Coded aperture polarization spectrum imaging device, method and calibration method

Abstract

The invention discloses a coded aperture polarization spectral imaging device, method and calibration method, and relates to the field of coded spectral imaging. The invention solves the problem that the existing double Amici prism has nonlinear dispersion of the optical system and the dispersion element produces a deflection angle, which increases the difficulty of spectral calibration and correction and affects the quality of spectral imaging. The device comprises: a telescope objective lens, a plane reflector, a digital micromirror array, a filter, a relay lens, an optimized double Amici prism, a first reflector, a second reflector, an imaging objective lens and a micro-polarization array detector; the digital micromirror array, the filter, the relay lens, the optimized double Amici prism, the second reflector, the imaging objective lens and the micro-polarization array detector are coaxially arranged in sequence on a plane; the plane reflector is arranged between the digital micromirror array and the collimating lens and is located outside the optical axes of the two; the telescope objective lens is arranged on one side of the reflective surface of the plane reflector; the reflective surfaces of the first reflector and the second reflector are opposite. It is applied to the field of industrial applications.

Description

Technical Field

[0001] The present invention relates to the technical field of coded spectral imaging, and in particular to a coded aperture polarization spectral imaging device. Background Art

[0002] The coded aperture polarization spectrometer encodes and selects the optical signal of the observed target, and combines the dispersion device to measure the spectrum to reconstruct the spectrum image. There are two main structures: spatial dimension encoding and spectral dimension encoding. Dispersive spectrometers will cause dispersion nonlinearity and spectral line bending due to the inherent problems of dispersion elements such as prisms or gratings. These phenomena directly affect the application of spectral image data. Therefore, it is necessary to monitor the changes in the central wavelength and bandwidth of each spectral channel before use to ensure the accuracy of spectral calibration.

[0003] The coded aperture polarization spectrometer uses a digital micromirror array (DMD) instead of a slit. This structural change greatly undermines the premise of spectral calibration of traditional imaging systems. In addition, in a single imaging process, the original image obtained by the coded aperture polarization spectral imaging system is essentially the result of the superposition of multiple wavelengths, and obtaining a single wavelength image requires an algorithm. This special structure and imaging method make the classic spectral calibration scheme no longer applicable.

[0004] As a dispersive element, prism has the advantages of high energy transmittance, wide imaging spectrum, and simple structure. However, ordinary prisms have poor performance in terms of spectral resolution, spectral linearity, and optical path directness. In addition, there is inherent spectral line bending when used in spectral imaging systems. The existence of spectral line bending will lead to spectral aliasing, increasing the difficulty of subsequent data processing; poor optical path directness will cause the system optical path to bend, increasing the complexity of the system and the difficulty of installation and adjustment. In order to overcome the defects of single prism as a spectroscopic element, the system's detection ability for weak signals can be improved by correcting the system's spectral dispersion nonlinearity and spectral line bending. Calibration of the detector can ensure its measurement accuracy, especially in multi-spectral or hyper-spectral imaging. The data after spectral calibration is more convenient for data processing and decoding, including spectral reconstruction, feature extraction and analysis, which is crucial to ensure the accuracy and precision of the spectral measurement system. It can not only improve the measurement performance of the system, but also ensure the reliability and comparability of the data, providing a solid foundation for scientific research and practical applications. Spectral calibration plays an important role and significance in scientific research, industrial applications, medical diagnosis and other fields.

[0005] Typical components of the monochromatic dispersion coded aperture system include digital micromirror devices (DMDs) and double Amici prisms (DAPs). As a spectroscopic element, the double Amici prism itself causes dispersion nonlinearity and dispersion spectrum bending in the optical system due to its dispersion principle. At the same time, since the dispersion element produces a certain deflection angle, it increases the difficulty of spectrum calibration and correction, greatly affecting the quality of spectral imaging, and introducing large errors during assembly and debugging. Summary of the invention

[0006] The present invention aims at the problems of optical system dispersion nonlinearity and dispersion spectrum bending in the double Amici prism in the existing monochromatic dispersion coded aperture system. At the same time, the dispersion element produces a certain deflection angle, which increases the difficulty of spectrum calibration and correction, greatly affects the quality of spectrum imaging, and introduces large errors during assembly and debugging. The present invention proposes a coded aperture polarization spectrum imaging device, which includes:

[0007] Telescope objective, plane mirror, digital micromirror array, filter, relay lens, optimized double Amici prism, first mirror, second mirror, imaging objective and micro-polarization array detector;

[0008] The digital micromirror array, the filter, the relay mirror, the optimized dual-Amici prism, the second reflector, the imaging objective lens and the micro-polarization array detector are coaxially arranged in sequence on a plane;

[0009] The plane reflector is arranged between the digital micromirror array and the collimating lens and is located outside the optical axes of the two.

[0010] The telephoto objective lens is arranged on one side of the reflective surface of the plane reflector;

[0011] The first reflector and the second reflector have opposite reflective surfaces.

[0012] Furthermore, a preferred embodiment is proposed, wherein the micro-polarization array detector is composed of a focal plane polarimeter and a sensor, and each superpixel on the sensor constitutes a 2*2 micropixel.

[0013] Furthermore, a preferred method is proposed, wherein the optimized dual-Amici prism acquisition method is:

[0014] Determine the refractive material of the prism, the deflection angle, the focal length of the imaging mirror, and the refractive index of light passing through the bi-Amici prism;

[0015] According to the constraints of the detector pixel size, the structural parameter values ​​and dispersion linearity that meet the design indicators of the actual spectrometer dispersion angle and the central wavelength light deflection angle are obtained under the selected optical material.

