Image sharpening method and related apparatus

Abstract

The present disclosure provides an image sharpening method and related device. The image sharpening method comprises: extracting high frequency components from an image to be sharpened to obtain an intermediate image, the intermediate image comprising information of pixels at edges and information of pixels outside the edges, the information of pixels at edges being high frequency components of pixels at edges in the image to be sharpened, and the information of pixels outside the edges being original image information of pixels near the edges in the image to be sharpened; performing compensation based on a sub-pixel rendering color borrowing coefficient on the information of pixels outside the edges to offset color cast caused by superimposition of the information of pixels at edges onto the image to be sharpened; and superimposing the information of pixels at edges and the compensated information of pixels outside the edges onto the image to be sharpened. The present disclosure solves the problem of color cast caused by unbalanced change of sub-pixels after execution of a traditional image sharpening method.

Description

Technical Field

[0001] This disclosure relates to the field of image processing technology, and in particular to an image sharpening method and related apparatus. Background Technology

[0002] In the traditional arrangement of pixels, each pixel contains three sub-pixels: RGB (e.g., ...). Figure 1 As shown, R represents red, G represents green, and B represents blue. To improve resolution, RGBG (such as...) Figure 2 As shown in the image, new pixel arrangements such as delta_RGB have emerged. In these new arrangements, each pixel contains only two colors of subpixels. This means that displaying the same number of pixels requires only 2 / 3 of the area needed by traditional arrangements, increasing pixel density. However, the lost subpixel information can cause color casts in the image. To ensure accurate color reproduction, subpixel rendering (SPR) is used. This involves each pixel borrowing color from neighboring subpixels to compensate for lost pixel information. However, SPR uses a weighted average method for color borrowing, which, when applied to image details, results in blurred image details.

[0003] To address the issue of unclear image details caused by subpixel rendering techniques, the image needs further sharpening. Image sharpening enhances boundaries and highlights blurred details of objects. Specifically, since the brightness values ​​of objects in an image differ, with significant brightness variations at edges, calculating the rate of change of the signal to extract and enhance high-frequency components, and then superimposing these enhanced high-frequency components back into the original image, can sharpen the image contours. Figure 3 The diagram shows the original signal and the first and second derivatives of various typical edge types. It can be seen that the first and second derivatives enhance the high-frequency components in the signal. Figure 4 The image shown is a grayscale image sharpened using the traditional image sharpening method described above. The sharpening process proceeds sequentially from the original image to the uncalibrated image, then to the calibrated image, and finally to the sharpened image. In this process, (2) and (3) indicate the enhanced high-frequency components. The calibration in (2) and (3) refers to whether each pixel calibrates which pixel in the original image.

[0004] However, applying the aforementioned traditional image sharpening methods to color images can cause color casts. A typical example of this color cast is... Figure 5As shown, different fill values ​​indicate different pixel values. Originally, the subpixel rendering technology at the edge ensured that there would be no color cast. However, after sharpening, the RG on one side increases while the BG on the other side decreases. As a result, the red component at the edge is higher than the blue component, which will cause the color to appear reddish. Summary of the Invention

[0005] In view of the above problems, this disclosure provides an image sharpening method and related apparatus, which aims to solve the color cast phenomenon caused by the imbalance of sub-pixel changes after the execution of traditional image sharpening methods.

[0006] According to a first aspect of this disclosure, an image sharpening method is provided, comprising:

[0007] An intermediate image is obtained by extracting high-frequency components from the image to be sharpened. The intermediate image includes information about pixels at the edges and information about pixels outside the edges. The information about pixels at the edges is the high-frequency components of pixels at the edges in the image to be sharpened, and the information about pixels outside the edges is the original image information of pixels near the edges in the image to be sharpened.

[0008] The information of pixels outside the edge is compensated based on the sub-pixel rendering color borrowing coefficient to offset the color cast caused by the information of pixels at the edge being superimposed on the image to be sharpened;

[0009] The information of the pixels at the edge and the compensated information of the pixels outside the edge are superimposed onto the image to be sharpened.

[0010] Optionally, high-frequency components are extracted from the image to be sharpened, including:

[0011] The image to be sharpened is converted to a color space with luminance information through color conversion;

[0012] The brightness information of the converted image to be sharpened is subjected to high-pass filtering to obtain the high-frequency components of the brightness information;

[0013] The high-frequency components of the brightness information are subjected to the inverse color conversion to obtain the high-frequency components extracted from the image to be sharpened.

