A high dynamic range image reconstruction method and device with guaranteed image quality

Abstract

The present invention discloses a method and device for reconstructing a high dynamic range image with guaranteed image quality. The method comprises: performing global brightness mapping on a high dynamic range image, importing the image after global brightness mapping into a mapping function calculation to obtain an image after global brightness reconstruction; importing the image after global brightness reconstruction into a local detail function calculation to obtain a detail image of the whole image; substituting the detail image into a local detail compensation algorithm to obtain a detail image after detail compensation; fusing the detail image after detail compensation with the image after global brightness reconstruction to obtain an image reconstructed globally after brightness redistribution and detail compensation; by reconstructing a high dynamic range image through the method of the present invention, the overall visual effect of the reconstructed image is significantly improved, and compared with the original high dynamic range, the clarity, overall image contrast, local details and texture features of the reconstructed image are effectively enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of high dynamic range image reconstruction, and in particular relates to a high dynamic range image reconstruction method and device for ensuring image quality. Background Art

[0002] The dynamic range of existing image sensors is much higher than that of conventional digital displays, so distorted images often appear on conventional displays. Existing displays use logarithmic domain image reconstruction technology, photographic image reconstruction technology, gradient domain image reconstruction technology, etc. to reconstruct distorted images. Although these classic methods have a certain effect in improving the quality of reconstructed images, there are still distortions in the rationality of the overall brightness distribution of the reconstructed image and the retention of local details and textures. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method and device for reconstructing high dynamic range images with guaranteed image quality; by reconstructing high dynamic range images through the method of the present invention, the overall visual effect of the reconstructed image is significantly improved. Compared with the original high dynamic range, the clarity, overall image contrast, local details, and texture features of the reconstructed image are effectively enhanced.

[0004] Technical solution: In the first aspect, the present invention provides a high dynamic range image reconstruction method for ensuring image quality, comprising:

[0005] A high dynamic range image is input, and global brightness mapping is performed on the high dynamic range image. The image after global brightness mapping is imported into a mapping function for calculation to obtain an image after global brightness reconstruction;

[0006] The image after global brightness reconstruction is imported into the local detail function calculation to obtain the global detail image of the image;

[0007] Substituting the detail image into a local detail compensation algorithm to obtain a detail image after detail compensation;

[0008] The detail image after detail compensation is fused with the image after global brightness reconstruction to obtain an image with redistributed brightness and globally reconstructed after detail compensation.

[0009] In a further embodiment, a method of inputting a high dynamic range image, performing global brightness mapping on the high dynamic range image, importing the image after global brightness mapping into a mapping function calculation, and obtaining an image after global brightness reconstruction includes:

[0010] According to the global brightness value range of the high dynamic range image, determine the low illumination area and high illumination area of ​​the image;

[0011] Select the brightness value range associated with the low illumination area and the brightness value range associated with the high illumination area respectively, calculate the probability of occurrence that the number of brightness pixels in the brightness value range of the low illumination area is higher than other brightnesses, and the probability of occurrence that the number of brightness pixels in the brightness value range of the high illumination area is higher than other brightnesses within the dynamic range, and convert the number of brightness pixels higher than other brightnesses into corresponding brightness values;

[0012] Substitute the occurrence probability of the low illumination area and the occurrence probability of the high illumination area into the logarithmic operation respectively to obtain the mapping coefficients of the low illumination area and the high illumination area respectively;

[0013] The mapping coefficients of the low illumination area and the high illumination area and the brightness value associated with the occurrence probability are imported into the mapping function calculation to obtain the low illumination area image and the high illumination area image with the brightness redistributed respectively;

[0014] Based on the low illumination area image and the high illumination area image with redistributed brightness, an image after global brightness reconstruction is obtained.

