A Monte Carlo-based polarization three-dimensional inversion imaging method

Abstract

This invention discloses a Monte Carlo-based polarization-based 3D inversion imaging method, comprising: acquiring the Stokes information of each pixel of a target object after it has passed through a transmission medium; establishing a complex environment imaging model using polarization Monte Carlo numerical simulation, and obtaining the Mueller matrix of the surface light source in the scattering medium using simulation; recovering the polarization information before light transmission based on the Mueller matrix of the scattering medium and the polarization information data of the target object detected by the detector; and reconstructing the 3D data of the object using the polarization information before light transmission. Based on the Monte Carlo method, this invention establishes a long-distance complex environment imaging model, recovers the polarization information before transmission using the inversion concept, and accurately solves the incident angle of the normal vector of each micro-surface element. This overcomes the influence of various complex scattering particles in different environments on traditional polarization-based 3D technology, solves the problem of polarization information distortion, and effectively expands the application scenarios of polarization-based 3D imaging.

Description

Technical Field

[0001] This invention belongs to the field of three-dimensional reconstruction technology, specifically involving a Monte Carlo-based polarization three-dimensional inversion imaging method, which can improve the accuracy of polarization three-dimensional imaging technology reconstruction and broaden its application range in complex environments at long distances, thereby expanding the application scope of three-dimensional reconstruction technology. Background Technology

[0002] 3D reconstruction technology can provide depth information that cannot be obtained from 2D images. Through 3D reconstruction, we can obtain complete 3D information of objects, including structure, texture, and scale. With the widespread application of polarization 3D reconstruction technology, the requirements for the accuracy and high precision of polarization 3D reconstruction details in complex environments at long distances, such as smoke, fog, haze, and underwater, are becoming increasingly stringent. Therefore, polarization 3D imaging of targets in complex environments at long distances has a wide range of applications.

[0003] Traditional polarization-based 3D imaging technology is affected by the strong absorption or scattering characteristics of polarized light by various complex scattering particles (fog, haze, micro-dispersible particles, etc.) in different environments. The polarization information of the target is also affected by the transmission medium during transmission, causing distortion of the detected information. This results in significant errors and uncertainties in the 3D imaging, detection, and identification of targets in complex environments using polarization information. Therefore, it is necessary to research a new technology and method for polarization-based 3D imaging of distant targets in complex scattering media, based on existing techniques, to achieve higher reconstruction accuracy and wider applicability. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a Monte Carlo-based polarization three-dimensional inversion imaging method. The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] This invention provides a Monte Carlo-based polarization three-dimensional inversion imaging method, comprising:

[0006] S1: Obtain Stokes information for each pixel of the target object after it has passed through the transmission medium;

[0007] S2: A complex environment imaging model is established using the polarization Monte Carlo numerical simulation method, and the Mueller matrix of the surface light source in the scattering medium is obtained by simulation.

[0008] S3: Based on the Mueller matrix of the scattering medium and the polarization information data of the target object detected by the detector, recover the polarization information before light transmission;

[0009] S4: Reconstruct the three-dimensional data of the object using the polarization information before light transmission.

[0010] In one embodiment of the present invention, S1 includes:

[0011] S1a: Under natural light conditions, a polarization camera is used to collect reflected light from the surface of the target object, thereby obtaining four polarization images I0, I10, and I20 of the target object at different polarization angles. 45 I 90 I 135 ;

[0012] S1b: By adding and subtracting (I0+I) different polarization images 45 I 45 -I0、I 45 +I 135 -I0-I 90 This allows us to obtain the I, Q, and U values ​​for each pixel in the real-world environment.

[0013] In one embodiment of the present invention, S2 includes:

[0014] A complex environment imaging model is constructed, and a large number of photons are emitted in the complex environment imaging model to simulate the process of photons acting in the scattering medium of the complex environment imaging model. The photons arriving at the receiving end are processed to obtain the Mueller matrix of the scattering medium.

[0015] In one embodiment of the present invention, S2 includes:

[0016] S2a: Defines the initial state of the incident light, including the initial position coordinates of the photon, the direction coordinates of motion, the energy weight threshold, and the light with four different Stokes vectors;

[0017] S2b: Move the photon in the complex environment imaging model and make it collide with the scattering medium to obtain the scattered Stokes vector value;

[0018] S2c: Determine the scattering direction and rotation angle of the next scattering based on the current scattering direction, azimuth angle, and scattering angle;

[0019] S2d: Multiple scattering of photons: Records various information about the polarized light after scattering, and the photons continue to collide with particles in the scattering system;

[0020] S2e: Photon transmission terminates and is received by the probe surface: The probe surface obtains the Stokes vector of the photon;

[0021] S2f: The Mueller matrix of the point source of the scattering medium in the complex environment imaging model is obtained based on the Stokes vector that receives a large number of photons;

[0022] S2g: Obtain the effective Mueller matrix of a surface light source by shifting and superimposing the Mueller matrices of a point light source.