[0014] Optionally, extracting high-frequency components from the image to be sharpened further includes: enhancing the high-frequency components of the brightness information to obtain updated high-frequency components of the brightness information.

[0015] Performing the inverse color conversion on the high-frequency components of the brightness information includes: performing the inverse color conversion on the high-frequency components of the updated brightness information.

[0016] Optionally, compensation is performed on the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient, including performing the following operations on the pixels outside the edge:

[0017] Edge information is generated based on the pixel's position relative to the edge and the edge's type;

[0018] The filter coefficients are determined based on the edge information and the sub-pixel rendering color borrowing coefficients.

[0019] The filter coefficients are used to filter the information of the pixels outside the edge that correspond to that pixel.

[0020] Optionally, compensating for the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient further includes:

[0021] The information obtained by the filtering operation on the pixels outside the edge is converted into the pixel arrangement used for screen display, and the information of the pixels outside the edge is compensated.

[0022] Optionally, the information of the pixels at the edge and the compensated information of the pixels outside the edge are superimposed onto the image to be sharpened, including:

[0023] The image to be sharpened is converted into the pixel arrangement used for screen display to obtain the image to be superimposed.

[0024] The information of the pixels at the edge is converted into the pixel arrangement used for screen display to obtain the information of the pixels at the edge to be superimposed;

[0025] The information of the pixels at the edge to be superimposed and the information of the pixels outside the edge after compensation are aligned with the image to be superimposed according to their respective corresponding pixels and then superimposed.

[0026] According to a second aspect of this disclosure, an image sharpening apparatus is provided, comprising:

[0027] The sharpening module is used to extract high-frequency components from the image to be sharpened to obtain an intermediate image. The intermediate image includes information about pixels at the edges and information about pixels outside the edges. The information about pixels at the edges is the high-frequency components of the pixels at the edges in the image to be sharpened, and the information about pixels outside the edges is the original image information of pixels near the edges in the image to be sharpened.

[0028] The compensation module is used to compensate the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient, so as to offset the color cast caused by the information of pixels at the edge being superimposed on the image to be sharpened;

[0029] The overlay module is used to overlay the information of the pixels at the edge and the compensated information of the pixels outside the edge onto the image to be sharpened.

[0030] Optionally, the compensation module includes:

[0031] An encoder is used to generate edge information based on the position of pixels outside the edge relative to the edge and the type of the edge;

[0032] A filter is used to perform a filtering operation on the information of the pixels outside the edge based on filter coefficients, wherein the filter coefficients are determined based on the edge information and the sub-pixel rendering color borrowing coefficient.

[0033] According to a third aspect of this disclosure, an electronic device is provided, comprising: a processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of any of the image sharpening methods described in the first aspect.

[0034] According to a fourth aspect of this disclosure, a computer-readable storage medium is provided, on which a computer program or instructions are stored, which, when executed by a processor, implement the steps of any of the image sharpening methods described in the first aspect.

[0035] This disclosure brings the following beneficial effects:

[0036] The image sharpening method disclosed herein first extracts high-frequency components from the image to be sharpened to obtain an intermediate image. This intermediate image includes information about pixels at the edges and information about pixels outside the edges. The information about pixels at the edges is the extracted high-frequency components of pixels at the edges in the image to be sharpened, while the information about pixels outside the edges is the original image information of pixels near the edges in the image to be sharpened. Then, compensation based on a sub-pixel rendering color borrowing coefficient is applied to the information about pixels outside the edges to offset the color cast caused by the superposition of the information about pixels at the edges onto the image to be sharpened. Finally, the information about pixels at the edges and the compensated information about pixels outside the edges are superimposed onto the image to be sharpened, thereby obtaining a sharpened image without color cast. Therefore, this disclosure solves the color cast problem caused by the imbalance of sub-pixel changes after the execution of traditional image sharpening methods.

[0037] Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the disclosure. The objects and other advantages of this disclosure are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0038] To make the above-mentioned objects, features and advantages of this disclosure more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0039] The above and other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0040] Figure 1 The image shows the traditional arrangement of pixels;

[0041] Figure 2 The image shows the RGBG arrangement of the pixels;

[0042] Figure 3 The diagram shows the original signal and its first and second derivatives for various typical edge types.

