Polarization calibration method, system and device for aperture-divided polarization camera and storage medium

Abstract

The invention relates to the technical field of polarized optical imaging, in particular to a polarization calibration method, system and device for a sub-aperture polarization camera and a storage medium, and the method comprises the steps: obtaining theoretical Stokes vectors of incident light in different polarization states and the intensity distribution of images shot by the camera, and calculating the light intensity vectors of a camera receiving light field of the incident light in different polarization states; obtaining a normalized instrument matrix and a normalized coefficient according to the light intensity vector of the camera receiving light field of the incident light of different polarization states and the theoretical Stokes vector of the incident light of different polarization states; and finally, calculating an instrument matrix according to the normalization coefficient and the normalized instrument matrix, and realizing polarization calibration of the aperture-divided polarization camera by using the instrument matrix. The method is not limited to calibration of a linear polarization component, but carries out global polarization calibration from an overall angle including different polarization states, so that the accuracy of polarization calibration precision is improved, the polarization calibration precision is high, and the problems that an existing polarization calibration method is low in calibration precision and poor in reliability are solved.

Description

Technical Field

[0001] The present invention relates to the field of polarization optical imaging technology, and particularly to a polarization calibration method, system, device, and storage medium for a split-aperture polarization camera. Background Technique

[0002] Polarization optical imaging technology combines optical intensity imaging and polarization technology organically, and can simultaneously obtain the optical intensity information and polarization information of a target object in two-dimensional space. The application fields include polarization defogging imaging, polarization three-dimensional imaging, camouflage recognition, target enhanced detection, imaging through biological scattering media, etc. However, due to factors such as the angular deviation of the transmission axis of the analyzer and the optical performance differences of each channel caused by assembly errors in the split-aperture polarization camera, polarization measurement errors will occur. Therefore, in practical applications, it is crucial to perform polarization calibration on the split-aperture polarization camera.

[0003] The Chinese invention with the publication number CN113970374A discloses a calibration method for a split focal plane polarization detection system. Before performing micro-displacement radiation calibration and micro-displacement polarization calibration, equipment preparation is carried out; micro-displacement radiation calibration is performed on the split focal plane detection system, the gain coefficient and polarization coefficient are fitted, the background noise is obtained, and the response image after micro-displacement radiation correction is obtained; after micro-displacement radiation calibration, micro-displacement polarization calibration is performed on the system, and the polarization coefficients at different temperatures are calculated according to the polarization imaging model; and the average of the calculated polarization coefficient matrices at different temperatures is taken to obtain the final polarization coefficient, and the polarization camera is corrected according to the final polarization coefficient, so as to realize the polarization calibration of the polarization camera. This method can reduce the spatial noise of the camera and correct the non-uniformity of the polarization camera by using the calibration method of the infrared split focal plane polarization detection system. However, since the split focal plane polarization detection system can only detect the linear polarization component and only considers the calibration of the linear polarization component, this calibration method does not consider the global polarization calibration including the circular polarization component and the elliptical polarization component from an overall perspective, resulting in poor polarization calibration accuracy and low reliability. Summary of the Invention

[0004] Aiming at the problems of low calibration accuracy and poor reliability in the existing polarization calibration methods, the present invention provides a polarization calibration method, system, device, and storage medium for a split-aperture polarization camera.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a polarization calibration method for a split-aperture polarization camera, including: Obtaining the theoretical Stokes vectors of incident light with different polarization states; Obtaining the intensity distribution of the camera captured images of incident light with different polarization states; Calculate the light intensity vector of the light field received by the camera for incident light of different polarization states based on the intensity distribution of the images captured by the camera for incident light of different polarization states. Obtain the normalized instrument matrix based on the light intensity vector of the light field received by the camera for incident light of different polarization states and the theoretical Stokes vectors of the incident light of different polarization states. Obtain the normalization coefficient based on the normalized instrument matrix and the light intensity vector of the light field received by the camera for incident light of different polarization states. Calculate the instrument matrix based on the normalization coefficient and the normalized instrument matrix. Perform polarization calibration of the sub-aperture polarization camera using the instrument matrix.

