Target surface reconstruction system with de-wake scattering based on symmetrical arrangement

Abstract

The present invention discloses a symmetrically arranged target surface reconstruction system for eliminating wake scattering, which belongs to the field of target polarization detection. The system includes a Mueller matrix measurement module, a target surface reconstruction module, a wake bubble environment simulation module, and a computer processing module. The optical paths of the Mueller matrix measurement module and the target surface reconstruction module are equal, and the optical paths of the Mueller matrix measurement module and the target surface reconstruction module when passing through the wake bubble environment are symmetrical and equivalent, ensuring that the Mueller matrices of the wake bubble environment measured by the Mueller matrix measurement module and the target surface reconstruction module are consistent. The Mueller matrix measurement module and the target surface reconstruction module are respectively connected to the computer processing module, and the computer processing module completes the surface reconstruction of the target to be reconstructed. The present invention can suppress the influence of wake bubble interference, making it possible to reconstruct the surface of the target in the wake bubble environment, and expanding the application of target surface reconstruction to more complex scenarios.

Description

Technical Field

[0001] The present invention belongs to the field of target polarization detection, and in particular relates to a target surface reconstruction system based on symmetrical arrangement and without wake scattering. Background Art

[0002] Traditional target surface reconstruction techniques mostly rely on matching surface texture features. This can lead to data gaps when dealing with texture-poor targets, resulting in poor detection results. Polarized target surface reconstruction, on the other hand, leverages the unique physical properties of polarized light to estimate the target's normal vector by analyzing the polarization information reflected from the surface. This not only provides reliable 3D information on low-texture and even transparent targets, but also effectively suppresses interference from varying illumination, enabling high-precision surface reconstruction. This enables more accurate results when dealing with low-texture and highly reflective targets.

[0003] Generally, the target surface reconstruction process is mostly carried out in the air medium. However, in actual application, complex environmental conditions such as sea fog, dust, wake bubbles, etc. are often encountered. Light will be scattered during the transmission process of the medium, and important parameters such as light intensity and polarization will change. At this time, the accuracy of target surface reconstruction will be affected. In addition, the steps of previous related experimental studies are relatively cumbersome and the calculation amount is relatively large, which requires high robustness of computer programs. Summary of the Invention

[0004] The purpose of the present invention is to address the problem of the influence of the wake bubble environment on the reconstruction result when the target to be reconstructed is located in a wake bubble environment, and to propose a target surface reconstruction system based on symmetrical arrangement to remove the wake scattering.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a symmetrically arranged target surface reconstruction system without wake scattering, including a Mueller matrix measurement module, a target surface reconstruction module, a wake bubble environment simulation module and a computer processing module;

[0006] The wake bubble environment simulation module includes a water storage container and a bubbler. The water storage container is a cube structure. The bubbler is arranged in the water storage container and is used to generate bubbles in the water storage container to simulate the wake bubble environment.

[0007] The standard block in the Mueller matrix measurement module is arranged on the propagation path of the collimated light emitted by the light source of the Mueller matrix measurement module. The standard block is configured to receive incident light and reflect the incident light, and the incident light and the reflected light intersect at the center of the upper surface of the standard block, so that the optical path of the incident light and the reflected light of the Mueller matrix measurement module are equal; the Mueller matrix of the standard block is known;

[0008] The target to be reconstructed in the target surface reconstruction module is set on the propagation path of the collimated light emitted by the target surface reconstruction module. The target to be reconstructed is configured to receive incident light and reflect incident light, and the incident light and the reflected light intersect at the center of the upper surface of the target to be reconstructed, so that the optical path of the incident light and the reflected light of the target surface reconstruction module are equal;

[0009] The standard block and the target to be reconstructed are symmetrically arranged on the inner bottom surface of the water storage container, the center point of the inner bottom surface of the water storage container is defined as the intersection of the horizontal bisector and the vertical bisector, the standard block is located in the first quadrant with the center point as the origin, and the target to be reconstructed is located in the third quadrant with the center point as the origin, the vertices of the standard block and the target to be reconstructed coincide with the center point of the inner bottom surface, the upper surface of the target to be reconstructed is at the same height as the upper surface of the standard block, and the distance between the center of the upper surface of the target to be reconstructed and the midpoint of the lower surface of the water storage container is equal to the distance from the midpoint of the upper surface of the standard block to the midpoint of the lower surface of the water storage container; the optical paths of the Mueller matrix measurement module and the target surface reconstruction module when passing through the wake bubble environment are symmetrical and equivalent, ensuring that the incident light and the reflected light measured by the Mueller matrix measurement module and the target surface reconstruction module have consistency in the Mueller matrix of the wake bubble environment;

