Dynamically adaptive spatial smoothing method and system for local dimming

Abstract

A method for dynamically adapting to spatial smoothing includes determining a difference between a block duty cycle of a selected block of a current frame and a block duty cycle of a selected block of a previous frame, generating an original smoothing matrix of the selected block, generating a dynamic adaptation matrix according to the original smoothing matrix and the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame, updating the block duty cycle of each block by using the corresponding dynamic adaptation matrix to generate an updated frame, and performing spatial smoothing on the updated frame.

Description

Technical Field

[0001] The present invention relates to space smoothing, and in particular to a method and system for dynamically adaptive space smoothing. Background Art

[0002] Local dimming is a technology implemented in Light Emitting Diode (LED) TVs that improves contrast by dimming the backlight in specific areas of the screen, making the dark parts of the image appear darker while the bright parts of the image remain bright. This technology can improve the overall image quality, especially in dark scenes.

[0003] However, local dimming also comes with some disadvantages, including blooming, loss of detail in dark areas, and flicker. Blooming is a halo effect that can appear around bright objects in dark scenes. It is caused by the backlight not being dimmed perfectly, and some light leaking into the surrounding area. Loss of detail in dark areas can occur when the local dimming zone is too large. When a large area of ​​the screen is dimmed, details in the picture may be blurred. And if the local dimming algorithm is not implemented correctly, flickering may occur. When the backlight flickers at a high frequency, it can be irritating to the viewer. Summary of the invention

[0004] An embodiment of the present invention provides a method for dynamic adaptive spatial smoothing. The method includes determining the difference between the block duty cycle of a selected block of a current frame and the block duty cycle of a selected block of a previous frame, generating an original smoothing matrix for the selected block, generating a dynamic adaptive matrix based on the original smoothing matrix and the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame, updating the block duty cycle of each block using the corresponding dynamic adaptive matrix to generate an updated frame, and performing spatial smoothing on the updated frame.

[0005] Another embodiment of the present invention provides a dynamic adaptive spatial smoothing system, comprising a block duty cycle calculation module, a dynamic adaptive spatial smoothing module, and a final block duty cycle module. The block duty cycle calculation module is used to generate multiple block duty cycles of multiple blocks of a current frame and a previous frame. The dynamic adaptive spatial smoothing module is used to determine the difference between the block duty cycle of a selected block of multiple blocks of the current frame and the block duty cycle of a selected block of the previous frame, generate an original smoothing matrix of the selected block, and generate a dynamic adaptive matrix based on the original smoothing matrix and the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame. The final block duty cycle module is used to update the block duty cycle of each block using the corresponding dynamic adaptive matrix to generate an updated frame, and perform spatial smoothing on the updated frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1FIG. 4 is a schematic diagram of a dynamic adaptive spatial smoothing system for local dimming according to an embodiment of the present invention.

[0007] Figure 2 Reason Figure 1 Flowchart of the method implemented by the dynamic adaptive spatial smoothing module in.

[0008] Figure 3 Schematic diagram of the difference in block duty cycle between the current frame and the previous frame.

[0009] Figure 4A FIG. 4 is a schematic diagram of an original smoothing matrix according to an embodiment of the present invention.

[0010] Figure 4B Based on Figure 4A Schematic diagram of the dynamic adaptation matrix generated from the original smoothing matrix in .

[0011] Figure 5 FIG. 4 is a schematic diagram of a spatial smoothing filter according to an embodiment of the present invention.

[0012] Figure 6 FIG. 4 is a schematic diagram of a spatial smoothing filter according to another embodiment of the present invention.

[0013] The reference numerals are described as follows:

[0014] 100: Dynamic Adaptive Spatial Smoothing System

[0015] 102: Block duty cycle calculation module

[0016] 104: Dynamic Adaptive Spatial Smoothing Module

[0017] 106: Final block duty cycle module

[0018] 108: Backlight module

[0019] 200: Methods

[0020] S202-S210: Steps

[0021] 301, 302, 303: Blocks

[0022] W 11 -W 55 , W' 11 -W' 55 : Matrix elements

[0023] 501, 502, 601, 602: Curve DETAILED DESCRIPTION

[0024] The terms used in the description of the various embodiments described herein are only for the purpose of describing specific embodiments and are not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms "one", "an" and "the" are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "and / or" used herein refer to and encompass any and all possible combinations of one or more related listed items. It should also be understood that when the terms "include" and / or "comprising" are used in this specification, the existence of the stated features, integers, steps, operations, elements and / or components is specified, but the existence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof is not excluded.