[0016] Furthermore, a preferred embodiment is proposed, in which the propagation path of the light through the double Amici prism is:

[0017]

[0018] in, The wavelength of the incident light and the optical axis The angle below, + is the incident angle of the first prism to the normal, is the incident angle into the second prism, is the incident angle into the third prism, is the incident angle of the third prism with the normal, is the angle between the outgoing light and the optical axis; is the refractive index of air, is the refractive index of the first prism and the third prism, is the refractive index of the second prism; is the angle between the internal normal of the first prism and the tangent line of the circle, is the vertex angle of the first prism, is the apex angle of the second prism; is the exit angle into the first prism, is the exit angle into the second prism, is the exit angle into the third prism, is the exit angle of incoming air, is the tangent angle of the left sphere, is the tangent angle of the right sphere;

[0019] The wavelength is The beam passes through The deflection angle is:

[0020]

[0021] The difference in the deviation angle between the two extreme wavelengths transmitted by the prism is the dispersion angle :

[0022]

[0023] in, is the deflection angle of the light beam with the largest wavelength in the wavelength range, is the deflection angle of the smallest wavelength beam within the wavelength range, is the angle of incidence of the maximum wavelength light beam entering the air within the wavelength range, The angle at which the smallest wavelength light beam in the wavelength range enters the air.

[0024] Furthermore, a preferred embodiment is proposed, wherein the optimized dual-Amici prism acquisition method further comprises:

[0025] The spectral linearity index is used to evaluate the uniformity of spectral expansion;

[0026] The spectral linearity index includes a standard deviation SD and a spectral sampling rate SSR.

[0027] Furthermore, a preferred embodiment is proposed, wherein the constraint conditions of the first reflector and the second reflector are:

[0028]

[0029] in, is the horizontal distance from the prism center wavelength output light to the first reflector incident point, h is the vertical height from the principal optical axis to the first reflector incident point, is the angle between the central wavelength emitted light and the optical axis, is the horizontal distance from the light emitted from the first reflector to the incident point of the second reflector, is the angle between the incident light of the second reflector and the optical axis.

[0030] Based on the same inventive concept, the present invention also proposes a coded aperture polarization spectral imaging method, which is implemented based on the above-mentioned imaging device, and the method includes:

[0031] The reflected light of the target object passes through the telescope objective lens and the plane reflector and reaches the digital micromirror array, realizing the optical axis offset, so that the image plane of the imaging lens tilts backward and is parallel to the plane of the plane reflector;

[0032] The visible light with spatial information modulated by the digital micromirror array is selected through a filter to pass through a specific range of visible light bands, and then collimated by a relay lens to reach a double Amici prism for dispersion. After spectral separation and shifting, it is reflected by the first reflector and the second reflector, and is received by the imaging objective lens and the micro-polarization array detector to complete the imaging.

[0033] Furthermore, a preferred embodiment is proposed, wherein the method further comprises: analyzing the relationship between the target spectrum and the encoding and the transformation relationship between the coordinate systems of each imaging surface, specifically:

[0034] The spectral density of the target in different polarization directions is established as ,in, and are two spatial dimensions, represents the wavelength, represents the linear Stokes component, k =0, 1, 2;

[0035] The coordinates after the plane reflector space coordinate transformation are:

[0036]

[0037] The spectral density after digital micromirror array coding modulation is established as:

[0038]

[0039] in, Indicates the spectral density effect corresponding to the spatial coordinates of the coded aperture;

[0040] The spectral density after the optimized double Amici prism shift is:

[0041]

[0042] in, Describe the translationally invariant optical impulse response of the relay lens, double-Amici prism, and imaging objective, is the dispersion shift caused by the optimized double-Amici prism;

[0043] The spectral density after the spatial coordinate transformation of the first reflector and the second reflector is:

[0044]

[0045] in, , , is the coordinate of the plane mirror after space transformation, is the image plane coordinate system of the digital micromirror array plane, is the spatial coordinate after digital micromirror array coding modulation, is the spatial coordinate after displacement through the double Amici prism, is the image plane coordinate system on the micro-polarization array detector plane.

[0046] Based on the same inventive concept, the present invention also proposes a coded aperture polarization spectrum calibration method, which is implemented based on the above imaging device and includes:

[0047] Determine the transformation relationship between the coordinate system after the plane mirror space transformation, the image plane coordinate system of the digital micromirror array plane, and the image plane coordinate system on the micro-polarization array detector plane:

[0048]

[0049] in, for The homogeneous coordinate representation of for The homogeneous coordinate representation of for The homogeneous coordinate representation of represents the translation vector between coordinate systems, Indicates the scaling between coordinate systems. Represents the scaling and translation between coordinate systems, and Represents the affine transformation matrix between coordinate systems;

[0050] The relationship between two discrete coordinate systems and the corresponding continuous coordinate system is:

[0051]

[0052]

[0053] in, represents the pixel size on the micro-polarization array detector, Indicates the size of the digital micromirror on the digital micromirror array, represents the rotation between the discrete coordinate system on the surface of the micro-polarization array detector and the image continuous coordinate system on the micro-polarization array detector, Represents the rotation between the discrete coordinate system on the surface of the digital micromirror array and the image continuous coordinate system on the digital micromirror array, represents the discrete coordinate system of the micro-polarization array detector surface, represents the optical center coordinates on the discrete coordinate system of the digital micromirror array surface, represents the internal parameters of the micro-polarization array detector, represents the internal parameters of the digital micromirror array, is the image plane coordinate system of the digital micromirror array plane.

[0054] The present invention is beneficial in that:

[0055] (1) The coded aperture polarization spectral imaging device proposed in the present invention optimizes the double Amici prism and corrects the propagation paths of light of different wavelengths, so that the spectrum maintains a linear distribution in the entire imaging range and reduces the spectral line bending, thereby improving the spectral resolution accuracy and ensuring that the measurement results are more accurate and reliable.

[0056] (2) In the coded aperture polarization spectral imaging device proposed in the present invention, a direct-view co-axial optical path design is adopted, so that the centers of the collimation system and the spectral imaging system are on the same optical axis, ensuring that the central wavelength light is vertically incident on the collimation system and vertically outgoing from the focusing imaging lens to the detector, which not only improves the spectral nonlinearity, but also makes the system simpler and more efficient during assembly and debugging, while improving the imaging quality and the accuracy of spectral measurement;

[0057] (3) Model building and analysis were performed for the system's spectral calibration, template calibration, and polarization calibration. By building a mathematical model, the corresponding relationship between the spectrum and the code in the system and the transformation relationship between the coordinate systems of each imaging surface were analyzed, so that the code element and the detector pixel size were matched and aligned. This optimized design not only improved the spectral resolution and spatial resolution, making the measurement results more accurate, but also made the model more consistent with the actual working state of the system. Through future experimental verification and correction, it is ensured that the model can accurately reflect the actual situation, providing a solid theoretical basis and practical reference for subsequent system calibration.