[0010] The Mueller matrix measurement module and the target surface reconstruction module are respectively connected to a computer processing module, which is used to obtain the Mueller matrix of the wake bubble according to the light intensity pattern and reconstruct it according to the polarization image to complete the surface reconstruction of the target to be reconstructed;

[0011] The Mueller matrix measurement module is composed of a first laser, a first linear polarizer, a first quarter-wave plate, a standard block, a second quarter-wave plate, a second linear polarizer and a first CCD detector. The first laser and the first CCD detector are arranged at the same height. The first laser serves as the light source of the Mueller matrix measurement module and is used to emit laser light. The first linear polarizer and the first quarter-wave plate are sequentially arranged on the output light path of the first laser, and the first quarter-wave plate can be moved into or out of the output light path of the first laser, and cooperates with the first linear polarizer to generate 0-degree linear polarized light, 90-degree linear polarized light, +45-degree linear polarized light, -45-degree linear polarized light, left-handed circularly polarized light and right-handed circularly polarized light. The polarized light is transmitted to the standard block, and after being reflected by the standard block, the reflected light passes through the second quarter-wave plate and the second linear polarizer in sequence and is then incident on the first CCD detector. The first CCD detector is connected to a computer processing module, and the computer processing module calculates the Mueller matrix of the wake bubble according to the signal received by the first CCD detector.

[0012] The target surface reconstruction module is composed of a second laser, a target to be reconstructed, a third quarter-wave plate, a third linear polarizer, and a second CCD detector. The second laser and the second CCD detector are arranged at the same height. After the laser light emitted by the second laser is reflected by the target to be reconstructed, the reflected light passes through the third quarter-wave plate and the third linear polarizer in sequence and is received by the second CCD detector to generate a polarization image. The polarization image is sent to a computer processing module for realizing surface reconstruction of the target to be reconstructed.

[0013] The first laser in the Mueller matrix measurement module and the second laser in the target surface reconstruction module are arranged at the same height; the first CCD detector and the second CCD detector in the Mueller matrix measurement module are arranged at the same height.

[0014] Furthermore, the combination of the first linear polarizer and the first quarter-wave plate is configured as follows:

[0015] When the first quarter-wave plate is moved out of the optical path, the first linear polarizer is adjusted to a horizontal direction or a vertical direction, and the first linear polarizer alone generates 0-degree or 90-degree linear polarized light;

[0016] When the first quarter-wave plate is moved into the optical path and the fast axis direction is ±45 degrees, it cooperates with the first linear polarizer to produce left-handed or right-handed circularly polarized light;

[0017] When the first quarter-wave plate is moved into the optical path and the fast axis direction is 0 degrees or 90 degrees, it cooperates with the first linear polarizer to generate ±45 degree linear polarized light.

[0018] Furthermore, the standard block is made of gold-plated titanium alloy, and the surface of the standard block is ion beam polished and covered with a silicon dioxide waterproof layer to ensure that the standard block is not corroded and affects the experimental results.

[0019] Furthermore, the wake bubble environment simulation module also includes a hemispherical iron frame, which is a hemispherical structure. The hemispherical iron frame is used to fix the first laser, the first linear polarizer, the first quarter wave plate, the second quarter wave plate, the second linear polarizer, the first CCD detector, the second laser, the third quarter wave plate, the third linear polarizer and the second CCD detector. The diameter of the hemispherical iron frame is greater than the side length of the water storage container, and the centers of the water storage container and the hemispherical iron frame are arranged to coincide with each other.

[0020] Through the above-mentioned design scheme, the present invention can bring the following beneficial effects: the symmetrically arranged de-wake scattering target surface reconstruction system provided by the present invention, in order to solve the problem of the influence of wake bubbles on target surface reconstruction in practical underwater applications, adopts a wake bubble environment simulation method to prepare a real underwater wake bubble medium, adopts a Mueller matrix measurement method to measure the Mueller matrix of the wake bubble environment, measures the polarization Stokes vector under the influence of the wake bubble through the target surface reconstruction module, and establishes a mapping relationship with the Mueller matrix, further solves the normal zenith angle and azimuth angle of the target to be reconstructed, establishes a normal gradient field, and finally reconstructs the surface of the target. Compared with the existing target surface reconstruction method, this system can suppress the influence of wake bubble interference, making it possible to reconstruct the surface of the target in the wake bubble environment, and expand the application of target surface reconstruction to more complex scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to understand the present invention and do not constitute improper limitations of the present invention. In the drawings:

[0022] Figure 1 An optical principle diagram of a target surface reconstruction system with symmetrical arrangement for removing wake scattering provided by an embodiment of the present invention;

[0023] Figure 2 A top view of a symmetrically arranged target surface reconstruction system for removing wake scattering provided by an embodiment of the present invention;

