Mini LED area dynamic dimming method

Abstract

The application discloses a Mini LED area dynamic light adjusting method, comprising the following steps: step 1, obtaining a gray image of a current frame image and determining a backlight partition of a Mini LED; carrying out a viewpoint tracking to obtain a gaze point of each backlight partition on a Mini LED backlight panel; step 2, based on a human eye foveal vision characteristic, each backlight partition is divided into a gaze area and a peripheral area respectively; the initial maximum backlight value and the initial average backlight value of the gaze area and the peripheral area are calculated; step 3, based on a human eye foveal visual sensitivity characteristic curve, a correction coefficient is determined, and the initial maximum backlight value of the gaze area and the initial average backlight value of the peripheral area are corrected by using the correction coefficient to obtain a final backlight value; step 4, based on the final backlight value of the gaze area and the peripheral area, the backlight value of the corresponding backlight partition is adjusted. The application can reduce the visual error of display and improve the human eye visual effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of liquid crystal display dimming method, and particularly to a MiniLED regional dynamic dimming method. BACKGROUND

[0002] In recent years, with the continuous innovation of display technology, liquid crystal display has been widely used in flat panel display field, and LCD display technology is becoming more and more mature. LED backlight is gradually developing towards smaller pitch, and Mini-LED backlight technology is developing rapidly. Compared with traditional LED backlight, Mini-LED lamp beads are smaller, which can integrate more lamp beads in the same size, thereby realizing more backlight partition and more precise control of partitioned backlight. The reaction is faster, the power consumption is lower, and the display brightness and contrast can be effectively improved.

[0003] In order to make the display have lower energy consumption and higher display effect, the dynamic dimming algorithm is also very important. The dynamic dimming algorithm is divided into global dynamic dimming algorithm and regional dynamic dimming algorithm. At present, regional dynamic backlight technology is the forefront of dynamic dimming technology research. Regional dimming can be controlled individually according to different regions to realize more precise control of backlight and further reduce the power consumption of the display.

[0004] The display effect of an image is not only related to objective evaluation indexes, but also closely related to human visual sensory effect. PSNR, SSIM and information entropy are the current mainstream objective evaluation indexes. Through the characteristic analysis of the image, a mathematical model is constructed to calculate the quantitative value to evaluate the display image. However, in image display, the subjective feeling of the human eye is the direct manifestation of the image display quality, and the subjective quality scoring method is the most representative evaluation method for image quality. The backlight control algorithm based on image features has gradually become popular in the field of backlight control. The features that the human eye is more sensitive to, such as brightness and texture, are selected, and the display effect is optimized for different features. However, the image content information extracted by this dimming method is not necessarily the information that the human eye is interested in in real time. It is only a prediction of the region of interest and then processing. Therefore, a backlight control method for dynamic dimming according to the real-time focus of the human eye is invented to improve the display effect and reduce the energy consumption to the greatest extent on the basis of ensuring the subjective visual effect of the human eye.

[0005] The existing dimming methods based on image content and features are all for predicting the direction of information that the human eye may be interested in. According to the prediction result, the information content with high visual attention in the image, such as edge, texture and brightness, is obtained, and then the dynamic dimming algorithm is used for backlight control. However, in actual image viewing, due to different users and different environmental information, the above method may have a large visual error. SUMMARY

[0006] The MiniLED area dynamic light adjustment method provided by the application can solve the problem of large error vision in the prior art MiniLED area dynamic light adjustment method.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the application is:

[0008] A MiniLED area dynamic light adjustment method, comprising the following steps:

[0009] Step 1, obtaining the current frame image of MiniLED display and converting it into a gray scale image, and determining the backlight partition of the MiniLED backlight panel;

[0010] Tracking the viewpoint of the current frame image, and matching the viewpoint tracking result to the MiniLED backlight panel, so as to obtain the backlight partition where each fixation point is located in the MiniLED backlight panel;

[0011] Step 2, based on the foveal vision characteristics of the human eye, taking the fixation point as the center of the field of view in each backlight partition of the MiniLED backlight panel, dividing the area within the θ angle around the center of the field of view into the fixation area B1, and dividing the area outside the θ angle around the center of the field of view into the peripheral area B2, wherein the value range of θ angle is 5°-15°;