[0058] The present invention is applicable to the fields of scientific research, industrial application and medical diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Schematic diagram of the coded aperture polarization spectral imaging device according to the first embodiment, wherein 1 represents a target object, 2 represents a telescope objective, 3 represents a plane reflector, 4 represents a digital micromirror array, 5 represents a filter, 6 represents a relay mirror, 7 represents an optimized double Amici prism, 8 represents a first reflector, 9 represents a second reflector, 10 represents an imaging objective, and 11 represents a micro-polarization array detector;

[0060] Figure 2 The dual-Amici prism optimization design flow chart described in Implementation Example 11;

[0061] Figure 3 is the optimized dual-Amici prism ray tracing diagram of the eleventh embodiment, wherein R is the length of the base of the prism, The wavelength of the incident light and the optical axis The angle below, is the angle between the incident light normal and the optical axis, is the incident angle into the second prism, is the incident angle into the third prism, is the incident angle of the third prism with the normal, is the angle between the outgoing light and the optical axis; is the refractive index of air, is the refractive index of the first prism and the third prism, is the refractive index of the second prism; is the angle between the internal normal of the first prism and the tangent line of the circle, is the vertex angle of the first prism, is the apex angle of the second prism; is the exit angle into the first prism, is the exit angle into the second prism, is the exit angle into the third prism, is the exit angle of incoming air, The wavelength is The deflection angle of the light beam passing through are the central angles of the first prism and the second prism respectively;

[0062] Figure 4 The optical path diagram of the central light of the optimized double-Amici prism described in the eleventh embodiment;

[0063] Figure 5 A comparison diagram of the dispersion nonlinearity of the conventional double-Amisi prism and the optimized double-Amisi prism described in Embodiment 11, wherein Wavelength is wavelength and nm represents nanometers (unit of wavelength);

[0064] Figure 6 This is a schematic diagram of the double-Amici prism line spectrum bending according to the eleventh embodiment, wherein: Figure 6 (a) is the spectral line bending diagram of the conventional double-Amici prism. Figure 6 (b) is the spectral line bending diagram of the curved double-Amici prism, Fy is the image height on the Y axis, and Field is the field of view;

[0065] Figure 7 Design a flow chart for the coded aperture polarization spectral imaging device. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0067] Implementation method 1, see Figure 1 The coded aperture polarization spectral imaging device described in this embodiment includes:

[0068] Telescope objective 2, plane reflector 3, digital micromirror array 4, filter 5, relay lens 6, optimized double Amici prism 7, first reflector 8, second reflector 9, imaging objective 10 and micro polarization array detector 11;

[0069] The digital micromirror array 4, the filter 5, the relay lens 6, the optimized dual-Amici prism 7, the second reflector 9, the imaging objective lens 10 and the micro-polarization array detector 11 are coaxially arranged in sequence on a plane;

[0070] The plane reflector 3 is arranged between the digital micromirror array 4 and the collimating lens and is located outside the optical axes of the two;

[0071] The telephoto objective lens 2 is arranged on one side of the reflecting surface of the plane reflecting mirror 3;

[0072] The reflection surfaces of the first reflector 8 and the second reflector 9 are opposite to each other.

[0073] The traditional double Amici prism causes dispersion nonlinearity in the optical system, which makes the light of different wavelengths in the spectrum unevenly distributed during the spectroscopic process, thus affecting the accuracy and clarity of spectral imaging. The optimized double Amici prism in this embodiment can reduce the dispersion effect by optimizing the structure and materials, making the dispersion rate more linear when light passes through, thereby solving the dispersion problem of spectral imaging.

[0074] Due to the deflection angle and dispersion nonlinearity introduced by the traditional double Amici prism, the calibration and correction of the spectral imaging system become complicated and difficult. In this embodiment, the use of the optimized double Amici prism structure not only reduces the influence of the deflection angle, but also optimizes the optical path design, simplifies the calibration and correction process, and reduces the error through the reasonable arrangement of the digital micromirror array, relay mirror and filter, and the relative emission surfaces of the first reflector and the second reflector.

[0075] In the traditional assembly process, due to the complex optical path and component adjustment, large errors are often introduced, affecting the stability of spectral imaging quality. In this embodiment, by coaxially arranging optical components and reasonably setting the plane reflector and telescope objective lens, the optical path is made more stable and controllable, the errors in the assembly and debugging process are reduced, and the reliability and repeatability of the system are improved.

[0076] The coded aperture polarization spectral imaging device proposed in this embodiment effectively reduces dispersion nonlinearity and improves the resolution and accuracy of spectral imaging, thereby improving the imaging quality, through the optimized dual-Amici prism structure and overall optical layout.

[0077] The coded aperture polarization spectral imaging device proposed in this embodiment has a new optical path design and coaxial arrangement, which makes the assembly and debugging process simpler and more accurate, and reduces the complexity of system calibration and correction. Furthermore, it reduces the changes caused by assembly errors and optical element adjustments, improves the stability and reliability of the spectral imaging system, and makes it more reliable in practical applications.

[0078] In summary, the coded aperture polarization spectral imaging device effectively solves many problems existing in the traditional monochromatic dispersion coded aperture system by optimizing the optical design, reducing dispersion nonlinearity and simplifying the assembly and debugging process, and brings significant technological progress and improvement in spectral imaging quality, accuracy and stability.

[0079] Embodiment 2. This embodiment further limits the coded aperture polarization spectral imaging device described in embodiment 1. The micro-polarization array detector 11 is composed of a focal plane polarimeter and a sensor. Specifically, a group of micro-polarization filters are integrated on the focal plane, and each filter corresponds to one or more pixels. These filters are arranged in a regular array, and the polarization direction of each filter is different (for example, 0 degrees, 45 degrees, 90 degrees, 135 degrees) to detect polarized light in different directions. The detector chip is arranged behind or below the micro-polarization filter array to directly sense the light signal after passing through the filter. Each pixel or multiple sub-pixels in the super-pixel array correspond to filters with different polarization directions.

[0080] Each superpixel on the sensor consists of 2*2 micropixels.