[0025] Although some of the figures show multiple logical stages in a particular order, stages that are not order-dependent may be reordered, and other stages may be combined or decomposed. Although some reordering or other groupings are specifically mentioned, other reorderings or other groupings are obvious to those of ordinary skill in the art, and thus the ordering and groupings presented herein are not an exhaustive list of alternatives. In addition, it should be understood that the stages may be implemented in hardware, firmware, software, or any combination thereof.

[0026] Generally speaking, the backlight of a display can be divided into multiple blocks. Block duty cycle in this article is a term used in local dimming to describe the percentage of time that a backlight block is on. A block duty cycle of 100% means that the block is always on, while a block duty cycle of 0% means that the block is always off. Taking a display frame as an example, the block duty cycle of each block is determined by the brightness of the display frame in that area. For example, if a portion of the display frame within a block is very dark, the block duty cycle of the block can be 0%, meaning that the block will be turned off, which will improve the contrast of the display frame. The block duty cycle of the backlight block is an important factor in determining the contrast of the display. A higher block duty cycle will result in better contrast, but it will also consume more power.

[0027] Figure 1FIG. 1 is a schematic diagram of a dynamic adaptive spatial smoothing system 100 for local dimming according to an embodiment of the present invention. The dynamic adaptive spatial smoothing system 100 can be implemented in a display. The dynamic adaptive spatial smoothing system 100 includes a block duty cycle calculation module 102, a dynamic adaptive spatial smoothing module 104, a final block duty cycle module 106, and a backlight module 108. The block duty cycle calculation module 102 can receive a frame sequence of a movie in a grayscale format. A frame (more specifically, the backlight of the display) can be divided into a plurality of blocks (e.g., 200-1000 blocks). The block duty cycle calculation module 102 will generate a plurality of block duty cycles of a plurality of blocks of a current frame and a previous frame from the frame sequence. Then, the dynamic adaptive spatial smoothing module 104 and the final block duty cycle module 106 will implement an algorithm to apply a dynamic adaptive spatial smoothing filter to the frame sequence so as to reduce visual halo and visual flicker when performing local dimming.

[0028] Figure 2 2 is a flow chart of a method 200 implemented by the dynamic adaptive spatial smoothing module 104. The method 200 describes an algorithm for improving visual quality when performing local dimming. The method 200 includes the following steps:

[0029] Step S202: determining the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame;

[0030] Step S204: generating an original smoothing matrix of the selected block;

[0031] Step S206: generating a dynamic adaptive matrix according to the original smoothing matrix and the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame;

[0032] Step S208: using the corresponding dynamic adaptation matrix to update the block duty cycle of each block to generate an updated frame;

[0033] Step S210: performing spatial smoothing on the update frame.

[0034] In step S202, the difference in the block duty cycle of the selected block can be determined by subtracting the block duty cycle of the current frame from the block duty cycle of the previous frame in the selected block. If the difference is not zero, motion occurs in the area containing the selected block.

[0035] Figure 3 is a schematic diagram of the result of step S202, that is, a schematic diagram of the difference in block duty cycle between the current frame and the previous frame. A block with the number "1" may represent that the difference is not zero, and a block with the number "0" may represent that the difference is zero.

[0036] In step S204, an original smoothing matrix may be generated for each block with a non-zero difference. The original smoothing matrix may include M×M blocks, with the selected block with a non-zero difference located at the center, where M may be a positive odd number. Each block of the original smoothing matrix has a block duty cycle. For example, Figure 3 The original smoothing matrix may be a 5×5 matrix including the blocks in the frame, with the block 301 in the frame as the center. This matrix includes a block 302 located at the corner of the frame and a block 303 located at the top of the frame. The size of the original smoothing matrix may be adjusted according to the movement of the actual frame (e.g., 3×3, 7×7, etc.), but the present invention is not limited thereto.