[0012] Based on the luminance value and the gray value of the pixel points in the corresponding part of each backlight partition in the gray scale image, the maximum value method and the average value method are used to calculate the initial maximum backlight value BL1 max , the initial average backlight value BL1 ave of the fixation area B1 of each backlight partition, and the initial maximum backlight value BL2 max , the initial average backlight value BL2 ave of the peripheral area B2 of each backlight partition;

[0013] Step 3, based on the foveal visual sensitivity characteristic curve of the human eye, determining the correction coefficient ω;

[0014] Using the correction coefficient ω to correct the initial maximum backlight value BL1 max of the fixation area B1 of each backlight partition obtained in step 2, and taking the correction result as the final backlight value BL1 of the fixation area B1 of each backlight partition;

[0015] Using the correction coefficient ω to correct the initial average backlight value BL2 ave of the peripheral area B2 of each backlight partition obtained in step 2, and taking the correction result as the final backlight value BL2 of the peripheral area B2 of each backlight partition;

[0016] Step 4, based on the final backlight value BL1 of each backlight partition gaze area B1 and the final backlight value BL2 of the peripheral area B2 obtained in step 3, adjust the backlight value of the corresponding backlight partition.

[0017] In further step 1, the eye tracker is used to track the user's viewing point of the current frame image, and the gaze point of the human eye in the current frame image is obtained. The gaze point position of the human eye in the current frame image is matched to the MiniLED backlight panel, and the backlight partition where the gaze point is located is obtained in the MiniLED backlight panel.

[0018] In further step 2, when calculating the initial maximum backlight value of each backlight partition gaze area B1 or peripheral area B2 using the maximum value method, the value of the channel with the maximum luminance information in the R, G, and B channels of each pixel point in the corresponding part of the grayscale image of each backlight partition gaze area B1 or peripheral area B2 is taken as the luminance value of the pixel point. Then, the maximum value of the luminance values of the pixel points in the gaze area B1 or the peripheral area B2 is taken as the initial maximum backlight value of the gaze area B1 or the peripheral area B2.

[0019] In further step 2, when calculating the initial average backlight value of each backlight partition gaze area B1 or peripheral area B2 using the average value method, the grayscale values of the pixel points in the corresponding part of the grayscale image of each backlight partition gaze area B1 or peripheral area B2 are added and averaged to obtain the result as the initial average backlight value of the gaze area B1 or the peripheral area B2.

[0020] In further step 3, the central foveal visual acuity characteristic curve of the human eye is as follows:

[0021] A(θ) = 2.5 / (θ + 2.5),

[0022] Substitute the θ angle used to divide the gaze area B1 and the peripheral area B2 in each backlight partition into the above formula, and the calculated A(θ) is the correction coefficient ω.

[0023] In further step 4, based on the final backlight value BL1 of each backlight partition gaze area B1 and the final backlight value BL2 of the peripheral area B2, the backlight module modulation factor K of the corresponding backlight partition is determined. The pulse width modulation PWM signal of the backlight LED in the corresponding backlight module of each backlight partition is set according to the backlight module modulation factor K, and is sent to the LED drive module of the corresponding backlight module, thereby completing the adjustment of the backlight value of the corresponding backlight partition.

[0024] Further step 4 also includes: obtaining the pixel compensation factor for each pixel in each backlight partition based on the final backlight value BL1 of the viewing area B1 and the final backlight value BL2 of the peripheral area B2, and compensating each pixel in the MiniLED display image according to the pixel compensation factor of each pixel.

[0025] This invention reduces visual errors and improves visual effects by analyzing the real-time gaze point of the human eye on the display screen and dynamically adjusting the brightness according to the foveal visual characteristics of the human eye. Furthermore, it also reduces energy consumption while optimizing the display effect. Attached Figure Description

[0026] Figure 1 This is a flowchart of the method according to an embodiment of the present invention.

[0027] Figure 2 This is a graph showing the sensitivity characteristics of the human eye's fovea in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the human eye viewing an image in an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the MiniLED backlight panel partitioning in an embodiment of the present invention. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] like Figure 1 As shown, this embodiment discloses a method for dynamic dimming of a MiniLED area, including the following steps:

[0032] Step 1: Obtain the current frame image of the MiniLED display and convert it to grayscale, and determine the backlight partition of the MiniLED backlight panel; perform viewpoint tracking on the current frame image and match the viewpoint tracking results to the MiniLED backlight panel, thereby obtaining the backlight partition where each gaze point is located on the MiniLED backlight panel.