[0015] In a further embodiment, the expression for calculating the probability of occurrence of the number of brightness pixels in the brightness value domain of the low illumination area in the dynamic range being higher than other brightnesses is:

[0016]

[0017] Where N represents the brightness value of the high dynamic range image, max represents the maximum value, and z represents the brightness value range [N min ,(N max -N min ) / 2], N min and N max They represent the lower and upper limit brightness of the high dynamic range image respectively. Function h represents the probability of calculating the brightness. m l Indicates that the number of brightness pixels in the brightness value range of the low-illuminance area is higher than the probability of occurrence of other brightness;

[0018] The calculation formula for the brightness value of the brightness pixel number higher than other brightness conversions is:

[0019] t l = argmax(h(z)) z∈[N min ,(N max -N min ) / twenty two)

[0020] In the formula, argmax represents the brightness value of the independent variable z corresponding to the maximum value of the function h(z), t l Indicates that the number of brightness pixels in the low-illuminance area is higher than the brightness value converted from other brightness;

[0021] The expression for calculating the mapping coefficient of the low illumination area is:

[0022]

[0023] In the formula, ln represents the natural logarithm operation, K l Represents the mapping coefficient of the low illumination area;

[0024] The expression for calculating the mapping function of the low illumination area is:

[0025]

[0026] In the formula, exp represents the exponential function with the natural constant e as the base, f l () represents the mapping function of the low illumination area.

[0027] In a further embodiment, the expression for calculating the probability of occurrence of the number of brightness pixels in the brightness value domain of the high illumination area in the dynamic range being higher than other brightnesses is:

[0028]

[0029] In the formula, m h Indicates that the number of brightness pixels in the brightness value range of the high illumination area is higher than the probability of occurrence of other brightness;

[0030] The calculation formula for the brightness value of the brightness pixel number higher than other brightness conversions is:

[0031] t h = argmax(h(z)) z∈[(N max -N min ) / 2,N max ] (6)

[0032] Where, t h Indicates that the number of brightness pixels in the high illumination area is higher than the brightness value converted from other brightness;

[0033] The expression for calculating the mapping coefficient of the high illumination area is:

[0034]

[0035] In the formula, ln represents the natural logarithm operation, K h Mapping coefficients for high illumination areas;

[0036] The expression for calculating the mapping function of the high illumination area is:

[0037]

[0038] In the formula, exp represents the exponential function with the natural constant e as the base, f h() represents the mapping function of the high illumination area.

[0039] In a further embodiment, based on the low illumination area image and the high illumination area image with redistributed brightness, the calculation expression for obtaining the image after global brightness reconstruction is:

[0040]

[0041] In the formula, I w is the image reconstructed after global brightness, f l (N) and f h (N) corresponds to the low illumination mapping function of formula (4) and the high illumination mapping function of formula (8) respectively.

[0042] In a further embodiment, the method of importing the image after global brightness reconstruction into the local detail function calculation to obtain the detail image of the global image includes:

[0043] The image after global brightness reconstruction is divided with the unit pixel as the center to obtain a number of overlapping image sub-blocks;

[0044] Numbering several image sub-blocks, and importing them into the local detail function calculation in the order of the numbers to obtain the detail image of each image sub-block;

[0045] Based on the detail image of each image sub-block, a detail image of the entire image is obtained;

[0046] Among them, the expression of the local detail function is as follows:

[0047]

[0048] Where s represents the detail image, min represents the minimum value, and function u is a step function.

[0049] In a further embodiment, a method for fusing a detail image after detail compensation with an image after global brightness reconstruction to obtain an image after detail compensation and global brightness reconstruction includes:

[0050] Normalizing all detail images after detail compensation and images after global brightness reconstruction respectively to obtain normalized detail images and images after global brightness reconstruction;

[0051] The normalized detail compensated detail image and the global brightness reconstructed image are fused to obtain a detail compensated and globally brightness reconstructed image, and the detail compensated and globally brightness reconstructed image is normalized and then output;

[0052] Among them, the formula for normalizing the detail image after global detail compensation is as follows:

[0053]

[0054] In the formula, represents the normalized detail image;

[0055] The formula for normalizing the image after global reconstruction of brightness is as follows:

[0056]

[0057] In the formula, Reconstruct the augmented image for the normalized global brightness;

[0058] The formula for fusing the normalized detail compensated detail image and the image reconstructed after global brightness is as follows:

[0059]

[0060] In the formula, It is the global brightness image after detail compensation;

[0061] The formula for image normalization with detail compensation and global brightness reconstruction is as follows:

[0062]

[0063] In the formula, Indicates rounding up operation, I d It is a grayscale image that can be displayed directly.

[0064] In a second aspect, the present invention provides a processing device, including a memory and a processor, wherein the memory stores a computer program, which is executed by the processor to implement the above-mentioned high dynamic range image reconstruction method that ensures image quality.

[0065] In a third aspect, the present invention provides a readable storage medium having a computer program stored thereon, which implements the steps of the above method when executed by a processor.