[0006] Furthermore, the method for obtaining the theoretical Stokes vectors of the incident light of different polarization states is as follows: Obtain the Mueller matrix of the polarization state generator. Calculate the theoretical Stokes vectors of the incident light of different polarization states based on the Mueller matrix of the polarization state generator.

[0007] Preferably, the polarization state generator includes a broadband filter, a linear polarizer, and a rotatable achromatic quarter-wave plate that are sequentially arranged on the output optical axis of the light source.

[0008] Furthermore, the method for calculating the light intensity vector of the light field received by the camera for incident light of different polarization states based on the intensity distribution of the images captured by the camera for incident light of different polarization states is as follows:

[0009] where, is the light intensity vector of the light field received by the camera for incident light of a certain polarization state, is the average light intensity of the 0° linear polarization channel of the sub-aperture polarization camera, is the average light intensity of the 45° linear polarization channel of the sub-aperture polarization camera, is the average light intensity of the 90° linear polarization channel of the sub-aperture polarization camera, is the average light intensity of the right-handed circular polarization channel of the sub-aperture polarization camera.

[0010] Furthermore, the method for obtaining the normalized instrument matrix based on the light intensity vector of the light field received by the camera for incident light of different polarization states and the theoretical Stokes vectors of the incident light of different polarization states is as follows:

[0011] where, represents the Frobenius norm, 𝜆 is the regularization factor, represents the matrix transpose, is the Minkowski metric matrix, , represents a matrix, is the light intensity vector of the camera receiving light field of incident light of a certain polarization state, is the normalized instrument matrix, is the normalized theoretical Stokes vector,

[0012] wherein, is the theoretical Stokes vector of incident light of different polarization states.

[0013] Furthermore, the method for obtaining the normalization coefficient according to the normalized instrument matrix and the light intensity vector of the camera receiving light field of incident light of different polarization states is as follows: Obtain the maximum light intensity value , specifically:

[0014] According to the maximum light intensity value , calculate the normalization coefficient, specifically:

[0015] wherein, is the normalization coefficient, is the normalized instrument matrix, is the light intensity vector of the camera receiving light field of incident light of a certain polarization state.

[0016] Furthermore, the method for calculating the instrument matrix according to the normalization coefficient and the normalized instrument matrix is as follows:

[0017] wherein, is the normalized instrument matrix, is the instrument matrix.

[0018] The present invention provides a polarization calibration system for a sub-aperture polarization camera, including: Theoretical Stokes vector acquisition module: used to acquire the theoretical Stokes vector of incident light of different polarization states; Intensity distribution acquisition module of the camera-captured image: used to acquire the intensity distribution of the camera-captured images of incident light of different polarization states; Light intensity vector calculation module of the camera receiving light field: used to calculate the light intensity vector of the camera receiving light field of incident light of different polarization states according to the intensity distribution of the camera-captured images of incident light of different polarization states; Normalized instrument matrix acquisition module: used to obtain a normalized instrument matrix based on the light intensity vector of the camera-received light field of incident light with different polarization states and the theoretical Stokes vectors of incident light with different polarization states; Normalized coefficient acquisition module: used to obtain a normalized coefficient based on the normalized instrument matrix and the light intensity vector of the camera-received light field of incident light with different polarization states; Instrument matrix acquisition module: calculates an instrument matrix based on the normalized coefficient and the normalized instrument matrix; Polarization calibration module: used to perform polarization calibration of a split-aperture polarization camera by using the instrument matrix.

