A non-uniform vignetting correction method for infrared images based on gradient prior

Abstract

The present invention relates to the field of infrared image processing technology, and more particularly to a method for correcting infrared image non-uniformity vignetting based on gradient priors. The method comprises obtaining a uniformly radiated infrared noise image of a target imaging system, obtaining a gradient trend of infrared non-uniformity vignetting based on the infrared noise image; obtaining a real-time infrared image of the target imaging system, obtaining a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend; constructing an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, solving the objective function to obtain an optimal value of the real-time gradient operator; obtaining an optimal real-time gradient trend based on the optimal value of the real-time gradient operator, and correcting the real-time infrared image using the optimal real-time gradient trend to obtain a target infrared image after non-uniform vignetting correction. The method of the present invention can better achieve correction of infrared non-uniformity vignetting.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared image processing, and in particular to a method for correcting infrared image non-uniformity vignetting based on gradient prior. Background Art

[0002] Infrared imaging systems are widely used in military and civilian applications, including remote sensing, astronomical imaging, automatic target recognition, and video surveillance. However, in uncooled long-wave infrared (LWIR) imaging systems, temperature fluctuations in lenses and other mechanical components can cause a smooth intensity bias field to appear in the output image. This phenomenon is particularly pronounced when the infrared camera is capturing low-contrast scenes. This non-uniform intensity bias noise seriously affects the performance of infrared imaging systems. This non-uniform noise is spatially continuous, low in amplitude, and temperature-dependent, and is characterized by being referred to as infrared non-uniform vignetting. Traditional non-uniformity correction (NUC) technology, designed specifically for focal plane array (FPA) detectors, has difficulty effectively eliminating fixed-directional noise caused by optical factors. Therefore, it is necessary to develop effective image processing methods to compensate for the hardware defects of infrared detectors.

[0003] The first type of saliency class is based on spatial filtering and spectral filtering, which attempts to remove drastic changes in the image, thereby producing a smoothly varying intensity deviation. The filtering-based method has an inherent disadvantage. That is, it is difficult to appropriately select a threshold in both the spatial and spectral domains to distinguish the intensity changes between the latent infrared image and the intensity deviation. The second main method is based on intensity or gradient domain fitting, using a function model to construct pseudo-contrast in the intensity domain. Another method is to learn the derivatives and intensity deviations of the differential ideal infrared image. The third type creatively attempts to solve infrared non-uniformity vignetting in a variational framework. This method fully considers the salient features of the real degraded infrared image. The alternating minimization method is used to solve the non-convex energy function to estimate the intensity deviation and the latent image. However, all of the above methods have some common defects: (1) they are easy to affect the real signal, resulting in the loss of the real signal; (2) they converge slowly and have severe ghosting; (3) they rely on scene changes and information from previous and next frames. Therefore, it is of great significance to study a low-cost method to achieve infrared image non-uniformity vignetting correction. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] Therefore, the first object of the present invention is to propose a method for correcting infrared image non-uniform vignetting based on gradient prior, so as to better achieve the correction of infrared non-uniform vignetting.

[0006] The second object of the present invention is to provide an infrared image non-uniformity vignetting correction system based on gradient prior.

[0007] A third object of the present invention is to provide an electronic device.

[0008] A fourth object of the present invention is to provide a computer-readable storage medium.

[0009] To achieve the above-mentioned object, the first aspect of the present invention proposes a method for correcting infrared image non-uniformity vignetting based on gradient prior, comprising:

[0010] Acquire an infrared noise image of uniform radiation of a target imaging system, and obtain a gradient trend of infrared non-uniformity vignetting based on the infrared noise image;

[0011] Acquire a real-time infrared image of a target imaging system, and obtain a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend;

[0012] Constructing an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and solving the objective function to obtain an optimal value of the real-time gradient operator;

[0013] An optimal real-time gradient trend is obtained based on the optimal value of the real-time gradient operator, and the real-time infrared image is corrected using the optimal real-time gradient trend to obtain a target infrared image after non-uniform vignetting correction.

[0014] In the method of the first aspect of the present invention, obtaining the gradient trend of infrared non-uniformity vignetting based on the infrared noise image includes: performing polynomial surface fitting on the infrared noise image to obtain the gradient direction and gradient operator of the infrared noise image, and obtaining the gradient trend of infrared non-uniformity vignetting based on the gradient direction and gradient operator.