[0066] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0067] The present invention redistributes the brightness of the high dynamic range through a global brightness mapping method, thereby satisfying the human eye's need for image visualization as a whole; on the basis of global brightness mapping, it is also necessary to calculate the local details of the high dynamic range image, perform local detail compensation, and thus fuse the global brightness mapping image and the local detail image to reconstruct a brightness image that can be directly displayed. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1is a flow chart of a high dynamic range image reconstruction method for ensuring image quality according to the present invention;

[0069] Figure 2 is a schematic diagram of an embodiment of the present invention for obtaining a plurality of overlapping image sub-blocks;

[0070] Figure 3 It is the direct display result of the high dynamic range image of the present invention;

[0071] Figure 4 is the simulation result of the high dynamic range image of the present invention;

[0072] Figure 5 It is the direct display result of the high dynamic range image of the present invention;

[0073] Figure 6 It is the simulation result of the high dynamic range image of the present invention. DETAILED DESCRIPTION

[0074] In order to more fully understand the technical content of the present invention, the technical solution of the present invention is further introduced and illustrated in conjunction with specific embodiments below, but is not limited thereto.

[0075] Example 1

[0076] like Figure 1 to Figure 2 This embodiment provides a high dynamic range image reconstruction method that ensures image quality, including:

[0077] A high dynamic range image is input, and global brightness mapping is performed on the high dynamic range image. The image after global brightness mapping is imported into a mapping function for calculation to obtain an image after global brightness reconstruction;

[0078] The image after global brightness reconstruction is imported into the local detail function calculation to obtain the global detail image of the image;

[0079] Substituting the detail image into a local detail compensation algorithm to obtain a detail image after detail compensation;

[0080] The detail image after detail compensation is fused with the image after global brightness reconstruction to obtain an image with redistributed brightness and globally reconstructed after detail compensation.

[0081] The uneven brightness distribution of high dynamic range images can easily cause the target and background in the low illumination area to be unable to be displayed normally, and the high illumination area has a strong stimulation effect on the human eye. Therefore, the global brightness mapping method redistributes the brightness of the high dynamic range, thereby satisfying the human eye's visualization requirements for the image as a whole. In this embodiment, a high dynamic range image is input, and global brightness mapping is performed on the high dynamic range image. The image after global brightness mapping is imported into the mapping function calculation, and the method for obtaining the image after global brightness reconstruction includes:

[0082] According to the global brightness value range of the high dynamic range image, determine the low illumination area and high illumination area of ​​the image;

[0083] Select the brightness value range associated with the low illumination area and the brightness value range associated with the high illumination area respectively, calculate the probability of occurrence that the number of brightness pixels in the brightness value range of the low illumination area is higher than other brightnesses, and the probability of occurrence that the number of brightness pixels in the brightness value range of the high illumination area is higher than other brightnesses within the dynamic range, and convert the number of brightness pixels higher than other brightnesses into corresponding brightness values;

[0084] Substitute the occurrence probability of the low illumination area and the occurrence probability of the high illumination area into the logarithmic operation respectively to obtain the mapping coefficients of the low illumination area and the high illumination area respectively;

[0085] The mapping coefficients of the low illumination area and the high illumination area and the brightness value associated with the occurrence probability are imported into the mapping function calculation to obtain the low illumination area image and the high illumination area image with the brightness redistributed respectively;

[0086] Based on the low illumination area image and the high illumination area image with redistributed brightness, an image after global brightness reconstruction is obtained.

[0087] In a further embodiment, the expression for calculating the probability of occurrence of the number of brightness pixels in the brightness value domain of the low illumination area in the dynamic range being higher than other brightnesses is:

[0088] m l =max(h(z)) z∈[N min ,(N max -N min ) / twenty one)

[0089] Where N represents the brightness value of the high dynamic range image, max represents the maximum value, and z represents the brightness value range [N min ,(N max -N min ) / 2], N min and N max They represent the lower and upper limit brightness of the high dynamic range image respectively. Function h represents the probability of calculating the brightness. m l Indicates that the number of brightness pixels in the brightness value range of the low-illuminance area is higher than the probability of occurrence of other brightness;

[0090] The calculation formula for the brightness value of the brightness pixel number higher than other brightness conversions is:

[0091] t l = argmax(h(z)) z∈[N min ,(N max -Nmin ) / twenty two)

[0092] In the formula, argmax represents the brightness value of the independent variable z corresponding to the maximum value of the function h(z), t l Indicates that the number of brightness pixels in the low-illuminance area is higher than the brightness value converted from other brightness;

[0093] The expression for calculating the mapping coefficient of the low illumination area is:

[0094]

[0095] In the formula, ln represents the natural logarithm operation, K l Represents the mapping coefficient of the low illumination area;

[0096] The expression for calculating the mapping function of the low illumination area is:

[0097]

[0098] In the formula, exp represents the exponential function with the natural constant e as the base, f l () represents the mapping function of the low illumination area.

[0099] In a further embodiment, the expression for calculating the probability of occurrence of the number of brightness pixels in the brightness value domain of the high illumination area in the dynamic range being higher than other brightnesses is:

[0100] m h =max(h(z))z∈[(N max -N min ) / 2,N max ] (5)

[0101] In the formula, m h Indicates that the number of brightness pixels in the brightness value range of the high illumination area is higher than the probability of occurrence of other brightness;

[0102] The calculation formula for the brightness value of the brightness pixel number higher than other brightness conversions is:

[0103] t h =arg max(h(z))z∈[(N max -N min ) / 2,N max ] (6)

[0104] Where, t h Indicates that the number of brightness pixels in the high illumination area is higher than the brightness value converted from other brightness;

[0105] The expression for calculating the mapping coefficient of the high illumination area is:

[0106]

[0107] In the formula, ln represents the natural logarithm operation, K h Mapping coefficients for high illumination areas;

[0108] The expression for calculating the mapping function of the high illumination area is:

[0109]

[0110] In the formula, exp represents the exponential function with the natural constant e as the base, f h () represents the mapping function of the high illumination area.

[0111] In a further embodiment, based on the low illumination area image and the high illumination area image with redistributed brightness, the calculation expression for obtaining the image after global brightness reconstruction is:

[0112]

[0113] In the formula, I w is the image reconstructed after global brightness, f l (N) and f h (N) corresponds to the low illumination mapping function of formula (4) and the high illumination mapping function of formula (8) respectively.

[0114] After global brightness reconstruction, the overall brightness of the image has been rationally distributed. However, global brightness mapping cannot guarantee the integrity of local details of the image, which results in blurry local details of the brightness image after mapping. Therefore, local details of the high dynamic range image need to be calculated on the basis of global brightness mapping. Therefore, this embodiment performs the following operations:

[0115] The method of importing the image reconstructed by global brightness into the local detail function calculation to obtain the global detail image of the image includes:

[0116] The image after global brightness reconstruction is divided with the unit pixel as the center to obtain a number of overlapping image sub-blocks;

[0117] Numbering several image sub-blocks, and importing them into the local detail function calculation in the order of the numbers to obtain the detail image of each image sub-block;

[0118] Based on the detail image of each image sub-block, a detail image of the entire image is obtained;

[0119] Among them, the expression of the local detail function is as follows:

[0120]

[0121] Where s represents the detail image, min represents the minimum value, and function u is a step function.

[0122] Through the above operations, we can get the global brightness mapping image and the local detail image.

[0123] The method of fusing the detail image after detail compensation with the image after global brightness reconstruction to obtain the image after detail compensation and global brightness reconstruction includes:

[0124] The detail images after all detail compensation and the images after global brightness reconstruction are normalized respectively to obtain the normalized detail images and the images after global brightness reconstruction; local detail compensation is also required to fuse the global brightness mapping image and the local detail image to reconstruct a brightness image that can be directly displayed. Therefore, the following operations are performed in this embodiment:

[0125] The normalized detail compensated detail image and the global brightness reconstructed image are fused to obtain a detail compensated and globally brightness reconstructed image, and the detail compensated and globally brightness reconstructed image is normalized and then output;

[0126] Among them, the formula for normalizing the detail image after global detail compensation is as follows:

[0127]

[0128] In the formula, represents the normalized detail image;

[0129] The formula for normalizing the image after global reconstruction of brightness is as follows:

[0130]

[0131] In the formula, Reconstruct the augmented image for the normalized global brightness;

[0132] The formula for fusing the normalized detail compensated detail image and the image reconstructed after global brightness is as follows:

[0133]

[0134] In the formula, It is the global brightness image after detail compensation;

[0135] The formula for image normalization with detail compensation and global brightness reconstruction is as follows:

[0136]

[0137] In the formula, Indicates rounding up operation, I d It is a grayscale image that can be displayed directly.