[0081] In this embodiment, the focal plane polarimeter can accurately measure and analyze the polarization state of the incident light, which is particularly important for applications involving polarization information in spectral imaging. Through the application of the polarimeter, the polarization information of different wavelengths in the spectrum can be effectively obtained, thereby improving the accuracy and resolution of imaging. The 2*2 micro-pixel structure composed of each sensor super-pixel effectively increases the information collection and processing capacity of each pixel. This design can more finely capture subtle changes and signals in the optical system, such as dispersion correction or slight fluctuations in the spectrum, thereby improving the sensitivity and accuracy of imaging. The focal plane polarimeter combined with the configuration of the 2*2 micro-pixel sensor ensures that the optical signals on the entire focal plane are captured and processed uniformly and consistently. This consistency is very important for the performance of the spectral imaging system, which can reduce system errors and ensure the stability of imaging quality under different conditions.

[0082] Embodiment 3: This embodiment further limits the coded aperture polarization spectrum imaging device described in Embodiment 1. The optimized dual-Amici prism 7 acquisition method is:

[0083] Determine the refractive material of the prism, the deflection angle, the focal length of the imaging mirror, and the refractive index of light passing through the bi-Amici prism;

[0084] According to the constraints of the detector pixel size, the structural parameter values ​​and dispersion linearity that meet the design indicators of the actual spectrometer dispersion angle and the central wavelength light deflection angle are obtained under the selected optical material.

[0085] By determining the refractive material, deflection angle and focal length of the prism, as well as the refractive index of light passing through the prism, the optical structure that meets the requirements of the actual spectrometer can be accurately designed. This precise design ensures the dispersion control of the optical system and the accuracy of the light deflection angle during the imaging process, thereby improving the accuracy and stability of imaging.

[0086] According to the constraints of the detector pixel size, the prism structure parameter values ​​under the selected optical material are designed. This ensures that the light can be effectively captured and processed when passing through the prism, maximizing the signal-to-noise ratio and resolution of spectral imaging. By optimizing the dispersion linearity, the wavelength drift caused by dispersion can be reduced, further improving the reliability and accuracy of spectral data.

[0087] Embodiment 4: This embodiment further limits the coded aperture polarization spectrum imaging device described in Embodiment 3. The propagation path of the light through the double Amici prism is:

[0088]

[0089] in, The wavelength of the incident light and the optical axis The angle below, + is the incident angle of the first prism to the normal, is the incident angle into the second prism, is the incident angle into the third prism, is the incident angle of the third prism with the normal, is the angle between the outgoing light and the optical axis; is the refractive index of air, is the refractive index of the first prism and the third prism, is the refractive index of the second prism; is the angle between the internal normal of the first prism and the tangent line of the circle, is the vertex angle of the first prism, is the vertex angle of the second prism; is the exit angle into the first prism, is the exit angle into the second prism, is the exit angle into the third prism, is the exit angle of incoming air, is the tangent angle of the left sphere, is the tangent angle of the right sphere;

[0090] The wavelength is The deflection angle of the beam passing through for:

[0091]

[0092] The difference in the deviation angle between the two extreme wavelengths transmitted by the prism is the dispersion angle :

[0093]

[0094] in, is the deflection angle of the light beam with the largest wavelength in the wavelength range, is the deflection angle of the smallest wavelength beam within the wavelength range, is the angle of incidence of the maximum wavelength light beam entering the air within the wavelength range, The angle at which the smallest wavelength light beam in the wavelength range enters the air.

[0095] Embodiment 5: This embodiment further limits the coded aperture polarization spectrum imaging device described in Embodiment 3. The optimized dual-Amici prism 7 acquisition method further includes:

[0096] The spectral linearity index is used to evaluate the uniformity of spectral expansion;

[0097] The spectral linearity index includes a standard deviation SD and a spectral sampling rate SSR.

[0098] Embodiment 6: This embodiment further limits the coded aperture polarization spectroscopy device described in Embodiment 1, and the constraints of the first reflector 8 and the second reflector 9 are:

[0099]

[0100] in, is the horizontal distance from the prism center wavelength output light to the first reflector 8 incident point, h is the vertical height from the main optical axis to the first reflector 8 incident point, is the angle between the central wavelength emitted light and the optical axis, is the horizontal distance from the light emitted from the first reflector 8 to the incident point of the second reflector 9, is the angle between the incident light of the second reflector 9 and the optical axis at the central wavelength.

[0101] Embodiment 7: The coded aperture polarization spectral imaging method described in this embodiment is implemented based on the imaging device described in embodiment 1, and the method includes:

[0102] The reflected light of the target object 1 passes through the telephoto objective lens 2 and the plane reflector 3 and reaches the digital micromirror array 4, realizing the optical axis offset, so that the image plane of the imaging lens tilts backward and is parallel to the plane of the plane reflector 3;

[0103] The visible light with spatial information modulated by the digital micromirror array 4 is selected through a filter 5 to pass through a specific range of visible light bands, collimated by a relay lens 6, and then reaches a double Amici prism 7 for dispersion. After spectral separation and shifting, it is reflected by a first reflector 8 and a second reflector 9, and is received by an imaging objective lens 10 and a micro-polarization array detector 11 to complete imaging.

[0104] Embodiment 8: This embodiment further limits the coded aperture polarization spectral imaging method described in Embodiment 7. The method further includes: analyzing the relationship between the target spectrum and the code and the transformation relationship between the coordinate systems of each imaging surface, specifically:

[0105] The spectral density of the target in different polarization directions is established as ,in, and are two spatial dimensions, represents the wavelength, represents the linear Stokes component, k=0, 1, 2;

[0106] The coordinates after the plane reflector space coordinate transformation are:

[0107]

[0108] The spectral density after digital micromirror array coding modulation is established as:

[0109]

[0110] in, Indicates the spectral density effect corresponding to the spatial coordinates of the coded aperture;

[0111] The spectral density after the optimized double Amici prism shift is:

[0112]

[0113] in, Describe the translationally invariant optical impulse response of the relay lens, double-Amici prism, and imaging objective, is the dispersion shift caused by the optimized double-Amici prism;

[0114] The spectral density after the spatial coordinate transformation of the first reflector and the second reflector is:

[0115]

[0116] in, , , is the coordinate of the plane mirror after space transformation, is the image plane coordinate system of the digital micromirror array plane, is the spatial coordinate after digital micromirror array coding modulation, is the spatial coordinate after displacement through the double Amici prism, is the image plane coordinate system on the micro-polarization array detector plane.