[0037] Figure 4A Schematic diagram of a 5×5 original smoothing matrix generated in step S204 according to an embodiment of the present invention. In this original smoothing matrix, block 301 may correspond to matrix element W 33 , which represents the block duty cycle of block 301; the block 302 located in the corner may correspond to the matrix element W 11 , which represents the block duty cycle of block 302. The top block 303 may correspond to the matrix element W 12 , which represents the block duty cycle of block 303, and so on. An example of the matrix elements of the original smoothing matrix is ​​shown below (also see Figure 4A middle):

[0038] 6 6 6 6 6 6 13 13 13 6 6 13 56 13 6 6 13 13 13 6

[0039] In some embodiments, when the block in the upper left corner (eg, block 302) corresponds to matrix element W33, some matrix elements do not have corresponding block duty cycles (eg, W 11 -W 15 , W 21 -W 25 , W 31 , W 32 , W 41 , W 42 , W 51 , W 52 ), so the missing block duty cycle (e.g. W 11 -W 15 , W 21 -W 25 , W 31 , W 32 , W 41 , W 42 , W 51 , W 52 ) will fill in the matrix element W 33 In some embodiments, when the top block (e.g., block 303) corresponds to the matrix element W 33, there is no corresponding matrix element of the block duty cycle (such as W 11 -W 15 , W 21 -W 25 ) will fill in the matrix element W 33 The above description is only an example and the present invention is not limited thereto.

[0040] Next, in step S206, according to Figure 4A The original smoothing matrix can generate a dynamic adaptation matrix. Figure 4B FIG. 5 is a schematic diagram of a 5×5 dynamic adaptive matrix generated in step S206 .

[0041] The dynamic adaptation matrix can be generated according to the following equation:

[0042]

[0043] W ij is the matrix element of the i-th column and j-th row of the original smoothing matrix. W' ij is the matrix element of the i-th column and j-th row of the dynamic adaptation matrix. Wc is the matrix element of the center of the original smoothing matrix, which is the matrix element W in this example. 33 BD_diff(Wc) is the difference between the block duty cycle of the selected block in the current frame and the block duty cycle of the selected block in the previous frame. Max_duty is the maximum block duty cycle (e.g., 255). Note that for calculation purposes, W' 33 =W 33 The calculations described herein may be performed by the dynamically adaptive spatial smoothing module 104 .

[0044] Therefore, the dynamic adaptation matrix can be calculated as follows:

[0045]

[0046]

[0047] exist Figure 4B After the dynamic adaptation matrix in is obtained through the above calculation, in step S208, the block duty cycle of block 301 can be updated according to the dynamic adaptation matrix. The updated block duty cycle can be obtained by the following equation:

[0048]

[0049] Updated_BD is the updated block duty cycle of the selected block (eg, block 301 ). The calculations described herein may be performed by the final block duty cycle module 106 .

[0050] Therefore, the updated block duty cycle can be calculated as follows:

[0051] Updated_BD=(W 11 ×W' 11 +W 12 ×W' 12 +…W 55 ×W' 55 ) / (W' 11 +W' 12 +…W' 55 )

[0052] After updating the block duty cycles of all blocks with non-zero differences through the above process, in step S210, a spatial smoothing filter can be generated according to the updated block duty cycle and applied to all blocks of the updated frame. The result is then sent to the backlight module 108 for improving the block duty cycle lighting control.

[0053] Figure 5 Schematic diagram of a spatial smoothing filter according to an embodiment of the present invention. Curve 501 is a one-dimensional profile of a spatial smoothing filter without implementing method 200. In contrast, curve 502 is a one-dimensional profile of a spatial smoothing filter with implementing method 200. The horizontal axis represents the block number, and the vertical axis represents the block duty cycle. Figure 5 As shown, curve 502 is more centered than curve 501. Thus, curve 502 may represent a better optimized spatial smoothing filter for situations where there are fewer changes from the previous frame to the current frame.

[0054] Figure 6 601 is a one-dimensional profile of a spatial smoothing filter without implementing method 200. In contrast, curve 602 is a one-dimensional profile of a spatial smoothing filter with implementing method 200. The horizontal axis represents the block number, and the vertical axis represents the block duty cycle. Figure 6 As shown, curve 602 has a similar shape to curve 601. Curve 602 may represent a better optimized spatial smoothing filter for situations where more changes occur from the previous frame to the current frame.

[0055] The above embodiments illustrate a method and system for adaptively implementing a spatial smoothing filter by implementing a dynamic adaptive matrix, thereby effectively reducing light leakage, detail loss, halo and flicker that annoy viewers.

[0056] The various illustrative logical blocks, modules, and circuits described in conjunction with the various aspects disclosed herein may be implemented or executed with a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic element, discrete gate or transistor logic, separate hardware elements, or any combination thereof, in order to perform the functions described herein. The processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0057] The embodiments disclosed herein may be embodied in hardware and instructions stored in the hardware and may be located, for example, in a random access memory (RAM), a flash memory, a read only memory (ROM), an electrically programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a register, a hard disk, a removable disk, a CD-ROM, or any other form of computer readable media known in the art. For example, a storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium may be located in an ASIC. The ASIC may be located in a remote station. In an alternative, the processor and the storage medium may be located as discrete components in a remote station, a base station, or a server.

