A full polarization distribution probing imaging system and method

Abstract

The application discloses a full-polarization distribution detection imaging system and method, and relates to the field of polarization detection. In the system, an anti-exposure automatic control system performs automatic light shielding processing on a sky polarization imaging system to prevent exposure. After obtaining the linear polarization information of the sky, a circular polarization light receiving control system obtains the circular polarization information of the sky through phase modulation, and then obtains the full-polarization information of the sky. A computer processing and control system is used to generate system combination instructions according to the meteorological state, obtain the linear polarization information of the sky when the instructions represent the combined work of the sky polarization imaging system and the anti-exposure automatic control system, obtain the full-polarization information of the sky when the instructions represent the combined work of the sky polarization imaging system and the circular polarization light receiving control system, and process the linear polarization information of the sky and / or the full-polarization information of the sky to further improve the imaging quality of the micro-polarization array. The application can be applied to different weather environments, and can efficiently and accurately obtain the full-polarization mode distribution information of the sky.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polarization detection, in particular to a full polarization distribution detection imaging system and method. BACKGROUND

[0002] Traditional sky polarization pattern detection methods have certain limitations in precision and efficiency: some detection methods cannot achieve complete coverage of the full sky range, resulting in missing polarization pattern information, which is difficult to meet the demand for global polarization characteristic analysis. Especially under strong sunlight, long-time exposure has a great impact on imaging. In addition, the existing technology has weak anti-interference ability when processing polarization signals in complex sky environment, and is easily affected by factors such as cloud layer and atmospheric scattering, making the detection result inaccurate.

[0003] Specifically, the sky polarization pattern detection device generally adopts a mechanical rotating polarizer scheme, which reverses the polarization information by collecting light intensity data in different polarization directions in time division. This method is limited by the speed and stability of mechanical rotation, and cannot synchronously acquire the polarization state distribution of the full field of view in real time. To solve the real-time problem, solid-state detection technology based on micro-polarizer array has gradually emerged, which realizes parallel collection of linear polarization information by integrating fixed-direction micro-polarizers at the detector pixel level, significantly improving the detection speed. However, the existing micro-polarizer array technology is still limited to the detection of linearly polarized light. In the presence of fog, dust and smoke, the incident unpolarized light is converted into partially circularly polarized light, resulting in the problem that the circular polarization component cannot be completely detected during the use of the micro-polarizer array. Especially in foggy weather, the circular polarization information is significantly improved. As an important part of the sky polarization pattern, the lack of circular polarization information leads to the inability of the existing system to completely describe the full polarization state of light, limiting the development of polarization navigation technology to higher precision and more widely applicable scenarios. SUMMARY

[0004] The purpose of the present application is to provide a full polarization distribution detection imaging system and method, which can be applied to different weather environments and efficiently and accurately acquire the full polarization pattern distribution information of the sky.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions.

[0006] In a first aspect, the present application provides a full polarization distribution detection imaging system, comprising a sky polarization imaging system, a circularly polarized light receiving control system, an anti-exposure automatic control system and a computer processing and control system.

[0007] The sky polarization imaging system is used to collect linear polarization information of the sky.

[0008] The anti-exposure automatic control system is used to automatically shield the sky polarization imaging system according to the sun's position to prevent exposure.

[0009] The circularly polarized light receiving control system is used to obtain the sky circular polarization information by phase modulation after obtaining the sky linear polarization information, and then obtain the sky full polarization information.

[0010] The computer processing and control system is connected with the sky polarization imaging system, the circularly polarized light receiving control system and the anti-exposure automatic control system, and is used to generate a system combination instruction according to a meteorological state, obtain the sky linear polarization information when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, obtain the sky full polarization information when the system combination instruction represents that the sky polarization imaging system and the circularly polarized light receiving control system work in combination, and interpolate and reconstruct the sky linear polarization information and / or the sky full polarization information in a spatial domain and perform a discrete Fourier transform to calculate all Stokes parameters.

[0011] In a second aspect, the present application provides a full polarization distribution detection imaging method, comprising the following steps.

[0012] A full polarization distribution detection imaging system is built.

[0013] The computer processing and control system generates a system combination instruction according to a meteorological state.

[0014] When the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, the computer processing and control system obtains the sky linear polarization information.

[0015] When the system combination instruction represents that the sky polarization imaging system and the circularly polarized light receiving control system work in combination, the computer processing and control system obtains the sky full polarization information.

[0016] The sky linear polarization information and / or the sky full polarization information are interpolated and reconstructed in a spatial domain and are subjected to a discrete Fourier transform to calculate all Stokes parameters.