[0015] In the method of the first aspect of the present invention, constructing the objective function based on the gradient trend, the real-time gradient operator and the real-time gradient trend includes: adopting a standard least squares problem method to construct the objective function based on the gradient trend, the real-time gradient operator and the real-time gradient trend.

[0016] In the method of the first aspect of the present invention, the constructed objective function further includes a bias field smoothing prior term.

[0017] In the method of the first aspect of the present invention, solving the objective function is to adopt a ridge regression estimation method.

[0018] In the method of the first aspect of the present invention, after acquiring the infrared noise image, it is necessary to preprocess the infrared noise image and use the preprocessed infrared noise image to obtain the gradient trend of infrared non-uniformity vignetting.

[0019] In the method of the first aspect of the present invention, the uniformly radiated infrared noise image refers to an image captured by the target imaging system when the lens of the target imaging system is completely covered.

[0020] To achieve the above-mentioned object, the second aspect of the present invention provides a system for correcting infrared image non-uniformity vignetting based on gradient prior, comprising:

[0021] A first acquisition module is configured to acquire an infrared noise image of uniform radiation of a target imaging system, and obtain a gradient trend of infrared non-uniform vignetting based on the infrared noise image;

[0022] A second acquisition module is used to acquire a real-time infrared image of the target imaging system, and obtain a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend;

[0023] a processing module, configured to construct an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and solve the objective function to obtain an optimal value of the real-time gradient operator;

[0024] The vignetting correction module is used to obtain an optimal real-time gradient trend based on the optimal value of the real-time gradient operator, and use the optimal real-time gradient trend to correct the real-time infrared image to obtain a target infrared image after non-uniform vignetting correction.

[0025] To achieve the above-mentioned purpose, the third aspect of the present invention proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method proposed in the first aspect of the present invention.

[0026] To achieve the above-mentioned purpose, the fourth aspect of the present invention proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method proposed in the first aspect of the present invention.

[0027] The present invention provides a method, system, electronic device, and storage medium for correcting infrared image non-uniformity vignetting based on a gradient prior. The method comprises obtaining a uniformly radiated infrared noise image of a target imaging system and obtaining a gradient trend of infrared non-uniformity vignetting based on the infrared noise image. A real-time infrared image of the target imaging system is obtained and a real-time gradient operator and a real-time gradient trend of the real-time infrared image are obtained based on the gradient trend. An objective function is constructed based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and the objective function is solved to obtain an optimal value of the real-time gradient operator. An optimal real-time gradient trend is obtained based on the optimal value of the real-time gradient operator, and the real-time infrared image is corrected using the optimal real-time gradient trend to obtain a target infrared image corrected for non-uniformity vignetting. In this case, the uniformly radiated infrared noise image of the target imaging system is used to identify the gradient trend of non-uniformity vignetting generated by the target imaging system. The gradient trend is used as a prior to obtain an optimal value of the real-time gradient operator of the real-time infrared image, thereby obtaining an optimal real-time gradient trend. Finally, the real-time infrared image is corrected using the optimal real-time gradient trend to obtain a target infrared image corrected for non-uniformity vignetting. Compared with real-time infrared images, target infrared images eliminate deviations and can more accurately restore the grayscale distribution of the real scene, thereby better correcting infrared non-uniformity vignetting.

[0028] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A schematic flow chart of a method for correcting infrared image non-uniformity vignetting based on gradient prior provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of infrared vignetting trends of different infrared imaging systems provided by an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of gradient trends of different infrared imaging systems provided by embodiments of the present invention;

[0033] Figure 4 Graphs showing infrared non-uniformity vignetting correction results for different infrared imaging systems provided by embodiments of the present invention;

[0034] Figure 5 This is a block diagram of a gradient prior-based infrared image non-uniformity vignetting correction system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0036] The following describes a method and system for correcting infrared image non-uniformity vignetting based on gradient prior according to an embodiment of the present invention with reference to the accompanying drawings.

[0037] The embodiment of the present invention provides a method for correcting infrared image non-uniform vignetting based on gradient prior, so as to better achieve the correction of infrared non-uniform vignetting.

[0038] Figure 1 A flowchart of a gradient prior-based infrared image non-uniformity vignetting correction method provided by an embodiment of the present invention is provided.

[0039] like Figure 1 As shown, the gradient prior-based infrared image non-uniformity vignetting correction method includes the following steps:

[0040] Step S101 : acquiring a uniformly radiated infrared noise image of a target imaging system, and obtaining a gradient trend of infrared non-uniform vignetting based on the infrared noise image.