[0019] A terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0020] A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of the above method are implemented.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a polarization calibration method for a split-aperture polarization camera. This method calculates the light intensity vector of the camera-received light field of incident light with different polarization states by obtaining the theoretical Stokes vectors of incident light with different polarization states and the intensity distribution of the camera-captured images; obtains a normalized instrument matrix and a normalized coefficient based on the light intensity vector of the camera-received light field of incident light with different polarization states and the theoretical Stokes vectors of incident light with different polarization states; finally calculates the instrument matrix based on the normalized coefficient and the normalized instrument matrix, and uses the instrument matrix to achieve polarization calibration of the split-aperture polarization camera. This method is not limited to the calibration of linear polarization components, but starts from an overall perspective including different polarization states for global polarization calibration, thereby improving the accuracy of polarization calibration. After detection, after calibration by this method, the average absolute error of the detection of the degree of linear polarization (DoLP) drops from about 0.0358 to about 0.0060; the average absolute error of the detection of the degree of circular polarization (DoCP) drops from about 0.0742 to about 0.0089; the average absolute error of the detection of the degree of polarization (DoP) drops from about 0.0695 to about 0.0050, which can greatly improve the reliability of calibration and the accuracy of polarization information detection.

[0022] The present invention also provides a polarization calibration system for a split-aperture polarization camera. Through the settings of a theoretical Stokes vector acquisition module, an intensity distribution acquisition module for the images captured by the camera, a light intensity vector calculation module, a normalized instrument matrix acquisition module, a normalization coefficient acquisition module, an instrument matrix acquisition module, and a polarization calibration module, rapid and accurate polarization calibration of the split-aperture polarization camera is achieved. The system has a simple structure, a small amount of calculation, a small storage space occupied, and a fast calculation speed.

[0023] The present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The feature is that when the processor executes the computer program, the steps of the above method are implemented. The device has a simple structure, a low transformation cost, and a small resource occupancy.

[0024] A computer-readable storage medium stores a computer program. The feature is that when the computer program is executed by a processor, the steps of the above method are implemented. This storage medium has good portability and strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of a polarization calibration method for a split-aperture polarization camera of the present invention.

[0026] Figure 2 It is a diagram of a polarization calibration device for a split-aperture polarization camera in an embodiment of the present invention.

[0027] Figure 3 It is a simplified diagram of the process of a polarization calibration method for a split-aperture polarization camera in an embodiment of the present invention.

[0028] Figure 4 It is a curve graph of the degree of linear polarization (DoLP) before and after calibration using a polarization calibration method for a split-aperture polarization camera in an embodiment of the present invention.

[0029] Figure 5 It is a curve graph of the degree of circular polarization (DoCP) before and after calibration using a polarization calibration method for a split-aperture polarization camera in an embodiment of the present invention.

[0030] Figure 6 It is a curve graph of the degree of polarization (DoP) before and after calibration using a polarization calibration method for a split-aperture polarization camera in an embodiment of the present invention.

[0031] Figure 7 It is a structure diagram of a polarization calibration system for a split-aperture polarization camera of the present invention.

[0032] In the figure: 1-uniform light source, 2-broadband filter, 3-linear polarizer, 4-rotatable achromatic quarter-wave plate, 5-electrically controlled rotating stage, 6-polarization camera, 7-control mechanism Detailed implementation mode In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0033] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] The present invention will be further described in detail below in conjunction with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0035] Embodiment 1 The present invention discloses a polarization calibration method for a split-aperture polarization camera. Refer to Figure 1 , including: S1: Obtain the theoretical Stokes vector of incident light with different polarization states; S2: Obtain the intensity distribution of the camera-captured images of incident light with different polarization states; S3: Calculate the light intensity vector of the light field received by the camera for incident light with different polarization states according to the intensity distribution of the camera-captured images of incident light with different polarization states; S4: Obtain the normalized instrument matrix according to the light intensity vector of the light field received by the camera for incident light with different polarization states and the theoretical Stokes vector of incident light with different polarization states; S5: Obtain the normalization coefficient according to the normalized instrument matrix and the light intensity vector of the light field received by the camera for incident light with different polarization states; S6: Calculate the instrument matrix according to the normalization coefficient and the normalized instrument matrix; S7: Use the instrument matrix to perform polarization calibration on the split-aperture polarization camera.