[0043] Figure 4 The image shown is a schematic diagram illustrating the process of sharpening a grayscale image using traditional image sharpening methods.

[0044] Figure 5 The image shown is a schematic diagram of a color image with pixels arranged in a novel manner, sharpened using a traditional image sharpening method.

[0045] Figure 6 The diagram shown is a flowchart of an image sharpening method provided in an embodiment of this disclosure;

[0046] Figure 7 The diagram shown is a flowchart of an embodiment of this disclosure for extracting high-frequency components from an image to be sharpened;

[0047] Figure 8 The diagram illustrates an exemplary process for extracting high-frequency components from an image to be sharpened.

[0048] Figure 9 The image shown is a schematic diagram of a color image with pixels arranged in a novel manner after being sharpened by the image sharpening method provided in this embodiment of the present disclosure.

[0049] Figure 10 The diagram shown is a structural block diagram of an image sharpening device provided in an embodiment of this disclosure;

[0050] Figure 11 The diagram shown is a structural block diagram of a compensation module provided in an embodiment of this disclosure;

[0051] Figure 12 The diagram shown is a structural schematic of an electronic device provided in an embodiment of this disclosure. Detailed Implementation

[0052] Various embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various portions in the drawings are not drawn to scale.

[0053] Image sharpening aims to enhance boundaries, specifically by increasing the brightness contrast at the edges of an image to enhance details, thereby resulting in a clearer overall image appearance. However, when image sharpening is applied to a color image with pixels arranged in a novel pattern, the increased brightness contrast at the edges can cause an imbalance in sub-pixel changes, leading to color cast. To address this, this disclosure provides an image sharpening method designed to resolve the color cast caused by the imbalance in sub-pixel changes after the execution of traditional image sharpening methods.

[0054] Figure 6 The diagram shows a flowchart of an image sharpening method provided in an embodiment of this disclosure. (Refer to...) Figure 6 The image sharpening method provided in this disclosure includes:

[0055] Step S110: Extract high-frequency components from the image to be sharpened to obtain an intermediate image. The intermediate image includes information about pixels at the edges and information about pixels outside the edges.

[0056] Specifically, the high-frequency components extracted from the image to be sharpened include high-frequency components extracted from various parts of the image to be sharpened, including high-frequency components extracted from pixels at the edges and high-frequency components extracted from pixels outside the edges. The high-frequency components extracted from pixels at the edges are the information of the pixels at the edges mentioned above; while the information of pixels outside the edges is the original image information of pixels near the edges in the image to be sharpened that is retained.

[0057] It should be noted that, in the embodiments of this disclosure, the edge refers to the intersection of different spaces, including the intersection of different objects. In some examples, the edge includes one pixel on each side of the boundary line between the different spaces. In other examples, the edge may be slightly larger, for example, including two pixels on each side of the boundary line between the different spaces.

[0058] Step S120: Compensate the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient to offset the color cast caused by the information of pixels at the edge being superimposed on the image to be sharpened.

[0059] Specifically, the information of pixels at the edge consists of high-frequency components extracted from these pixels. These components are used to enhance the brightness contrast of pixels at the edge. Therefore, when superimposed on the image to be sharpened, the brightness of pixels on one side of the boundary line increases while the brightness of pixels on the other side decreases. The information of pixels outside the edge is compensated based on a sub-pixel rendering color borrowing coefficient. This means that a pixel at the edge borrows color from a neighboring sub-pixel outside the edge based on the sub-pixel rendering color borrowing coefficient to eliminate color cast. The sub-pixel to which the borrowed color belongs already has the corresponding compensated information from the sub-pixel outside the edge superimposed on it.

[0060] It should be noted that if the brightness of the pixels outside the edge of the adjacent edge to which the aforementioned borrowed sub-pixel belongs changes significantly due to the superposition of the corresponding compensated information of the pixels outside the edge, then it can further borrow color from the sub-pixels of the adjacent pixels outside the edge based on the sub-pixel rendering borrowing coefficient, thereby eliminating the color cast caused near the edge in this case.