[0117] Embodiment 9: The coded aperture polarization spectrum calibration method of this embodiment is characterized in that the method is implemented based on the imaging device described in embodiment 1, and the method includes:

[0118] Determine the transformation relationship between the coordinate system after the plane mirror space transformation, the image plane coordinate system of the digital micromirror array plane, and the image plane coordinate system on the micro-polarization array detector plane:

[0119]

[0120] in, for The homogeneous coordinate representation of for The homogeneous coordinate representation of for The homogeneous coordinate representation of represents the translation vector between coordinate systems, Indicates the scaling between coordinate systems. Represents the scaling and translation between coordinate systems, and Represents the affine transformation matrix between coordinate systems;

[0121] The relationship between two discrete coordinate systems and the corresponding continuous coordinate system is:

[0122]

[0123]

[0124] in, represents the pixel size on the micro-polarization array detector, Indicates the size of the digital micromirror on the digital micromirror array, represents the rotation between the discrete coordinate system on the surface of the micro-polarization array detector and the image continuous coordinate system on the micro-polarization array detector, Represents the rotation between the discrete coordinate system on the surface of the digital micromirror array and the image continuous coordinate system on the digital micromirror array, represents the discrete coordinate system of the micro-polarization array detector surface, represents the optical center coordinates on the discrete coordinate system of the digital micromirror array surface, represents the internal parameters of the micro-polarization array detector, represents the internal parameters of the digital micromirror array, is the image plane coordinate system of the digital micromirror array plane.

[0125] Implementation Method 11: See Figures 2 to 7This embodiment provides a specific example of the coded aperture polarization spectrum imaging device described in the first embodiment, and is also used to explain the second to sixth embodiments. Specifically:

[0126] Step 1: construct a coded aperture polarization spectroscopy device, the imaging device comprising: a target object 1, a telephoto objective 2, a plane reflector 3, a digital micromirror array 4, a filter 5, a relay lens 6, an optimized dual Amici prism 7, a first reflector 8, a reflector 9, an imaging objective 10 and a micro-polarization array detector 11. The light splitting module comprises an optimized dual Amici prism 7, a first reflector 8, and a second reflector 9, and each component is placed in sequence; the dual Amici prism is composed of three prisms, namely a first prism, a second prism, and a third prism, wherein the first prism is made of the same material as the second prism; the collimation system comprises a filter 5 and a relay lens 6.

[0127] The working principle of the device is as follows: the reflected light of the target object 1 passes through the telescope objective lens 2 and the plane reflector 3 and reaches the digital micromirror array 4. The plane reflector 3 realizes the optical axis offset, so that the image plane of the imaging lens is tilted backward and parallel to the plane of the digital micromirror array 4. The visible light with spatial information modulated by the coding template passes through the filter 5 to select a specific range of visible light bands, and then passes through the relay lens 6 for collimation and reaches the optimized double Amici prism 7 for dispersion. After the spectral separation and shift is generated, it is reflected by the first reflector 8 and the second reflector 9 and received by the imaging objective lens 10 and the micro-polarization array detector 11. The micro-polarization array detector is composed of a focal plane polarimeter and a sensor. Each superpixel on the sensor constitutes a 2*2 micropixel and has four micro-polarizers in different directions.

[0128] The plane reflector 3 is located between the digital micromirror array 4 and the collimating lens and outside the optical axis of the two. The light is first reflected by the plane reflector 3 to the digital micromirror array 4. A plane reflector is added after the telescope objective lens to achieve optical axis offset. The surface of the plane reflector is vertical, and the calculation formula of the plane reflector angle is: ,in, is the refractive index of air, , is the incident angle, is the angle of incidence, that is, the angle of incidence is equal to the angle of reflection.

[0129] Step 2: Optimize the structure of the double Amisi prism: determine the prism refractive material, deflection angle, and focal length of the imaging mirror, and obtain the actual spectrometer dispersion angle Δ and the central wavelength light deflection angle under the selected optical material according to the detector pixel size constraint. The structural parameter values ​​and dispersion linearity of the design indicators include the angle between the second refractive surface of the first prism and the horizontal direction. and the angle between the third prism and the horizontal direction According to the structure of the conventional double Amisi prism, on the basis of the double Amisi prism, the two side surfaces are deformed into spherical surfaces with a certain curvature, and the propagation process of light in the improved double Amisi prism is further analyzed. The angle follows the modern symbol convention. By applying Snell's law on each interface, the wavelength is derived as The light is refracted through DAP;

[0130] The design parameters of the double-Amici prism optimized in step 2 depend on the number of spectral bands, the specifications of the imaging sensor, and the requirements of some other optical components within the system. The dispersion angle can also be expressed as:

[0131] (1)

[0132] in, Represents the wavelength on the imaging sensor With the central wavelength The distance between the clustering points, Represents the wavelength on the imaging sensor With the central wavelength The distance between the clustering points, represents the focal length of the imaging objective lens 10.

[0133] The double Amisi prism is a completely symmetrical structure consisting of three prisms. The first prism is a crown glass with medium dispersion, the second prism is a flint glass with high dispersion, and the third prism glass material is the same as the first prism, that is:

[0134] (2)

[0135] in, is the refractive index of the first prism, is the refractive index of the second prism.