[0036] It should be noted that the execution order of S1 - S3 can be set according to actual needs and is not limited to the sequential execution of steps S1 - S3.

[0037] This method is not limited to the calibration of linear polarization components. Instead, it starts from the overall perspective including different polarization states to perform global polarization calibration, thereby improving the accuracy of polarization calibration. The method is simple, with a small amount of calculation, easy to implement, and applicable to the fast and accurate polarization calibration of different split-aperture polarization cameras.

[0038] Embodiment 2 The present invention discloses a polarization calibration method for a split-aperture polarization camera. Referring to Figure 1 , it includes: S1: Obtain the theoretical Stokes vectors of incident light with different polarization states, specifically: Obtain the Mueller matrix of the polarization state generator; According to the Mueller matrix of the polarization state generator, calculate the theoretical Stokes vectors of incident light with different polarization states; S2: Obtain the intensity distribution of the camera-captured images of incident light with different polarization states; S3: According to the intensity distribution of the camera-captured images of incident light with different polarization states, calculate the light intensity vectors of the camera-received light fields of incident light with different polarization states, specifically:

[0039] Wherein, is the light intensity vector of the camera-received light field of incident light with a certain polarization state, is the average light intensity of the 0° linear polarization channel of the split-aperture polarization camera, is the average light intensity of the 45° linear polarization channel of the split-aperture polarization camera, is the average light intensity of the 90° linear polarization channel of the split-aperture polarization camera, is the average light intensity of the right-handed circular polarization channel of the split-aperture polarization camera; S4: According to the light intensity vectors of the camera-received light fields of incident light with different polarization states and the theoretical Stokes vectors of incident light with different polarization states, obtain the normalized instrument matrix, specifically:

[0040] Wherein, represents the Frobenius norm, 𝜆 is the regularization factor, represents the matrix transpose, is the Minkowski metric matrix, , represents a matrix, is the light intensity vector of the light field received by the camera for incident light of a certain polarization state, is the normalized instrument matrix, is the normalized theoretical Stokes vector,

[0041] wherein, is the theoretical Stokes vector of incident light of different polarization states; S5: According to the normalized instrument matrix and the light intensity vector of the light field received by the camera for incident light of different polarization states, obtain the normalization coefficient, specifically: Obtain the maximum light intensity value , specifically:

[0042] According to the maximum light intensity value , calculate the normalization coefficient, specifically:

[0043] wherein, is the normalization coefficient, is the normalized instrument matrix, is the light intensity vector of the light field received by the camera for incident light of a certain polarization state; S6: According to the normalization coefficient and the normalized instrument matrix, calculate the instrument matrix, specifically:

[0044] wherein, is the normalized instrument matrix, is the instrument matrix; S7: Use the instrument matrix to perform polarization calibration of the sub-aperture polarization camera.

[0045] Embodiment 3 See Figure 2 and Figure 3, taking the polarization calibration test device of a certain sub-aperture polarization camera as an example, the device includes a uniform light source 1, a broadband filter 2, a linear polarizer 3, a rotatable achromatic quarter-wave plate 4, and a polarization camera 6 arranged on the exit optical axis of the light source. The rotatable achromatic quarter-wave plate 4 is connected to an electric control rotating table 5 for controlling the rotation of the rotatable achromatic quarter-wave plate 4; the polarization camera 6 and the electric control rotating table 5 are connected to a control mechanism 7. The broadband filter 2, the linear polarizer 3, and the rotatable achromatic quarter-wave plate 4 together constitute a polarization state generator; the rotation step of the rotatable achromatic quarter-wave plate 4 usually takes a value of 1° to 5°, and the rotation step can be set according to requirements, not limited to this, and it rotates 180 / rotation step times in total. In this embodiment, the rotation step is taken as 1° for illustration.