[0061] Step S130: Superimpose the information of the pixels at the edge and the information of the compensated pixels outside the edge onto the image to be sharpened.

[0062] In this embodiment of the disclosure, information of pixels outside the edge is compensated based on the subpixel rendering color borrowing coefficient to offset the color cast problem caused by the superposition of information of pixels at the edge onto the image to be sharpened. This can improve the sharpening effect while ensuring that no color cast problem occurs. In other words, it provides a sharpening scheme that effectively reduces the damage to details caused by subpixel rendering, so that the image after subpixel rendering can become clearer and without color cast problem.

[0063] In an optional embodiment, such as Figure 7 As shown, step S110 involves extracting high-frequency components from the image to be sharpened, including:

[0064] Step S111: Convert the image to be sharpened to a color space with brightness information through color conversion.

[0065] For example, color conversion from RGB to HSL (RGB2HSL) converts the image to be sharpened into the HSL color space. In this color space: H (Hue) refers to hue, i.e., the color name, such as "red" or "blue"; S (Saturation) refers to saturation, i.e., the purity of the color; and L (Lightness) refers to lightness, i.e., the brightness of the color, which is also the brightness information in this color space. Another example is color conversion from RGB to YUV (RGB2YUV). In this color space: Y represents lightness (Luminance or Luma), i.e., the grayscale value, which is also the brightness information in this color space; U and V represent chromaticity, which describes color and saturation and is used to specify the color.

[0066] Step S112: Process the brightness information of the converted image to be sharpened to obtain the high-frequency components of the brightness information.

[0067] Specifically, high-frequency components of brightness information can be obtained by processing brightness information using methods such as differential calculation or high-pass filtering; alternatively, high-frequency components of brightness information can be extracted from the converted image to be sharpened and enhanced to obtain high-frequency components of brightness information. A typical approach is to use the Laplacian operator to perform differential operations on the brightness information, where the high-frequency components of brightness information obtained are the enhanced high-frequency components of brightness information.

[0068] Step S113: Perform the inverse transformation of the above color conversion on the high-frequency components of the brightness information to obtain the high-frequency components extracted from the image to be sharpened.

[0069] It should be noted that the above color conversion is a conversion from the RGB color space to a color space with luminance information, while the inverse color conversion is a conversion from a color space with luminance information to the RGB color space. Finally, the high-frequency components extracted from the image to be sharpened in step S113 are represented by the pixel values ​​of the red, green and blue sub-pixels in the pixel.

[0070] Figure 8 The diagram illustrates an exemplary execution process for step S110. (Refer to...) Figure 8The image to be sharpened is converted from RGB to HSL (RGB2HSL) to obtain the lightness information L in the HSL color space. The lightness information L is then filtered to extract the high-frequency component HF. The high-frequency component HF undergoes detail enhancement to obtain the enhanced high-frequency component L_out. The enhanced high-frequency component L_out is then converted from HSL to RGB (HSL2RGB) to obtain the high-frequency component extracted from the image to be sharpened. In some examples, the high-frequency component extracted from the image to be sharpened is also referred to as enhanced detail, as shown above, where enhanced detail is output in RGB format.

[0071] In another optional embodiment, step S120 compensates for the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient. This includes performing the following operations on the pixels outside the edge: generating edge information based on the pixel's position relative to the edge and the edge type; determining filter coefficients based on the edge information and the sub-pixel rendering color borrowing coefficient; and filtering the information of the pixels outside the edge corresponding to that pixel based on the filter coefficients. This ultimately compensates for the information of each pixel in the information of pixels outside the edge, so that the information of the pixels at the edge and the compensated information of the pixels outside the edge are superimposed as a detail onto the image to be sharpened, and no color cast occurs after sharpening the image. Specifically, the edge type is as follows: Figure 3 There are various methods, and the position of a pixel relative to the edge includes whether the pixel is on the brighter or darker side of the edge and the distance between the pixel and the edge. The above edge information can be generated by encoding the position of the pixels outside the edge relative to the edge and the type of the edge.

[0072] Furthermore, in step S120, the compensation of the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient also includes: converting the information of pixels outside the edge obtained by filtering into the pixel arrangement used for screen display, so as to obtain the compensated information of pixels outside the edge.