[0058] It should also be understood that the operation steps described in any embodiment herein are intended to provide examples. The described operations can be performed in a variety of different orders different from the order shown. In addition, the operations described in a single operation step can actually be performed in a plurality of different steps. In addition, one or more operation steps discussed in the embodiment can be combined. The operation steps shown in the flow chart can be modified in a variety of different ways, which is obvious to those skilled in the art. Those skilled in the art will also understand that information and signals can be represented using any of a variety of different techniques and skills. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be cited in the above can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0059] The above description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications of the present disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the examples and designs described herein, but to conform to the widest scope consistent with the principles and novel features disclosed herein.

[0060] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A method for dynamically adapting spatial smoothing, comprising: Determine a difference between a block duty cycle of a selected block in a current frame and a block duty cycle of the selected block in a previous frame; Generate an original smoothing matrix for the selected block; generating a dynamic adaptive matrix according to the original smoothing matrix and the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame; updating a block duty cycle of each block using a corresponding dynamic adaptation matrix to generate an updated frame; and Spatial smoothing is performed on the update frame.

2. The method of claim 1, wherein: The original smoothing matrix and the dynamic adaptation matrix are both M×M matrices. The method of claim 2 , wherein M is a positive odd number. 4 . The method of claim 3 , wherein the original smoothing matrix comprises a plurality of block duty cycles of M×M blocks, and the selected block is located at a center of the original smoothing matrix.

5. The method of claim 4, wherein the dynamic adaptation matrix is ​​generated according to the following equation: in: W ij is a matrix element in the i-th column and j-th row of the original smoothing matrix; W' ij is a matrix element in the i-th column and j-th row of the dynamic adaptation matrix; Wc is a matrix element of the center of the original smoothing matrix; BD_diff(Wc) is the difference between the block duty cycle of the selected block in the current frame and the block duty cycle of the selected block in the previous frame; and Max_duty is a maximum block duty cycle.

6. The method of claim 5, wherein updating the block duty cycle of each block is based on the following equation: Updated_BD is an updated block duty cycle of the selected block.

7. A dynamic adaptive spatial smoothing system comprising: a block duty cycle calculation module for generating a plurality of block duty cycles of a plurality of blocks in a current frame and a previous frame; and A dynamically adaptive spatial smoothing module, for: Determine a difference between a block duty cycle of a selected block of the plurality of blocks of the current frame and a block duty cycle of the selected block of the previous frame; Generate an original smoothing matrix for the selected block; and generating a dynamic adaptive matrix according to the original smoothing matrix and the difference between the block duty cycle of the selected block of the current frame and the block duty cycle of the selected block of the previous frame; A final block duty cycle module for: updating a block duty cycle of each block using a corresponding dynamic adaptation matrix to generate an updated frame; and Spatial smoothing is performed on the update frame.

8. The dynamically adaptive spatial smoothing system of claim 7, wherein: The original smoothing matrix and the dynamic adaptation matrix are both M×M matrices.

9. The dynamic adaptive spatial smoothing system as claimed in claim 8, wherein M is a positive odd number. 10 . The dynamic adaptive spatial smoothing system of claim 9 , wherein the original smoothing matrix comprises a plurality of block duty cycles of M×M blocks, and the selected block is located at a center of the original smoothing matrix.

11. The dynamically adaptive spatial smoothing system of claim 10, wherein the dynamically adaptive matrix is ​​generated according to the following equation: in: W ij is a matrix element in the i-th column and j-th row of the original smoothing matrix; W' ij is a matrix element in the i-th column and j-th row of the dynamic adaptation matrix; Wc is a matrix element of the center of the original smoothing matrix; BD_diff(Wc) is the difference between the block duty cycle of the selected block in the current frame and the block duty cycle of the selected block in the previous frame; and Max_duty is a maximum block duty cycle.

12. The dynamically adaptive spatial smoothing system of claim 11, wherein the block duty cycle of each block is updated according to the following equation: Updated_BD is an updated block duty cycle of the selected block.

13. The dynamic adaptive spatial smoothing system of claim 8, further comprising a backlight module for performing lighting control according to the update frame.

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