[0041] In step S101, the target imaging system refers to any infrared imaging system. The uniformly radiated infrared noise image refers to an image captured by the target imaging system when the lens of the target imaging system is completely covered.

[0042] It is easy to understand that the low-frequency non-uniform noise generated in the infrared imaging system is mainly caused by the radiation attenuation of the optical system and the radiation interference of the core shell. The presence of this noise will significantly affect the imaging quality, resulting in uneven brightness distribution in the image, which in turn affects subsequent image processing and analysis. In the same imaging system, the characteristics of this non-uniform noise are mainly affected by the working environment of the detector. In addition, with changes in ambient temperature and working time, the characteristics of the non-uniform noise will gradually evolve. For example, an increase in temperature may cause thermal expansion of optical components, thereby changing the optical path and radiation characteristics of the optical system; and long-term operation may cause the performance of the detector to decline, further exacerbating the impact of non-uniform noise. For pixels , the infrared thermal radiation obtained It can be expressed as:

[0043] (1)

[0044] in, represents the thermal radiation of the scene, is the radiation attenuation of the optical system, is the thermal radiation generated by the camera housing. Therefore, infrared non-uniformity vignetting as an additive noise.

[0045] In order to avoid the influence of real scene signals on the extraction of infrared non-uniform vignetting, it is necessary to obtain an infrared noise image under uniform radiation. Previous methods rely on expensive blackbody devices, etc. The present invention uses a lens cap to cover the lens to obtain an infrared noise image under uniform radiation.

[0046] To prevent the influence of real-world scene signals on the gradient trend of infrared non-uniform vignetting, it is necessary to obtain an infrared noise image under uniform radiation. Previous methods rely on expensive blackbody devices, etc. In this invention, a lens cap is used to cover the lens, and then the infrared noise image under uniform radiation is obtained using this target imaging system. In this case, covering the lens with a lens cap effectively eliminates the influence of external environmental factors on image quality, ensuring that the acquired infrared noise image reflects only the characteristics of uniform radiation.

[0047] Figure 2 Schematic diagram of infrared vignetting trends of different infrared imaging systems provided by embodiments of the present invention. Figure 2 As shown in the figure, the first row shows the infrared noise image and the corresponding infrared vignetting trend obtained by the infrared imaging system (a). The second row shows the infrared noise image and the corresponding infrared vignetting trend obtained by the infrared imaging system (b). Figure 2 As shown in Figure 2, the infrared vignetting trends of different imaging systems vary greatly.

[0048] In step S101, after acquiring the infrared noise image, it is necessary to preprocess the infrared noise image. The preprocessed infrared noise image is used to determine the gradient trend of infrared non-uniform vignetting. This preprocessing can be performed by low-pass filtering. The preprocessed infrared noise image is a vignetted planar image. Specifically, the infrared noise image is processed using a low-pass filter to remove high-frequency noise and unnecessary details while retaining low-frequency non-uniform vignetting noise, thereby highlighting the vignetting characteristics in the image.

[0049] In step S101, a gradient trend of infrared non-uniform vignetting is obtained based on an infrared noise image, including: performing polynomial surface fitting on the infrared noise image to obtain a gradient direction and a gradient operator of the infrared noise image, and obtaining a gradient trend of infrared non-uniform vignetting based on the gradient direction and the gradient operator.

[0050] Specifically, Figure 3 Schematic diagram of the gradient trend of different infrared imaging systems provided by the embodiment of the present invention. Figure 3 (a) is a schematic diagram of the gradient trend under an infrared imaging system. Figure 3 (b) is a schematic diagram of the gradient trend under another infrared imaging system. G u Indicates the gradient trend under the corresponding infrared imaging system. U xy Represents the gradient operator corresponding to the infrared imaging system. It represents the gradient direction under the corresponding infrared imaging system. Figure 3 As shown, for different infrared imaging systems, the intensity deviation trend is characterized by different gradient trends.

[0051] For the target imaging system, if the non-uniform vignetting of the infrared noise image is vignetted from the center to the outside, the corresponding noise center is obtained by polynomial surface fitting, and the change trend is analyzed to obtain the gradient direction. satisfy:

[0052] (2)

[0053] Where, represents the center of non-uniform noise under uniform radiation, represents the coordinates of any pixel, Represents a very small value to avoid division by 0. [] T Represents transpose. The gradient operator along the row / column of the preprocessed infrared noise image satisfies:

[0054] (3)

[0055] The gradient operator and gradient direction Combined with the characterization of the vignetting gradient trend of the image, the gradient trend satisfies:

[0056] (4)

[0057] Where, The gradient trend of infrared non-uniformity vignetting of the target imaging system reflects the non-uniformity of the target imaging system in infrared imaging.