[0073] Further, step S130, superimposing the information of pixels at the edge and the information of pixels outside the compensated edge onto the image to be sharpened, includes: converting the image to be sharpened into the pixel arrangement used for screen display to obtain the image to be superimposed; converting the information of pixels at the edge into the pixel arrangement used for screen display to obtain the information of pixels at the edge to be superimposed; superimposing the information of pixels at the edge to be superimposed and the information of pixels outside the compensated edge onto the image to be superimposed according to their respective corresponding pixels, and the image sharpening is completed after superimposition.

[0074] Figure 9The diagram shows an image sharpened by the image sharpening method provided in this embodiment. Different fill values ​​represent different pixel values, and the edges represent the boundary lines between different pixel values, with one pixel on each side. (Refer to...) Figure 9 Some pixels at the edges (marked with upward arrows) increase in brightness due to the superposition of information from corresponding edge pixels. The pixels outside the edge to which their color-borrowing sub-pixels belong (marked with upward arrows) also increase in brightness by superimposing the corresponding compensated information from the outside edge pixels. Thus, the brighter RG pixels achieve sub-pixel balance by borrowing blue from the brighter BG pixels to the left, preventing a reddish tint. Conversely, some pixels at the edges (marked with downward arrows) decrease in brightness due to the superposition of information from corresponding edge pixels. The pixels outside the edge to which their color-borrowing sub-pixels belong (marked with downward arrows) also decrease in brightness by superimposing the corresponding compensated information from the outside edge pixels. Thus, the brighter BG pixels achieve sub-pixel balance by borrowing red from the brighter RG pixels to the right, preventing a reddish tint. Figure 9 and Figure 5 In comparison, it can be seen that: the embodiments of this disclosure compensate for the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient, so that the information of pixels at the edge and the compensated information of pixels outside the edge are superimposed on the image to be sharpened as the overall details of the image to be sharpened, thereby achieving sharpening without causing color cast.

[0075] It should be noted that the image sharpening methods provided above must also avoid overshoot (i.e., excessive sharpening). This is because excessive overshoot results in significant changes in brightness information before and after sharpening, leading to noticeable white or black edges at detail edges, thus affecting the visual appeal of the sharpened image. In other words, traditional algorithms cannot simultaneously control overshoot and achieve good image sharpening clarity. The image sharpening method provided in this disclosure is a sub-pixel rendering-based method for eliminating color cast. It enhances image clarity while controlling overshoot, ultimately yielding a sharpened image with clear details, no overshoot, and no color cast.

[0076] This disclosure also provides an image sharpening apparatus. Figure 10 The diagram shown is a schematic representation of an image sharpening apparatus provided in an embodiment of this disclosure. (Refer to...) Figure 10The image sharpening device includes: a sharpening module 110, used to receive an image to be sharpened and extract high-frequency components from the received image to obtain an intermediate image, the intermediate image including information of pixels at the edge and information of pixels outside the edge, the information of pixels at the edge being the high-frequency components of pixels at the edge extracted in the image to be sharpened, and the information of pixels outside the edge being the original image information of pixels near the edge in the image to be sharpened; a compensation module 120, used to compensate the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient, so as to offset the color cast caused by the information of pixels at the edge being superimposed on the image to be sharpened; and a superposition module 130, used to superimpose the information of pixels at the edge and the compensated information of pixels outside the edge onto the image to be sharpened to obtain a sharpened image.

[0077] Specifically, when the overlay module 130 overlays the information of pixels at the edge and the compensated information of pixels outside the edge onto the image to be sharpened, the image to be sharpened may have been converted to the pixel arrangement used for screen display. Therefore, the image sharpening device also includes a subpixel rendering module 140. The subpixel rendering module 140 is used to convert the image to be sharpened into the pixel arrangement used for screen display, and uses any rendering method based on weight factors to perform color borrowing processing on the surrounding subpixels. The purpose of color borrowing processing is to eliminate the color shift phenomenon caused by the reduction of subpixels in the new pixel arrangement. By adjusting the color borrowing coefficient, an image without color shift can be obtained. That is to say, the image output by the subpixel rendering module 140 will have a slight decrease in sharpness due to the execution of subpixel rendering, but there will be no color shift problem. In this case, the information of pixels at the edge and the compensated information of pixels outside the edge to be overlaid onto the image to be sharpened also need to be converted into the pixel arrangement used for screen display. This can be done by the compensation module 120 converting the information of pixels at the edge into the pixel arrangement used for screen display and converting the information of pixels outside the edge after compensation into the pixel arrangement used for screen display. In addition, the overlay module 130 can overlay the information of pixels at the edge and the information of pixels outside the edge after compensation with the image to be sharpened after aligning them with their respective corresponding pixels. Therefore, the image sharpening device also includes an alignment module 150 that performs the alignment process according to the pixel arrangement method (i.e., display mode) used for screen display.