[0024] The marks in the figure are as follows: 1-Mueller matrix measurement module; 11-first laser; 12-first linear polarizer; 13-first quarter-wave plate; 14-standard block; 15-second quarter-wave plate; 16-second linear polarizer; 17-first CCD detector; 2-target surface reconstruction module; 21-second laser; 22-target to be reconstructed; 23-third quarter-wave plate; 24-third linear polarizer; 25-second CCD detector; 3-wake bubble environment simulation module; 31-hemispherical iron frame; 32-water storage container; 33-bubbler; 4-computer processing module. DETAILED DESCRIPTION

[0025] To make the objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the present invention are described clearly and completely below in conjunction with the accompanying drawings in accordance with the embodiments of the present invention. Obviously, the present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions. To avoid obscuring the essence of the present invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0026] like Figure 1 As shown, the symmetrically arranged target surface reconstruction system for removing wake scattering includes a Mueller matrix measurement module 1, a target surface reconstruction module 2, a wake bubble environment simulation module 3 and a computer processing module 4.

[0027] The Mueller matrix measurement module 1 is composed of a first laser 11, a first linear polarizer 12, a first quarter-wave plate 13, a standard block 14, a second quarter-wave plate 15, a second linear polarizer 16 and a first CCD detector 17. The first laser 11 is used as the light source of the Mueller matrix measurement module 1 to emit laser light; the first linear polarizer 12 is arranged on the outgoing light path of the first laser 11 to generate linearly polarized light; the first quarter-wave plate 13 can be switched into or out of the light path and cooperates with the first linear polarizer 12 to generate linearly polarized light. One of the following polarized light is generated: 0-degree linear polarized light, 90-degree linear polarized light, +45-degree linear polarized light, -45-degree linear polarized light, left-handed circularly polarized light, and right-handed circularly polarized light; the generated polarized light is transmitted to the standard block 14, and after being reflected by the standard block 14, it passes through the second quarter-wave plate 15 and the second linear polarizer 16 in sequence and then enters the first CCD detector 17; the first CCD detector 17 is connected to the computer processing module 4, and the computer processing module 4 calculates the Mueller matrix of the target wake bubble according to the signal received by the first CCD detector 17.

[0028] Specifically, the combination of the first linear polarizer 12 and the first quarter-wave plate 13 is configured as follows: when the first quarter-wave plate 13 is moved out of the light path, the first linear polarizer is adjusted to a horizontal direction or a vertical direction, and the first linear polarizer 12 alone generates 0-degree or 90-degree linear polarized light; when the first quarter-wave plate 13 is moved into the light path and the fast axis direction is ±45 degrees, it cooperates with the first linear polarizer 12 to generate left-handed or right-handed circularly polarized light; when the first quarter-wave plate 13 is moved into the light path and the fast axis direction is 0 degrees or 90 degrees, it cooperates with the first linear polarizer 12 to generate ±45-degree linear polarized light.

[0029] The target surface reconstruction module 2 is composed of a second laser 21, a target to be reconstructed 22, a third quarter-wave plate 23, a third linear polarizer 24 and a second CCD detector 25. The second laser 21 serves as the light source of the target surface reconstruction module 2. The laser emitted by the second laser 21 is reflected by the target to be reconstructed 22, and the reflected light passes through the third quarter-wave plate 23 and the third linear polarizer 24 in sequence and is received by the second CCD detector 25 to generate a polarization image; the polarization image is sent to the computer processing module 4 for realizing surface reconstruction of the target to be reconstructed 22.

[0030] The Mueller matrix of the standard block 14 in the Mueller matrix measurement module 1 is known, wherein the standard block 14 is made of titanium alloy gold-plated material (titanium alloy gold-plated is a composite material combining a titanium alloy substrate and a surface gold-plated layer), which has the advantages of being resistant to seawater corrosion, having stable reflectivity, and the Mueller matrix being less affected by temperature. In addition, the surface of the standard block 14 is ion beam polished and covered with a silicon dioxide waterproof layer, so that a stable and accurate Mueller matrix of the standard block 14 can be obtained, thereby ensuring the accuracy of the experimental data and having practical reference value.

[0031] The wake bubble environment simulation module 3 comprises a hemispherical iron frame 31, a water storage container 32, and a bubbler 33. The water storage container 32 is a cube. The hemispherical iron frame 31 is used to fix the first laser 11, the first linear polarizer 12, the first quarter-wave plate 13, the second quarter-wave plate 15, the second linear polarizer 16, the first CCD detector 17, the second laser 21, the third quarter-wave plate 23, the third linear polarizer 24, and the second CCD detector 25. The diameter of the hemispherical iron frame 31 is larger than the side length of the water storage container 32, and the centers of the water storage container 32 and the hemispherical iron frame 31 are arranged to coincide. The bubbler 33 is disposed within the water storage container 32 and is used to generate bubbles in the water storage container 32 to simulate the wake bubble environment. