WO2019101005A1

WO2019101005A1 - Pixel compensation method and apparatus, and terminal device

Info

Publication number: WO2019101005A1
Application number: PCT/CN2018/115836
Authority: WO
Inventors: 张涛; 巫红英; 李昌禄
Original assignee: 华为技术有限公司
Priority date: 2017-11-21
Filing date: 2018-11-16
Publication date: 2019-05-31
Also published as: CN109817170B; CN109817170A

Abstract

A pixel compensation method and apparatus, and a terminal device. The method comprises: acquiring a first backlight image of an image to be processed, wherein pixel points in the first backlight image correspond to backlight units in a backlight array on a one-to-one basis, and the backlight array is used for providing a backlight for displaying the image to be processed; according to a position attribute of the pixel points, dividing the pixel points in the first backlight image so as to obtain multiple areas of the first backlight image; filtering and enlarging images of the multiple areas respectively so as to obtain a second backlight image that has the same resolution as the image to be processed, wherein when the images of the multiple areas are filtered, different spatial filtering is applied to the images of at least two areas among from the multiple areas; and carrying out, according to a brightness value of the second backlight image, pixel compensation on the image to be processed.

Description

Pixel compensation method, device and terminal device

The present application claims priority to Chinese Patent Application No. JP-A No. No. No. No. No. No. No. No. No. No. No. No. No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No in.

Technical field

The present application relates to the field of display pixel compensation technology, and more particularly, to a pixel compensation method, apparatus and terminal device.

Background technique

In order to improve the dynamic range of the display, the backlight module of the display can be divided into several regions, and then the brightness of each region of the backlight module is adjusted according to the distribution of the image content, and pixel compensation is performed on the pixel values of the image, thereby ensuring the display effect. At the same time improve the dynamic range of the display of the display.

In the conventional scheme, when the image is pixel-compensated, the backlight is smoothed according to the brightness of the backlight area, and then the area after the backlight is smoothed is pixel-compensated to ensure the display effect. Specifically, in the backlight smoothing process, the same filtering template is used for low-pass filtering of the entire backlight region, and then pixel compensation is performed. Since the light diffusion of the backlight module in different regions is different, the same low-pass filtering template is used for filtering. Processing, can not simulate the diffusion of the backlight very well, will lead to poor display performance of the final display.

Summary of the invention

The application provides a pixel compensation method, device and terminal device to improve display effects.

In a first aspect, a pixel compensation method is provided. The method includes: acquiring a first backlight image of an image to be processed, where pixels in the first backlight image are in one-to-one correspondence with a backlight unit in a backlight array, the backlight The array is configured to provide a backlight for displaying the image to be processed; and dividing a pixel of the first backlight image according to a position attribute of the pixel to obtain a plurality of regions of the first backlight image; The images of the regions are respectively filtered and amplified to obtain a second backlight image having the same resolution as the image to be processed, wherein, when filtering the images of the plurality of regions, the plurality of regions The images of the at least two regions are applied with different spatial filtering; the image to be processed is pixel compensated according to the brightness value of the second backlight image.

The backlight array described above includes a plurality of backlight units, and the backlight array includes the same number of backlight units as the number of pixel points in the first backlight image.

In the present application, filtering processing is performed by using different types of spatial filtering for images of at least two of the plurality of regions, and the backlight diffusion can be better simulated compared with the filtering method using the unified filtering template, so that the pixels are better The compensated image can achieve a better display effect when displayed.

With reference to the first aspect, in some implementations of the first aspect, the pixel points of the first backlight image are divided according to a position attribute of the pixel point to obtain multiple regions of the first backlight image. The method includes: dividing the pixel points having the same position attribute into the same area, wherein the position attribute is the same including the same number of adjacent pixel points or the same distance from the center position of the first backlight image.

By dividing the pixels with the same position attribute into the same area, the same spatial filtering can be used for the pixels with the same positional property, and the pixels with different positions are differently filtered, which can better simulate the light diffusion phenomenon at different positions. Thereby, the effect of the display can be improved.

Optionally, the same location attribute may also mean that the number of adjacent pixel points is within a preset range. For example, a pixel point whose number of adjacent pixel points is less than or equal to 5 may belong to the same location attribute, and adjacent pixel points. A pixel with a number greater than 5 can be considered to belong to another location attribute.

With reference to the first aspect, in some implementations of the first aspect, the pixel points of the first backlight image are divided according to a position attribute of a pixel point to obtain multiple regions of the first backlight image. The method includes: dividing a pixel point position having 8 adjacent pixel points into a first area; dividing a pixel point position having 5 adjacent pixel points into a second area; and selecting a pixel point having 3 adjacent pixel points The position is divided into the third area.

In conjunction with the first aspect, in some implementations of the first aspect, the performing pixel compensation on the image to be processed according to the brightness value of the second backlight image comprises: obtaining an arbitrary from the image to be processed a first brightness value of a pixel; obtaining, from the second backlight image, a second brightness value of a pixel corresponding to the position of the arbitrary one of the pixels; acquiring a maximum brightness value, where the maximum brightness value is Determining, according to the maximum brightness value and the second brightness value, a compensation coefficient of the arbitrary one pixel point; The compensation coefficient compensates a first brightness value of the arbitrary one of the pixel points to obtain a target brightness value of the arbitrary one of the pixel points.

Since different spatial filtering is adopted for different regions in the process of acquiring the second backlight image, the backlight diffusion phenomenon can be better simulated, so that when the pixel to be processed is subjected to pixel compensation, the true brightness according to the backlight can be obtained. The value of the pixel to be processed is pixel compensated, so that a better pixel compensation effect is obtained.

With reference to the first aspect, in some implementations of the first aspect, the first brightness value of the any one of the pixel points is compensated according to the compensation coefficient, to obtain a target brightness of the any one of the pixel points And a value comprising: determining a product of the first brightness value and the compensation coefficient as a target brightness value of the arbitrary one of the pixel points.

In conjunction with the first aspect, in some implementations of the first aspect, the compensation coefficient is obtained according to the following formula:

K=log ₂ (BL _max /BL) ^1.0/γ

Where K is the compensation coefficient, BL _max is the maximum brightness value, BL is the second brightness value, γ is a preset gamma coefficient, and γ is generally 2.2.

Since the processing of the image signal by the human eye is similar to the processing of the approximate logarithmic algorithm, the contrast of the image can be effectively improved by taking the logarithm in the process of compensating the pixel. In addition, in the above formula, BL _max can make the compensation coefficient K not excessively large by taking the maximum luminance value, thereby avoiding pixel overflow when pixel compensation is performed.

With reference to the first aspect, in some implementations of the first aspect, when the image format to be processed is RGB, the acquiring the first brightness value of any one of the pixels to be processed includes: The maximum component value of the three component values of any one of the pixel points is determined as the first brightness value; or the first brightness value is calculated according to the three component values of the arbitrary one of the pixel points.

Optionally, when calculating the first brightness value according to three component values of any one pixel point, it may be specifically according to the formula: Y=((R*299)+(G*587)+(B*114))/ Calculated by 1000, where Y represents the first luminance value, and R, G, and B represent the three component values of the pixel to be processed, respectively.

In a second aspect, a pixel compensation apparatus is provided, the pixel compensation apparatus comprising means for performing the method of the first aspect or various implementations thereof.

In a third aspect, a pixel compensation apparatus is provided, the pixel compensation apparatus comprising: a memory for storing a program; a processor, configured to execute the program stored by the memory, when the program is executed, the processor uses The method of the first aspect or its various implementations is performed.

According to a fourth aspect, a terminal device is provided, the terminal device comprising the pixel compensation device and the display in the second aspect, wherein the display is configured to display the pixel compensation device to perform pixel compensation on the image to be processed After the image.

In a fifth aspect, a terminal device is provided, the terminal device includes: a memory for storing a program; a processor, configured to execute the program stored by the memory, when the program is executed, the processor is configured to execute The method of the first aspect or various implementations thereof.

In a sixth aspect, a computer readable medium storing program code for device execution, the program code comprising instructions for performing the method of the first aspect or various implementations thereof.

DRAWINGS

1 is a schematic flowchart of a pixel compensation method according to an embodiment of the present application;

2 is a schematic view of a backlight array;

3 is a schematic view of a first backlight image;

4 is a schematic view of a plurality of regions of a first backlight image;

Figure 5 is a schematic illustration of a plurality of regions of a first backlit image;

Figure 6 is a schematic illustration of a plurality of regions of a first backlit image;

FIG. 7 is a schematic flowchart of a pixel compensation method according to an embodiment of the present application; FIG.

Figure 8 is a schematic diagram of a filter template;

Figure 9 is a schematic diagram of a pixel compensation curve;

FIG. 10 is a schematic block diagram of a pixel compensation apparatus according to an embodiment of the present application; FIG.

FIG. 11 is a schematic block diagram of a terminal device according to an embodiment of the present application.

Detailed ways

The technical solutions in the present application will be described below with reference to the accompanying drawings.

The dynamic range of an image is generally the ratio of the darkest brightness to the brightest brightness. The larger the ratio, the larger the dynamic range, the more layers the image can display, and the better the display.

The range of brightness in nature is wide. From the night scene under the stars (10 ^-3 cd/m ² ) to the brightness of the sun itself (10 ⁵ cd/m ² ), there are about 8 orders of magnitude of brightness. The human eye has its own adjustment mechanism. You can capture 5 orders of magnitude brightness range from nature. However, current displays generally only exhibit dynamic range of 2 to 3 orders of magnitude, and cannot reflect the real information of natural scenes viewed by the human eye.

In order to improve the dynamic range of the display, the display can be closer to the dynamic range in the natural scene, thereby better reflecting the real information of the natural scene. Area backlight dimming technology can generally be adopted. The technology generally includes two parts: backlight brightness extraction and pixel compensation.

The backlight brightness extraction refers to dividing the backlight module into a plurality of partitions (the shape of the partition may be a rectangular area), and then dynamically extracting characteristic parameters capable of characterizing the brightness information of the partition according to image content corresponding to each partition, and then according to the parameter Determine the brightness of the backlight unit of each partition.

After determining the brightness of each partition of the backlight module, the brightness of the pixel should be adjusted to a certain extent, so that the image color before and after the adjustment does not appear large deviation, and the display effect is ensured. After obtaining the brightness of the backlight, it is necessary to simulate the diffusion mode of the backlight, thereby obtaining the brightness value corresponding to each pixel of the liquid crystal display (LCD) panel, and then performing pixel compensation according to the brightness value of each pixel point. Therefore, how to simulate Backlight diffusion, how to perform pixel compensation, to ensure display effect is a problem to be solved.

The pixel compensation method of the embodiment of the present application is described in detail below with reference to FIG. 1 .

FIG. 1 is a schematic flowchart of a pixel compensation method according to an embodiment of the present application. The method shown in FIG. 1 can be performed by a device capable of displaying video, such as a liquid crystal display device, a smart terminal, a tablet computer, a desktop computer, or the like. The method shown in FIG. 1 includes steps 101 to 104, and step 101 to step 104 are described in detail below with reference to specific examples.

101. Acquire a first backlight image of an image to be processed.

The first backlight image is a two-dimensional matrix composed of luminance values of a backlight array of a display device for displaying the image to be processed, and a pixel point and a backlight array in the first backlight image (the backlight array is used for The backlight units in the backlight for displaying the image to be processed are one-to-one correspondence, and the luminance value of each pixel is used to indicate the brightness of the corresponding backlight unit in the backlight array. In addition, the backlight array described above includes the same number of backlight units as the number of pixel points in the first backlight image.

It should be understood that the backlight array of the display device is composed of a plurality of backlight units, and the brightness of each backlight unit can be separately adjusted (the brightness of each backlight unit can be adjusted through the control unit of the display), and the area where each backlight unit is located can be called A partition for the backlight array.

For example, the backlight array of the display is composed of M×N (M and N are integers greater than or equal to 1) backlight units, then the entire area of the backlight array is composed of M×N partitions, correspondingly, the first backlight The image includes M x N pixels, each pixel corresponding to a partition in the backlight matrix.

As shown in FIG. 2, the entire area of the backlight array is composed of 6 × 10 partitions, and each partition is provided with a backlight unit. Correspondingly, the first backlight image is as shown in FIG. 3 , and the first backlight image comprises 6×10 pixel points, and each pixel point corresponds to one partition in the backlight array in FIG. 2 .

102. Divide a pixel of the first backlight image according to a position attribute of the pixel to obtain a plurality of regions of the first backlight image.

When dividing a pixel of the first backlight image, pixels having the same position attribute (or position type) may be divided into the same area, that is, pixels divided into the same area have the same The location attribute, thus having some similar features, can be processed using the same filter template in subsequent filtering processes.

Optionally, as an embodiment, the pixel of the first backlight image is divided into regions according to the position attribute of the pixel to obtain a plurality of regions of the first backlight image, including: dividing pixel points with the same position attribute Go to the same area.

The same position attribute may include the same number of adjacent pixels or the same distance from the center position of the second backlight image.

Specifically, in the first backlight image, if the number of adjacent pixel points of some pixels is the same, the positional attributes of the pixels may be considered to be the same.

Optionally, as an embodiment, dividing a pixel point of the first backlight image according to a position attribute of the pixel point to obtain a plurality of regions of the first backlight image, including: having 8 adjacent pixel points The pixel point position is divided into the first area; the pixel point position having 5 adjacent pixel points is divided into the second area; and the pixel point position having 3 adjacent pixel points is divided into the third area.

For example, as shown in FIG. 4, in the first area, the number of adjacent pixel points of each pixel point is 8, and the number of adjacent pixel points of each pixel point in the second area is 5, The number of adjacent pixels of each pixel in the three regions is three.

Optionally, in the first backlight image, if some pixels are equal in distance from the center position of the first backlight image, the positional attributes of the pixels may also be considered to be the same.

Specifically, a pixel point whose distance from the center position of the first backlight image is smaller than the first distance may be divided into one area, and a pixel point whose distance from the center position of the first backlight image is larger than the first distance may be divided into another area.

For example, as shown in FIG. 5, a pixel point having a distance greater than two pixel points from a center position of the first backlight image is divided into the first area, and a distance from a center position of the first backlight image is less than or equal to two pixel points. The pixels are divided into the second area. In FIG. 5, the pixel points in the first region are mainly pixel points that are relatively close to the center position, and the pixel points in the second region are mainly pixel points that are relatively far from the center position. It should be understood that the distance of each pixel point from the center position of the first backlight image refers to the horizontal distance or vertical distance of the edge of the pixel point from the center position point.

Optionally, the same location attribute may also mean that the number of adjacent pixel points is within a preset range. For example, in the first backlight image, pixels of the number of adjacent pixel points less than or equal to 5 may be considered to belong to the same type. The position attribute, a pixel whose number of adjacent pixels is greater than 5, can be considered to belong to another position attribute.

For example, as shown in FIG. 6, a pixel point having a number of adjacent pixel points greater than 5 is divided into a first area (the number of adjacent pixel points of each pixel point in the first area is 8), and adjacent A pixel point whose number of pixels is less than or equal to 5 is divided into the second region (the number of adjacent pixel points of the pixel in the second region is 5 or 3).

Alternatively, it is also considered that the pixels at the edge of the backlit image have the same positional property, while the pixels within the backlit image have the same positional property. As also shown in FIG. 6, the pixel at the edge of the first backlight image may be divided into the first region, and the remaining pixel dots may be divided into the second region.

It should be understood that the same area division result can be obtained by using different division manners. For example, the division result shown in FIG. 6 may be obtained by dividing the area according to whether it is at the edge, or may be according to the number of adjacent pixel points. Obtained by dividing within the preset range.

By dividing the pixels with the same position attribute into the same area, the same spatial filtering can be applied to the pixels with the same position attribute, which can improve the filtering effect.

103. Filter and amplify the images of the multiple regions to obtain a second backlight image with the same resolution as the image to be processed.

Wherein, when filtering images of a plurality of regions, images of at least two of the plurality of regions are applied with different spatial filtering.

In addition, applying different spatial filtering to the images of the at least two regions may mean that different filtering templates (specifically, low-pass filtering templates) may be used when filtering the images of the at least two regions, and different filtering templates are used. The filter coefficients can be different.

104. Perform pixel compensation on the image to be processed according to the brightness value of the second backlight image.

In the present application, filtering processing is performed by using different types of spatial filtering for images of at least two of the plurality of regions, which can better simulate backlight diffusion and achieve pixel compensation compared with filtering using a unified filtering template. The latter image can achieve a better display effect when displayed.

It should be understood that pixel compensation of the image to be processed in the present application refers to compensating or adjusting the luminance value of each pixel in the image to be processed.

Since the second backlight image has the same image resolution as the image to be processed, each pixel in the image to be processed has a corresponding position in the second backlight image, indicating the backlight brightness value of the image to be processed at the above position. The pixel of the second backlight image may be compensated according to the pixel corresponding to the position of the image to be processed.

Optionally, as an embodiment, performing pixel compensation on the image to be processed according to the brightness value of the second backlight image, specifically: acquiring a first brightness value of any one pixel point from the image to be processed; and from the second backlight image Obtaining a second brightness value of a pixel corresponding to the position of the arbitrary one of the pixels; acquiring a maximum brightness value; determining a compensation coefficient of any one of the pixel points according to the maximum brightness value and the second brightness value; The first luminance value of the pixel is compensated to obtain a target luminance value of the pixel.

The maximum brightness value described above refers to the upper limit value of the brightness of the second backlight image or the upper limit value of the brightness that the backlight unit can display.

Optionally, when the first brightness value of any one of the pixel points is compensated according to the compensation coefficient, to obtain the target brightness value of any one of the pixel points, the compensation coefficient and the first brightness value of the arbitrary one of the pixel points may be specifically The product of the product is the target luminance value of the arbitrary one of the pixels.

The above compensation coefficient can be calculated by the formula K=log ₂ (BL _max /BL) ^1.0/γ , where K is the compensation coefficient, BL _max is the maximum brightness value, BL is the second brightness value, and γ is the preset gamma. The coefficient, γ, can be an empirical value determined experimentally, and γ can generally be taken as 2.2.

Since the processing of the image signal by the human eye is similar to the processing of the approximate logarithmic algorithm, the contrast of the image can be effectively improved by taking the logarithm in the process of compensating the pixel. In turn, a better pixel compensation effect is obtained. In addition, in the above formula, BL _max can make the compensation coefficient K not excessively large by taking the maximum luminance value, thereby avoiding pixel overflow when pixel compensation is performed.

In addition, when determining the first brightness value of any one of the pixel points, if the image format of the image to be processed is RGB, then the maximum component value of the three component values of the arbitrary one of the pixel points may be determined as the first brightness. The value, or the first brightness value is calculated from the three component values of the arbitrary one of the pixel points.

When the first brightness value is calculated according to the three component values of the pixel to be processed, it can be calculated according to the formula Y=((R*299)+(G*587)+(B*114))/1000, where Y represents the first luminance value, and R, G, and B represent the three component values of the pixel to be processed, respectively.

By directly determining the maximum component value among the three components as the first luminance value, the first luminance value can be quickly determined, and a certain computational complexity can be reduced. When the first brightness value is calculated by three component values, a more accurate brightness value can be obtained, which is convenient for subsequent pixel compensation.

The embodiments of the present application are described in more detail below with reference to specific examples. It should be understood that the embodiment shown in FIG. 7 is to help those skilled in the art understand the embodiments of the present application, and is not intended to limit the embodiments of the present application to the drawings. The specific values and specific scenarios shown in the method of 7. A person skilled in the art can make various equivalent modifications or changes according to the embodiment shown in FIG. 7, and these modifications or variations are also within the scope of the embodiments of the present application.

FIG. 7 is a schematic flowchart of a pixel compensation method according to an embodiment of the present application. The method shown in FIG. 7 can be performed by a liquid crystal display device, a smart terminal, a tablet computer, a desktop computer, or the like that can display video. The method shown in Figure 7 specifically includes the following steps:

201. Determine a first backlight image.

The backlight array of the display may include a plurality of backlight units, and the brightness value of each backlight unit may be dynamically adjusted according to the image content corresponding to the backlight unit, so that the dynamic range of the display is increased. The brightness values of all the backlight units in the backlight array after the backlight adjustment may constitute a first backlight image, and the brightness value of each pixel in the first backlight image corresponds to the brightness of each backlight unit in the backlight array.

The size of the first backlight image is related to the number of backlight units included in the backlight array. If the backlight array includes M×N backlight units, the luminance values of the pixels of the first backlight image also form an M×N size. The matrix, the luminance value of each pixel in the first backlight image BL _init can be specifically expressed by the formula (1).

202. Divide pixel points of the first backlight image.

It should be understood that each pixel point in the first backlight image corresponds to one backlight unit in the backlight array, and the brightness value of each pixel point is used to indicate the brightness of the corresponding backlight unit.

The first backlight image BL _init is composed of a total of M×N pixels. For the first backlight image, the number of adjacent pixels of different pixels may be different, for the pixel at the edge of the first backlight image. In other words, the number of adjacent pixels is smaller than the number of adjacent pixels located in the pixel inside the first backlight image, that is, there are different regions in the first backlight image, and in some regions The number of adjacent pixels of the pixel is small, and the number of adjacent pixels in some areas is relatively large, so that in the process of light diffusion, light diffusion and mixing in different regions are different.

Therefore, in order to better simulate the backlight diffusion phenomenon of different types of regions, the pixels of the first backlight image may be divided according to the position of each pixel in the first backlight image, thereby obtaining different regions.

As shown in FIG. 4, for a first backlight image composed of 6×10 pixels, the first backlight image may be divided into three regions, wherein adjacent to each pixel in the first region The number of pixels is three, the number of adjacent pixels of each pixel in the second region is five, and the number of adjacent pixels for each pixel in the third region is eight.

203. Differently filtering different regions of the first backlight image by using different filtering templates to obtain a mixed backlight image BL _mixed .

When the first backlight image obtained in step 202 is divided into three regions as shown in FIG. 4, the first filter template, the second filter template, and the third filter template shown in FIG. 8 may be used to respectively pair the first backlight. The first area, the second area, and the third area in the image are mixed.

Specifically, for the first region, the processing can be performed using equation (2) to obtain the processed luminance value of each pixel in the first region.

For the second region, the light mixing process can be performed using Equation (3) to obtain the luminance value of each pixel in the second region after the light mixing process.

For the third region, the light mixing process can be performed using Equation (4) to obtain the luminance value of each pixel in the third region after the light mixing process.

In the above formulas (2) to (4), a, b, c, and d are coefficients of the first filter template, the second filter template, and the third filter template, respectively. Where a is located at the center of the diffusion template, indicating the coefficient of light energy remaining after the diffusion of the light diffusion center, and b, c, and d are distributed around the diffusion template, respectively indicating the coefficient of diffusion of the light diffusion center to the surrounding. Assuming that the energy of the light is conserved during propagation, the coefficient of the first filtering template satisfies a+b+c+d=1, and the coefficient of the second filtering template satisfies a+2b+c+2d=1, the third filtering template The coefficient satisfies a+2b+2c+4d=1.

The specific values of a, b, c, and d above can be obtained through a large number of experiments. The coefficients of different filter templates are as follows:

The first type of filtering template: a = 0.4, b = 0.2, c = 0.2, d = 0.2

The second type of filtering template: a=0.38, b=0.15, c=0.12, d=0.1

The third type of filtering template: a=0.38, b=0.112, c=0.02, d=0.06

204. Expanding the _mixed backlight image BL to obtain an extended backlight image BL _expand .

In the case of extending the backlit image after the light mixing, a linear interpolation method may be employed, and further, the mixed backlight image may be expanded by bilinear interpolation. When extended backlight image light may be mixed every time the light mixing backlit images expanded to twice its original, e.g., a light mixing matrix BL _mixed before expansion of size M × N, the extended light mixing matrix BL The size of _expand is 2M x 2N. It should be understood that any of the interpolation methods may be used to expand the backlit image after the light mixing.

205. Determine whether the backlight smoothing between the respective regions of the extended backlight image BL _expand reaches a preset effect.

If the backlight between the regions in the BL _expand reaches the preset effect, then step 206 is performed. If the smoothing effect is not achieved, the above steps 203 and 204 can be continued until a smooth smoothness is achieved between the regions of the BL _expand . The effect, that is, there is no obvious block boundary between the various areas of BL _expand .

206. Expand the extended backlight image to the size of the image to be processed to obtain a target backlight image BL _final that is finally used for pixel compensation.

It should be understood that when expanding BL _expand , if the size of the image to be processed is 160×160 and the size of BL _expand is 64×64, then BL _expand can be expanded twice and then interpolated (specifically, Bilinear interpolation method) obtains the target backlight image BL _{final of the} same size as the image to be processed.

207. Convert the image to be processed from RGB format to YUV format.

208. Perform pixel compensation on the image to be processed according to the target backlight image BL _final .

Specifically, pixel compensation can be performed in a logarithmic manner using equation (5).

In formula (5), Y _i,j is the pixel brightness before the pixel point (i,j) in the image to be processed is compensated, and Y′ _i,j is compensated for the pixel point (i,j) in the image to be processed. pixel luminance, BL _'max is the maximum target backlight BL _final image of an object takes the maximum value here is to avoid overflow during pixel pixel _{compensation,} BL' _{i, j} is the target backlight BL _final image corresponding to the to be The backlight brightness of the pixel (i, j) in the image is processed, K _i,j is the brightness compensation coefficient of the pixel, γ is the gamma coefficient, and γ is generally taken as 2.2.

In order to make the image without color distortion after the area is dimmed, it is necessary to compensate the UV component with the same Y component, and the UV component can also be compensated according to the formula (6).

The curve for pixel compensation based on the above formula (5) and formula (6) is shown by the logarithmic curve in FIG. 9. In FIG. 9, as the original pixel luminance value Y _in increases, the degree of pixel compensation gradually decreases. (The increase in Y _out is gradually reduced). That is to say, for low-brightness pixels, since the degree of backlight is reduced more, in order to effectively compensate for the decrease in display brightness caused by the decrease in backlight brightness, a large degree of compensation for low-brightness pixels is required to ensure full backlighting. The display effect is basically the same when it is high; for high-brightness pixels, since the backlight brightness is less than that when the backlight is fully lit, it is only necessary to make a small degree of compensation to ensure the display effect when the backlight is fully lit. be consistent. Therefore, pixel overflow distortion due to excessive pixel compensation can be effectively avoided when pixel compensation is performed in the present application.

209. Converting the pixel-compensated image to be processed from the YUV format to the RGB format, and obtaining the pixel-compensated image.

The main purpose of pixel compensation is to ensure that the color of the image is not distorted after adjusting the brightness of the backlight.

Optionally, after performing pixel compensation, in order to further improve the contrast of the image, the image may be subjected to contrast stretching after pixel compensation of the image. The subjective effect of the image after backlight brightness adjustment and pixel compensation is that the darker the image is, the brighter the bright part is. Therefore, the pixel compensated image can be divided into low brightness according to the brightness. Segment, intermediate luminance segment and high luminance segment, for the low luminance segment and the high luminance segment, respectively, exponential transformation can be used, and the low luminance segment is subjected to grayscale compression, and for the high luminance segment, grayscale expansion is performed, and the intermediate luminance is performed. The segment is linearly transformed, and the specific transformation formula can be as shown in (7).

In the formula (7), Y′ _i,j is the pixel-compensated brightness, Y′′ _i,j is the pixel brightness after the contrast stretching, and H ₁ and H ₂ are the pixel-compensated image total pixels 10 respectively. The pixel brightness value corresponding to % and 90% is also the segmentation point of the brightness conversion curve. Since the brightness of the low brightness segment is compressed and darkened, and the brightness of the high brightness segment is brightened due to expansion, the difference between the brightness and the darkness of the image is more obvious. , which effectively improves the image contrast.

In order to ensure that the color is not distorted, it is also necessary to perform the same multiple conversion of the UV component as the Y component. Specifically, the UV component can be subjected to the same processing using Equation (8).

_Wherein, Y _{'i, j} is the brightness of the pixel _{compensation,} Y _{"i, j} is the pixel brightness contrast _stretching, K _{i, j} is the pixel luminance compensation _coefficient, U' _{i, j} and V _{'i, j} is a U component and a V component after pixel compensation, and U′′ _{i, j} and V′′ _{i, j} are U components and V components after contrast stretching.

The pixel compensation method of the embodiment of the present application is described in detail with reference to FIG. 1 to FIG. 9 . The pixel compensation device and the terminal device of the embodiment of the present application are described in detail below with reference to FIG. 10 and FIG. 11 . The pixel compensation device and the terminal device shown in FIG. 11 are capable of performing the pixel compensation method of the embodiment of the present application, and the steps of the pixel compensation method of the embodiment of the present application can be implemented. For the sake of brevity, the pixel compensation of the embodiment of the present application is described below. The repeated description is appropriately omitted in the device and the terminal device.

FIG. 10 is a schematic block diagram of a pixel compensation apparatus according to an embodiment of the present application. The pixel compensation device 300 shown in FIG. 10 is capable of performing the pixel compensation method of the embodiment of the present application. The pixel compensation device 300 specifically includes:

The acquiring module 301 is configured to acquire a first backlight image of the image to be processed, where the pixel points in the first backlight image are in one-to-one correspondence with the backlight unit in the backlight array, and the backlight array is configured to display the image to be processed Providing backlighting;

The processing module 302 is configured to divide, according to a position attribute of the pixel point, a pixel point of the first backlight image to obtain a plurality of regions of the first backlight image;

The processing module 302 is further configured to separately filter and enlarge the images of the plurality of regions to obtain a second backlight image having the same resolution as the image to be processed, where the images of the plurality of regions are performed When filtering, images of at least two of the plurality of regions are applied with different spatial filtering;

The pixel compensation module 303 is configured to perform pixel compensation on the image to be processed according to the brightness value of the second backlight image.

Optionally, as an embodiment, the processing module 302 is specifically configured to:

Dividing a pixel point position having 8 adjacent pixel points into the first area;

Dividing a pixel point position having 5 adjacent pixel points into a second area;

A pixel point position having 3 adjacent pixel points is divided into a third area.

Optionally, as an embodiment, the pixel compensation module 303 is specifically configured to:

Obtaining, from the image to be processed, a first brightness value of any one of the pixel points;

Obtaining, from the second backlight image, a second brightness value of a pixel point corresponding to the position of the arbitrary one of the pixels;

Obtaining a maximum brightness value, where the maximum brightness value is a brightness upper limit value of the second backlight image or a brightness upper limit value that the backlight unit can display;

Determining a compensation coefficient of the arbitrary one of the pixel points according to the maximum brightness value and the second brightness value;

And compensating, according to the compensation coefficient, a first brightness value of the arbitrary one of the pixel points to obtain a target brightness value of the arbitrary one of the pixel points.

The product of the first brightness value and the compensation coefficient is determined as the target brightness value of the arbitrary one of the pixel points.

Optionally, as an embodiment, the compensation coefficient is obtained according to the following formula:

K=log ₂ (BL _max /BL) ^1.0/γ (9)

Where K is the compensation coefficient, BL _max is the maximum brightness value, BL is the second brightness value, and γ is a preset gamma coefficient.

Optionally, as an embodiment, when the image format to be processed is RGB, the acquiring module 301 is specifically configured to:

Determining a maximum component value of the three component values of any one of the pixel points as the first brightness value;

or,

The first brightness value is calculated based on three component values of any one of the pixel points.

FIG. 11 is a schematic block diagram of a terminal device according to an embodiment of the present application. The terminal device 400 shown in FIG. 11 includes a pixel compensation device 401 and a display 402. The pixel compensation device 401 herein may be the pixel compensation device 300 shown in FIG. 10, and the pixel compensation device 401 in the terminal device can perform the embodiment of the present application. The pixel compensation method performs pixel compensation on the image to be processed, and the display 402 can display the image after the pixel compensation device 401 performs pixel compensation.

The present application also provides a pixel compensation apparatus, the pixel compensation apparatus comprising: a memory for storing a program; a processor, configured to execute the program stored by the memory, when the program is executed, the processor uses The pixel compensation method of the embodiment of the present application is executed.

The present application also provides a terminal device, the terminal device comprising: a memory for storing a program; a processor, configured to execute the program stored by the memory, when the program is executed, the processor is configured to execute The pixel compensation method of the embodiment of the present application.

The application further provides a computer readable medium storing program code for execution by a device, the program code comprising instructions for performing a pixel compensation method of an embodiment of the present application.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods to implement the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present application.

A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

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

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

The functions may be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a standalone product. Based on such understanding, the technical solution of the present application, which is essential or contributes to the prior art, or a part of the technical solution, may be embodied in the form of a software product, which is stored in a storage medium, including The instructions are used to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like, which can store program code. .

The foregoing is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application. It should be covered by the scope of protection of this application. Therefore, the scope of protection of the present application should be determined by the scope of the claims.

Claims

A pixel compensation method, comprising:

Acquiring a first backlight image of the image to be processed, the pixel points in the first backlight image are in one-to-one correspondence with the backlight unit in the backlight array, and the backlight array is configured to provide backlight for displaying the image to be processed;

Dividing pixel points of the first backlight image according to a position attribute of a pixel to obtain a plurality of regions of the first backlight image;

Filtering and amplifying the images of the plurality of regions to obtain a second backlight image having the same resolution as the image to be processed, wherein when filtering the images of the plurality of regions, the plurality of regions Images of at least two of the regions are applied with different spatial filtering;

And performing pixel compensation on the image to be processed according to the brightness value of the second backlight image.
The method according to claim 1, wherein the dividing the pixel points of the first backlight image to obtain the plurality of regions of the first backlight image according to the position attribute of the pixel point comprises:

Dividing a pixel point position having 8 adjacent pixel points into the first area;

Dividing a pixel point position having 5 adjacent pixel points into a second area;

A pixel point position having 3 adjacent pixel points is divided into a third area.
The method according to claim 1 or 2, wherein the pixel compensation of the image to be processed according to the brightness value of the second backlight image comprises:

Obtaining, from the image to be processed, a first brightness value of any one of the pixel points;

Obtaining, from the second backlight image, a second brightness value of a pixel point corresponding to the position of the arbitrary one of the pixels;

Obtaining a maximum brightness value, where the maximum brightness value is a brightness upper limit value of the second backlight image or a brightness upper limit value that the backlight unit can display;

Determining a compensation coefficient of the arbitrary one of the pixel points according to the maximum brightness value and the second brightness value;

And compensating, according to the compensation coefficient, a first brightness value of the arbitrary one of the pixel points to obtain a target brightness value of the arbitrary one of the pixel points.
The method according to claim 3, wherein the first brightness value of the arbitrary one of the pixel points is compensated according to the compensation coefficient to obtain a target brightness value of the arbitrary one of the pixel points, including :

The product of the first brightness value and the compensation coefficient is determined as the target brightness value of the arbitrary one of the pixel points.
The method of claim 3 or 4, wherein the compensation coefficient is obtained according to the following formula:

K=log 2 (BL max /BL) 1.0/γ

Where K is the compensation coefficient, BL max is the maximum brightness value, BL is the second brightness value, and γ is a preset gamma coefficient.
The method according to any one of claims 3-5, wherein when the image format of the image to be processed is RGB, the acquiring the first brightness value of any one of the pixels to be processed ,include:

Determining a maximum component value of the three component values of any one of the pixel points as the first brightness value;

or,

The first brightness value is calculated based on three component values of any one of the pixel points.
A pixel compensation device, comprising:

An acquiring module, configured to acquire a first backlight image of the image to be processed, where the pixel points in the first backlight image are in one-to-one correspondence with the backlight unit in the backlight array, and the backlight array is configured to provide the image to be processed Backlight

a processing module, configured to divide a pixel of the first backlight image according to a position attribute of a pixel to obtain a plurality of regions of the first backlight image;

The processing module is further configured to separately filter and enlarge images of the plurality of regions to obtain a second backlight image having the same resolution as the image to be processed, wherein the images in the plurality of regions are When filtering is performed, images of at least two of the plurality of regions are applied with different spatial filtering;

a pixel compensation module, configured to perform pixel compensation on the image to be processed according to the brightness value of the second backlight image.
The device according to claim 7, wherein the processing module is specifically configured to:

Dividing a pixel point position having 8 adjacent pixel points into the first area;

Dividing a pixel point position having 5 adjacent pixel points into a second area;

A pixel point position having 3 adjacent pixel points is divided into a third area.
The device according to claim 7 or 8, wherein the pixel compensation module is specifically configured to:

Obtaining, from the image to be processed, a first brightness value of any one of the pixel points;

Obtaining, from the second backlight image, a second brightness value of a pixel point corresponding to the position of the arbitrary one of the pixels;

Obtaining a maximum brightness value, where the maximum brightness value is a brightness upper limit value of the second backlight image or a brightness upper limit value that the backlight unit can display;

Determining a compensation coefficient of the arbitrary one of the pixel points according to the maximum brightness value and the second brightness value;

And compensating, according to the compensation coefficient, a first brightness value of the arbitrary one of the pixel points to obtain a target brightness value of the arbitrary one of the pixel points.
The device according to claim 9, wherein the pixel compensation module is specifically configured to:

The product of the first brightness value and the compensation coefficient is determined as the target brightness value of the arbitrary one of the pixel points.
The device according to claim 9 or 10, characterized in that the compensation coefficient is obtained according to the following formula:

K=log 2 (BL max /BL) 1.0/γ

Where K is the compensation coefficient, BL max is the maximum brightness value, BL is the second brightness value, and γ is a preset gamma coefficient.
The device according to any one of claims 9-11, wherein the acquisition module is specifically configured to:

Determining a maximum component value of the three component values of any one of the pixel points as the first brightness value;

or,

The first brightness value is calculated based on three component values of any one of the pixel points.
A terminal device, comprising: the pixel compensation device according to any one of claims 7 to 12, and a display, wherein the display is configured to display the pixel compensation device to the Process the image for pixel compensated images.