[0078] from Figure 10 As can be seen, an image to be sharpened needs to be processed by the subpixel rendering module 140 to obtain an image to be superimposed with slightly reduced clarity but no color cast problem. On the other hand, it also needs to be processed by the sharpening module 110, compensation module 120, alignment module 150 and superimposition module 130 to extract the details required for sharpening. These details are then superimposed on the image to be superimposed to achieve colorless sharpening of the image, which will make the image to be superimposed clear without introducing color cast problem.

[0079] Furthermore, such as Figure 11 As shown, the compensation module 120 includes: an encoder 121, used to generate edge information based on the position of the pixels outside the edge relative to the edge and the type of the edge; and a filter 122, used to perform filtering operations on the information of corresponding pixels in the information of pixels outside the edge based on filter coefficients, wherein the filter coefficients are determined based on the edge information and the sub-pixel rendering color borrowing coefficient.

[0080] Furthermore, when the information of pixels at the edge output by the compensation module 120 and the information of pixels outside the compensated edge need to be converted into the pixel arrangement used for screen display, the compensation module 120 also includes a rearrangement unit 123. The rearrangement unit 123 is used to receive the filtering result from the filter 122 and perform the conversion of the received filtering result into the pixel arrangement used for screen display.

[0081] Since the implementation details of the above-mentioned device have been described in the detailed description of the method embodiments above, they will not be repeated here for the sake of saving space.

[0082] Figure 12 The image shows an exemplary electronic device. (As shown) Figure 12 As shown, the electronic device 1300 includes a memory 1310 and a processor 1320, as well as a program stored in the memory 1310 and executable on the processor 1320. When executed by the processor 1320, the program can implement the various processes of the embodiments of the above-described image sharpening method and achieve the same technical effect. Of course, the electronic device may also include auxiliary sub-devices such as a power supply component 1330, a network interface 1340, and an input / output interface 1350. The input / output interface 1350 or the network interface 1340 allows the electronic device 1300 to connect to external devices, enabling the electronic device 1300 to receive the image to be sharpened and obtain a color-biased sharpened image by executing the above-described image sharpening method.

[0083] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor. Therefore, this disclosure also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program can implement the various processes of the embodiments of the above image sharpening methods. The computer-readable storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0084] Since the program stored in the readable storage medium can execute the steps of any of the image sharpening methods provided in the embodiments of this disclosure, the beneficial effects achievable by any of the image sharpening methods provided in the embodiments of this disclosure can be realized, as detailed in the preceding embodiments, and will not be repeated here. Specific implementations of the above operations can be found in the preceding embodiments, and will not be repeated here.

[0085] It should be noted that in describing the various embodiments in this specification, the focus is on the differences from other embodiments, while the same or similar parts between the various embodiments can be understood by referring to each other. Regarding the electronic device embodiment, since it is basically similar to the method embodiment, the relevant parts can be referred to the description of the method embodiment. Because this electronic device embodiment has the beneficial effects that can be achieved by the above-described method embodiments, as detailed in the preceding embodiments, it will not be repeated here.

[0086] Furthermore, it should be noted that in the apparatus and method of this disclosure, it is obvious that the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered equivalent solutions of this disclosure. Moreover, the steps performing the above series of processes can naturally be executed in the order described, but are not necessarily required to be executed in chronological order; some steps can be executed in parallel or independently of each other. Those skilled in the art will understand that all or any step or component of the method and apparatus of this disclosure can be implemented in any computing device (including processors, storage media, etc.) or network of computing devices, in hardware, firmware, software, or a combination thereof, which can be achieved by those skilled in the art using their basic programming skills after reading the description of this disclosure.