[0136] According to the Schott formula in Zemax, six constant coefficients are required to calculate the refractive index of any wavelength, namely :

[0137] (3)

[0138] The incident light is traced through the double Amici prism. Figure 3 As shown:

[0139] Since the degree of the chord tangent angle is equal to half of the degree of the center angle of the arc it encloses, that is:

[0140] (4)

[0141] (5)

[0142] in, are the chord tangent angles of the left and right spheres, are the central angles of the first prism and the second prism respectively;

[0143] For the optimized bi-Amici prism, the angles follow the modern notation convention, e.g. Figure 2 As shown, based on ray tracing, by applying Snell's law at each interface, the wavelength is given by The propagation path of light through the optimized double-Amici prism:

[0144] (6)

[0145] in, The wavelength of the incident light and the optical axis The angle below, + is the incident angle of the first prism to the normal, is the incident angle into the second prism, is the incident angle into the third prism, is the incident angle of the third prism with the normal, is the angle between the outgoing light and the optical axis; is the refractive index of air, is the refractive index of the first prism and the third prism, is the refractive index of the second prism; is the angle between the internal normal of the first prism and the tangent line of the circle, is the vertex angle of the first prism, is the vertex angle of the second prism; is the exit angle into the first prism, is the exit angle into the second prism, is the exit angle into the third prism, is the exit angle of incoming air;

[0146] The wavelength is The deflection angle of the beam passing through It can be calculated as follows:

[0147] (7)

[0148] The difference in the deviation angle between the two extreme wavelengths transmitted by the prism is the dispersion angle ∆:

[0149] (8)

[0150] Step 3: Formulate the spectral linearity index requirements, including: when the discrete spectrum passing through the spectrometer is absolutely linear, the spectral linearity index does not vary with wavelength However, in actual practice, it is difficult for the spectrum to be absolutely linear, so the standard deviation (SD) and spectral sampling rate (SSR) must be met as spectral linearity index requirements.

[0151] The spectral linearity indexes SD and SSR specifically include: The derivative obtained is the role dispersion rate , when the angular dispersion rate is constant, the deflection angle δ does not vary with the wavelength This indicates that the spectrum dispersed by the spectrometer module is uniform and linear, which can be evaluated by standard deviation (SD) and spectrum sampling rate (SSR):

[0152]

[0153] The derivative of the deviation angle is The spectral dispersion is given per unit wavelength and n represents the number of bands between the defined wavelength ranges.

[0154] The standard deviation (SD) indicates the dispersion of the dispersion. The smaller the value, the more stable the dispersion.

[0155] The spectral sampling rate (SSR) indicates the maximum variation range of dispersion. The closer the value is to 1, the more uniform the dispersion of the system. The above two indicators are used to impose certain constraints on the selection of materials.

[0156] Finalization For H-LAK54, For H-FK95N, Figure 5 The dispersion nonlinearity comparison diagram of the conventional double Amici prism and the optimized double Amici prism is shown, where the double Amici prism imaged to the detector position curve optimized by Zemax simulation uses linear fitting and uses the coefficient of determination Determine the linearity of the two curves, The value range is between 0 and 1. The value closer to 1 indicates that the model has stronger explanatory power, that is, the data points are closer to the fitted straight line. Figure 6 As shown, the maximum spectral line bending of the conventional double-Amici prism is 5.69μm, and the maximum spectral line bending of the curved double-Amici prism is 4.51μm. The spectral line bending of the wavelength has been corrected to a certain extent, and the spectral lines of other wavelengths are bent to both sides of the central wavelength spectral line.

[0157] Step 4 The co-axial design of the system's optical splitter module specifically includes: The co-axial design of the optical splitter module means that the center of the collimation system and the spectral imaging system are on the same optical axis, and the central wavelength The angle between the incident and emitted light is 0, so the spatial positions of the first reflector 8 and the second reflector 9 need to be constrained. The value of .

[0158] The constraints include:

[0159] The height h of the center of the first reflector 8, the horizontal distance between the center of the first reflector 8 and the center of the third prism, and the angle between the center wavelength light emitting from the third prism and the optical axis The tangent theorem of the construction;

[0160] The height h of the center of the first reflector 8, the horizontal distance between the center of the second reflector 9 and the center of the first reflector 8, and the angle formed by the center wavelength light exiting the first reflector 8 and the second reflector 9 The tangent theorem of the construction;

[0161] Angle between the normal line of the first reflector 8 and the normal line of the second reflector 9 and the vertical direction , There is a geometric relationship between them.

[0162] Combination Figure 4 The geometric position relationship between the first reflector 8 and the second reflector 9 in the optical path diagram of the central wavelength light can be obtained:

[0163] (11)

[0164] in, is the angle between the central wavelength emitted light and the optical axis, is the angle between the incident light of the second reflector 9 and the optical axis at the central wavelength.

[0165] When the central wavelength light is emitted along the optical axis, that is, the optical axis offset between the emitted light and the incident light is 0,

[0166] (12)

[0167] The angle between the second reflector 9 and the optical axis is obtained by solving the above formula:

[0168] (13)

[0169] Step 5. In the coded aperture polarization spectroscopy device, the dispersion coding principle is the core technology for realizing spectral calibration. In order to ensure that the system can accurately calibrate spectra of different wavelengths, a complete polarization spectroscopy calibration model is established. The dispersion characteristics of the optical components are determined by a detailed analysis of the optical structure of the system. These components will disperse the incident light into spectra of different wavelengths and form different position distributions on the imaging surface. Through the precise modeling of these processes, the model is calibrated and verified using experimental data to ensure that it can accurately reflect the working status of the actual system. The purpose of establishing this model is to provide a theoretical basis and reference for subsequent system calibration, thereby improving the measurement accuracy and reliability of the system.

[0170] The flowchart of the polarization spectrum calibration analysis method proposed in this embodiment for the coded aperture polarization spectrum device is as follows: Figure 7 The incident light containing a continuous spectrum forms a perfect image at the plane of the digital micromirror array, forms a dispersed image after being refracted by the optimized double Amici prism, and forms a perfect image again at the plane of the micropolarization array detector.

[0171] The spectral density of the target in different polarization directions is established as ,in, and are two spatial dimensions, represents the wavelength, represents the linear Stokes component, where k=0, 1, 2.

[0172] Adding a reflector will change the optical path and spatial coordinates, and the coordinate transformation relationship needs to be redefined. If the reflection angle of the reflector is , assuming that the reflector changes the light path from the coordinate system Convert to new coordinate system The new coordinates can be transformed by the rotation matrix:

[0173] (14)

[0174] Among them, the reflection angles of the plane reflector 3, the first reflector 8, and the second reflector 9 are respectively ,

[0175] After the spatial coordinate transformation by plane reflector 3, the coordinates are

[0176] (15)

[0177] The spectral density after digital micromirror array coding modulation is established as

[0178] (16)

[0179] It represents the influence of spectral density corresponding to the spatial coordinates of the coded aperture. Because of the optical design alignment, the spatial dimensions and the spatial coordinates of the digital micromirror array and the micro-polarization array detector target surface correspond to each other. Then:

[0180] (17)

[0181] in, Represents the target surface of DMD, is the position on the coding plane The binary transmission value at Represents the size of the digital micromirror array micromirror.

