A method for constructing a target infrared polarization characteristic model based on a Monte Carlo method

Abstract

The present application relates to the technical field of target detection, in particular to a target infrared polarization characteristic model construction method based on Monte Carlo method, comprising: S1, determining the position, scattering angle and azimuth angle of the scattered photon according to the propagation distance of the photon, the initial Stokes vector of the photon, the Mueller matrix and the phase function of the incident light when the photon occurs scattering; S2, updating the new Stokes matrix after the elastic interaction of the photon according to the rotation matrix and the initial Stokes vector; S3, updating the direction cosine of the scattered photon. The present application can construct a model for simulating the infrared polarization characteristics of the target.

Description

Technical Field

[0001] This invention relates to the field of target detection technology, and in particular to a method for constructing a target infrared polarization characteristic model based on the Monte Carlo method. Background Technology

[0002] Infrared polarization imaging technology is a new infrared detection technology that has been developed in recent years. It mainly detects and identifies targets by observing the differences in infrared radiation and polarization characteristics between targets and scenery. The infrared polarization characteristics (degree of polarization, polarization angle) of a target can reflect some information about the target scenery that is difficult to obtain from traditional infrared radiation information, which is beneficial for infrared imaging systems to detect and identify targets more effectively.

[0003] Currently, the analysis of the infrared polarization characteristics of targets in China is mainly conducted through experimental analysis. However, the method of summarizing the infrared polarization characteristics of targets based on experimental analysis is difficult to estimate the influencing factors in the polarization transmission process, and cannot quantitatively describe the impact of various related parameters on infrared polarization information. Therefore, it is necessary to explore other methods to systematically analyze the infrared polarization characteristics of targets. Summary of the Invention

[0004] This invention provides a method, apparatus, electronic device, and storage medium for constructing a target infrared polarization characteristic model based on the Monte Carlo method, which can construct a model for simulating the infrared polarization characteristics of a target.

[0005] In a first aspect, embodiments of the present invention provide a method for constructing a target infrared polarization characteristic model based on the Monte Carlo method, including: S1. Based on the propagation distance of the photon, the initial Stokes vector of the photon, the Müller matrix, and the phase function of the incident light when the photon is scattered, determine the position, scattering angle, and azimuth angle of the scattered photon. S2, update the new Stokes matrix after photon elastic interaction based on the rotation matrix and the initial Stokes vector; S3, update the direction cosine of the scattered photons.

[0006] Optionally, in S1, the formula for calculating the propagation distance of the photon is as follows: Where, Δ s The propagation distance is... g The propagation distance is based on pseudo-random numbers generated within the interval (0,1). m t =m a +m s ,m a It is the absorption coefficient. m s It is the scattering coefficient of the medium, and the mean free path between each scattering and absorption event is 1 / m t .

[0007] Alternatively, in S1, the position of the scattered photon is calculated using the following formula: Where x, y, and z are the positions of the photon before scattering, and x', y', and z' are the positions of the photon after scattering. u x , u y , u z Let Δ be the direction cosine of the unit vector of the incident photon propagation direction. s The propagation distance is denoted as .

[0008] Alternatively, in S1, the scattering angle and azimuth angle are calculated using the following formulas: in, P(α，β) The phase function includes the scattering angle and the azimuth angle. α and β These are the scattering angle and azimuth angle, respectively. 11 and S 12 The polarization scattering Müller matrix M( α Elements in ).

[0009] Optionally, in S2, the new Stokes matrix is ​​obtained by multiplying the initial Stokes matrix by the rotation matrix, where the initial Stokes matrix S0=[I0, Q0, U0, V0], I is the total light intensity, Q is the difference between the horizontal and vertical polarization components of the light intensity, U is the difference between the +45° and -45° linear polarization components, and V is the difference between the right-hand and left-hand circular polarization components. Rotation matrix R(β) for Rotation matrix R(-γ) for The resulting Stokes matrix: Among them, S new For the new Stokes matrix, S old For the old Stokes matrix, M( α ) is the polarization scattering Müller matrix.

[0010] Alternatively, in S3, the new direction cosine is calculated using the following formula: in, Let u be the new direction cosine, and let u be the old direction cosine. α and β These are the scattering angle and the azimuth angle, respectively.

[0011] Secondly, embodiments of the present invention also provide a target infrared polarization characteristic model construction device based on the Monte Carlo method, used to implement the method described in any one of the above methods, the device comprising: The calculation unit is used to determine the position, scattering angle, and azimuth angle of the scattered photon based on the photon's propagation distance, initial Stokes vector, Müller matrix, and phase function of the incident light when the photon is scattered. The first update unit is used to update the new Stokes matrix after the photon elastic interaction based on the rotation matrix and the initial Stokes vector. The second update unit is used to update the direction cosine of the scattered photons.

[0012] Thirdly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0013] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: This invention addresses the complex influencing factors in polarization transmission. By analyzing the polarization transmission process of scattered radiation from the target surface, it proposes a method for constructing a target infrared polarization characteristic model based on the Monte Carlo method, and simulates and calculates the infrared polarization characteristics of the target under different conditions and states. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the meridian in plan view. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] The specific implementation of the above concept is described below.