[0087] Finally, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the embodiments described above are merely specific implementations of this disclosure, used to illustrate the technical solutions of this disclosure, and not to limit it. The scope of protection of this disclosure is not limited thereto. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this disclosure; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure, and should all be covered within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An image sharpening method, comprising: An intermediate image is obtained by extracting high-frequency components from the image to be sharpened. The intermediate image includes information about pixels at the edges and information about pixels outside the edges. The information about pixels at the edges is the high-frequency components of the pixels at the edges in the image to be sharpened, and the information about pixels outside the edges is the original image information of pixels near the edges in the image to be sharpened. The information of pixels outside the edge is compensated based on the sub-pixel rendering color borrowing coefficient to offset the color cast caused by the information of pixels at the edge being superimposed on the image to be sharpened; The information of the pixels at the edge and the compensated information of the pixels outside the edge are superimposed onto the image to be sharpened. The compensation of information of pixels outside the edge based on sub-pixel rendering color borrowing coefficients includes: encoding edge information according to the pixel's position relative to the edge and the edge type; determining filter coefficients based on the edge information and sub-pixel rendering color borrowing coefficients; filtering the information of the pixels outside the edge corresponding to that pixel based on the filter coefficients; and converting the information of the pixels outside the edge obtained by the filtering operation into a pixel arrangement used for screen display to obtain the compensated information of the pixels outside the edge. Superimposing the information of the pixels at the edge and the compensated information of the pixels outside the edge onto the image to be sharpened includes: converting the image to be sharpened into a pixel arrangement used for screen display to obtain an image to be superimposed; converting the information of the pixels at the edge into a pixel arrangement used for screen display to obtain the information of the pixels at the edge to be superimposed; and superimposing the information of the pixels at the edge to be superimposed and the compensated information of the pixels outside the edge with the image to be superimposed according to their respective corresponding pixels.

2. The image sharpening method according to claim 1, wherein, Extracting high-frequency components from the image to be sharpened, including: The image to be sharpened is converted to a color space with luminance information through color conversion; The brightness information of the converted image to be sharpened is subjected to high-pass filtering to obtain the high-frequency components of the brightness information; The high-frequency components of the brightness information are subjected to the inverse color conversion to obtain the high-frequency components extracted from the image to be sharpened.

3. The image sharpening method according to claim 2, wherein, Extracting high-frequency components from the image to be sharpened further includes: enhancing the high-frequency components of the brightness information to obtain updated high-frequency components of the brightness information. Performing the inverse color conversion on the high-frequency components of the brightness information includes: performing the inverse color conversion on the high-frequency components of the updated brightness information.

4. An image sharpening device, comprising: The sharpening module is used to extract high-frequency components from the image to be sharpened to obtain an intermediate image. The intermediate image includes information about pixels at the edges and information about pixels outside the edges. The information about pixels at the edges is the high-frequency components of the pixels at the edges in the image to be sharpened, and the information about pixels outside the edges is the original image information of pixels near the edges in the image to be sharpened. The compensation module is used to compensate the information of pixels outside the edge based on the sub-pixel rendering color borrowing coefficient, so as to offset the color cast caused by the information of pixels at the edge being superimposed on the image to be sharpened; The overlay module is used to overlay the information of pixels at the edge and the compensated information of pixels outside the edge onto the image to be sharpened. The compensation module includes: an encoder for encoding edge information based on the position of pixels outside the edge relative to the edge and the type of the edge; a filter for filtering the information of pixels outside the edge based on filter coefficients, wherein the filter coefficients are determined based on the edge information and sub-pixel rendering color borrowing coefficients; and a rearrangement unit for receiving the filtering result from the filter and converting the received filtering result into a pixel arrangement for screen display. The overlay module converts the image to be sharpened into a pixel arrangement used for screen display to obtain an image to be overlaid; converts the information of the pixels at the edge into a pixel arrangement used for screen display to obtain the information of the pixels at the edge to be overlaid; and overlays the information of the pixels at the edge to be overlaid and the compensated information of the pixels outside the edge with the image to be overlaid according to their respective corresponding pixels.

5. An electronic device, comprising: A processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the image sharpening method as described in any one of claims 1-3.

6. A computer-readable storage medium storing a computer program or instructions that, when executed by a processor, implement the steps of the image sharpening method as described in any one of claims 1-3.

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