[0033] In this embodiment, an eye tracker is used to track the user's viewpoint when observing the current frame image. Based on the angle at which the user views the current frame image, the eye tracker tracks the user's viewpoint in the current frame image to determine the user's fixation point. The fixation point of the human eye in the current frame image is then matched to the corresponding point on the MiniLED backlight panel, thereby completing the matching of the viewpoint tracking result to the backlight panel, and obtaining the backlight zone where the current fixation point of the human eye is located on the backlight panel.

[0034] Step 2, based on the human foveal vision characteristics, the gaze point is taken as the center of the field of view of each backlight partition of the MiniLED backlight panel, the area within the θ angle around the center of the field of view is divided into the gaze area B1, and the area outside the θ angle around the center of the field of view is divided into the peripheral area B2, wherein the value range of the θ angle is 5°-15°.

[0035] The human foveal vision characteristics show that the highest range of the acuity factor of the human eye at the foveal vision is only 5° field of view, the resolution of the periphery decreases in a decreasing trend, the resolution at 5° around the center of the field of view is about one third of the highest resolution, and the resolution at 10° around the center of the field of view is about one fifth of the highest resolution. According to this principle, the θ angle in the range of 5°-10° is taken in the embodiment, the area within the θ angle around the center of the field of view of each backlight partition is divided into the gaze area B1, and the area outside the θ angle around the center of the field of view is divided into the peripheral area B2.

[0036] As shown in Figure 3 , Figure 4 , in the embodiment, according to the vertical distance L between the human eye and the screen, the θ angle corresponding to each backlight partition is calculated according to the distance L, 10° within the central gaze point is taken as the gaze B1, and 10° outside is taken as the peripheral area B2.

[0037] Based on the luminance value and the gray value of the pixel points of the corresponding part of each backlight partition in the gray scale diagram, the maximum value method and the average value method are used to calculate the initial maximum backlight value BL1 max of the gaze area B1 of each backlight partition, the initial average backlight value BL1 ave , and the initial maximum backlight value BL2 max of the peripheral area B2 of each backlight partition, and the initial average backlight value BL2 ave .

[0038] In the embodiment, the resolution of the current frame image in step 1 is 1920×1080, and the image with the resolution of 1920×1080 is converted into a gray scale image. As shown in Figure 4 , according to the number of backlight partitions 64×32 of the MiniLED backlight module, the number of pixels of the corresponding part of each backlight partition in the gray scale image is 30×33 or 30×34.

[0039] When the maximum value method is used to calculate the initial maximum backlight value of the gaze area B1 and the peripheral area B2 of each backlight partition, based on the sub-pixel method, the value of the channel with the maximum luminance information in the R, G, B three channels of each pixel point is taken as the luminance value of the pixel point, and the maximum value in the luminance values of the pixel points of the gaze area B1 or the peripheral area B2 of each backlight partition is taken as the initial maximum backlight value BL max, the calculation formula is as follows:

[0040] BL max (i,j)=Max(Max(R(i,j),G(i.j),B(i,j))) (1),

[0041] Where i, j represent the i-th row and j-th column pixel in the image, R(i,j), G(i,j), and B(i,j) represent the R, G, and B channel pixel values of the pixel point, respectively.

[0042] When calculating the initial average backlight value of each backlight partition gaze area B1 and peripheral area B2 using the average method, the gray values of each pixel point in each backlight partition are accumulated, and the average value is taken as the initial average backlight BL ave of the backlight partition gaze area B1 or peripheral area B2.

[0043]

[0044] Where i, j represent the i-th row and j-th column pixel in the image, L gray (i,j) represents the luminance value of the pixel point in the gray scale image, M and N represent the rows and columns of different partitions.

[0045] According to formulas (1) and (2), the initial maximum backlight value BL1 max , the initial average backlight value BL1 ave of each backlight partition gaze area B1, and the initial maximum backlight value BL2 max , the initial average backlight value BL2 ave of each backlight partition peripheral area B2 can be calculated.

[0046] Step 3, determine the correction coefficient ω based on the central foveal visual sensitivity characteristic curve of the human eye.