[0182] The spectral density after the optimized double Amici prism shift is:

[0183] (18)

[0184] in, Describe the translationally invariant optical impulse responses of the relay lens, double-Amici prism, and imaging objective, and Describe the dispersion shift caused by a double-Amici prism.

[0185] The spectral density after the spatial coordinate transformation of the first reflector 8 and the second reflector 9 is:

[0186] (19)

[0187] in, , , coordinate system , , , , They respectively represent the coordinates after spatial transformation of the plane reflector, the image plane coordinate system of the digital micromirror array plane, the spatial coordinates after digital micromirror array coding modulation, the spatial coordinates after shifting through the double Amici prism, and the image plane coordinate system on the plane of the micro-polarization array detector. In addition, the light has corresponding spatial transformation coordinates after passing through the first reflector 8 and the second reflector 9, and the coordinate representation method is given in formula (14). It should be pointed out that the above five coordinate systems are all continuous image plane coordinate systems.

[0188] Step 6: Since the digital micromirror array and micro-polarization array detectors each have their own discrete coordinate systems, they can be defined as , , and because the digital micromirror units of the digital micromirror array rotate around their diagonals, the digital micromirror array is usually installed along a 45° direction. Therefore, it is necessary to calibrate the relationship between the seven continuous coordinate systems described in step 5 and the two discrete coordinate systems mentioned above, a total of nine coordinate systems, which is called template calibration. At the same time, it is also necessary to calibrate the dispersion displacement of the system The calibration is called spectral calibration. Through spectral calibration, the dispersion wavelength corresponding to the size of a digital micromirror at the position of the digital micromirror array can be calculated, which is the highest spectral resolution of the system.

[0189] The transformation relationship between the three continuous coordinate systems can be expressed as:

[0190]

[0191] in, , and They are , and The homogeneous coordinate representation of represents the translation vector between coordinate systems, Represents scaling and translation between coordinate systems. and Represent the affine transformation matrix between the coordinate systems. The three continuous coordinate systems have the same direction, so It should be a matrix containing only scaling transformations. The spatial coordinate transformations of the three reflectors are shown in formula (14).

[0192] The relationship between two discrete coordinate systems and the corresponding continuous coordinate systems can be expressed as:

[0193] (twenty two)

[0194] (twenty three)

[0195] in , They represent the pixel size on the micro-polarization array detector and the size of the digital micromirror on the digital micromirror array, represents the rotation between the discrete coordinate system on the surface of the micro-polarization array detector and the image continuous coordinate system on the micro-polarization array detector, Represents the rotation between the discrete coordinate system on the surface of the digital micromirror array and the image continuous coordinate system on the digital micromirror array, and They represent the optical center coordinates on the discrete coordinate system of the micro-polarization array detector surface and the discrete coordinate system of the digital micromirror array surface respectively. and They represent the internal parameters of the micro-polarization array detector and the digital micromirror array respectively. The parameters are known and no calibration is required.

[0196] Through spectral calibration and template calibration, the position parameters in equations (20) to (23) can be determined. In addition, the dispersion shift in equation (19) Also got calibration.

[0197] Step 7: Since the imaging device needs to perform polarization detection, it is also necessary to calibrate the polarization transmission in the imaging device. The polarization state of light can be represented by the Stokes vector, and the transformation of polarized light by the system can be represented by the Mueller matrix:

[0198] (twenty four)

[0199] in, and Denote the Stokes vectors of the incident light and the outgoing light, respectively, and M denotes the Mueller matrix of the system. Since the micro-polarization array detector used in the imaging device contains micro-polarization arrays with transmission directions along the reference axis at 0°, 45°, 90°, and 135°, the response of the detector also needs to be modulated by the micro-polarization array. This process can be expressed as

[0200] (25)

[0201] in, They represent the light intensity detected along the transmission direction of 0°, 45°, 90° and 135° respectively. is the known modulation matrix of the micro-polarization array and does not require calibration. The rank of is 3, and its fourth column is all 0, so the device cannot measure and obtain the circular polarization component of the incident light. In nature, only a few objects have strong circular polarization characteristics, so when using a micro-polarization array detector, only the linear polarization component of the target is detected. Assuming that the circular polarization component of the incident light, that is, the fourth component of the Stokes vector, is 0, the process of using the least squares method to invert the first three components of the Stokes vector modulated by the system can be expressed as

[0202] (26)

[0203] By performing polarization calibration, the Mueller matrix M of the system can be determined.

[0204] This embodiment corrects the dispersion nonlinearity and spectral line bending by improving the geometric structure of the double Amici prism, and optimizes the optical path design of the splitter module, improves the spectral nonlinearity and reduces the difficulty of debugging. At the same time, due to the increase of the improved structure and the increase of the device, the system error increases, resulting in a decrease in the system spectral resolution and a weakened polarization effect. This embodiment also analyzes the spatial coordinate transformation relationship of the light passing through each device of the system, and provides a method for establishing a system polarization spectrum model to guide the calibration process of the system, so that each device including the digital micromirror array and the micro-polarization array detector pixel alignment and matching to improve the spatial resolution and spectral resolution, and uses the established system model to guide the calibration process and detection reconstruction process of the system, and improve the reconstruction accuracy of coded aperture compression polarization spectrum imaging.

[0205] Although preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present disclosure. Obviously, those skilled in the art may make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

[0206] It should be understood by those skilled in the art that the embodiments of the present disclosure may be provided as methods, systems or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present disclosure may take 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.) containing computer-usable program code.

[0207] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks 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 produce 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 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in 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.

[0208] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure rather than to limit its protection scope. Although the present disclosure has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the present disclosure, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the disclosed claims to be approved.

