Liquid crystal screen backlight partition dynamic adjusting system for enhancing picture contrast

Abstract

The invention relates to the technical field of liquid crystal display screen brightness adjustment, in particular to a liquid crystal display screen backlight partition dynamic adjustment system capable of enhancing picture contrast. The system comprises the steps of obtaining an image currently displayed by a liquid crystal screen, enhancing the local contrast of the image, determining a brightness influence coefficient equation of each partition according to an established backlight model, solving the brightness influence coefficient equation based on an optimization algorithm, determining a brightness influence coefficient of each partition, and displaying the brightness influence coefficient of each partition. And solving the brightness influence coefficient equation based on an optimization algorithm, determining the brightness influence coefficient of each partition, and adjusting the backlight brightness of the partitions based on a regional dynamic dimming algorithm. According to the invention, the brightness of each backlight subarea can be adjusted in real time according to the image content, so that black and white in the picture are darker, the contrast ratio is obviously improved, the backlight brightness is intelligently adjusted according to the brightness and color distribution of the image content, and unnecessary energy consumption is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of liquid crystal display screen brightness adjustment, and in particular to a liquid crystal screen backlight partition dynamic adjustment system for enhancing picture contrast. Background Art

[0002] Traditional LCD TVs use global backlight technology, that is, there is only one backlight area behind the entire screen, which cannot handle the brightness and blackness of different areas on the screen well. This results in light pollution in the brighter areas of the screen when displaying dark scenes, resulting in loss of dark details, reduced contrast, and reduced picture quality.

[0003] Zoning backlight technology is a TV technology that divides the backlight behind the screen into multiple zones, each of which can be controlled individually. In this way, after receiving the signal, the system can control the switch or brightness of the zone backlight according to the different light and dark scenes in each place. When displaying a dark scene, the backlight of the corresponding area will reduce the brightness or even turn off, and when displaying a bright scene, the backlight will turn on or increase the brightness accordingly. This technology can make the black in the picture darker, the white whiter, the contrast higher, and the picture more colorful.

[0004] In the prior art, there is no liquid crystal screen backlight partition dynamic adjustment system for enhancing picture contrast. Summary of the invention

[0005] The purpose of the present invention is to provide a dynamic adjustment system for the backlight partitions of a liquid crystal screen for enhancing the contrast of the picture: to solve the technical problem that when traditional liquid crystal displays extract image brightness information and calculate backlight adjustment parameters, there may be certain errors and limitations, resulting in inaccurate backlight adjustment and affecting the effect of improving picture quality.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A dynamic backlight partition adjustment system for LCD screens to enhance picture contrast, the system comprising an image enhancement module, a brightness influence coefficient calculation module, a partition backlight brightness calculation module and a partition backlight brightness adjustment module;

[0008] An image enhancement module is used to obtain the image currently displayed on the LCD screen, divide the image into several sub-block partitions, perform histogram statistics on each sub-block partition to obtain a histogram of each sub-block partition, determine a clipping point of the histogram of each sub-block partition and clip the histogram based on the clipping point, and enhance the local contrast of the image based on the clipped histogram;

[0009] A brightness influence coefficient calculation module is used to determine the brightness influence coefficient equations of N×M partitions according to the established backlight model, solve the brightness influence coefficient equations based on the optimization algorithm, and determine the brightness influence coefficients of the N×M partitions;

[0010] A partition backlight brightness calculation module is used to determine the partition backlight brightness of each partition based on the brightness influence coefficient;

[0011] The zone backlight brightness adjustment module is used to adjust the zone backlight brightness based on the regional dynamic dimming algorithm.

[0012] Furthermore, determining the clipping point of the histogram of each sub-block partition and clipping the histogram based on the clipping point specifically includes the following process:

[0013] Get the total number of pixels T of the histogram of each sub-block partition. For each gray level l, if h(l) is greater than the clipping point C, h(l) will be reduced to C, and the excess h(l)-C will be evenly distributed to other gray levels, where h(l) represents the number of pixels with gray level l in the sub-block partition, and the clipping point C is expressed as:

[0014]

[0015] Wherein, P is the preset proportional coefficient.