[0058] Step S102 : acquiring a real-time infrared image of the target imaging system, and obtaining a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend.

[0059] In step S102 , the real-time infrared image may be an image captured by the target imaging system under any condition of the lens being covered or not covered.

[0060] Since real-time infrared images include non-uniform vignetting B , refer to the gradient trend of step S101 to obtain the non-uniform vignetting in the real-time infrared image B Real-time gradient operator and real-time gradient trend.

[0061] Real-time gradient trend meets:

[0062] (5)

[0063] (6)

[0064] Where, Non-uniform vignetting B Real-time gradient trend. Non-uniform vignetting B The real-time gradient operator of . The value of is affected by infrared radiation. is the gradient direction.

[0065] Step S103 : constructing an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and solving the objective function to obtain an optimal value of the real-time gradient operator.

[0066] In step S103, an objective function is constructed based on the gradient trend, the real-time gradient operator, and the real-time gradient trend. This includes constructing the objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend using a standard least squares problem. The constructed objective function also includes a bias field smoothing prior. A ridge regression estimation method is used to solve the objective function.

[0067] Specifically, considering the gradient representation in step S101 and step S102, the lower the thermal radiation of the real scene, the less the real-time infrared image is affected by the intensity bias. Therefore, the goal of the present invention is to find However, low-frequency non-uniform noise has smoothness. To constrain smoothness, the bias field smoothness prior is also introduced into the objective function. .in, It is the real-time infrared image along the gradient direction At the same time, in order to avoid excessive correction of the image like other existing methods and to make the calculated value contain a unique solution, the present invention also adds a Finally, the problem is simplified to a standard least squares problem, and the objective function is obtained. The objective function satisfies:

[0068] (7)

[0069] Where, is the objective function, is the bias field smoothing prior, Set to 2, Set it to a very small value, such as 0.0001. To indicate along The objective function is to minimize the difference between the non-uniformity in the image and the real scene.

[0070] Since the least squares problem here is irreversible or ill-conditioned, in order to ensure stability and reliability, the ridge regression estimation method is used to estimate the objective function Solve and get the estimated The estimated This is the optimal value of the real-time gradient operator.

[0071] Step S104 , obtaining an optimal real-time gradient trend based on the optimal value of the real-time gradient operator, and using the optimal real-time gradient trend to correct the real-time infrared image to obtain a target infrared image after non-uniform vignetting correction.

[0072] In step S104, since vignetting is additive noise, the estimated value is subtracted from the real-time infrared image to correct the non-uniform vignetting. Specifically, the optimal value of the real-time gradient operator is substituted into Equation (5) to obtain the optimal real-time gradient trend. This optimal real-time gradient trend is the actual non-uniform vignetting of the real-time infrared image. Subtracting the optimal real-time gradient trend from the real-time infrared image yields the target infrared image after non-uniform vignetting correction.

[0073] Figure 4 The infrared non-uniformity vignetting correction results of different infrared imaging systems provided by the embodiments of the present invention are shown in FIG. Figure 4 As shown in the figure, the first row shows the real-time infrared image and the corresponding target infrared image obtained by the infrared imaging system (a). The second row shows the real-time infrared image and the corresponding target infrared image obtained by the infrared imaging system (b).

[0074] In order to implement the above embodiment, the present invention further proposes a gradient prior-based infrared image non-uniformity vignetting correction system.

[0075] Figure 5 This is a block diagram of a gradient prior-based infrared image non-uniformity vignetting correction system provided by an embodiment of the present invention.

[0076] like Figure 5 As shown, the infrared image non-uniformity vignetting correction system based on gradient prior includes a first acquisition module 11, a second acquisition module 12, a processing module 13 and a vignetting correction module 14, wherein:

[0077] A first acquisition module 11 is configured to acquire an infrared noise image of uniform radiation of a target imaging system, and obtain a gradient trend of infrared non-uniform vignetting based on the infrared noise image;

[0078] A second acquisition module 12 is used to acquire a real-time infrared image of the target imaging system, and obtain a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend;

[0079] A processing module 13 is configured to construct an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and solve the objective function to obtain an optimal value of the real-time gradient operator;

[0080] The vignetting correction module 14 is configured to obtain an optimal real-time gradient trend based on an optimal value of a real-time gradient operator, and to correct the real-time infrared image using the optimal real-time gradient trend to obtain a target infrared image after non-uniform vignetting correction.