Claims

1. A coded aperture polarization spectral imaging device, characterized in that: The device comprises: A telescope objective lens (2), a plane reflector (3), a digital micromirror array (4), a filter (5), a relay lens (6), an optimized double Amici prism (7), a first reflector (8), a second reflector (9), an imaging objective lens (10), and a micro-polarization array detector (11); The digital micromirror array (4), the filter (5), the relay mirror (6), the optimized dual-Amici prism (7), the second reflector (9), the imaging objective lens (10) and the micro-polarization array detector (11) are coaxially arranged in sequence on a plane; The plane reflector (3) is arranged between the digital micromirror array (4) and the collimating lens and is located outside the optical axes of the two. The telescopic objective lens (2) is arranged on one side of the reflection surface of the plane reflection mirror (3); The reflective surfaces of the first reflector (8) and the second reflector (9) are opposite to each other; The optimized dual-Amici prism (7) acquisition method is: Determine the refractive material of the prism, the deflection angle, the focal length of the imaging mirror, and the propagation path of light through the double Amici prism; According to the detector pixel size constraint, the structural parameter values ​​and dispersion linearity that meet the actual spectrometer dispersion angle and the central wavelength light deflection angle design indicators under the selected optical material are obtained; The propagation path of the light through the double Amici prism is: in, The wavelength of the incident light and the optical axis The angle below, + is the incident angle of the first prism to the normal, is the incident angle into the second prism, is the incident angle into the third prism, is the incident angle of the third prism with the normal, is the angle between the outgoing light and the optical axis; is the refractive index of air, is the refractive index of the first prism and the third prism, is the refractive index of the second prism; is the angle between the internal normal of the first prism and the tangent line of the circle, is the vertex angle of the first prism, is the apex angle of the second prism; is the exit angle into the first prism, is the exit angle into the second prism, is the exit angle into the third prism, is the exit angle of incoming air, is the tangent angle of the left sphere, is the tangent angle of the right sphere; The wavelength is The deflection angle of the beam passing through for: The difference in the deviation angle between the two extreme wavelengths transmitted by the prism is the dispersion angle : in, is the deflection angle of the light beam with the largest wavelength in the wavelength range, is the deflection angle of the smallest wavelength beam within the wavelength range, is the angle of incidence of the maximum wavelength light beam entering the air within the wavelength range, The angle at which the smallest wavelength light beam in the wavelength range enters the air.

2. The coded aperture polarization spectral imaging device according to claim 1, characterized in that: The micro-polarization array detector (11) is composed of a focal plane polarimeter and a sensor, and each superpixel on the sensor is composed of 2*2 micropixels.

3. The coded aperture polarization spectral imaging device according to claim 1, characterized in that: The optimized dual-Amici prism (7) acquisition method further includes: The spectral linearity index is used to evaluate the uniformity of spectral expansion; The spectral linearity index includes a standard deviation SD and a spectral sampling rate SSR.

4. The coded aperture polarization spectral imaging device according to claim 1, characterized in that: The constraints of the first reflector (8) and the second reflector (9) are: in, is the horizontal distance from the prism center wavelength output light to the first reflector (8) incident point, h is the vertical height from the principal optical axis to the first reflector (8) incident point, is the angle between the central wavelength emitted light and the optical axis, is the horizontal distance from the light emitted from the first reflector (8) to the incident point of the second reflector (9), is the angle between the incident light of the second reflector (9) and the optical axis at the central wavelength.

5. A coded aperture polarization spectral imaging method, characterized in that: The method is implemented based on the imaging device according to claim 1, and the method includes: The reflected light of the target object (1) passes through the telephoto objective lens (2) and the plane reflector (3) and reaches the digital micromirror array (4), thereby achieving an optical axis shift, so that the image plane of the imaging lens is tilted backward and parallel to the plane of the plane reflector (3); Visible light with spatial information modulated by the digital micromirror array (4) is selected through a filter (5) to pass through a specific visible light band, is collimated through a relay mirror (6), and then reaches a double Amici prism (7) for dispersion. After spectral separation and shifting, the light is reflected by a first reflector (8) and a second reflector (9) and is received by an imaging objective lens (10) and a micro-polarization array detector (11), thereby completing imaging.

6. The coded aperture polarization spectral imaging method according to claim 5, characterized in that: The method further includes: analyzing the relationship between the target spectrum and the code and the transformation relationship between the coordinate systems of each imaging surface, specifically: The spectral density of the target in different polarization directions is established as ,in, and are two spatial dimensions, represents the wavelength, represents the linear Stokes component, k =0, 1, 2; The coordinates after the plane reflector space coordinate transformation are: The spectral density after digital micromirror array coding modulation is established as: in, Indicates the spectral density effect corresponding to the spatial coordinates of the coded aperture; The spectral density after the optimized double Amici prism shift is: in, Describe the translationally invariant optical impulse response of the relay lens, double-Amici prism, and imaging objective, is the dispersion shift caused by the optimized double-Amici prism; The spectral density after the spatial coordinate transformation of the first reflector and the second reflector is: in, , , is the coordinate of the plane mirror after space transformation, is the image plane coordinate system of the digital micromirror array plane, is the spatial coordinate after digital micromirror array coding modulation, is the spatial coordinate after displacement through the double Amici prism, is the image plane coordinate system on the micro-polarization array detector plane.

7. A coded aperture polarization spectrum calibration method, characterized in that: The method is implemented based on the imaging device according to claim 1, and the method includes: Determine the transformation relationship between the coordinate system after the plane mirror space transformation, the image plane coordinate system of the digital micromirror array plane, and the image plane coordinate system on the micro-polarization array detector plane: in, for The homogeneous coordinate representation of for The homogeneous coordinate representation of for The homogeneous coordinate representation of represents the translation vector between coordinate systems, Indicates the scaling between coordinate systems. Represents the scaling and translation between coordinate systems, and Represents the affine transformation matrix between coordinate systems; The relationship between two discrete coordinate systems and the corresponding continuous coordinate system is: in, represents the pixel size on the micro-polarization array detector, Indicates the size of the digital micromirror on the digital micromirror array, represents the rotation between the discrete coordinate system on the surface of the micro-polarization array detector and the image continuous coordinate system on the micro-polarization array detector, Represents the rotation between the discrete coordinate system on the surface of the digital micromirror array and the image continuous coordinate system on the digital micromirror array, represents the discrete coordinate system of the MPA detector surface, represents the optical center coordinates on the discrete coordinate system of the digital micromirror array surface, represents the internal parameters of the micro-polarization array detector, represents the internal parameters of the digital micromirror array, is the image plane coordinate system of the digital micromirror array plane.

Images