[0016] Furthermore, enhancing the local contrast of the image based on the cropped histogram specifically includes the following process:

[0017] Based on the standard deviation and average pixel value of each block, the dynamic clipping point C is calculated. 1 :

[0018]

[0019] Among them, σ is the standard deviation of the pixel value of the block, Avg is the average pixel value of the block, c is a constant, and L max is the maximum pixel value of the block, R represents the overall dynamic range of the image, and G is the parameter that controls the dynamic range and entropy weight;

[0020] In the block area with rich texture, a high clipping point C is assigned 1 , to enhance the details and contrast of the area;

[0021] In areas with less texture, assign a low clip point C 1 , to avoid artifacts and over-enhancement.

[0022] Furthermore, determining the brightness influence coefficient equations of the N×M partitions according to the established backlight model specifically includes the following process:

[0023] Backlight model: LCD screen backlight brightness control model consisting of N groups of independently controlled LED light strings on the short side and N groups of independently drawn LED light strings on the long side;

[0024] Construct the brightness influence coefficient equation of N×M partitions:

[0025] L BL (i, j) = L 1 *X 1 (i, j)+L 2 *X 2 (i,j)+...+L (N×M)×2 *X (N×M)×2 (i, j);

[0026] Among them, L BL (i, j) backlight brightness of the partition, L 1 , L 2 , ..., L (N×M)×2 are the brightness of the 1st, 2nd, ..., (N×M)×2 LED light strings, X 1 (i, j), X 2 (i, j), ..., X (N×M)×2 (i, j) is the brightness influence coefficient for the (i, j)th partition, i ranges from [1, N], and j ranges from [1, M].

[0027] Furthermore, solving the brightness influence coefficient equation based on the optimization algorithm and determining the brightness influence coefficients of the N×M partitions specifically includes the following process:

[0028] Establish the optimization algorithm formula:

[0029]

[0030] Among them, I i is the maximum brightness of 1, 2, ..., (N×M)×2 LED light strings, I i，j represents the brightness of the i-th LED string assigned to the j-th block, min represents the minimum value operation, S g The brightness attenuation value from the i-th LED string to the j-th block.

[0031] Furthermore, adjusting the zone backlight brightness based on the zone dynamic dimming algorithm specifically includes the following process:

[0032]

[0033] Among them, PL full Indicates the pixel value of the grayscale image currently displayed on the LCD screen, BL full Indicates the maximum brightness value of the backlight source without adjustment by the regional dynamic dimming algorithm, PLzz Indicates the pixel size after linear compensation based on the regional dynamic dimming algorithm, BL zz Indicates the backlight brightness after adjustment by the regional dynamic dimming algorithm.

[0034] Furthermore, the electrical specifications of the LED light string are 24V, 40mA.

[0035] Furthermore, the zone backlight brightness adjustment module supports 12-way OWC signal output, 288-zone dimming, develops an SPI interface with a frequency of 25MHz, obtains brightness information from the main board, supports calculation of mixed modes based on brightness settings, supports VLED feedback signal control, and supports black frame embedding and scanning functions.

[0036] Compared with the existing solutions, the present invention achieves the following beneficial effects:

[0037] The present invention adjusts the brightness of each backlight partition in real time according to the image content, so that the black in the picture is darker and the white is whiter, thereby significantly improving the contrast.

[0038] Furthermore, the backlight brightness is intelligently adjusted according to the brightness and color distribution of the image content to avoid unnecessary energy consumption. When displaying dark scenes or static images, the system can reduce the backlight brightness or even turn off some backlight partitions to reduce overall energy consumption.