[0138] Example 2 Figures 3 to 6 The present embodiment provides a processing device, including a memory and a processor, wherein the memory stores a computer program, which is executed by the processor to implement the following high dynamic range image reconstruction method with guaranteed image quality:

[0139] A high dynamic range image is input, and global brightness mapping is performed on the high dynamic range image. The image after global brightness mapping is imported into a mapping function for calculation to obtain an image after global brightness reconstruction;

[0140] The image after global brightness reconstruction is imported into the local detail function calculation to obtain the global detail image of the image;

[0141] Substituting the detail image into a local detail compensation algorithm to obtain a detail image after detail compensation;

[0142] The detail image after detail compensation is fused with the image after global brightness reconstruction to obtain an image with redistributed brightness and globally reconstructed after detail compensation.

[0143] Example 3 Figures 3 to 6 The embodiment shown provides a readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the following method are implemented:

[0144] A high dynamic range image is input, and global brightness mapping is performed on the high dynamic range image. The image after global brightness mapping is imported into a mapping function for calculation to obtain an image after global brightness reconstruction;

[0145] The image after global brightness reconstruction is imported into the local detail function calculation to obtain the global detail image of the image;

[0146] Substituting the detail image into a local detail compensation algorithm to obtain a detail image after detail compensation;

[0147] The detail image after detail compensation is fused with the image after global brightness reconstruction to obtain an image with redistributed brightness and globally reconstructed after detail compensation.

[0148] The present invention redistributes the brightness of the high dynamic range through a global brightness mapping method, thereby satisfying the human eye's need for image visualization as a whole; on the basis of global brightness mapping, it is also necessary to calculate the local details of the high dynamic range image, perform local detail compensation, and thus fuse the global brightness mapping image and the local detail image to reconstruct a brightness image that can be directly displayed.

[0149] The embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0150] The embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0151] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0152] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0153] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0154] The above is only a preferred embodiment of the present invention. Without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A high dynamic range image reconstruction method for ensuring image quality, characterized in that: include: A high dynamic range image is input, and global brightness mapping is performed on the high dynamic range image. The image after global brightness mapping is imported into a mapping function for calculation to obtain an image after global brightness reconstruction; The image after global brightness reconstruction is imported into the local detail function calculation to obtain the global detail image of the image; Substituting the detail image into a local detail compensation algorithm to obtain a detail image after detail compensation; The detail image after detail compensation is fused with the image after global brightness reconstruction to obtain an image with redistributed brightness and globally reconstructed after detail compensation; A method for inputting a high dynamic range image, performing global brightness mapping on the high dynamic range image, importing the image after global brightness mapping into a mapping function for calculation, and obtaining an image after global brightness reconstruction includes: According to the global brightness value range of the high dynamic range image, determine the low illumination area and high illumination area of ​​the image; Select the brightness value range associated with the low illumination area and the brightness value range associated with the high illumination area respectively, calculate the probability of occurrence that the number of brightness pixels in the brightness value range of the low illumination area is higher than other brightnesses, and the probability of occurrence that the number of brightness pixels in the brightness value range of the high illumination area is higher than other brightnesses within the dynamic range, and convert the number of brightness pixels higher than other brightnesses into corresponding brightness values; Substitute the occurrence probability of the low illumination area and the occurrence probability of the high illumination area into the logarithmic operation respectively to obtain the mapping coefficients of the low illumination area and the high illumination area respectively; The mapping coefficients of the low illumination area and the high illumination area and the brightness value associated with the occurrence probability are imported into the mapping function calculation to obtain the low illumination area image and the high illumination area image with the brightness redistributed respectively; Based on the low-illuminance area image and the high-illuminance area image with redistributed brightness, an image after global brightness reconstruction is obtained; The method of importing the image reconstructed by global brightness into the local detail function calculation to obtain the global detail image of the image includes: The image after global brightness reconstruction is divided with the unit pixel as the center to obtain a number of overlapping image sub-blocks; Numbering several image sub-blocks, and importing them into the local detail function calculation in the order of the numbers to obtain the detail image of each image sub-block; Based on the detail image of each image sub-block, a detail image of the entire image is obtained; Among them, the expression of the local detail function is as follows: In the formula, s represents the detail image, min represents the minimum value, function u is a step function, L, L n are the sequence numbers of the image sub-block and the image sub-block overlapping with L respectively; The method of fusing the detail image after detail compensation with the image after global brightness reconstruction to obtain the image after detail compensation and global brightness reconstruction includes: Normalizing all detail images after detail compensation and images after global brightness reconstruction respectively to obtain normalized detail images and images after global brightness reconstruction; The normalized detail compensated detail image and the global brightness reconstructed image are fused to obtain a detail compensated and globally brightness reconstructed image, and the detail compensated and globally brightness reconstructed image is normalized and then output; Among them, the formula for normalizing the detail image after global detail compensation is as follows: In the formula, represents the normalized detail image; The formula for normalizing the image after global reconstruction of brightness is as follows: In the formula, is the normalized global brightness reconstruction image, I w The image reconstructed for global brightness; The formula for fusing the normalized detail compensated detail image and the global brightness reconstructed image is as follows: In the formula, It is the global brightness image after detail compensation; The formula for image normalization with detail compensation and global brightness reconstruction is as follows: In the formula, Indicates rounding up operation, I d It is a grayscale image that can be displayed directly.