[0023] In one embodiment of the present invention, the four different Stokes vectors of light include: natural light S = [1 00 0], horizontally linearly polarized light S = [1 1 0 0], 45° linearly polarized light S = [1 0 1 0], and right-hand circularly polarized light S = [1 0 0 1].

[0024] In one embodiment of the present invention, S2b includes:

[0025] S2b1: Photon movement, obtaining the position coordinates of the photon after it collides with the scattering medium in the complex environment imaging model based on the photon's current position coordinates;

[0026] S2b2: Photon Survival: After photon scattering, it is determined whether the photon energy is less than a preset weight threshold. If the weight is less than the weight threshold, the current photon is considered dead, and tracking stops. The weight expression after this collision between the photon and the medium is:

[0027]

[0028] Where w represents the weight of the photon and the medium before this collision.

[0029] S2b3: Update polarization information: Determine the new position coordinates of the photon after the collision event, and give the next direction cosine and scattering Mueller matrix of the photon to determine the next polarization state.

[0030] In one embodiment of the present invention, S2b3 includes:

[0031] The expression for obtaining the HG scattering phase function is:

[0032]

[0033] Where θ is the photon scattering angle and g represents the asymmetry factor;

[0034] Using the HG scattering phase function, the azimuth angle φ and scattering angle θ of the next scattering of the photon are selected;

[0035] The change in polarization state of the incident photon during scattering was analyzed using the meridional plane method, and the Stokes vector after scattering was obtained:

[0036] S new =R(-γ)M(θ)R(φ)S

[0037] Among them, S new Let θ represent the new Stokes vector after scattering, S represent the Stokes vector before scattering, R represent the rotation matrix, φ and γ represent the angles between the meridional plane and the scattering plane, and M(θ) represent the single scattering matrix.

[0038] In one embodiment of the present invention, in step S2c, the scattering direction of the next scattering is:

[0039] when|u z |<0.9999

[0040]

[0041]

[0042]

[0043] when|u z |≥0.9999

[0044]

[0045] In one embodiment of the present invention, the Stokes vector of the photon received by the detector surface is represented as:

[0046]

[0047] Where k' represents the number of collisions between photons, and S out S represents the Stokes value of the received light. in The value represents the Stokes value of the incident light, φ and γ are the angles between the meridional plane and the scattering plane, respectively, and M is the value of the incident light. k (θ) represents the scattering matrix of the k-th collision, and M represents the Mueller matrix of the scattering system.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] 1. The polarization three-dimensional inversion imaging method of the present invention is based on the Monte Carlo method. It establishes an imaging model of a complex environment at a long distance, uses the inversion idea to recover the polarization information before transmission, and accurately solves the incident angle of the normal vector of each micro-surface element. It overcomes the influence of various complex scattering particles in different environments on traditional polarization three-dimensional technology, solves the problem of polarization information distortion, breaks the limitation of traditional polarization three-dimensional imaging in complex environments at a long distance, effectively expands the application scenarios of polarization three-dimensional imaging, and expands the application scope of three-dimensional reconstruction technology.

[0050] 2. This invention utilizes the Monte Carlo method to effectively recover polarization information affected by the transmission medium and correct the polarization degree information, enabling it to accurately solve the incident angle of the normal vector of each micro-surface element in complex environments. This overcomes the influence of scattering on polarization information and improves the reconstruction accuracy of polarization three-dimensional imaging of targets in complex environments at long distances.

[0051] 3. This invention solves the problem that traditional polarization 3D reconstruction technology cannot accurately obtain the polarization information of the target surface due to the change of light wave polarization information caused by the scattering of the transmission medium in complex environments at long distances. It also overcomes the problem of inaccurate incident angle and azimuth angle caused by polarization information distortion, thus reducing the difficulty of polarization 3D imaging technology and making it more widely applicable.

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0053] Figure 1 This is a flowchart of a Monte Carlo-based polarization three-dimensional inversion imaging method provided in an embodiment of the present invention;

[0054] Figure 2 This is a schematic diagram of the structure of a complex environment imaging model provided in an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of a meridional plane one-sided scattering model provided in an embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram showing the relationship between the normal to a point on the surface of an object and the azimuth and zenith angle of that point. Detailed Implementation

[0057] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following describes in detail a Monte Carlo-based polarization three-dimensional inversion imaging method proposed according to the present invention, in conjunction with the accompanying drawings and specific embodiments.

[0058] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used merely 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 are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element.

[0060] Please see Figure 1 , Figure 1 This is a flowchart of a Monte Carlo-based polarization three-dimensional inversion imaging method provided in an embodiment of the present invention. The imaging method includes:

[0061] S1: Obtain Stokes information for each pixel of the target object after it passes through the transmission medium.

[0062] Specifically, step S1 includes:

[0063] S1a: Under natural light conditions, a polarization camera is used to collect reflected light from the surface of the target object, thereby obtaining four polarization images I0, I1, ..., I2 at different polarization angles. 45 I 90 I 135 .

[0064] S1b: By adding and subtracting (I0+I) different polarization images 45 I 45 -I0、I 45 +I 135 -I0-I 90 This allows us to obtain the I, Q, and U values ​​for each pixel in the real-world environment.

[0065] S2: A complex environment imaging model is established using the polarization Monte Carlo numerical simulation method, and the Mueller matrix of the surface light source in the scattering system is obtained by simulation.

[0066] In this step, several important physical parameters of the simulated object, i.e., the medium environment, are first determined in the complex environment imaging model: the effective radius of the medium (r), the incident light wavelength (λ), the asymmetry factor (g), the effective relative refractive index of the dispersed system (m), the particle number density (ρ), the transmission distance (L), and the scattering coefficient (u). s ), absorption coefficient (u) a ) and extinction coefficient (u t By constructing a complex environment imaging model and emitting a large number of photons in the complex environment imaging model, the process of photons acting in the scattering medium of the complex environment imaging model is simulated, and the photons arriving at the receiving end are processed to obtain the Mueller matrix of the scattering medium.

[0067] Specifically, S2 in this embodiment includes:

[0068] S2a: Photon Initiation: Defines the initial state of the incident light, including the initial position coordinates (0,0,0), direction of motion coordinates (0,0,1), energy weight threshold, and four different Stokes vectors: natural light S = [1 0 0 0], horizontally linearly polarized light S = [1 1 0 0], 45° linearly polarized light S = [1 0 1 0], and right-hand circularly polarized light S = [1 0 0 1].

[0069] S2b: Move the photon in the complex environment imaging model and have it collide with the scattering medium to obtain the scattered Stokes vector value.

[0070] In this embodiment, S2b includes:

[0071] S2b1: Photon movement, based on the current position coordinates of the photon, the position coordinates after the photon collides with the scattering medium in the complex environment imaging model are obtained.

[0072] Specifically, the path length traversed between two collision events between a photon and the scattering medium in a complex environment imaging model is based on a random number and can be defined as Δs:

[0073]

[0074] Where ζ is a random number between (0,1], u t =u a +u s , where u t U represents the extinction coefficient. s Represents the scattering coefficient, u a This represents the absorption coefficient. The direction cosine of the photon is [u...]. x ,u y ,u z If a photon moves to a new position with coordinates [x', y', z'], the following equations must be satisfied:

[0075]

[0076] Wherein, the position coordinates [x,y,z] represent the position coordinates at the time of the last collision with the scattering medium.

[0077] S2b2: Photon Survival: After photon scattering, it is determined whether the photon energy is less than a pre-set weight threshold. The weight after one scattering can be obtained by a formula. If the weight is less than the weight threshold, the current photon is considered dead, and tracking stops. The expression for the weight after this collision between the photon and the medium is:

[0078]

[0079] Where w represents the weight of the photon and the medium before this collision.

[0080] S2b3: Update polarization information: Determine the new position coordinates of the photon after the collision event, and give the next direction cosine and scattering Mueller matrix of the photon to determine the next polarization state.

[0081] Specifically, the expression for obtaining the HG scattering phase function (i.e., the Henyey-Greenstein scattering phase function) is as follows:

[0082]

[0083] Where θ is the photon scattering angle and g represents the asymmetry factor.

[0084] The photon scattering angle is obtained by sampling the HG scattering phase function:

[0085]

[0086] The azimuth angle of the scattered light is:

[0087] φ=2πks2

[0088] Among them, ks1 and ks2 are pseudo-random numbers that are uniformly distributed in the range of 0 to 1.

[0089] Using the HG scattering phase function, the azimuth angle φ and scattering angle θ of the next photon scattering are selected.

[0090] The change in polarization state of the incident photon during scattering was analyzed using the meridional plane method, and the Stokes vector after scattering was obtained.

[0091] Specifically, based on the meridional method to analyze the change in polarization state of incident photons during scattering, the Stokes vector is first rotated from the incident meridional plane to the scattering plane, then scattering occurs, and after scattering, the Stokes vector is rotated from the scattering plane to the scattering meridional plane. (See [link to relevant documentation]). Figure 3 , Figure 3 This is a schematic diagram of a meridional plane one-sided scattering model provided in an embodiment of the present invention, wherein D1 is the direction before the collision and D2 is the direction after the collision. D1 and the z-axis form the meridional plane COA before scattering, and D2 and the z-axis form the meridional plane COB after scattering.

[0092] The Stokes variation after scattering can be expressed by the following formula:

[0093] S new =R(-γ)M(θ)R(φ)S

[0094] Among them, S newLet represent the new Stokes value after scattering, S represent the Stokes value before scattering, R represent the rotation matrix, γ represent the rotation angle, and φ and γ represent the angles between the meridional plane and the scattering plane, respectively. M(θ) represents the single scattering matrix, which can be expressed as:

[0095]

[0096] Where, m 11 (θ), m 12 (θ), m 33 (θ), m 34 (θ) can be obtained from the scattering amplitudes S1 and S2; S1 and S2 are obtained from Mie theory, and their magnitudes are related to the photon radius and the effective relative refractive index.

[0097] Since the reference plane of the Mueller matrix is ​​the scattering plane in this scattering process, the reference plane needs to be adjusted twice during each photon collision. This process is implemented using a rotation matrix. The rotation matrix is ​​represented as:

[0098]

[0099] Where β represents the angle, which can be represented by γ or φ.

[0100] S2c: Determine the scattering direction and rotation angle of the next scattering based on the current scattering direction, azimuth angle, and scattering angle.

[0101] Specifically, the scattering direction of the next scattering is determined by the current scattering direction, azimuth angle, and scattering angle according to the formula:

[0102] when|u z |<0.9999

[0103]

[0104]

[0105]

[0106] when|u z |≥0.9999

[0107]

[0108] The rotation angle γ can be obtained using the following expression:

[0109]

[0110] S2d: Multiple scattering of photons: After scattering, all information about the polarized light has been recorded. The photon will then enter step 2b and continue to collide with particles in the scattering system.

[0111] S2e: Photon transmission termination and photon reception at the probed surface: The Stokes vector of the photon is obtained at the probed surface.

[0112] Before a photon is finally received by the detector surface, its Stokes vector needs to be rotated to the meridional plane where the detector surface is located for correction. Therefore, the rotation angle when the photon reaches the detector surface is...

[0113]

[0114] Wherein, the direction cosine of the photon is [u x ,u y ,u z ],

[0115] The Stokes vector for the photon received by the detector surface can then be expressed as:

[0116]

[0117] Where k' represents the number of collisions between photons, and S out S represents the Stokes value of the received light. in R represents the Stokes value of the incident light. k M represents the rotation matrix at the k-th collision. k (θ) represents the scattering matrix of the k-th collision, and M represents the Mueller matrix of the scattering system.

[0118] S2f: The Mueller matrix of the point source of the scattering medium in the complex environment imaging model is obtained based on the Stokes vector that receives a large number of photons.

[0119] Because the Stokes vector is additivity, all photons that have moved into the detector plane can be accumulated, provided that the Stokes vector has been rotated relative to the reference plane where the detector plane is located. The photon information in each pixel is processed, and the Mueller matrix of the scattering system is obtained by solving for 16 elements.

[0120] Specifically, let's assume the effective Mueller of the turbid medium under study is:

[0121]

[0122] Stokes vector S of the emitted light out Using the Stokes vector S of the incident light in The Mueller matrix M of the scattering system is expressed as:

[0123]

[0124] Observation revealed that to solve the Mueller matrix of the scattering system, it is only necessary to find the 16 elements of the matrix. This can be achieved by irradiating several uncorrelated polarized lights, resulting in 16 equations from which the value of each element can be determined. Typically, the polarization states incident on this turbid medium are (1) natural light S = [1 0 0 0], (2) horizontally linearly polarized light S = [1 10 0], (3) 45° linearly polarized light S = [1 0 1 0], and (4) right-hand circularly polarized light S = [1 0 0 1]. Thus, the Mueller matrix of the scattering system can be expressed as:

[0125]

[0126] Wherein, I1, Q1, U1, V1 represent the Stokes vectors of the naturally emitted light, I2, Q2, U2, V2 represent the Stokes vectors of the horizontally linearly polarized emitted light, I3, Q3, U3, V3 represent the Stokes vectors of the 45° linearly polarized emitted light, and I4, Q4, U4, V4 represent the Stokes vectors of the right-hand circularly polarized emitted light.

[0127] S2g: The effective Mueller matrix of a surface light source is obtained by shifting and superimposing the Mueller matrices of a point light source. Its expression is:

[0128]

[0129] Among them, M S (x,y) is the effective Mueller matrix of the surface light source, M (i,j) (x,y) is the effective Mueller matrix of the point light source at position (x,y), and H and G are the values ​​of the maximum position of the incident light in the x and y directions, respectively.

[0130] S3: Based on the Mueller matrix of the scattering medium and the polarization information data of the target detected by the detector, recover the polarization information before light transmission;

[0131] Specifically, the inverse matrix of the Mueller matrix of the scattering system obtained from the simulation is fused with the polarization information data of the target detected by the detector. For each pixel, the polarization information of the target before transmission is recovered using the mathematical relationship of the Stokes matrix.

[0132] S in (x,y)=M s -1 (x,y)*S out (x,y)

[0133] Among them, S in S represents the Stokes vector before photon transmission. out (x,y) represents the Stokes vector of the received light, M s -1(x,y) represents the inverse of the Mueller matrix of the scattering system surface light source.

[0134] S4: Reconstruct the three-dimensional data of the object using the polarization information before light transmission.

[0135] Specifically, step S4 in this embodiment includes:

[0136] S4a: Calculate the degree of polarization P on the object's surface:

[0137] The formula for calculating the degree of polarization P using the Stokes vector is:

[0138]

[0139] Where I', Q', and U' represent the Stokes vector S before photon transmission recovered in step S3. in The three components.

[0140] S4b: Utilizing polarization images I0 and I at different angles 45 I 90 I 135 The azimuth angle of the incident light normal can be calculated based on the Stokes vector. The calculation formula is:

[0141]

[0142] S4c: The angle of incidence can be calculated based on the relationship between the degree of polarization P and the angle of incidence θ. The calculation formula is:

[0143]

[0144] Where n represents the refractive index of the object's surface.

[0145] S4d: Represent the normal vector as a gradient field based on the relationship between the normal vector at a point on the object's surface, the azimuth angle of that point, and the zenith angle. Figure 4 As shown, the normal vector is represented as follows:

[0146]

[0147] Then, by integrating the surface of the object, the true three-dimensional information of the object to be reconstructed can be obtained.

[0148] This invention presents a polarization-based 3D inversion imaging method. Based on the Monte Carlo method, it establishes an imaging model for complex long-distance environments and utilizes the inversion concept to recover the polarization information before transmission. It accurately calculates the incident angle of the normal vector for each micro-facet element, overcoming the influence of various complex scattering particles in different environments on traditional polarization-based 3D technology. This solves the problem of polarization information distortion, breaks through the limitations of traditional polarization-based 3D imaging in complex long-distance environments, effectively expands the application scenarios of polarization-based 3D, and broadens the application scope of 3D reconstruction technology. This invention utilizes the Monte Carlo method to effectively recover polarization information affected by the transmission medium, correcting the degree of polarization information, and enabling accurate calculation of the incident angle of the normal vector for each micro-facet element in complex environments. This overcomes the influence of scattering on polarization information, thereby improving the reconstruction accuracy of polarization-based 3D imaging of targets in complex long-distance environments. This invention solves the problem that traditional polarization-based 3D reconstruction technology cannot accurately obtain accurate polarization information of the target surface due to changes in light wave polarization information caused by scattering of the transmission medium in complex long-distance environments. It overcomes the problem of inaccurate incident angles and azimuth angles caused by polarization information distortion, thus reducing the difficulty of polarization-based 3D imaging technology and broadening its applicability.