[0046] Construct the polarization calibration test device of the sub-aperture polarization camera as described above. By rotating the rotatable achromatic quarter-wave plate 4, incident light with different polarization states is generated. The specific method is as follows: S1: Obtain the theoretical Stokes vectors of incident light with different polarization states, specifically: Obtain the Mueller matrix of the polarization state generator; According to the Mueller matrix of the polarization state generator, calculate the theoretical Stokes vectors of incident light with different polarization states, then:

[0047] Among them, is the theoretical Stokes vector of incident light with different polarization states, is the azimuth angle of the fast axis of the achromatic quarter-wave plate 4; S2: Obtain the intensity distribution of the camera-captured images of incident light with different polarization states; by rotating the achromatic quarter-wave plate 4 and using the polarization camera 7 to capture the original frame images, record the intensity distribution of the light field of incident light with different polarization states after passing through the four polarization channels of the camera; the original frame images captured by the polarization camera 7 include: 0° linearly polarized image, 45° linearly polarized image, 90° linearly polarized image, and right-handed circularly polarized image.

[0048] S3: According to the intensity distribution of the camera-captured images of incident light with different polarization states, calculate the light intensity vectors of the light fields received by the camera for incident light with different polarization states, specifically: Construct a set of 4×1 light intensity vectors from each original frame image : The 4×1 light intensity vector is composed of the average values of the gray values corresponding to the polarization images of the 4 polarization channels of the camera.

[0049]

[0050] Among them, is the light intensity vector of the camera receiving light field of incident light in a certain polarization state, is the average light intensity of the 0° linear polarization channel of the sub-aperture polarization camera, is the average light intensity of the 45° linear polarization channel of the sub-aperture polarization camera, is the average light intensity of the 90° linear polarization channel of the sub-aperture polarization camera, is the average light intensity of the right-handed circular polarization channel of the sub-aperture polarization camera; S4: Obtain the normalized instrument matrix according to the light intensity vector of the camera receiving light field of incident light in different polarization states and the theoretical Stokes vector of incident light in different polarization states, specifically:

[0051] Among them, represents the Frobenius norm, 𝜆 is the regularization factor, represents matrix transpose, is the Minkowski metric matrix, , represents a matrix, is the light intensity vector of the camera receiving light field of incident light in a certain polarization state, is the normalized instrument matrix, is the normalized theoretical Stokes vector,

[0052] Among them, is the theoretical Stokes vector of incident light in different polarization states; The initial value of ; S5: Obtain the normalization coefficient according to the normalized instrument matrix, specifically: Obtain the maximum light intensity value , where:

[0053] According to the maximum light intensity value , calculate the normalization coefficient, specifically:

[0054] Among them, is the normalization coefficient, is the normalized instrument matrix, is the light intensity vector of the camera receiving light field of incident light in a certain polarization state; S6: Calculate the instrument matrix according to the normalization coefficient and the normalized instrument matrix, specifically:

[0055] Among them, is the normalized instrument matrix, is the instrument matrix; S7: Use the instrument matrix to perform polarization calibration of the segmented aperture polarization camera.

[0056] To test the feasibility and beneficial effects of the method of the present invention, a multi-functional uniform light source integrating sphere from Lanfei Optics is used as the light source with a spatially uniform intensity distribution in the experiment. The light emitted after the LED white light passes through the integrating sphere is used as the incident light, and successively passes through the broadband filter 2 with a wavelength range of 450 nm to 650 nm, the horizontal polarizer 3, the achromatic quarter-wave plate 4 clamped by the electronically controlled rotating stage 5, and the segmented aperture polarization camera 6 to be calibrated. The experimental test environment is the Windows 11 (64-bit) operating system, and experimental calculations and data processing are performed on the MATLAB R2022b platform. The test results are shown in Figures 4 to 6 . It can be seen that the average absolute error of the degree of linear polarization (DoLP) after calibration by this method drops from about 0.0358 to about 0.0060; the average absolute error of the degree of circular polarization (DoCP) drops from about 0.0742 to about 0.0089; the average absolute error of the degree of polarization (DoP) drops from about 0.0695 to about 0.0050. It can be seen that compared with the traditional method, this method greatly improves the reliability of calibration.