[0081] Furthermore, in a possible implementation of the embodiment of the present invention, the uniformly radiated infrared noise image in the first acquisition module 11 refers to an image captured by the target imaging system when the lens of the target imaging system is completely covered.

[0082] Furthermore, in a possible implementation of an embodiment of the present invention, in the first acquisition module 11, after acquiring the infrared noise image, it is also necessary to preprocess the infrared noise image, and use the preprocessed infrared noise image to obtain the gradient trend of infrared non-uniformity vignetting.

[0083] Furthermore, in a possible implementation of an embodiment of the present invention, in the first acquisition module 11, a gradient trend of infrared non-uniform vignetting is obtained based on the infrared noise image, including: performing polynomial surface fitting on the infrared noise image to obtain the gradient direction and gradient operator of the infrared noise image, and obtaining the gradient trend of infrared non-uniform vignetting based on the gradient direction and gradient operator.

[0084] Furthermore, in a possible implementation of an embodiment of the present invention, the processing module 13 constructs an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, including: adopting a standard least squares problem method to construct an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend.

[0085] Furthermore, in a possible implementation of the embodiment of the present invention, the objective function constructed in the processing module 13 also includes a bias field smoothing prior term.

[0086] Furthermore, in a possible implementation of the embodiment of the present invention, the objective function is solved in the processing module 13 by using a ridge regression estimation method.

[0087] It should be noted that the above explanation of the embodiment of the infrared image non-uniformity vignetting correction method based on gradient prior is also applicable to the infrared image non-uniformity vignetting correction system based on gradient prior in this embodiment, and will not be repeated here.

[0088] In an embodiment of the present invention, a uniformly radiated infrared noise image of a target imaging system is obtained, and a gradient trend of infrared non-uniformity vignetting is obtained based on the infrared noise image. A real-time infrared image of the target imaging system is obtained, and a real-time gradient operator and a real-time gradient trend of the real-time infrared image are obtained based on the gradient trend. An objective function is constructed based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and the objective function is solved to obtain an optimal value of the real-time gradient operator. An optimal real-time gradient trend is obtained based on the optimal value of the real-time gradient operator, and the real-time gradient trend is used to correct the real-time infrared image to obtain a target infrared image corrected for non-uniformity vignetting. In this case, the uniformly radiated infrared noise image of the target imaging system is used to identify the gradient trend of the non-uniformity vignetting generated by the target imaging system. The gradient trend is used as a priori to obtain the optimal value of the real-time gradient operator of the real-time infrared image, thereby obtaining the optimal real-time gradient trend. Finally, the real-time infrared image is corrected using the optimal real-time gradient trend to obtain a target infrared image corrected for non-uniformity vignetting. Compared to the real-time infrared image, the target infrared image eliminates deviations and can more accurately restore the grayscale distribution of the actual scene, thereby better correcting infrared non-uniformity vignetting.

[0089] The method and system of the present invention belong to the technical field of infrared image non-uniformity correction. Images captured under uniform radiation conditions are used to identify the trend of intensity deviation generated by each system, and various image gradient definitions are designed as priors to help identify and eliminate deviations. The enhanced image can accurately restore the grayscale distribution of the real scene. By using the pre-known trend of infrared non-uniform vignetting to construct a gradient prior function, correction of infrared non-uniform vignetting is achieved based on the gradient prior. The problem that temperature fluctuations of lenses and other mechanical components in infrared imaging cause non-uniform vignetting noise that seriously affects the performance of the infrared imaging system is solved. The vignetting trend is used to establish a gradient prior to achieve correction of infrared non-uniform vignetting. Low-cost correction of infrared image non-uniform vignetting can be achieved.

[0090] In order to implement the above embodiments, the present invention also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0091] In order to implement the above embodiments, the present invention further provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided in the above embodiments.

[0092] In order to implement the above embodiments, the present invention further provides a computer program product, including a computer program, which implements the methods provided in the above embodiments when executed by a processor.

