p is the gray level.
  • the overflow rate value is configured to determine the gray
  • the second determining sub-module is configured to determine the critical backlight brightness Lt of each backlight zone by using the following formula:
  • Lmax is the original brightness value of the backlight
  • gamma is the gamma value of the display panel
  • ⁇ is the power exponent operation
  • Gt is the critical overflow gray scale
  • Gmax is the maximum gray scale value.
  • the size of the neighborhood is 3 ⁇ 3 backlight partitions or 5 ⁇ 5 backlight partitions.
  • the device further includes:
  • the adjustment module is configured to reduce the compensation rate if the compensated grayscale value is greater than the maximum grayscale value, so that the compensated grayscale value is equal to the maximum grayscale value.
  • the device further includes:
  • the conversion module is used to convert the image to be displayed from a color image to a gray image.
  • An embodiment of the present disclosure also provides a display device, including the above-mentioned dynamic local dimming display control device.
  • the embodiments of the present disclosure also provide a display device, including a processor, a memory, and a computer program stored on the memory and capable of running on the processor, and the computer program implements any of the foregoing when the computer program is executed by the processor.
  • a display device including a processor, a memory, and a computer program stored on the memory and capable of running on the processor, and the computer program implements any of the foregoing when the computer program is executed by the processor.
  • the embodiments of the present disclosure also provide a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the dynamic local dimming display control method in any of the above-mentioned embodiments is implemented A step of.

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Abstract

本公开提供一种动态局部调光显示控制方法及装置、显示装置，该方法包括：根据待显示图像的灰阶确定各显示分区的灰阶统计函数；获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；根据所述补偿后的灰阶值进行图像显示。本公开能够确保像素补偿中像素溢出率不高于预设值。

Description

动态局部调光显示控制方法及装置、显示装置
相关申请的交叉引用
本申请主张在2020年04月30日在中国提交的中国专利申请号No.202010360889.X的优先权，其全部内容通过引用包含于此。
技术领域
本公开实施例涉及显示技术领域，尤其涉及一种动态局部调光显示控制方法及装置、显示装置。
背景技术
在高亮度显示领域，液晶显示面板由于其固有的漏光现象会造成显示画面对比度的下降，为了提高显示画面的对比度，动态局部调光技术被广泛应用在高质量显示领域中。与传统的液晶显示面板照明采用均匀背光不同，动态局部调光技术采用了分区背光方案，这种方案将液晶显示面板分为M*N(行*列)个分区，每个分区拥有独立可控的背光，在显示暗画面时，可以调低背光亮度，以降低漏光，提高画面的对比度。与此同时，背光的调低可以有效降低整机功耗，对于移动设备、超大尺寸显示设备具有特别的意义。
早期的动态局部调光技术是将液晶显示面板在行列方向各划分为数个分区，总共提供数十个分区。随着LED(发光二极管)背光灯的小型化及控制技术的发展，为显示面板提供更多的分区成为可能。现在已经出现了在行列上分别划分为数百个，共计数万背光分区的动态局部调光显示产品。
动态局部调光技术是在现有背光的基础上降低背光的亮度，为了保证显示画面的理论亮度输出，需要调高显示面板中对应像素的灰阶(提高面板的透过率)作为补偿。然而，显示面板的灰阶是不能无限提高的，对于常用的8位显示面板，其最高灰阶仅为255，一旦补偿灰阶大于255，则会造成溢出。灰阶溢出会造成显示的色偏。因此，如何确定合适的区域背光亮度，限制灰阶溢出成为动态局部调光技术的核心。
发明内容
本公开实施例提供一种动态局部调光显示控制方法及装置、显示装置，用于解决现有的动态局部调光技术容易造成灰阶溢出的问题。
为了解决上述技术问题，本公开是这样实现的：
第一方面，本公开实施例提供了一种动态局部调光显示控制方法，包括：
根据待显示图像的灰阶确定各显示分区的灰阶统计函数；
获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；
根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；
根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；
根据所述补偿后的灰阶值进行图像显示。
可选的，所述根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号包括：
根据所述各显示分区的灰度图像的灰阶统计函数和灰阶控制参数，确定所述各显示分区的临界溢出灰阶；
根据所述各显示分区的临界溢出灰阶，确定各背光分区的临界背光亮度；
根据所述各背光分区的临界背光亮度，确定所述各背光分区的初始背光控制信号；
根据所述各背光分区的初始背光控制信号，确定所述各背光分区的目标背光控制信号，其中，所述各背光分区的目标背光控制信号为其所在的邻域内的初始背光控制信号的最大值，所述背光分区的邻域由所述背光分区及其周围的多个背光分区组成。
可选的，所述根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值包括：
根据各所述背光分区的背光控制信号和背光扩散模型，确定显示面板上的各像素的背光亮度信息；
根据所述各像素的背光亮度信息，确定所述各像素的补偿后的灰阶值。
可选的，所述灰阶统计函数为灰阶-累积分布函数，所述根据待显示图像 的灰阶确定各显示分区的灰阶统计函数包括：
针对每个所述显示分区，获取所述显示分区的灰度图像中各像素的灰阶值；
获取各所述灰阶值的概率密度分布函数；
根据所述显示分区内所有所述灰阶值的概率密度分布函数，得到所述显示分区的灰度图像的灰阶-累积分布函数。
可选的，所述灰阶控制参数为预设的溢出率值，所述灰阶统计函数为灰阶-累积分布函数；
所述根据所述各显示分区的灰度图像的灰阶统计函数和灰阶控制参数，确定所述各显示分区的临界溢出灰阶包括：
根据所述灰阶-累积分布函数，确定累计分布概率k对应的灰阶作为所述临界溢出灰阶，其中，k等于1-p，所述p为所述溢出率值。
可选的，所述根据所述各显示分区的临界溢出灰阶，确定各背光分区的临界背光亮度包括：
采用下述公式确定所述各背光分区的临界背光亮度Lt：
Lt＝Lmax*(Gt/Gmax)^gamma
其中，Lmax为背光的原亮度值，gamma为所述显示面板的伽马值，^为幂指数运算，Gt为所述临界溢出灰阶，Gmax为最大灰阶值。
可选的，所述邻域的大小为3×3背光分区或5×5背光分区。
可选的，所述根据所述各像素的背光亮度信息，确定所述各像素的补偿后的灰阶值包括：
计算所述显示面板上的各像素的补偿率，所述补偿率S＝(Lmax/Lnew)^(1/gamma)，其中，Lmax为像素的原背光亮度值，Lnew为计算得到的像素的背光亮度信息，gamma为所述显示面板的伽马值，^为幂指数运算；
确定各像素的补偿后的灰阶值，所述补偿后的灰阶值Gnew＝Gori*S，其中，Gori为像素的原始灰阶值。
可选的，所述确定各像素的补偿后的灰阶值之后还包括：
若补偿后的灰阶值大于最大灰阶值，调低所述补偿率，使得补偿后的灰 阶值等于最大灰阶值。
可选的，所述根据待显示图像的灰阶确定各显示分区的灰阶统计函数之前还包括：
将所述待显示图像由彩色图像转换为灰度图像。
第二方面，本公开实施例提供了一种动态局部调光显示控制装置，包括：
第一确定模块，用于根据待显示图像的灰阶确定各显示分区的灰阶统计函数；
获取模块，用于获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；
计算模块，用于根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；
第二确定模块，用于根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；
显示模块，用于根据所述补偿后的灰阶值进行图像显示。
第三方面，本公开实施例提供了一种显示装置，包括上述动态局部调光显示控制装置。
第四方面，本公开实施例提供了一种显示装置，包括处理器、存储器及存储在所述存储器上并可在所述处理器上运行的计算机程序，所述计算机程序被所述处理器执行时实现上述动态局部调光显示控制方法的步骤。
第五方面，本公开实施例提供了一种计算机可读存储介质，所述计算机可读存储介质上存储计算机程序，所述计算机程序被处理器执行时实现上述动态局部调光显示控制方法的步骤。
在本公开实施例中，通过与溢出率相关的灰阶控制参数以及各显示分区的灰阶统计函数，确定各背光分区的背光控制信号，然后确定像素的需要补偿的灰阶值，以此确保像素补偿中像素溢出率不高于预设值。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本邻域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的， 而并不认为是对本公开的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：
图1为显示面板不同分区的背光相互串扰形成均匀背光的示例图；
图2为实测的背光亮度关于距离(像素)的分布与采用双高斯拟合的背光亮度关于距离(像素)的分布的比对图；
图3为背光串扰导致的背光亮度降低超出预期的示例图；
图4为本公开一实施例的动态局部调光显示控制方法的流程示意图；
图5为本公开一实施例中的灰阶-概率密度函数的示意图；
图6为本公开一实施例中的灰阶-累积分布函数的示意图；
图7为初始背光控制信号阵列Lt(m,n)转换为背光信号控制阵列Lc(m,n)的方法示意图；
图8为本公开实施例中的背光亮度示例图；
图9为本公开另一实施例的动态局部调光显示控制方法的流程示意图；
图10为本公开实施例的动态局部调光显示控制装置的结构示意图。
具体实施方式
下面将结合本公开实施例中的附图，对本公开实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本公开一部分实施例，而不是全部的实施例。基于本公开中的实施例，本邻域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本公开保护的范围。
相关的动态局部调光方法中，较早采用的平均值法、平方根法、最大值法等方法采用简单的方法确定背光控制信号，缺点在于对溢出率完全无法控制。
随着板载计算资源的增加，基于像素统计的背光确定算法在一定程度上改善了溢出率的控制，但是这些算法中，溢出率的计算基础是在背光分区内背光亮度均匀，即将背光控制信号直接作为背光使用，这种方法在分区较少，分区间背光串扰小的情况下是适用的。然而，光源的照明区域是有一定范围的，在这个范围内背光亮度从中间到周边逐步递减；另外背光间的相互串扰(混光)也是形成均匀背光的一个重要条件。
请参考图1，图1为显示面板不同分区的背光相互串扰形成均匀背光的示例图，图1中共展示了11个分区的背光，各背光分布均呈高斯分布
Figure PCTCN2021079851-appb-000001
其中，L为亮度，d为距离，单位为像素(pix)，μn为均值，σ为方差，图1中的坐标轴的横坐标为距离(d)，单位为像素(pix)，纵坐标为亮度(L)，单位为尼特(nit)，当μ n＝25+15*n,σ＝10，n为分区个数，各分区的等量背光扩散叠加形成均匀背光。为了便于说明，图1中只展示了一维空间的光束扩散，实际光束扩散是二维的。
请参考图2，图2为实测的背光亮度关于距离(像素)的分布与采用双高斯拟合的背光亮度关于距离(像素)的分布的比对图；实曲线为测量数据(data)，虚曲线为双高斯拟合数据(fit)，从图2中可以看出双高斯拟合能够很好地符合测量结果。
在背光分区调节的情况下，背光串扰导致区域内背光的亮度与背光控制信号不是严格对应，这会导致如果相邻分区背光的调低比例高于本分区背光的调低比例，本区域实际背光亮度会低于背光控制信号对应的亮度水平。如图3所示为背光串扰导致的背光亮度降低超出预期的示例图。图3中，分区6的背光控制信号对应的亮度维持1，周边分区背光控制信号对应的亮度降低为0.8。在不考虑串扰情况下，区域6应维持预期亮度(参加附图3中，区域6对应的预期亮度，约为1.65)。实际上由于周边光源辐射到区域6的背光成分降低，周边分区对分区6的贡献降低，分区6已经不能维持原来的背光亮度(参见附图3中，区域6对应的实际亮度，约为1.5)。而这种情况造成的亮度降低在溢出率的计算中是没有考虑到的。由于溢出率的计算是根据本分区的背光控制信号计算的，而分区内实际背光亮度低于背光控制信号对应的预期亮度，这会导致需要补偿的像素数量及补偿程度高于预期，造成溢出率超标。
为解决上述问题，请参考图4，本公开实施例提供一种动态局部调光显示控制方法，包括：
步骤41：根据待显示图像的灰阶确定各显示分区的灰阶统计函数；
本公开实施例中，将显示面板划分为多个显示分区。可选的，可以将显示面板的显示区域划分为M*N(行*列)个显示分区，进一步可选的，M和N均为大于1的正整数。
步骤42：获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；
步骤43：根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；
本公开实施例中，将背光源划分为多个背光分区。可选的，可以将背光源的背光区域划分为M*N(行*列)个背光分区，进一步可选的，M和N均为大于1的正整数。可选的，背光分区和显示分区一一对应。
步骤44：根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；
步骤45：根据所述补偿后的灰阶值进行图像显示。
本公开实施例中，通过与溢出率相关的灰阶控制参数以及各显示分区的灰阶统计函数，确定各背光分区的背光控制信号，然后确定像素的需要补偿的灰阶值，以此确保像素补偿中像素溢出率不高于预设值。
在本公开的一些实施例中，所述根据待显示图像的灰阶确定各显示分区的灰阶统计函数之前还包括：将所述待显示图像由彩色图像转换为灰度图像。
在本公开的一些实施例中，在将待输入显示面板的待显示图像由彩色图像转换为灰度图像时，可以将所述彩色图像的每个像素的RGB(红绿蓝)分量中的最大值作为所述灰度图像中对应像素的灰阶值，原因在于RGB分量中的最大值与溢出率直接相关。
当然，在本公开的其他一些实施例中，也可以采用其他方法将彩色图像转换为灰度图像，例如将彩色图像的每个像素的RGB分量的平均值作为灰度图像中对应像素的灰阶值。
本公开实施例中，可选的，所述灰阶统计函数为灰阶-累积分布函数(Cumulative Distribution Function，CDF)。累积分布函数(CDF)是概率密度函数(Probability Density Function，PDF)的积分，能完整描述一个实随机变量X的概率分布。本公开实施例中，实随机变量X为灰阶。
当然，在本公开的其他一些实施例中，灰阶统计函数也可以为其他类型的函数。
本公开实施例中，当所述灰阶统计函数为灰阶-累积分布函数时，所述根 据待显示图像的灰阶确定各显示分区的灰阶统计函数包括：
步骤411：针对每个所述显示分区，获取所述显示分区的灰度图像中各像素的灰阶值；
步骤412：获取各所述灰阶值的概率密度分布函数；
步骤413：根据所述显示分区内所有所述灰阶值的概率密度分布函数，得到所述显示分区的灰度图像的灰阶-累积分布函数。
下面对概率密度函数的定义举例说明，假设灰度图像中灰阶为0的像素有N0个，灰阶为1的像素有N1个，……，灰阶为i的像素为Ni个，其中，i小于或等于255；灰度图像中像素的总数为Nt；则灰阶i的概率密度分布函数PDF(i)＝Ni/Nt。
请参考图5和图6，图5为本公开一实施例中的灰阶-概率密度函数的示意图，图6为本公开一实施例中的灰阶-累积分布函数的示意图。采用PDF和CDF是一种比较简单的统计灰阶的概率信息的方法。
本公开实施例中，可选的，所述根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号包括：
步骤431：根据所述各显示分区的灰度图像的灰阶统计函数和灰阶控制参数，确定所述各显示分区的临界溢出灰阶；
本公开实施例中，可选的，灰阶控制参数为预设的溢出率值。
溢出率为灰阶溢出的像素数目占总像素数据的比率。而所谓溢出，举例来说，对于8位的图像，灰阶超过255为溢出。
本公开实施例中，所述溢出率值为预设值，该预设值可以根据经验值设定。本公开实施例中，各显示分区的溢出率相同。
本公开实施例中，可以采用下述方式确定各显示分区的临界溢出灰阶：根据所述灰阶-累积分布函数，确定累计分布概率k对应的灰阶作为所述临界溢出灰阶，其中，k等于1-p，所述p为所述溢出率。
临界溢出灰阶的意义在于：当临界溢出灰阶Gt恰好溢出时，灰阶高于Gt的像素已经溢出，占比为p，而占比为k的部分由于灰阶低于Gt不会溢出。
当然，在本公开的其他一些实施例中，也不排除灰阶控制参数为其他参数，例如为溢出率乘以指定系数等。
步骤432：根据各所述显示分区的临界溢出灰阶，确定各背光分区的临界背光亮度；
本公开实施例中，可选的，采用下述公式确定各背光分区的临界背光亮度Lt：
Lt＝Lmax*(Gt/Gmax)^gamma
其中，Lmax为背光的原亮度值，gamma为所述显示面板的伽马值，^为幂指数运算，Gt为所述临界溢出灰阶，Gmax为最大灰阶值，例如对于8位图像，Gmax为255。
步骤433：根据所述各背光分区的临界背光亮度，确定所述各背光分区的初始背光控制信号；
本公开实施例中，背光亮度与背光控制信号具有映射关系，该映射关系可以预先确定。
各背光分区的初始背光控制信号可以组成一初始背光控制信号阵列Lt(m,n)。
步骤434：根据各所述背光分区的初始背光控制信号，确定各所述背光分区的目标背光控制信号，其中，各所述背光分区的目标背光控制信号为其所在的邻域内的初始背光控制信号的最大值，所述背光分区的邻域由所述背光分区及其周围的多个背光分区组成；
可选的，所述邻域的大小为3×3背光分区(3行3列背光分区)或5×5背光分区(5行5列背光分区)，或者，也可以是其他更大的邻域。具体的大小根据背光分区受周边背光分区的影响程度确定。可选的，本背光分区位于邻域的中心。
各背光分区的目标背光控制信号组成目标背光信号控制阵列Lc(m,n)。
请参考图7，图7为初始背光控制信号阵列Lt(m,n)转换为目标背光信号控制阵列Lc(m,n)的方法示意图。图7所示的实施例中，邻域的大小为3×3背光分区。
本公开实施例中，各所述背光分区的目标背光控制信号为其所在的邻域内的初始背光控制信号的最大值，可以保证本背光分区的周边背光分区的背光调低后，本背光分区的光亮度不低于本背光分区计算得到的理论值(即预 期亮度)。
请参考图8，使用上述方法得到的背光示意图，本公开实施例中，采用的3×3背光分区的邻域，从图8中可以看出，区域6的实际亮度约为1.65，基本达到了预期亮度。
本公开实施例中，考虑了各背光分区间背光存在的串扰，在确定各背光分区的背光控制信号前使用邻域内的最大值确定本分区的背光控制信号，确保本分区的背光不低于理论值，以此确保像素补偿中像素溢出率不高于预设值。
本公开实施例中，可选的，所述根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值包括：
步骤441：根据各所述背光分区的背光控制信号和背光扩散模型，确定显示面板上的各像素的背光亮度信息；所述背光扩散模型是单组背光点亮时，在显示面板背面的背光二维分布状况，可以由成像亮度计测量得到数据，再经过数据去噪、拟合得到的数学模型。
本公开实施例中，可选的，所述背光扩散模型采用多高斯拟合方法建立。多高斯拟合方法可以很好地建立背光扩散模型，例如，在图1中所展示的测量数据可以使用双高斯分布很好地拟合出来。
背光信号为离散的背光点阵列，各背光点发出的光经扩散板扩散在显示面板上呈现为面状光源。在数学上，这个过程可以通过各点的背光信号与背光扩散模型卷积实现。
即，本公开实施例中，可以将各背光点的背光控制信号与背光扩散模型进行卷积计算，得到所述显示面板上的各像素的背光亮度信息。
步骤442：根据所述各像素的背光亮度信息，确定所述各像素的补偿后的灰阶值。
本公开实施例中，可以通过以下方式确定各像素的补偿后的灰阶值包括：
步骤4421：计算所述显示面板上的各像素的补偿率，所述补偿率S＝(Lmax/Lnew)^(1/gamma)，其中，Lmax为像素的原背光亮度值，Lnew为计算得到的像素的背光亮度信息，gamma为所述显示面板的伽马值，^为幂指数运算；
步骤4422：确定各像素的补偿后的灰阶值，补偿后的灰阶值Gnew＝Gori*S，其中，Gori为像素的原始灰阶值。
灰阶的溢出会导致像素产生色偏，造成比亮度失真更明显的显示不良。因而，本公开实施例中，可选的，在理论算出的补偿率S会导致灰阶溢出的情况下(例如，可以将补偿率与RGB分量分别相乘，三个乘积中的最大值如果大于最大灰阶值(如255)，则判断存在溢出)，实际补偿中需要根据溢出率调低补偿率S，例如使得max(R、G、B)*S＝255。此时RGB通道中的最大值被补偿至255灰阶，达到饱和，其他通道未达到饱和，可以避免实际溢出造成色偏。
即，本公开实施例中，可选的，请参考图9，所述确定各像素的补偿后的灰阶值之后还包括：若补偿后的灰阶值大于最大灰阶值(溢出)，调低所述补偿率，使得补偿后的灰阶值等于最大灰阶值。
本公开实施例中的动态局部调光显示控制方法，适用于将显示面板划分为超多显示分区，且显示分区间的背光存在串扰的情况。
基于同一公开构思，请参考图10，本公开还提供一种动态局部调光显示控制装置100，包括：
第一确定模块101，用于根据待显示图像的灰阶确定各显示分区的灰阶统计函数；
获取模块102，用于获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；
计算模块103，用于根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；
第二确定模块104，用于根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；
显示模块105，用于根据所述补偿后的灰阶值进行图像显示。
可选的，所述计算模块103包括：
第一确定子模块，用于根据所述各显示分区的灰度图像的灰阶统计函数和灰阶控制参数，确定所述各显示分区的临界溢出灰阶；
第二确定子模块，用于根据所述各显示分区的临界溢出灰阶，确定各背 光分区的临界背光亮度；
第三确定子模块，用于根据所述各背光分区的临界背光亮度，确定所述各背光分区的初始背光控制信号；
第四确定子模块，用于根据所述各背光分区的初始背光控制信号，确定所述各背光分区的目标背光控制信号，其中，所述各背光分区的目标背光控制信号为其所在的邻域内的初始背光控制信号的最大值，所述背光分区的邻域由所述背光分区及其周围的多个背光分区组成。
可选的，所述第二确定模块104包括：
第五确定子模块，用于根据各所述背光分区的背光控制信号和背光扩散模型，确定显示面板上的各像素的背光亮度信息；
第六确定子模块，用于根据所述各像素的背光亮度信息，确定所述各像素的补偿后的灰阶值。
可选的，所述灰阶统计函数为灰阶-累积分布函数，所述第一确定模块101包括：
第一获取子模块，用于针对每个所述显示分区，获取所述显示分区的灰度图像中各像素的灰阶值；
第二获取子模块，用于获取各所述灰阶值的概率密度分布函数；
第三获取子模块，用于根据所述显示分区内所有所述灰阶值的概率密度分布函数，得到所述显示分区的灰度图像的灰阶-累积分布函数。
可选的，所述灰阶控制参数为预设的溢出率值，所述灰阶统计函数为灰阶-累积分布函数；
所述第一确定子模块，用于根据所述灰阶-累积分布函数，确定累计分布概率k对应的灰阶作为所述临界溢出灰阶，其中，k等于1-p，所述p为所述溢出率值。
可选的，所述第二确定子模块，用于采用下述公式确定所述各背光分区的临界背光亮度Lt：
Lt＝Lmax*(Gt/Gmax)^gamma
其中，Lmax为背光的原亮度值，gamma为所述显示面板的伽马值，^为幂指数运算，Gt为所述临界溢出灰阶，Gmax为最大灰阶值。
可选的，所述邻域的大小为3×3背光分区或5×5背光分区。
可选的，第六确定子模块，用于计算所述显示面板上的各像素的补偿率，所述补偿率S＝(Lmax/Lnew)^(1/gamma)，其中，Lmax为像素的原背光亮度值，Lnew为计算得到的像素的背光亮度信息，gamma为所述显示面板的伽马值，^为幂指数运算；确定各像素的补偿后的灰阶值，所述补偿后的灰阶值Gnew＝Gori*S，其中，Gori为像素的原始灰阶值。
可选的，所述装置还包括：
调整模块，用于若补偿后的灰阶值大于最大灰阶值，调低所述补偿率，使得补偿后的灰阶值等于最大灰阶值。
可选的，所述装置还包括：
转换模块，用于将所述待显示图像由彩色图像转换为灰度图像。
本公开实施例还提供一种显示装置，包括上述动态局部调光显示控制装置。
本公开实施例还提供一种显示装置，包括处理器、存储器及存储在所述存储器上并可在所述处理器上运行的计算机程序，所述计算机程序被所述处理器执行时实现上述任一实施例中的动态局部调光显示控制方法的步骤。
本公开实施例还提供一种计算机可读存储介质，所述计算机可读存储介质上存储计算机程序，所述计算机程序被处理器执行时实现上述任一实施例中的动态局部调光显示控制方法的步骤。
上面结合附图对本公开的实施例进行了描述，但是本公开并不局限于上述的具体实施方式，上述的具体实施方式仅仅是示意性的，而不是限制性的，本邻域的普通技术人员在本公开的启示下，在不脱离本公开宗旨和权利要求所保护的范围情况下，还可做出很多形式，均属于本公开的保护之内。

Claims (14)

  1. 一种动态局部调光显示控制方法，其特征在于，包括：
    根据待显示图像的灰阶确定各显示分区的灰阶统计函数；
    获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；
    根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；