[0057] Embodiment 4 Refer to Figure 7 , a polarization calibration method system for a segmented aperture polarization camera, comprising: Theoretical Stokes vector acquisition module: used to acquire the theoretical Stokes vectors of incident light with different polarization states; Intensity distribution acquisition module of the camera-captured image: used to acquire the intensity distribution of the camera-captured images of incident light with different polarization states; Light intensity vector calculation module of the camera-received light field: used to calculate the light intensity vectors of the camera-received light fields of incident light with different polarization states according to the intensity distribution of the camera-captured images of incident light with different polarization states; Normalized instrument matrix acquisition module: used to obtain the normalized instrument matrix according to the light intensity vectors of the camera-received light fields of incident light with different polarization states and the theoretical Stokes vectors of incident light with different polarization states; Normalization coefficient acquisition module: used to acquire normalization coefficients based on the normalized instrument matrix and the light intensity vectors of the camera-received light fields of incident lights with different polarization states; Instrument matrix acquisition module: calculates the instrument matrix based on the normalization coefficients and the normalized instrument matrix; Polarization calibration module: used to perform polarization calibration of the split-aperture polarization camera by using the instrument matrix.

[0058] Through the settings of the theoretical Stokes vector acquisition module, the intensity distribution acquisition module of the camera-captured image, the light intensity vector calculation module, the normalized instrument matrix acquisition module, the normalization coefficient acquisition module, the instrument matrix acquisition module, and the polarization calibration module, the system realizes fast and accurate polarization calibration of the split-aperture polarization camera. The system structure is simple, the calculation amount is small, the storage space occupied is small, and the calculation speed is fast.

[0059] The present invention provides a terminal device, including: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned various method embodiments are realized. Alternatively, when the processor executes the computer program, the functions of each module / unit in the above-mentioned various device embodiments are realized.

[0060] The computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention.

[0061] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory.

[0062] The processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), off-the-shelf programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0063] The memory can be used to store the computer program and / or modules. The processor realizes various functions of the terminal device by running or executing the computer program and / or modules stored in the memory, and by calling the data stored in the memory.

[0064] If the modules / units integrated in the terminal device are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0065] In summary, the present invention provides a polarization calibration method, system, device, and storage medium for a split-aperture polarization camera. By obtaining the theoretical Stokes vectors of incident light with different polarization states and the intensity distribution of the images captured by the camera, the light intensity vectors of the camera receiving light fields of incident light with different polarization states are calculated; according to the light intensity vectors of the camera receiving light fields of incident light with different polarization states and the theoretical Stokes vectors of incident light with different polarization states, a normalized instrument matrix and a normalized coefficient are obtained; finally, according to the normalized coefficient and the normalized instrument matrix, the instrument matrix is calculated, and the instrument matrix is used to implement the polarization calibration of the split-aperture polarization camera. This method is not limited to the calibration of linear polarization components, but starts from the overall perspective including different polarization states for global polarization calibration, thereby improving the accuracy of polarization calibration, having a high polarization calibration accuracy, and having good application prospects.

[0066] The above are only the preferred embodiments of the present invention and are not used to limit the technical solutions of the present invention. Those skilled in the art should understand that without departing from the spirit and principles of the present invention, the technical solutions can be subject to several simple modifications and substitutions, and these modifications and substitutions also fall within the protection scope covered by the claims.

Claims

1. A polarization calibration method for a split-aperture polarization camera, characterized in that: include: Obtain the theoretical Stokes vector of incident light with different polarization states; Obtaining intensity distribution of camera-captured images of incident light of different polarization states; According to the intensity distribution of the camera-captured image of the incident light with different polarization states, the light intensity vector of the camera-received light field of the incident light with different polarization states is calculated; A normalized instrument matrix is ​​obtained according to the light intensity vector of the camera received light field of the incident light with different polarization states and the theoretical Stokes vector of the incident light with different polarization states; Obtaining a normalization coefficient according to a normalized instrument matrix and a light intensity vector of a camera-received light field of incident light of different polarization states; Calculate the instrument matrix according to the normalization coefficient and the normalized instrument matrix; The polarization calibration of the split-aperture polarization camera is performed using the instrument matrix.