[0039] Furthermore, visual fatigue is reduced: the zone-based dynamic brightness control can automatically adjust the screen brightness according to the ambient light and image content, reducing screen stimulation to the eyes and reducing visual fatigue caused by long-term screen viewing. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is a system block diagram of a liquid crystal screen backlight partition dynamic adjustment system for enhancing picture contrast according to an embodiment of the present invention;

[0042] Figure 2 The present invention is a flowchart of a system for dynamically adjusting the backlight partitions of a liquid crystal screen for enhancing the picture contrast according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, well-known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0045] This embodiment provides a liquid crystal screen backlight partition dynamic adjustment system for enhancing picture contrast. Figure 1 : is a system block diagram of a liquid crystal screen backlight partition dynamic adjustment system for enhancing picture contrast according to an embodiment of the present invention. Figure 1 As shown, the system includes an image enhancement module, a brightness influence coefficient calculation module, a partition backlight brightness calculation module and a partition backlight brightness adjustment module;

[0046] An image enhancement module is used to obtain the image currently displayed on the LCD screen, divide the image into several sub-block partitions, perform histogram statistics on each sub-block partition to obtain a histogram of each sub-block partition, determine a clipping point of the histogram of each sub-block partition and clip the histogram based on the clipping point, and enhance the local contrast of the image based on the clipped histogram;

[0047] A brightness influence coefficient calculation module is used to determine the brightness influence coefficient equations of N×M partitions according to the established backlight model, solve the brightness influence coefficient equations based on the optimization algorithm, and determine the brightness influence coefficients of the N×M partitions;

[0048] A partition backlight brightness calculation module is used to determine the partition backlight brightness of each partition based on the brightness influence coefficient;

[0049] The zone backlight brightness adjustment module is used to adjust the zone backlight brightness based on the regional dynamic dimming algorithm.

[0050] In summary, the present invention obtains the image currently displayed on the liquid crystal screen, and enhances the local contrast of the image, determines the brightness influence coefficient equation of N×M partitions according to the established backlight model, solves the brightness influence coefficient equation based on the optimization algorithm, determines the brightness influence coefficient of N×M partitions, solves the brightness influence coefficient equation based on the optimization algorithm, determines the brightness influence coefficient of N×M partitions, and adjusts the partition backlight brightness based on the regional dynamic dimming algorithm. It can adjust the brightness of each backlight partition in real time according to the image content, so that the black in the picture is darker and the white is whiter, thereby significantly improving the contrast. According to the brightness and color distribution of the image content, the backlight brightness is intelligently adjusted to avoid unnecessary energy consumption. When displaying dark scenes or static images, the system can reduce the backlight brightness or even turn off some backlight partitions, thereby reducing overall energy consumption. The regional dynamic brightness control can automatically adjust the screen brightness according to the ambient light and image content, reduce the stimulation of the screen to the eyes, and reduce the visual fatigue caused by watching the screen for a long time.

[0051] In some embodiments, determining the clipping point of the histogram of each sub-block partition and clipping the histogram based on the clipping point specifically includes the following process:

[0052] Get the total number of pixels T of the histogram of each sub-block partition. For each gray level l, if h(l) is greater than the clipping point C, h(l) will be reduced to C, and the excess h(l)-C will be evenly distributed to other gray levels, where h(l) represents the number of pixels with gray level l in the sub-block partition, and the clipping point C is expressed as:

[0053]

[0054] Wherein, P is the preset proportional coefficient.

[0055] In some embodiments, Figure 2 FIG. 1 is a flowchart of a system for dynamically adjusting backlight partitions of a liquid crystal screen for enhancing picture contrast according to an embodiment of the present invention. Figure 2 As shown, enhancing the local contrast of an image based on the cropped histogram specifically includes the following steps:

[0056] Step 1: Calculate the dynamic clipping point C based on the standard deviation and average pixel value of each block 1 :

[0057]

[0058] Among them, σ is the standard deviation of the pixel value of the block, Avg is the average pixel value of the block, c is a constant, and L max is the maximum pixel value of the block, R represents the overall dynamic range value of the image, and G is the parameter that controls the dynamic range and entropy term weight;

[0059] Step 2: In the block area with rich texture, a higher clipping point C will be assigned 1 , to enhance the details and contrast of the area;

[0060] Step 3: Assign a lower clipping point C to areas with less texture. 1 , to avoid artifacts and over-enhancement.