[0017] According to the specific embodiments provided in the application, the application discloses the following technical effects: according to the weather state generation system combination instruction, different system combinations are used, so that the application can be suitable for different weather conditions. When the system combination instruction represents the combination of the sky polarization imaging system and the anti-exposure automatic control system, the sky linear polarization information is acquired, and this case can realize automatic light shielding processing under sunny weather, prevent long-time exposure of the camera, and improve the sky linear polarization imaging quality. When the system combination instruction represents the combination of the sky polarization imaging system and the circular polarization light receiving control system, the sky full polarization information is acquired, and this case can detect the sky circular polarization information under the condition of haze and smoke. Finally, the sky linear polarization information and / or the sky full polarization information are interpolated and reconstructed in the spatial domain and are subjected to discrete Fourier transform, so as to further improve the imaging quality of the micro-polarization array. In summary, the application realizes the acquisition of the sky full polarization mode under different weather conditions, can automatically adjust the system, so that the detection efficiency is higher, and because the anti-exposure processing can be performed by using the anti-exposure automatic control system, the detection accuracy can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0019] Figure 1 FIG. 1 is a structural schematic diagram of a full polarization distribution detection imaging system in an embodiment of the application.

[0020] Figure 2 FIG. 2 is a distribution diagram of a photosensitive detection unit.

[0021] Figure 3 FIG. 3 is a flowchart of a full polarization distribution detection imaging method in an embodiment of the application.

[0022] Figure 4 FIG. 4 is a schematic diagram of a full polarization distribution detection imaging method in another embodiment of the application.

[0023] Figure 5 FIG. 5 is a polarization angle arrangement diagram of a micro-polarization array.

[0024] The drawings show that: 101-lens; 102-micro-polarization array camera; 201-quarter wave plate; 202-first motor; 203-first rotating table; 301-baffle; 302-photosensitive detection unit; 3021-photosensitive element; 303-second motor; 304-second rotating table; 401-computer processing and control system. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0026] The present application provides a full-polarization distribution detection imaging system and method suitable for different weather changes by combining the advantages of a micro-polarization array. The system has a simple structure, is easy to integrate, and has excellent performance. The system can solve the problems of suppressing long-time exposure under sunlight and full-polarization imaging of the sky in a foggy environment in the process of polarization mode distribution detection, and efficiently and accurately obtain the full-polarization mode distribution information of the sky, thereby providing strong support for the research and application of polarization navigation.

[0027] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0028] In an exemplary embodiment, as shown in Figure 1 a full-polarization distribution detection imaging system is provided, which includes a sky polarization imaging system, a circularly polarized light receiving control system, an anti-exposure automatic control system, and a computer processing and control system.

[0029] The sky polarization imaging system is used to collect sky linear polarization information. Specifically, the sky polarization imaging system includes a lens 101 and a micro-polarization array camera 102. The lens 101 is arranged on the micro-polarization array camera 102, and the imaging optical axis of the micro-polarization array camera 102 is perpendicular to the horizontal plane and points to the sky. In operation, the sun's scattered light passes through the lens 101 and enters the micro-polarization array camera 102 to realize sky imaging and obtain sky linear polarization information.

[0030] In actual application, a bottom plate is further arranged, and the micro-polarization array camera 102 is horizontally placed on the bottom plate. The lens 101 above the micro-polarization array camera 102 can be hemispherical to image the sky.

[0031] The anti-exposure automatic control system is used to automatically shield the sky polarization imaging system according to the sun's azimuth to prevent exposure. Specifically, the anti-exposure automatic control system includes a baffle 301, a photosensitive detection unit 302, a second motor 303, and a second rotating table 304.

[0032] The light-sensitive detection unit 302 is arranged on the baffle 301, the baffle 301 is located above the lens 101 and is connected with the second motor 303; the light-sensitive detection unit 302 is used for detecting the current solar azimuth corresponding solar irradiance information, and then sending to the computer processing and control system 401. Figure 2 As shown in the figure, the light-sensitive detection unit 302 includes four light-sensitive elements 3021, and the four light-sensitive elements 3021 are distributed in a cross-shaped array on the baffle 301 (specifically, the back of the baffle 301, to face the sun), each light-sensitive element 3021 is equidistantly arranged with the geometric center of the baffle 301 as the symmetric point, the center angle of adjacent light-sensitive elements 3021 is 90°, to constitute a four-quadrant light detection matrix, which can detect light intensity in different directions, and then convert into solar irradiance information.

[0033] The second motor 303 is arranged on the second rotating table 304, and the second motor 303 and the second rotating table 304 are connected with the computer processing and control system 401. When the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, the system combination instruction further includes an azimuth angle instruction and an elevation angle instruction determined according to the solar irradiance information; the second rotating table 304 is used for adjusting the azimuth angle of the baffle according to the azimuth angle instruction, and the second motor 303 is used for adjusting the elevation angle of the baffle according to the elevation angle instruction, so as to realize anti-exposure of the micro-polarization array camera 102 at different angles.

[0034] In work, the second rotating table 304 and the second motor 303 track the solar azimuth according to the solar irradiance information, adjust the azimuth angle and the elevation angle of the baffle correspondingly, perform light shielding processing on the micro-polarization array camera 102, realize real-time anti-exposure, and obtain sky linear polarization information.