2. The polarization calibration method for a split-aperture polarization camera according to claim 1, characterized in that: The method for obtaining the theoretical Stokes vector of incident light in different polarization states is: Obtain the Mueller matrix of the polarization state generator; According to the Mueller matrix of the polarization state generator, the theoretical Stokes vector of the incident light with different polarization states is calculated.

3. The polarization calibration method for a split-aperture polarization camera according to claim 2, characterized in that: The polarization state generator comprises a broadband filter (2), a linear polarizer (3) and a rotatable achromatic quarter-wave plate (4) which are sequentially arranged on the output light axis of the light source.

4. The polarization calibration method for a divided-aperture polarization camera according to claim 1, characterized in that: The method for calculating the light intensity vector of the light field received by the camera of incident light with different polarization states according to the intensity distribution of the camera-captured image of incident light with different polarization states is: in, The light intensity vector of the light field received by the camera for incident light of a certain polarization state, is the average light intensity of the 0° linear polarization channel of the aperture polarization camera, is the average light intensity of the 45° linear polarization channel of the aperture polarization camera, is the average light intensity of the 90° linear polarization channel of the aperture polarization camera, is the average light intensity of the right circular polarization channel of the split-aperture polarization camera.

5. The polarization calibration method for a split-aperture polarization camera according to claim 1, characterized in that: The method for obtaining the normalized instrument matrix according to the light intensity vector of the camera receiving light field of incident light of different polarization states and the theoretical Stokes vector of the incident light of different polarization states is: in, represents the Frobenius norm, 𝜆 is the regularization factor, represents the matrix transpose, is the Minkowski metric matrix, , represents the matrix, The light intensity vector of the light field received by the camera for incident light of a certain polarization state, is the normalized instrument matrix, is the normalized theoretical Stokes vector, in, is the theoretical Stokes vector of incident light with different polarization states.

6. The polarization calibration method for a divided-aperture polarization camera according to claim 1, characterized in that: The method for obtaining the normalization coefficient according to the normalized instrument matrix and the light intensity vector of the camera receiving the light field of the incident light of different polarization states is: Get the maximum light intensity value , specifically: According to the maximum light intensity , calculate the normalization coefficient, specifically: in, is the normalization coefficient, is the normalized instrument matrix, The light intensity vector of the light field received by the camera for incident light of a certain polarization state.

7. The polarization calibration method for a split-aperture polarization camera according to claim 1, characterized in that: The method for calculating the instrument matrix according to the normalization coefficient and the normalized instrument matrix is: in, is the normalized instrument matrix, is the instrument matrix.

8. A polarization calibration system for a split-aperture polarization camera, characterized in that: include: Theoretical Stokes vector acquisition module: used to obtain the theoretical Stokes vector of incident light in different polarization states; The intensity distribution acquisition module of the camera-photographed image is used to acquire the intensity distribution of the camera-photographed image of the incident light in different polarization states; A light intensity vector calculation module for a light field received by a camera: used to calculate the light intensity vector of a light field received by the camera with incident light in different polarization states according to the intensity distribution of the camera-captured image with incident light in different polarization states; Normalized instrument matrix acquisition module: used to obtain the normalized instrument matrix according to the light intensity vector of the camera receiving light field of the incident light with different polarization states and the theoretical Stokes vector of the incident light with different polarization states; Normalization coefficient acquisition module: used to obtain normalization coefficient according to the normalized instrument matrix and the light intensity vector of the camera receiving light field of incident light of different polarization states; Instrument matrix acquisition module: calculates the instrument matrix according to the normalization coefficient and the normalized instrument matrix; Polarization calibration module: used to perform polarization calibration of aperture polarization cameras using the instrument matrix.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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