[0047] The ω correction coefficient is determined according to the central foveal visual sensitivity characteristic curve of the human eye. According to the distance between the human eye and the screen, the distance between the backlight partition and the gaze point, and the visual sensitivity angle, the ω value corresponding to different partitions is calculated. The central foveal visual sensitivity characteristic curve of the human eye in this embodiment is shown in Figure 2 , and the central foveal visual sensitivity characteristic curve of the human eye is as follows:

[0048] A(θ)=2.5 / (θ+2.5) (3),

[0049] Substituting the angle θ of each backlight zone into formula (3), the calculated A(θ) is the correction coefficient ω. Taking the distance L from the human eye to the screen as an example, the backlight zone at a distance of 4.4cm from the center fixation point corresponds to 5° in the fovea region, that is, the angle θ is 5°. According to the sensitivity curve A(θ)=2.5 / (θ+2.5), the fovea sensitivity coefficient A(θ) corresponding to 5° is the correction coefficient ω of that backlight zone.

[0050] In this embodiment, for the fixation area B1 of each backlight zone, error correction is performed based on the maximum value of the correction coefficient ω. Combined with the foveal visual acuity curve of the human eye, the visual characteristics of the fixation area are largely preserved. Meanwhile, since the peripheral area B2 of each backlight zone is a non-fixation area, this embodiment performs error correction based on the average value of the correction coefficient ω. This allows for the appropriate ignoring of some detailed information in the non-fixation area, thereby reducing energy consumption.

[0051] Specifically, the initial maximum backlight value BL1 of each backlight zone viewing area B1 obtained in step 2 is adjusted using the correction coefficient ω. max The formula has been revised as follows:

[0052] BL1 = BL1 max +ω×BL correction

[0053] The corrected result BL1 is the final backlight value of the viewing area B1 for each backlight zone.

[0054] The initial average backlight value BL2 of the peripheral region B2 of each backlight partition obtained in step 2 is adjusted using the correction factor ω. ave The formula has been revised as follows:

[0055] BL2 = BL2 ave -ω×BL correction

[0056] The corrected result BL2 is the final backlight value of the outer region B2 of each backlight zone.

[0057] In formulas (4) and (5): BL correction Here are the correction parameters corresponding to the dimming area, and we have:

[0058]

[0059] BL diff =BL max -BL ave (7),

[0060] Among them, BL maxFor regional dimming, the maximum gray value of the current region extracted by real-time operation, BL ave For regional dimming, the average gray value of the current region extracted by real-time operation, BL diff For the maximum value of the dimming region gray BL max Difference from the average BL ave .

[0061] Step 4, based on the final backlight value BL1 of each backlight partition gaze region B1 and the final backlight value BL2 of the peripheral region B2 obtained in step 3, the obtained value is a 64x32 matrix, and the backlight value of the corresponding backlight partition is adjusted according to the obtained 64x32 backlight matrix.

[0062] Specifically, according to the 64x32 backlight matrix, the backlight module dimming factor K of the corresponding backlight partition is determined, the pulse width modulation PWM signal of the backlight LED in the backlight module corresponding to each backlight partition is set according to the backlight module dimming factor K, and is sent to the LED drive module of the corresponding backlight module, thereby completing the adjustment of the backlight value of the corresponding backlight partition.

[0063] Step 4 further includes: smoothing the above-mentioned 64x32 backlight brightness matrix by a commonly used method in the field of regional dimming, a blur mask-diffusion method BMA, to accurately obtain the backlight value corresponding to each pixel point on the liquid crystal panel, so as to obtain the pixel compensation factor of the pixel point at the corresponding position, and obtain the brightness adjustment signal of each pixel point according to the pixel compensation factor, and send it to the liquid crystal control module to finally display the image, thereby completing the compensation of each pixel point in the MiniLED display image.

[0064] The preferred embodiments of the present application are described in detail above in combination with the drawings, and the embodiments described in the present application are only used to describe the preferred embodiments of the present application, and do not limit the concept and scope of the present application. In the above specific embodiments, each specific technical feature described above can be combined in any appropriate manner without contradiction, and such combination shall be regarded as disclosed by the present disclosure as long as it does not deviate from the technical concept of the present application. In order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

[0065] The present application is not limited to the specific details in the above embodiments, and various modifications and improvements of the technical solutions of the present application made by those skilled in the art within the scope of the technical concept of the present application and without departing from the design idea of the present application shall fall within the protection scope of the present application. The technical content claimed by the present application has been fully recorded in the claims.