[0035] The circularly polarized light receiving control system is used to obtain the sky circular polarization information through phase modulation after obtaining the sky linear polarization information, and then obtain the sky full polarization information. Specifically, the circularly polarized light receiving control system includes a quarter-wave plate 201, a first motor 202 and a first rotating table 203. After obtaining the sky polarization information, the first rotating table 203 is used to move the quarter-wave plate 201 to the top of the lens 101, and the optical axis of the quarter-wave plate 201 coincides with the optical axis of the lens 101; the first motor 202 is used to rotate to adjust the included angle between the fast axis of the quarter-wave plate 201 and the 0° polarization direction of the micro-polarization plate in the micro-polarization array camera 102 to 45°. In operation, the sun scattered light passes through the quarter-wave plate 201, the lens 101 and the micro-polarization array camera 102 in turn to realize sky imaging, obtain the sky circular polarization information, and then obtain the sky full polarization information.

[0036] The computer processing and control system 401 is connected with the sky polarization imaging system, the circularly polarized light receiving control system and the anti-exposure automatic control system respectively, and is used to generate a system combination instruction according to the weather state; when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, the sky linear polarization information is obtained; when the system combination instruction represents that the sky polarization imaging system and the circularly polarized light receiving control system work in combination, the sky full polarization information is obtained; and the sky linear polarization information and / or the sky full polarization information is interpolated and reconstructed in the spatial domain and is subjected to discrete Fourier transform, so as to accurately calculate all Stokes parameters and further improve the imaging quality of the micro-polarization array.

[0037] In actual application, taking the weather state as sunny or foggy as an example. When the weather state is sunny, the Rayleigh scattering dominates the atmospheric scattering, at this time, the linearly polarized light exists in the atmosphere, and the circularly polarized light content is small and can be ignored, the circularly polarized light receiving control system is not used, the anti-exposure automatic control system is used according to the actual sunlight change, that is, the anti-exposure automatic control system and the sky polarization imaging system are combined, the anti-exposure is effectively realized, and the accurate sky linear polarization information is obtained.

[0038] When the weather state is foggy, the Mie scattering dominates the atmospheric scattering, at this time, the linearly polarized light and the circularly polarized light are converted from the non-polarized sunlight and the fog particles, and the sunlight is not strong due to the foggy weather, the anti-exposure automatic control system is not used, and the circularly polarized light receiving control system is used, that is, the circularly polarized light receiving control system and the sky polarization imaging system are combined, and the sky full polarization information is obtained.

[0039] Through the above system adjustment facing different meteorological states, the application can be applied to the sky full polarization mode distribution detection of different weather changes.

[0040] Based on the same inventive concept, the application also provides a full polarization distribution detection imaging method. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme described in the above system, so the specific limitations in one or more method embodiments provided below can refer to the limitations of the system in the above text, which will not be repeated here.

[0041] In an exemplary embodiment, as shown in Figure 3 , a full polarization distribution detection imaging method is provided, comprising the following steps 10-50.

[0042] Step 10, build the full polarization distribution detection imaging system as described above, as shown in Figure 1 .

[0043] Step 20, the computer processing and control system generates system combination instructions according to the meteorological state.

[0044] In actual application, according to the meteorological state, the sky polarization imaging system and the anti-exposure automatic control system combination work, or the sky polarization imaging system and the circular polarization light receiving control system combination work are selected. The former can work in sunny day, and the latter can work in foggy day.

[0045] When the meteorological state is sunny, Rayleigh scattering is dominant at this time, only linear polarization needs to be considered. Under the condition of sunny light, when the output signal of any photosensitive element in the photosensitive detection unit of the anti-exposure automatic control system reaches the preset threshold, the anti-exposure automatic control system is automatically started. Then, the computer processing and control system executes the following operations.

[0046] (1) Based on the current geographical position and the current time (real-time time) of the full polarization distribution detection imaging system, the solar azimuth parameter is calculated.

[0047] (2) Determine the initial control instruction according to the solar azimuth parameter; the initial control instruction is used to adjust the position of the baffle in the anti-exposure automatic control system to form a preliminary shading state. Wherein, for the adjustment of the position of the baffle, the second motor and the second rotating table are needed. Drive the second rotating table to make the baffle and the sun have the same azimuth angle relative to the lens, and control the second motor to adjust the altitude angle of the baffle, so as to form a preliminary shading state.

[0048] (3) When the sun azimuth deviates due to time lapse, the sun illumination information collected by the light-sensitive detection unit in the anti-exposure automatic control system is obtained, and the azimuth angle instruction and the elevation angle instruction are determined according to the sun illumination information; the azimuth angle instruction and the elevation angle instruction are used to control the second rotating table and the second motor in the anti-exposure automatic control system to change the position of the baffle.

[0049] In actual application, when the sun azimuth deviates due to time lapse, the sun light irradiating to the back of the baffle will trigger the light-sensitive detection unit, which is composed of four light-sensitive elements distributed in southeast, southwest and northwest directions, and can collect real-time sun illumination information in different directions , and the calculation formula is as follows:

[0050] ; ; .

[0051] Because the polarization camera has a micro-polarization array in front of the detector, which forms an obstruction, resulting in a loss of part of the light energy, additional exposure compensation is needed, is the exposure compensation caused by the micro-polarization array, Generally, 1.4 is taken; N is the aperture value, t is the shutter time, and ISO is the sensitivity. After the sun illumination signals detected by each light-sensitive element are converted into electrical signals S by the formula , they are transmitted to the computer processing and control system.