2. The high dynamic range image reconstruction method for ensuring image quality according to claim 1, characterized in that: The expression for calculating the probability that the number of brightness pixels in the brightness value range of the low illumination area within the dynamic range is higher than other brightness is: m l =max(h(z)) z∈[N min ,(N max -N min ) / 2] (6) Where N represents the brightness value of the high dynamic range image, max represents the maximum value, and z represents the brightness value range [N min ,(N max -N min ) / 2], N min and N max They represent the lower and upper limit brightness of the high dynamic range image respectively. Function h represents the probability of calculating the brightness. m l Indicates that the number of brightness pixels in the brightness value range of the low-illuminance area is higher than the probability of occurrence of other brightness; The calculation formula for the brightness value of the brightness pixel number higher than other brightness conversions is: t l =argmax(h(z)) z∈[N min ,(N max -N min ) / 2] (7) In the formula, argmax represents the brightness value of the independent variable z corresponding to the maximum value of the function h(z), t l Indicates that the number of brightness pixels in the low-illuminance area is higher than the brightness value converted from other brightness; The expression for calculating the mapping coefficient of the low illumination area is: In the formula, ln represents the natural logarithm operation, K l Represents the mapping coefficient of the low illumination area; The expression for calculating the mapping function of the low illumination area is: In the formula, exp represents the exponential function with the natural constant e as the base, f l () represents the mapping function of the low illumination area.

3. The high dynamic range image reconstruction method for ensuring image quality according to claim 2, characterized in that: The expression for calculating the probability that the number of brightness pixels in the brightness value range of the high illumination area within the dynamic range is higher than that of other brightness is: m h =max(h(z)) z∈[(N max -N min ) / 2,N max ] (10) In the formula, m h Indicates that the number of brightness pixels in the brightness value range of the high illumination area is higher than the probability of occurrence of other brightness; The calculation formula for the brightness value of the brightness pixel number higher than other brightness conversions is: t h =argmax(h(z)) z∈[(N max -N min ) / 2,N max ] (11) Where, t h Indicates that the number of brightness pixels in the high illumination area is higher than the brightness value converted from other brightness; The expression for calculating the mapping coefficient of the high illumination area is: In the formula, ln represents the natural logarithm operation, K h Mapping coefficients for high illumination areas; The expression for calculating the mapping function of the high illumination area is: In the formula, exp represents the exponential function with the natural constant e as the base, f h () represents the mapping function of the high illumination area.

4. The high dynamic range image reconstruction method for ensuring image quality according to claim 3, characterized in that: Based on the low-illuminance area image and the high-illuminance area image with redistributed brightness, the calculation expression for the image after global brightness reconstruction is obtained: In the formula, I w is the image reconstructed after global brightness, f l (N) and f h (N) corresponds to the low illumination mapping function of formula (9) and the high illumination mapping function of formula (13) respectively.

5. A processing device, comprising a memory and a processor, characterized in that: The memory stores a computer program, which is executed by the processor to implement the high dynamic range image reconstruction method with guaranteed image quality according to any one of claims 1 to 4.

6. A readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

Images