[0149] Another embodiment of the present invention provides a storage medium storing a computer program for executing the steps of the Monte Carlo-based polarization three-dimensional inversion imaging method described in the above embodiments. A further aspect of the present invention provides an electronic device including a memory and a processor. The memory stores a computer program, and the processor, when calling the computer program in the memory, implements the steps of the Monte Carlo-based polarization three-dimensional inversion imaging method described in the above embodiments. Specifically, the integrated modules implemented as software functional modules can be stored in a computer-readable storage medium. These software functional modules, stored in a storage medium, include several instructions to cause an electronic device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0150] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A Monte Carlo-based polarization three-dimensional inversion imaging method, characterized in that, include: S1: Obtain Stokes information for each pixel of the target object after it has passed through the transmission medium; S2: A complex environment imaging model is established using the polarization Monte Carlo numerical simulation method, and the Mueller matrix of the surface light source in the scattering medium is obtained by simulation. S3: Based on the Mueller matrix of the scattering medium and the polarization information data of the target object detected by the detector, recover the polarization information before light transmission; S4: Reconstruct the three-dimensional data of the object using the polarization information before light transmission; S1 includes: S1a: Under natural light conditions, a polarization camera is used to collect reflected light from the surface of the target object, thereby obtaining four polarization images of the target object at different polarization angles. , , , ; S1b: By adding and subtracting images with different polarizations + , - , + - - Obtain the I, Q, and U values ​​for each pixel in a real-world environment; S2 includes: A complex environment imaging model is constructed, and a large number of photons are emitted in the complex environment imaging model to simulate the process of photons acting in the scattering medium of the complex environment imaging model. The photons arriving at the receiving end are processed to obtain the Mueller matrix of the scattering medium. S2 includes: S2a: Defines the initial state of the incident light, including the initial position coordinates of the photon, the direction coordinates of motion, the energy weight threshold, and the light with four different Stokes vectors; S2b: Move the photon in the complex environment imaging model and make it collide with the scattering medium to obtain the scattered Stokes vector value; S2c: Determine the scattering direction and rotation angle of the next scattering based on the current scattering direction, azimuth angle, and scattering angle; S2d: Multiple scattering of photons: Records various information about the polarized light after scattering, and the photons continue to collide with particles in the scattering system; S2e: Photon transmission terminates and is received by the probe surface: The probe surface obtains the Stokes vector of the photon; S2f: The Mueller matrix of the point source of the scattering medium in the complex environment imaging model is obtained based on the Stokes vector that receives a large number of photons; S2g: Obtain the effective Mueller matrix of a surface light source by shifting and superimposing the Mueller matrices of a point light source.

2. The Monte Carlo-based polarization three-dimensional inversion imaging method according to claim 1, characterized in that, The four different Stokes vectors of light include: natural light S=[1 0 0 0], horizontally linearly polarized light S=[1 1 0 0], 45° linearly polarized light S=[1 0 1 0], and right-hand circularly polarized light S=[1 0 0 1].

3. The Monte Carlo-based polarization three-dimensional inversion imaging method according to claim 1, characterized in that, The S2b includes: S2b1: Photon movement, obtaining the position coordinates of the photon after it collides with the scattering medium in the complex environment imaging model based on the photon's current position coordinates; S2b2: Photon Survival: After photon scattering, it is determined whether the photon energy is less than a preset weight threshold. If the weight is less than the weight threshold, the current photon is considered dead, and tracking stops. The weight expression after this collision between the photon and the medium is: ， in, This represents the weight of the photon and the medium before this collision; S2b3: Update polarization information: Determine the new position coordinates of the photon after the collision event, and give the next direction cosine and scattering Mueller matrix of the photon to determine the next polarization state.

4. The Monte Carlo-based polarization three-dimensional inversion imaging method according to claim 3, characterized in that, The S2b3 includes: The expression for obtaining the HG scattering phase function is: in, The photon scattering angle, Indicates an asymmetric factor; Using the HG scattering phase function, the azimuth angle of the next photon scattering is determined. and scattering angle Selected; The change in polarization state of the incident photon during scattering was analyzed using the meridional plane method, and the Stokes vector after scattering was obtained: in, This represents the new Stokes vector after scattering. This represents the Stokes vector before scattering. Represents the rotation matrix. These are the angles between the meridional plane and the scattering plane, respectively. This represents the single scattering matrix.

5. The Monte Carlo-based polarization three-dimensional inversion imaging method according to claim 4, characterized in that, In step S2c, the scattering direction of the next scattering is: 。 6. The Monte Carlo-based polarization three-dimensional inversion imaging method according to claim 5, characterized in that, The Stokes vector for photons received by the detector surface is expressed as: in, This indicates the number of times a photon collides. This represents the Stokes value of the received light. The Stokes value represents the incident light. These are the angles between the meridional plane and the scattering plane, respectively. Indicates the first k The scattering matrix of the second collision. The Mueller matrix represents the scattering system.

Images