[0052] The computer processing and control system adjusts the azimuth angle and the elevation angle of the baffle according to the electrical signals corresponding to the received sun illumination information. (1) When adjusting the azimuth angle: adjust the sun illumination data collected by the two light-sensitive elements in the east-west direction, and select the direction with higher illumination as the first target adjustment direction. The computer processing and control system sends a rotating instruction to the second rotating table to make it rotate by one unit angle along the first target adjustment direction. If there is still a difference in illumination between the east-west light-sensitive elements, the second rotating table will be continuously driven to repeat the rotating operation until the illumination difference detected by the two light-sensitive elements is zero, realizing accurate calibration of the azimuth angle. (2) When adjusting the elevation angle: compare the sun illumination information collected by the north-south light-sensitive elements, and select the direction with higher illumination as the second target adjustment direction. The computer processing and control system sends a moving instruction to the second motor to drive it to move by one unit distance along the second target adjustment direction. If there is still a difference in illumination between the north-south light-sensitive elements, the second motor will be continuously controlled to repeat the moving operation until the light intensity difference of the two light-sensitive elements is zero, completing accurate adjustment of the elevation angle.

[0053] By the above-mentioned cooperative control of the second motor and the second rotating table, the computer processing and control system can adjust the azimuth angle and the elevation angle of the baffle in real time, realize dynamic tracking of the sun position, and thus achieve the effect of real-time automatic anti-exposure. When the output signals of all the photosensitive elements are lower than the threshold value, the anti-exposure automatic control system will be automatically turned off.

[0054] When the weather state is foggy, Mie scattering is the main scattering, at this time, the linear polarization and the circular polarization need to be considered simultaneously, then the anti-exposure automatic control system is removed, and the sky polarization imaging system and the circular polarization light receiving control system are combined to work. In the working process, after the sky linear polarization information is obtained, the circular polarization light receiving control system is used to move the quarter-wave plate above the lens, and the quarter-wave plate is rotated to make the included angle between the fast axis of the quarter-wave plate and the 0° polarization direction of the micro-polarization array be 45°, the sky circular polarization image passing through the micro-polarization array camera is obtained, and the left and right circular polarization light intensity information passing through the 0° and 90° polarization directions is obtained 、 , so as to obtain the sky full polarization information.

[0055] Step 30, when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system are combined to work, the sky linear polarization information is obtained by the computer processing and control system.

[0056] Step 40, when the system combination instruction represents that the sky polarization imaging system and the circular polarization light receiving control system are combined to work, the sky full polarization information is obtained by the computer processing and control system.

[0057] Step 50, the sky linear polarization information and / or the sky full polarization information is interpolated and reconstructed in the spatial domain and is subjected to discrete Fourier transform, so as to calculate all Stokes parameters, and further improve the imaging quality of the micro-polarization array.

[0058] In actual application, the sky linear polarization information is interpolated and reconstructed in the spatial domain and is subjected to discrete Fourier transform, so as to calculate the Stokes parameters, as shown in the following formula: Figure 4 ,

[0059] (1) the image corresponding to the sky linear polarization information is interpolated and reconstructed in the spatial domain; wherein the sun scattered light is received by the lens, sequentially passes through the micro-polarization array in the micro-polarization array camera and the detector, and the sky linear polarization image is shot, so as to obtain the light intensity information of 0°, 45°, 90° and 135° polarization 、 、 、 . The above-mentioned corresponding polarization image is interpolated and reconstructed in the spatial domain, the typical 4×4 pixel neighborhood in the micro-polarization array is interpolated and reconstructed to obtain the picture corresponding to the 2×2×2 arrangement mode, as shown in the following formula:Figure 5 Figure 2B is a 4x4 polar angle arrangement diagram, wherein Figure 5 Figure 2B is a 4x4 polar angle arrangement diagram, wherein Figure 2B is a 4x4 polar angle arrangement diagram, wherein Figure 5 Figure 2B is a 4x4 polar angle arrangement diagram, wherein Figure 5 Figure 2B is a 4x4 polar angle arrangement diagram, wherein

[0060] Figure 2B is a 4x4 polar angle arrangement diagram, wherein

[0061] .

[0062] .

[0063] .

[0064] .

[0065] Figure 2B is a 4x4 polar angle arrangement diagram, wherein

[0066] .

[0067] .

[0068] .

[0069] .