Claims

1. A Mini LED area dynamic dimming method, characterized in that, The method comprises the following steps: Step 1, obtaining the current frame image of the MiniLED display and converting it into a grayscale image, and determining the backlight partitions of the MiniLED backlight panel; Step 2, based on the foveal vision characteristics of the human eye, taking the gaze point as the center of the field of view in each backlight partition of the MiniLED backlight panel, dividing the region within the θ angle around the center of the field of view into the gaze region B1, and dividing the region outside the θ angle around the center of the field of view into the peripheral region B2, wherein the value range of θ angle is 5°-15°; Taking the correction result as the final backlight value BL1 of the gaze region B1 of each backlight partition; Based on the luminance value and the gray value of the pixel point corresponding to the part of the gray scale diagram of each backlight partition, the maximum value method and the average value method are used to calculate the initial maximum backlight value BL1 of the fixation area B1 of each backlight partition max , the initial average backlight value BL1 ave , and the initial maximum backlight value BL2 max , the initial average backlight value BL2 ave of the peripheral area B2 of each backlight partition; Step 3, determining a correction coefficient based on a human eye foveal visual acuity characteristic curve ; Using correction coefficients The initial maximum backlight value BL1 for each backlight zone viewing area B1 obtained in step 2. max The formula has been revised as follows: ， Taking the correction result as the final backlight value BL2 of the peripheral region B2 of each backlight partition; Using correction coefficients The initial average backlight value BL2 of the peripheral region B2 of each backlight partition obtained in step 2. ave The formula has been revised as follows: ， The foveal visual acuity characteristic curve of the human eye is as follows: The correction parameter corresponding to the dimming region is adjusted, and has: ， ， wherein, for area dimming, the maximum gray value of the current area extracted by real-time operation, for area dimming, the average gray value of the current area extracted by real-time operation, for dimming area gray maximum value of the sum of the squares of the differences between the values of the first and second signals difference from the mean difference from the mean Step 4, based on the final backlight value BL1 of the gaze region B1 and the final backlight value BL2 of the peripheral region B2 of each backlight partition obtained in step 3, adjusting the backlight value of the corresponding backlight partition. ， Substituting the θ angle for dividing the gaze region B1 and the peripheral region B2 in each backlight partition into the above formula, the calculated is the correction coefficient ; In step 1, the eye tracker is used to track the gaze point of the user observing the current frame image, and the gaze point of the human eye in the current frame image is obtained. The position of the gaze point of the human eye in the current frame image is matched to the MiniLED backlight panel, so that the gaze point of each backlight partition on the MiniLED backlight panel is obtained.

2. The Mini LED area dynamic dimming method of claim 1, wherein, In step 2, when calculating the initial maximum backlight value of each backlight partition gaze region B1 or peripheral region B2 using the maximum value method, the value of the channel with the maximum luminance information in the R, G, and B channels of each pixel point in the corresponding part of the grayscale image of each backlight partition gaze region B1 or peripheral region B2 is taken as the luminance value of the pixel point. Then, the maximum value among the luminance values of the pixel points of the gaze region B1 or the peripheral region B2 is taken as the initial maximum backlight value of the gaze region B1 or the peripheral region B2.

3. The Mini LED area dynamic dimming method of claim 1, wherein, In step 2, when calculating the initial average backlight value of each backlight partition gaze region B1 or peripheral region B2 using the average value method, the grayscale values of the pixel points in the corresponding part of the grayscale image of each backlight partition gaze region B1 or peripheral region B2 are added and averaged, and the result is taken as the initial average backlight value of the gaze region B1 or the peripheral region B2.

4. The Mini LED area dynamic dimming method of claim 1, wherein, In step 4, based on the final backlight value BL1 of the gaze region B1 and the final backlight value BL2 of the peripheral region B2 of each backlight partition, the backlight module light adjustment factor K of the corresponding backlight partition is determined. The pulse width modulation (PWM) signal of the backlight LED in the backlight module corresponding to each backlight partition is set according to the backlight module light adjustment factor K, and is sent to the LED driving module of the corresponding backlight module, thereby completing the adjustment of the backlight value of the corresponding backlight partition.

5. The Mini LED area dynamic dimming method of claim 1, wherein, ​ 6. The Mini LED area dynamic dimming method of claim 1, wherein, The step 4 further comprises: obtaining a pixel compensation factor of each pixel point in each backlight partition based on the final backlight value BL1 of each backlight partition gaze area B1 and the final backlight value BL2 of the peripheral area B2, and compensating each pixel point in the image displayed by the Mini LED display according to the pixel compensation factor of each pixel point.

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