[0061] In some embodiments, determining the brightness influence coefficient equations of N×M partitions according to the established backlight model specifically includes the following process:

[0062] Backlight model: LCD screen backlight brightness control model consisting of N groups of independently controlled LED light strings on the short side and N groups of independently drawn LED light strings on the long side;

[0063] Construct the brightness influence coefficient equation of N×M partitions:

[0064] L BL (i, j) = L 1 *X 1 (i, j)+L 2 *X 2 (i,j)+...+L (N×M)×2 *X (N×M)×2 (i, j);

[0065] Among them, L BL (i, j) backlight brightness of the partition, L 1 , L 2 , ..., L (N×M)×2 are the brightness of the 1st, 2nd, ..., (N×M)×2 LED light strings, X 1 (i, j), X 2 (i, j), ..., X (N×M)×2 (i, j) is the brightness influence coefficient for the (i, j)th partition, i ranges from [1, N], and j ranges from [1, M].

[0066] In some embodiments, solving the brightness influence coefficient equation based on the optimization algorithm to determine the brightness influence coefficients of the N×M partitions specifically includes the following process:

[0067] Establish the optimization algorithm formula:

[0068]

[0069] Among them, I i The maximum brightness of 1, 2, ..., (N×M)×2 LED light strings, l i，j represents the brightness of the i-th LED string assigned to the j-th block, min represents the minimum value operation, S gThe brightness attenuation value from the i-th LED string to the j-th block.

[0070] In some embodiments, adjusting the zone backlight brightness based on the zone dynamic dimming algorithm specifically includes the following process:

[0071]

[0072] Among them, PL full Indicates the pixel value of the grayscale image currently displayed on the LCD screen, BL full Indicates the maximum brightness value of the backlight source without adjustment by the regional dynamic dimming algorithm, PL zz Indicates the pixel size after linear compensation based on the regional dynamic dimming algorithm, BL zz Indicates the backlight brightness after adjustment by the regional dynamic dimming algorithm.

[0073] It is worth noting that the electrical specifications of the LED light string are 24V, 40mA. When using 24V high voltage LEDs, the constant current board does not need to perform voltage reduction processing, but directly outputs 24V voltage to power the LED through the power board and drives the LED with constant current through the constant current IC, which can save the 12V to 3.3V BUCK circuit of the constant current board. The driving current of the LED is reduced from 300mA to 40mA.

[0074] The zone backlight brightness adjustment module supports 12-way OWC signal output, 288-zone dimming, develops SPI interface, frequency is 25MHz, obtains brightness information from the main board, supports calculation of mixed mode based on brightness setting, supports VLED feedback signal control, and supports black field frame embedding and scanning functions.

[0075] Specifically, local dimming requires fast response processing provided by FPGA (Field-Programmable Gate Array) to analyze content, adjust backlight areas, and control LED brightness. Through the development of ARTIX-7 chip, the FPGA chip provides the computing power required to run these complex algorithms, and streams 4K / 60 video to FPGA through the VBY ONE interface. The internal video scaler takes the video data and scales it up to 2160p (60Hz). At the same time, the local dimming function dynamically controls the full LED array backlight of the panel. The DisplayPort transmitter IP then takes the amplified video and streams it to the 4K pixel panel in HBR2 (4-channel) format. Finally, the panel displays the video while the full LED array backlight is under continuous control.

[0076] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0077] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction 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 technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0078] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0079] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only some logical function divisions. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0080] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0081] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A dynamic adjustment system for LCD screen backlight partitions to enhance picture contrast, characterized in that: The system includes an image enhancement module, a brightness influence coefficient calculation module, a partition backlight brightness calculation module and a partition backlight brightness adjustment module; An image enhancement module is used to obtain the image currently displayed on the LCD screen, divide the image into several sub-block partitions, perform histogram statistics on each sub-block partition to obtain a histogram of each sub-block partition, determine a clipping point of the histogram of each sub-block partition and clip the histogram based on the clipping point, and enhance the local contrast of the image based on the clipped histogram; A brightness influence coefficient calculation module is used to determine the brightness influence coefficient equations of N×M partitions according to the established backlight model, solve the brightness influence coefficient equations based on the optimization algorithm, and determine the brightness influence coefficients of the N×M partitions; A partition backlight brightness calculation module is used to determine the partition backlight brightness of each partition based on the brightness influence coefficient; The zone backlight brightness adjustment module is used to adjust the zone backlight brightness based on the regional dynamic dimming algorithm.

2. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 1 is characterized in that: Determine the clipping point of the histogram of each sub-block partition and clip the histogram based on the clipping point The process includes: Get the total number of pixels T of the histogram of each sub-block partition. For each gray level l, if h(l) is greater than the clipping point C, h(l) will be reduced to C, and the excess h(l)-C will be evenly distributed to other gray levels, where h(l) represents the number of pixels with gray level l in the sub-block partition, and the clipping point C is expressed as: Wherein, P is the preset proportional coefficient.

3. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 1 is characterized in that: The local contrast enhancement of the image based on the cropped histogram specifically includes the following processes: Based on the standard deviation and average pixel value of each block, the dynamic clipping point C1 is calculated: Among them, σ is the standard deviation of the pixel value of the block, Avg is the average pixel value of the block, c is a constant, and L max is the maximum pixel value of the block, R represents the overall dynamic range of the image, and G is the parameter that controls the dynamic range and entropy weight; In the block area with rich texture, a high clipping point C1 is assigned to enhance the details and contrast of the area; In areas with little texture, a low clipping point C1 is assigned to avoid artifacts and over-enhancement.

4. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 1 is characterized in that: According to the established backlight model, the brightness influence coefficient equation of N×M partitions is determined specifically The process includes: Backlight model: LCD screen backlight brightness control model consisting of N groups of independently controlled LED light strings on the short side and N groups of independently drawn LED light strings on the long side; Construct the brightness influence coefficient equation of N×M partitions: L BL (i,j)=L1*X1(i,j)+L2*X2(i,j)+...+L (N×M)×2 *X (N×M)×2 (i,j); Among them, L BL (i, j) backlight brightness of the partition, L1, L2, ..., L (N×M)×2 are the brightness of the 1st, 2nd, ..., (N×M)×2 LED light strings, X1(i, j), X2(i, j), ..., X (N×M)×2 (i, j) is the brightness influence coefficient for the (i, j)th partition, i ranges from [1, N], and j ranges from [1, M].

5. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 4 is characterized in that: Solving the brightness influence coefficient equation based on the optimization algorithm and determining the brightness influence coefficients of N×M partitions specifically includes the following process: Establish the optimization algorithm formula: Among them, I i The maximum brightness of 1, 2, ..., (N×M)×2 LED light strings, l i，j represents the brightness of the i-th LED string assigned to the j-th block, min represents the minimum value operation, S g The brightness attenuation value from the i-th LED string to the j-th block.

6. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 1 is characterized in that: Adjusting the zone backlight brightness based on the regional dynamic dimming algorithm specifically includes the following processes: Among them, PL full Indicates the pixel value of the grayscale image currently displayed on the LCD screen, BL full Indicates the maximum brightness value of the backlight source without adjustment by the regional dynamic dimming algorithm, PL zz Indicates the pixel size after linear compensation based on the regional dynamic dimming algorithm, BL zz Indicates the backlight brightness after adjustment by the regional dynamic dimming algorithm.

7. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 1 is characterized in that: The electrical specifications of the LED light string are 24V, 40mA.

8. The LCD screen backlight partition dynamic adjustment system for enhancing picture contrast according to claim 1 is characterized in that: The zone backlight brightness adjustment module supports 12-way OWC signal output, 288-zone dimming, develops SPI interface, frequency is 25MHz, obtains brightness information from the main board, supports calculation of mixed mode based on brightness setting, supports VLED feedback signal control, and supports black field frame embedding and scanning functions.

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