[0070] wherein, I0(x+1,y+1) is the intensity value of the light passing through 0° polarization at the (x+1,y+1) pixel position after the reconstruction of the 0° and 90° polarization images, 0 I0(x-1,y-1) is the intensity value of the light passing through 0° polarization at the (x-1,y-1) pixel position, 0 I0(x+1,y-1) is the intensity value of the light passing through 0° polarization at the (x+1,y-1) pixel position, 0 I0(x+1,y-1) is the intensity value of the light passing through 0° polarization at the (x+1,y-1) pixel position, 0 I0(x-1,y+1) is the intensity value of the light passing through 0° polarization at the (x-1,y+1) pixel position, I90(x+1,y+1) is the intensity value of the light passing through 90° polarization at the (x+1,y+1) pixel position after the reconstruction of the 0° and 90° polarization images, 90 I90(x,y) is the intensity value of the light passing through 90° polarization at the (x,y) pixel position, 90(x, y+2) is the intensity value of the light passing through the 90° polarization at the (x, y+2) pixel position, I(x1+1, y1+1) is the intensity value of the light passing through the 0° polarization at the (x1+1, y1+1) pixel position after the 0° and 90° polarized image reconstruction, 90 (x+2, y) is the intensity value of the light passing through the 90° polarization at the (x+2, y) pixel position, 90 (x+2, y+2) is the intensity value of the light passing through the 90° polarization at the (x+2, y+2) pixel position, I(x1+1, y1+1) is the intensity value of the light passing through the 0° polarization at the (x1+1, y1+1) pixel position after the 0° and 90° polarized image reconstruction, I(x2, y2) is the intensity value of the light passing through the 45° polarization at the (x2, y2) pixel position after the 45° and 135° polarized image reconstruction, 45 (x, y-1) is the intensity value of the light passing through the 45° polarization at the (x, y-1) pixel position, 45 (x, y+1) is the intensity value of the light passing through the 45° polarization at the (x, y+1) pixel position, I(x2, y2+1) is the intensity value of the light passing through the 135° polarization at the (x2, y2+1) pixel position after the 45° and 135° polarized image reconstruction, 135 (x-1, y) is the intensity value of the light passing through the 135° polarization at the (x-1, y) pixel position, 135 (x+1, y+2) is the intensity value of the light passing through the 135° polarization at the (x+1, y+2) pixel position, 135 (x+1, y) is the intensity value of the light passing through the 135° polarization at the (x+1, y) pixel position, 135 (x-1, y+2) is the intensity value of the light passing through the 135° polarization at the (x-1, y+2) pixel position, I(x2+1, y2) is the intensity value of the light passing through the 135° polarization at the (x2+1, y2) pixel position after the 45° and 135° polarized image reconstruction, I(x2+1, y2+1) is the intensity value of the light passing through the 45° polarization at the (x2+1, y2+1) pixel position after the 45° and 135° polarized image reconstruction, 45 (x, y+1) is the intensity value of the light passing through the 45° polarization at the (x, y+1) pixel position, 45 (x+2, y+1) is the intensity value of the light passing through the 45° polarization at the (x+2, y+1) pixel position.

[0071] (2) performing a discrete Fourier transform on the image containing the 0° and 90° polarized images after the interpolation reconstruction to obtain a spectrum image containing , frequency components; performing a discrete Fourier transform on the image containing the 45° and 135° polarized images after the interpolation reconstruction to obtain a spectrum image containing , spectrum image of frequency components. Specifically, for the image containing 0°, 90° polarization in the 2x2x2 arrangement mode in the previous step, the discrete Fourier transform is performed to obtain a spectrum image containing , spectrum image of frequency components. Similarly, for the image containing 45°, 135° polarization, the spectrum image containing , spectrum image of frequency components is obtained.

[0072] (3) Filtering the spectrum image containing , spectrum image of frequency components, and the spectrum image containing , spectrum image of frequency components to obtain the spectrum information of , , spectrum image of frequency components; specifically, the positions of and frequency components in the two spectrum images obtained in the previous step are the same, so only two bandpass filters of and or are used for filtering, thereby obtaining the spectrum information of each Stokes frequency component , , .

[0073] (4) Performing inverse discrete Fourier transform and weighted processing on the spectrum information of , , spectrum image of frequency components to obtain the reconstructed Stokes parameter image, and calculating the linear polarization degree DOLP and the polarization azimuth AOP image. Specifically, performing inverse discrete Fourier transform on the spectrum information containing only , , spectrum image of frequency components, and then , , according to the corresponding weights to obtain the reconstructed Stokes parameter image, and further obtaining the linear polarization degree DOLP and the polarization azimuth AOP image according to the following formula:

[0074] .

[0075] .

[0076] In another practical application, for the sky full polarization information (including linear polarization information and circular polarization information), interpolation reconstruction in spatial domain and discrete Fourier transform are performed to calculate all Stokes parameters, including:

[0077] (1) For the linear polarization information, interpolation reconstruction in spatial domain and discrete Fourier transform are performed to obtain the spectral information of frequency components of , and , and the corresponding linear polarization degree and polarization azimuth angle images; the specific implementation of this step can refer to the steps (1)-(4) in the above practical application for finally obtaining the linear polarization degree DOLP and polarization azimuth angle AOP images.

[0078] (2) The interpolation reconstruction is performed on the image corresponding to the circular polarization information, and the discrete Fourier transform is performed on the interpolation reconstructed circular polarization image to obtain the spectral image containing the frequency components of ; wherein the calculation formula used in the interpolation reconstruction is consistent with the calculation formula of the interpolation reconstruction recorded in the above.

[0079] (3) The spectral image containing the frequency components of is filtered to obtain the spectral information of the frequency components of ; specifically, a band-pass filter corresponding to is selected for filtering, so as to obtain the spectral information of the Stokes component .