[0019] Please refer to Figure 1 This invention provides a method for constructing a target infrared polarization characteristic model based on the Monte Carlo method, comprising: S1. Based on the propagation distance of the photon, the initial Stokes vector of the photon, the Müller matrix, and the phase function of the incident light when the photon is scattered, determine the position, scattering angle, and azimuth angle of the scattered photon. S2, update the new Stokes matrix after photon elastic interaction based on the rotation matrix and the initial Stokes vector; S3, update the direction cosine of the scattered photons.

[0020] During scattering, the photon's propagation direction, Stokes vector, and direction cosine all change. Based on the photon's propagation distance, initial Stokes vector, Müller matrix, and phase function of the incident light at each scattering event, the position, scattering angle, and azimuth of the scattered photon can be determined. After scattering, both the Stokes vector and direction cosine change. Updating the Stokes vector and direction cosine, and then recalculating the position, scattering angle, and azimuth of the scattered photon with the new Stokes vector and direction cosine for subsequent scattering events, allows for repeated simulations of the scattering process. The final emitted photon's Stokes vector can then be used to determine its polarization state.

[0021] Treating the atmospheric system as an optical system, the Stokes vector of the incident light will differ from that of the outgoing light before and after passing through the atmospheric system. The initial Stokes vector S of a photon is defined as the result of reflection and self-radiation after exiting the surface.

[0022] First, for step S1, the photon's path of freedom, scattering angle, and azimuth angle are sampled. Suppose a photon is scattered at the origin. Before scattering, the monochromatic light propagates along the OA direction; after scattering at the origin, it propagates along the OB direction. The propagation direction of the photon before and after scattering can be uniquely determined by two angles θ and φ. The first angle θ is the angle between the initial direction of the photon and the Z-axis. The angle φ is the angle between the meridional plane and the XZ plane. The propagation direction of the photon can also be described by a unit vector I, whose elements are the direction cosines of that direction. u x , u y , u z The directions before and after scattering are called I1 and I2, respectively, and the angle α between them is the scattering angle. The unit vector I1 and the Z-axis determine the plane COA. The COA plane is the meridional plane of this scattering. The incident electric field is decomposed into two orthogonal components E|| and E⊥, which are the vibrations of the electric field parallel and perpendicular to the meridional plane, respectively. The polarization relative to the new meridional plane is described by the Stokes vector S.

[0023] In some embodiments of the present invention, in S1, the formula for calculating the propagation distance of the photon is as follows: Where, Δ s The propagation distance is... g The propagation distance is based on pseudo-random numbers generated within the interval (0,1). m t =m a +m s ,m a It is the absorption coefficient. m s It is the scattering coefficient of the medium, and the mean free path between each scattering and absorption event is 1 / m t .

[0024] In some embodiments of the present invention, in S1, the position of the scattered photon is calculated by the following formula: Where x, y, and z are the positions of the photon before scattering, and x', y', and z' are the positions of the photon after scattering. u x , u y , u z Let Δ be the direction cosine of the unit vector of the incident photon propagation direction. s The propagation distance is denoted as .

[0025] In some embodiments of the present invention, the scattering angle α and the azimuth angle β are selected based on the phase function of the scatterer under consideration and the suppression method, and the relationship between the initial Stokes vector S0=[I0, Q0, U0, V0] of the photon and the phase function P(α, β) of the incident light is as follows: in, P(α，β) The phase function includes the scattering angle and the azimuth angle. α and β These are the scattering angle and azimuth angle, respectively. 11 and S 12 The polarization scattering Müller matrix M( α Elements in ).

[0026] In some embodiments of the present invention, in S2, the new Stokes matrix is ​​obtained by multiplying the initial Stokes matrix by the rotation matrix, wherein the initial Stokes matrix S0=[I0, Q0, U0, V0], I is the total light intensity, Q is the difference between the horizontal and vertical polarization components of the light intensity, U is the difference between the +45° and -45° linear polarization components, and V is the difference between the right-hand and left-hand circular polarization components. Rotation matrix R(β) for Rotation matrix R(-γ) for The resulting Stokes matrix: Among them, S new For the new Stokes matrix, S old For the old Stokes matrix, M( α ) is the polarization scattering Müller matrix.

[0027] In some embodiments of the present invention, in S3, the new direction cosine is calculated using the following formula: in, Let u be the new direction cosine, and let u be the old direction cosine. α and β These are the scattering angle and the azimuth angle, respectively.

[0028] By emitting a certain number of photons, and after each photon undergoes a certain number of scatterings, its outgoing Stokes vector can be calculated, thereby obtaining the polarization state distribution of the target surface after atmospheric scattering.

[0029] Please refer to Tables 1 and 2 to calculate the mid- and long-wave infrared polarization characteristics of the target under different conditions using the model, and compare them with the measured values. The error should be less than 3dB.

[0030] Table 1 Note: Calculation error of the infrared polarization characteristic simulation model = 10 * log 10 (测试 / 仿真计算) .

[0031] Table 2 Note: Calculation error of the infrared polarization characteristic simulation model = 10 * log 10 (测试 / 仿真计算) .

[0032] This invention provides a device for constructing a target infrared polarization characteristic model based on the Monte Carlo method. The device can be implemented in software, hardware, or a combination of both. From a hardware perspective, the hardware architecture diagram of the electronic device housing the Monte Carlo method-based target infrared polarization characteristic model construction device provided in this invention includes, in addition to the processor, memory, network interface, and non-volatile memory, other hardware such as a forwarding chip responsible for processing packets. Taking software implementation as an example, as a logical device, it is formed by the CPU of the electronic device reading the corresponding computer program from the non-volatile memory into memory and running it. The target infrared polarization characteristic model construction device based on the Monte Carlo method provided in this embodiment includes: The calculation unit is used to determine the position, scattering angle, and azimuth angle of the scattered photon based on the photon's propagation distance, initial Stokes vector, Müller matrix, and phase function of the incident light when the photon is scattered. The first update unit is used to update the new Stokes matrix after the photon elastic interaction based on the rotation matrix and the initial Stokes vector. The second update unit is used to update the direction cosine of the scattered photons.

[0033] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on a target infrared polarization characteristic model construction device based on the Monte Carlo method. In other embodiments of the present invention, a target infrared polarization characteristic model construction device based on the Monte Carlo method may include more or fewer components than illustrated, or combine some components, or split some components, or arrange different components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0034] The information interaction and execution process between the modules in the above-mentioned device are based on the same concept as the method embodiment of the present invention, and the specific details can be found in the description of the method embodiment of the present invention, and will not be repeated here.

[0035] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to any embodiment of this invention.

[0036] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program causes the processor to perform a method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to any embodiment of this invention.

[0037] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0038] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0039] Storage media embodiments for providing program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0040] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0041] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a target infrared polarization characteristic model based on the Monte Carlo method, characterized in that, include: S1. Based on the propagation distance of the photon, the initial Stokes vector of the photon, the Müller matrix, and the phase function of the incident light when the photon is scattered, determine the position, scattering angle, and azimuth angle of the scattered photon. S2, update the new Stokes matrix after photon elastic interaction based on the rotation matrix and the initial Stokes vector; S3, update the direction cosine of the scattered photons.

2. The method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to claim 1, characterized in that, In S1, the formula for calculating the propagation distance of a photon is as follows: Where, Δ s The propagation distance is... ζ The propagation distance is based on pseudo-random numbers generated within the interval (0,1). μ t = μ a +μ s μ a It is the absorption coefficient. μ s It is the scattering coefficient of the medium, and the mean free path between each scattering and absorption event is 1 / μ t .

3. The method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to claim 1, characterized in that, In S1, the position of the scattered photon is calculated using the following formula: Where x, y, and z are the positions of the photon before scattering, and x', y', and z' are the positions of the photon after scattering. u x , u y , u z Let Δ be the direction cosine of the unit vector of the incident photon propagation direction. s The propagation distance is denoted as .

4. The method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to claim 1, characterized in that, In S1, the scattering angle and azimuth angle are calculated using the following formulas: in, P(α，β) The phase function includes the scattering angle and the azimuth angle. α and β These are the scattering angle and azimuth angle, respectively. 11 and S 12 The polarization scattering Müller matrix M( α Elements in ).

5. The method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to claim 1, characterized in that, In S2, the new Stokes matrix is ​​obtained by multiplying the initial Stokes matrix by the rotation matrix, where the initial Stokes matrix S0=[I0, Q0, U0, V0], I is the total light intensity, Q is the difference between the horizontal and vertical polarization components of the light intensity, U is the difference between the +45° and -45° linear polarization components, and V is the difference between the right-hand and left-hand circular polarization components. Rotation matrix R(β) for Rotation matrix R(-γ) for The resulting Stokes matrix: Among them, S new For the new Stokes matrix, S old For the old Stokes matrix, M( α ) is the polarization scattering Müller matrix.

6. The method for constructing a target infrared polarization characteristic model based on the Monte Carlo method according to claim 1, characterized in that, In S3, the new direction cosine is calculated using the following formula: in, Let u be the new direction cosine, and let u be the old direction cosine. α and β These are the scattering angle and the azimuth angle, respectively.

7. A device for constructing a target infrared polarization characteristic model based on the Monte Carlo method, characterized in that, The apparatus for implementing the method as described in any one of claims 1-6 comprises: The calculation unit is used to determine the position, scattering angle, and azimuth angle of the scattered photon based on the photon's propagation distance, initial Stokes vector, Müller matrix, and phase function of the incident light when the photon is scattered. The first update unit is used to update the new Stokes matrix after the photon elastic interaction based on the rotation matrix and the initial Stokes vector. The second update unit is used to update the direction cosine of the scattered photons.

8. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the method as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method of any one of claims 1-6.

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