    根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；
    根据所述补偿后的灰阶值进行图像显示。
  2. 如权利要求1所述的方法，其特征在于，所述根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号包括：
    根据所述各显示分区的灰度图像的灰阶统计函数和灰阶控制参数，确定所述各显示分区的临界溢出灰阶；
    根据所述各显示分区的临界溢出灰阶，确定各背光分区的临界背光亮度；
    根据所述各背光分区的临界背光亮度，确定所述各背光分区的初始背光控制信号；
    根据所述各背光分区的初始背光控制信号，确定所述各背光分区的目标背光控制信号，其中，所述各背光分区的目标背光控制信号为其所在的邻域内的初始背光控制信号的最大值，所述背光分区的邻域由所述背光分区及其周围的多个背光分区组成。
  3. 如权利要求2所述的方法，其特征在于，所述根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值包括：
    根据各所述背光分区的背光控制信号和背光扩散模型，确定显示面板上的各像素的背光亮度信息；
    根据所述各像素的背光亮度信息，确定所述各像素的补偿后的灰阶值。
  4. 如权利要求1所述的方法，其特征在于，所述灰阶统计函数为灰阶-累积分布函数，所述根据待显示图像的灰阶确定各显示分区的灰阶统计函数包括：
    针对每个所述显示分区，获取所述显示分区的灰度图像中各像素的灰阶值；
    获取各所述灰阶值的概率密度分布函数；
    根据所述显示分区内所有所述灰阶值的概率密度分布函数，得到所述显示分区的灰度图像的灰阶-累积分布函数。
  5. 如权利要求2所述的方法，其特征在于，所述灰阶控制参数为预设的溢出率值，所述灰阶统计函数为灰阶-累积分布函数；
    所述根据所述各显示分区的灰度图像的灰阶统计函数和灰阶控制参数，确定所述各显示分区的临界溢出灰阶包括：
    根据所述灰阶-累积分布函数，确定累计分布概率k对应的灰阶作为所述临界溢出灰阶，其中，k等于1-p，所述p为所述溢出率值。
  6. 如权利要求2所述的方法，其特征在于，所述根据所述各显示分区的临界溢出灰阶，确定各背光分区的临界背光亮度包括：
    采用下述公式确定所述各背光分区的临界背光亮度Lt：
    Lt＝Lmax*(Gt/Gmax)^gamma
    其中，Lmax为背光的原亮度值，gamma为显示面板的伽马值，^为幂指数运算，Gt为所述临界溢出灰阶，Gmax为最大灰阶值。
  7. 如权利要求2所述的方法，其特征在于，所述邻域的大小为3×3背光分区或5×5背光分区。
  8. 如权利要求3所述的方法，其特征在于，所述根据所述各像素的背光亮度信息，确定所述各像素的补偿后的灰阶值包括：
    计算所述显示面板上的各像素的补偿率，补偿率S＝(Lmax/Lnew)^(1/gamma)，其中，Lmax为像素的原背光亮度值，Lnew为计算得到的像素的背光亮度信息，gamma为所述显示面板的伽马值，^为幂指数运算；
    确定各像素的补偿后的灰阶值，所述补偿后的灰阶值Gnew＝Gori*S，其中，Gori为像素的原始灰阶值。
  9. 如权利要求8所述的方法，其特征在于，所述确定各像素的补偿后的灰阶值之后还包括：
    若补偿后的灰阶值大于最大灰阶值，调低所述补偿率，使得补偿后的灰阶值等于最大灰阶值。
  10. 如权利要求1所述的方法，其特征在于，所述根据待显示图像的灰阶确定各显示分区的灰阶统计函数之前还包括：
    将所述待显示图像由彩色图像转换为灰度图像。
  11. 一种动态局部调光显示控制装置，其特征在于，包括：
    第一确定模块，用于根据待显示图像的灰阶确定各显示分区的灰阶统计函数；
    获取模块，用于获取所述各显示分区的灰阶控制参数，所述灰阶控制参数与溢出率相关；
    计算模块，用于根据所述灰阶控制参数和所述各显示分区的灰阶统计函数计算各背光分区的背光控制信号；
    第二确定模块，用于根据所述各背光分区的背光控制信号和背光扩散模型确定补偿后的灰阶值；
    显示模块，用于根据所述补偿后的灰阶值进行图像显示。
  12. 一种显示装置，其特征在于，包括如权利要求11所述的动态局部调光显示控制装置。
  13. 一种显示装置，其特征在于，包括处理器、存储器及存储在所述存储器上并可在所述处理器上运行的计算机程序，所述计算机程序被所述处理器执行时实现如权利要求1至10中任一项所述的动态局部调光显示控制方法的步骤。
  14. 一种可读存储介质，其特征在于，所述可读存储介质上存储计算机程序，所述程序被处理器执行时实现如权利要求1至10中任一项所述的动态局部调光显示控制方法的步骤。
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