[0080] (4) The inverse discrete Fourier transform is performed on the spectral information of the frequency components of , and the weighted processing is performed on the spectral information of the frequency components of , and , so as to obtain the reconstructed new Stokes parameter image, and the full polarization DOP T and AOP T images containing the circular polarization information are calculated, and the calculation formula is as follows:

[0081] .

[0082] .

[0083] In summary, the application provides a full polarization distribution detection imaging system and method suitable for different weather changes. In sunny weather, the camera is exposed to sunlight for a long time. An anti-exposure automatic control system is used to adjust the azimuth and elevation angle of the baffle according to the current solar azimuth, and the position of the baffle is adjusted in real time by tracking the solar azimuth to realize real-time anti-exposure for the camera. The sky linear polarization information is obtained by using a sky polarization imaging system. In smog and dust weather, the anti-exposure automatic control system is removed, and a circular polarization light receiving control system is used to combine a quarter-wave plate with the sky polarization imaging system to obtain sky full polarization information.

[0084] In terms of algorithm improvement: the application uses a computer control and processing system to interpolate and reconstruct the sky polarization image in the spatial domain, interpolate and reconstruct a typical 4x4 pixel neighborhood in the micro-polarization array to obtain an image corresponding to the 2x2x2 micro-polarization array arrangement mode. The number of pixel points of the reconstructed image is halved, and the number and steps of filters required for subsequent frequency domain filtering can be reduced, effectively improving the image processing speed, avoiding frequency domain aliasing of different Stokes parameters, and further improving the imaging quality.

[0085] The technical features of the above embodiments can be combined in any way. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0086] The principles and implementation modes of the application are described by using specific examples in this paper, and the above examples are only used to help understand the method and its core idea; at the same time, for those skilled in the art, according to the idea of the application, the specific implementation mode and application range will be changed. In summary, the content of the specification should not be understood as a limitation of the application.

Claims

1. A full polarimetric distribution sounding imaging system, characterized in that, The system comprises a sky polarization imaging system, a circularly polarized light receiving control system, an anti-exposure automatic control system and a computer processing and control system; The sky polarization imaging system is used for collecting sky linear polarization information; The anti-exposure automatic control system is used for automatically shielding the sky polarization imaging system according to the sun azimuth to prevent exposure; The circularly polarized light receiving control system is used for obtaining sky circular polarization information through phase modulation after obtaining the sky linear polarization information, and then obtaining sky full polarization information; The computer processing and control system is connected with the sky polarization imaging system, the circularly polarized light receiving control system and the anti-exposure automatic control system, and is used for generating a system combination instruction according to a weather state, obtaining the sky linear polarization information when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, obtaining the sky full polarization information when the system combination instruction represents that the sky polarization imaging system and the circularly polarized light receiving control system work in combination, and performing interpolation reconstruction in a spatial domain and discrete Fourier transform on the sky linear polarization information and / or the sky full polarization information to calculate all Stokes parameters; The interpolation reconstruction of the image corresponding to the sky linear polarization information in the spatial domain comprises: The following formula is used to realize interpolation reconstruction of the image only existing 0° and 90° polarization: ； ； ； ； The following formula is used to realize interpolation reconstruction of the image only existing 45° and 135° polarization: ； ； ； ； wherein, I0(x1,y1) is the intensity value of 0° polarization passing through the (x1,y1) pixel position after 0° and 90° polarized image reconstruction, I 0 I0(x-1,y-1) is the intensity value of 0° polarization passing through the (x-1,y-1) pixel position, I 0 I0(x+1,y+1) is the intensity value of 0° polarization passing through the (x+1,y+1) pixel position, I 0 I0(x+1,y-1) is the intensity value of 0° polarization passing through the (x+1,y-1) pixel position, I 0 I0(x-1,y+1) is the intensity value of 0° polarization passing through the (x-1,y+1) pixel position, I I90(x1+1,y1) is the intensity value of 90° polarization passing through the (x1+1,y1) pixel position after 0° and 90° polarized image reconstruction, I 90 I90(x,y) is the intensity value of 90° polarization passing through the (x,y) pixel position, I 90 I90(x,y+2) is the intensity value of 90° polarization passing through the (x,y+2) pixel position, I I90(x1+1,y1) is the intensity value of 90° polarization passing through the (x1+1,y1) pixel position after 0° and 90° polarized image reconstruction, I 90 I90(x+2,y) is the intensity value of 90° polarization passing through the (x+2,y) pixel position, I 90 I90(x+2,y+2) is the intensity value of 90° polarization passing through the (x+2,y+2) pixel position, I I0(x1+1,y1+1) is the intensity value of 0° polarization passing through the (x1+1,y1+1) pixel position after 0° and 90° polarized image reconstruction, I I45(x2,y2) is the intensity value of 45° polarization passing through the (x2,y2) pixel position after 45° and 135° polarized image reconstruction, I 45 I45(x,y-1) is the intensity value of 45° polarization passing through the (x,y-1) pixel position, I 45 I45(x,y+1) is the intensity value of 45° polarization passing through the (x,y+1) pixel position, I I135(x2,y2+1) is the intensity value of 135° polarization passing through the (x2,y2+1) pixel position after 45° and 135° polarized image reconstruction, I 135 I135(x-1,y) is the intensity value of 135° polarization passing through the (x-1,y) pixel position, I 135 I135(x+1,y+2) is the intensity value of 135° polarization passing through the (x+1,y+2) pixel position, I 135 I135(x+1,y) is the intensity value of 135° polarization passing through the (x+1,y) pixel position, I 135 (x-1,y+2) is the intensity value of the light passing through 135° polarization at the (x-1,y+2) pixel position, I(x2+1,y2+1) is the intensity value of the light passing through 45° polarization at the (x2+1,y2+1) pixel position after reconstruction of the 45° and 135° polarized images, I(x2+1,y2+1) is the intensity value of the light passing through 45° polarization at the (x2+1,y2+1) pixel position after reconstruction of the 45° and 135° polarized images, 45 (x,y+1) is the intensity value of the light passing through 45° polarization at the (x,y+1) pixel position, 45 (x+2,y+1) is the intensity value of the light passing through 45° polarization at the (x+2,y+1) pixel position.