[0093] In the descriptions of the aforementioned embodiments, the reference terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0094] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0095] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0096] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" is any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (not exhaustive) of computer-readable media include: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0097] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the aforementioned embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following technologies known in the art may be used: a discrete logic circuit having logic gates for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gates, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0098] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0099] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

[0100] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and are not to be construed as limiting the present invention. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for correcting infrared image non-uniformity vignetting based on gradient prior, characterized in that: include: Acquire a uniformly radiated infrared noise image of the target imaging system, wherein the uniformly radiated infrared noise image refers to an image captured by the target imaging system when a lens of the target imaging system is completely covered; Performing polynomial surface fitting on the infrared noise image to obtain a gradient direction and a gradient operator of the infrared noise image, and obtaining a gradient trend of infrared non-uniformity vignetting based on the gradient direction and the gradient operator; Acquire a real-time infrared image of the target imaging system, and obtain a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend, wherein the real-time infrared image is an image captured when a lens of the target imaging system is covered or uncovered, and the real-time gradient operator and the real-time gradient trend of the real-time infrared image are obtained in the same manner as the gradient operator and the gradient trend of the infrared noise image; An objective function is constructed based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and the objective function is solved to obtain an optimal value of the real-time gradient operator, wherein the objective function is: Among them, (x, y) represents the coordinates of the pixel in the image, G u (x, y) is the gradient trend of infrared non-uniform vignetting of the target imaging system, is the gradient direction of the real-time infrared image, B xy (x, y) is the real-time gradient operator, λ and δ represent weight coefficients, and r represents the gradient along direction, B''(r) is the real-time infrared image along the gradient direction The second derivative of An optimal real-time gradient trend is obtained based on the optimal value of the real-time gradient operator, and the real-time infrared image is corrected using the optimal real-time gradient trend to obtain a target infrared image after non-uniform vignetting correction.

2. The method for correcting infrared image non-uniformity vignetting based on gradient prior according to claim 1, characterized in that: The constructing of the objective function based on the gradient trend, the real-time gradient operator and the real-time gradient trend includes: A standard least squares problem approach is adopted to construct an objective function based on the gradient trend, the real-time gradient operator and the real-time gradient trend.

3. The method for correcting infrared image non-uniformity vignetting based on gradient prior according to claim 1 or 2, characterized in that: The constructed objective function also includes a bias field smoothness prior.

4. The method for correcting infrared image non-uniformity vignetting based on gradient prior according to claim 1, wherein: The objective function is solved by using a ridge regression estimation method.

5. The method for correcting infrared image non-uniformity vignetting based on gradient prior according to claim 1, characterized in that: After acquiring the infrared noise image, it is necessary to preprocess the infrared noise image and use the preprocessed infrared noise image to obtain the gradient trend of infrared non-uniformity vignetting.

6. A gradient prior-based infrared image non-uniformity vignetting correction system, characterized in that: include: A first acquisition module is configured to acquire a uniformly radiated infrared noise image of a target imaging system, wherein the uniformly radiated infrared noise image refers to an image captured by the target imaging system when a lens of the target imaging system is completely covered; The first acquisition module is further configured to perform polynomial surface fitting on the infrared noise image to obtain a gradient direction and a gradient operator of the infrared noise image, and obtain a gradient trend of infrared non-uniformity vignetting based on the gradient direction and the gradient operator; a second acquisition module, configured to acquire a real-time infrared image of the target imaging system, and obtain a real-time gradient operator and a real-time gradient trend of the real-time infrared image based on the gradient trend, wherein the real-time infrared image is an image captured when a lens of the target imaging system is covered or uncovered, and the real-time gradient operator and the real-time gradient trend of the real-time infrared image are obtained in the same manner as the gradient operator and the gradient trend of the infrared noise image; A processing module is configured to construct an objective function based on the gradient trend, the real-time gradient operator, and the real-time gradient trend, and solve the objective function to obtain an optimal value of the real-time gradient operator, wherein the objective function is: Among them, (x, y) represents the coordinates of the pixel in the image, G u (x, y) is the gradient trend of infrared non-uniform vignetting of the target imaging system, is the gradient direction of the real-time infrared image, B xy (x, y) is the real-time gradient operator, λ and δ represent weight coefficients, and r represents the gradient along direction, B''(r) is the real-time infrared image along the gradient direction The second derivative of The vignetting correction module is used to obtain an optimal real-time gradient trend based on the optimal value of the real-time gradient operator, and use the optimal real-time gradient trend to correct the real-time infrared image to obtain a target infrared image after non-uniform vignetting correction.

7. An electronic device, characterized in that: include: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 5 when executed by a processor.

Images