2. The full-polarization tomographic imaging system of claim 1, wherein, The sky polarization imaging system comprises a lens and a micro-polarization array camera; the lens is arranged on the micro-polarization array camera, and the imaging optical axis of the micro-polarization array camera is perpendicular to the horizontal plane and points to the sky; In operation, the sun scattered light is incident into the micro-polarization array camera through the lens to realize sky imaging and obtain sky linear polarization information.

3. The full polarimetric tomographic imaging system of claim 2, wherein, The circularly polarized light receiving control system comprises a quarter-wave plate, a first motor and a first rotating table; The first rotating table is used for moving the quarter-wave plate to the top of the lens, and the optical axis of the quarter-wave plate coincides with the optical axis of the lens; The first motor is used for rotating to adjust the included angle between the fast axis of the quarter-wave plate and the 0° polarization direction of the micro-polarization plate in the micro-polarization array camera to 45°; In operation, the sun scattered light is sequentially incident through the quarter-wave plate, the lens and the micro-polarization array camera to realize sky imaging, obtain sky circular polarization information and then obtain sky full polarization information.

4. The full polarimetric tomographic imaging system of claim 2, wherein, The anti-exposure automatic control system comprises a baffle, a light-sensitive detection unit, a second motor and a second rotating table; The light-sensitive detection unit is arranged on the baffle, and the baffle is located above the lens; the light-sensitive detection unit is used for detecting the sun illumination information corresponding to the current sun azimuth, and then sending the sun illumination information to the computer processing and control system. The second motor is arranged on the second rotating table, and the second motor and the second rotating table are connected with the computer processing and control system; when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, the system combination instruction further comprises: an azimuth angle instruction and an elevation angle instruction determined according to the sunlight intensity information; the second rotating table is used for adjusting the azimuth angle of the baffle according to the azimuth angle instruction; and the second motor is used for adjusting the elevation angle of the baffle according to the elevation angle instruction. In operation, the second rotating table and the second motor track the sun azimuth according to the sunlight intensity information, and correspondingly adjust the azimuth angle and the elevation angle of the baffle, so as to perform light shielding on the micro-polarization array camera, prevent exposure in real time, and obtain the sky linear polarization information.

5. The full polarimetric tomographic imaging system of claim 4, wherein, The light-sensitive detection unit comprises four light-sensitive elements, and the four light-sensitive elements are arranged in a cross-shaped array on the baffle, each light-sensitive element is equidistantly arranged with the geometric center of the baffle as a symmetric point, and the center angle of adjacent light-sensitive elements is 90°, so as to form a four-quadrant light detection matrix.

6. A full polarimetric distribution probing imaging method, characterized in that, The method comprises: building the full polarization distribution detection imaging system according to any one of claims 1-5; generating a system combination instruction by the computer processing and control system according to the weather state; when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, obtaining the sky linear polarization information by the computer processing and control system; when the system combination instruction represents that the sky polarization imaging system and the circular polarization light receiving control system work in combination, obtaining the sky full polarization information by the computer processing and control system; interpolating and reconstructing the sky linear polarization information and / or the sky full polarization information in the spatial domain, and performing discrete Fourier transform, to calculate all Stokes parameters; wherein interpolating and reconstructing the image corresponding to the sky linear polarization information in the spatial domain comprises: using the following formula to realize interpolation and reconstruction of the image only existing 0° and 90° polarization: ； ； ； ； using the following formula to realize interpolation and reconstruction of the image only existing 45° and 135° polarization: ； ； ； ； wherein, I0(x1,y1) is the intensity value of 0° polarization passing through the (x1,y1) pixel position after reconstruction of 0° and 90° polarized images, I 0 I0(x-1,y-1) is the intensity value of 0° polarization passing through the (x-1,y-1) pixel position, I 0 I0(x+1,y+1) is the intensity value of 0° polarization passing through the (x+1,y+1) pixel position, I 0 I0(x+1,y-1) is the intensity value of 0° polarization passing through the (x+1,y-1) pixel position, I 0 I0(x-1,y+1) is the intensity value of 0° polarization passing through the (x-1,y+1) pixel position, I I90(x1+1,y1) is the intensity value of 90° polarization passing through the (x1+1,y1) pixel position after reconstruction of 0° and 90° polarized images, I 90 I90(x,y) is the intensity value of 90° polarization passing through the (x,y) pixel position, I 90 I90(x,y+2) is the intensity value of 90° polarization passing through the (x,y+2) pixel position, I I90(x1+1,y1) is the intensity value of 90° polarization passing through the (x1+1,y1) pixel position after reconstruction of 0° and 90° polarized images, I 90 I90(x+2,y) is the intensity value of 90° polarization passing through the (x+2,y) pixel position, I 90 I90(x+2,y+2) is the intensity value of 90° polarization passing through the (x+2,y+2) pixel position, I I0(x1+1,y1+1) is the intensity value of 0° polarization passing through the (x1+1,y1+1) pixel position after reconstruction of 0° and 90° polarized images, I I45(x2,y2) is the intensity value of 45° polarization passing through the (x2,y2) pixel position after reconstruction of 45° and 135° polarized images, I 45 I45(x,y-1) is the intensity value of 45° polarization passing through the (x,y-1) pixel position, I 45 I45(x,y+1) is the intensity value of 45° polarization passing through the (x,y+1) pixel position, I I135(x2,y2+1) is the intensity value of 135° polarization passing through the (x2,y2+1) pixel position after reconstruction of 45° and 135° polarized images, I 135 I135(x-1,y) is the intensity value of 135° polarization passing through the (x-1,y) pixel position, I 135 I135(x+1,y+2) is the intensity value of 135° polarization passing through the (x+1,y+2) pixel position, I 135 I135(x+1,y) is the intensity value of 135° polarization passing through the (x+1,y) pixel position, I 135 (x-1,y+2) is the intensity value of the light passing through 135° polarization at the (x-1,y+2) pixel position, I(x2+1,y2+1) is the intensity value of the light passing through 45° polarization at the (x2+1,y2+1) pixel position after reconstruction of the 45° and 135° polarized images, I(x2+1,y2+1) is the intensity value of the light passing through 45° polarization at the (x2+1,y2+1) pixel position after reconstruction of the 45° and 135° polarized images, 45 (x,y+1) is the intensity value of the light passing through 45° polarization at the (x,y+1) pixel position, 45 (x+2,y+1) is the intensity value of the light passing through 45° polarization at the (x+2,y+1) pixel position.

7. The full polarimetric tomographic imaging method of claim 6, wherein, the sky linear polarization information comprises light intensity information of 0°, 45°, 90° and 135° polarization; interpolating and reconstructing the sky linear polarization information in the spatial domain, and performing discrete Fourier transform, to calculate Stokes parameters, comprises: interpolating and reconstructing the image corresponding to the sky linear polarization information in the spatial domain; The discrete Fourier transform is performed on the interpolated and reconstructed image containing the 0°, 90° polarized images to obtain a spectral image containing , frequency components; the discrete Fourier transform is performed on the interpolated and reconstructed image containing the 45°, 135° polarized images to obtain a spectral image containing , frequency components; spectral image comprising , frequency components, the spectral image comprising , frequency components is filtered to obtain spectral information of , , frequency components; To , , The spectrum information of the frequency components is inverse discrete Fourier transformed and weighted processed to obtain a reconstructed Stokes parameter image, and a degree of linear polarization DOLP and a polarization azimuth AOP image are calculated.

8. The full polarimetric tomographic imaging method of claim 6, wherein, the sky full polarization information comprises linear polarization information and circular polarization information; interpolating and reconstructing the sky full polarization information in the spatial domain, and performing discrete Fourier transform, to calculate all Stokes parameters, comprises: For the linear polarization information, interpolation reconstruction in spatial domain and discrete Fourier transform are performed to obtain 、 and spectrum information of frequency components, and corresponding linear polarization degree and polarization azimuth angle images; interpolating and reconstructing the image corresponding to the circular polarization information, and performing a discrete Fourier transform on the circular polarization image after interpolation and reconstruction to obtain a spectrum image containing frequency components; filtering the spectral image of the frequency components to obtain spectral information of the frequency components frequency components right The spectral information of the frequency components is subjected to an inverse discrete Fourier transform and then compared with... , and The spectral information of the frequency components is weighted to obtain a reconstructed new Stokes parametric image, and the fully polarized DOP containing circular polarization information is calculated. T and AOP T image.

9. The full polarimetric tomographic imaging method of claim 6, wherein, when the system combination instruction represents that the sky polarization imaging system and the anti-exposure automatic control system work in combination, the method further comprises: when the weather state is sunny, calculating a sun azimuth parameter based on the current geographic position and the current time of the full polarization distribution detection imaging system; Determine an initial control instruction according to the solar azimuth parameter; the initial control instruction is used to adjust the position of the baffle in the anti-exposure automatic control system to form a preliminary light-shielding state; When the solar azimuth is offset over time, acquire solar irradiance information collected by a photosensitive detection unit in the anti-exposure automatic control system in real time, and determine an azimuth angle instruction and an altitude angle instruction according to the solar irradiance information; the azimuth angle instruction and the altitude angle instruction are used to control a second rotary table and a second motor in the anti-exposure automatic control system to change the position of the baffle.

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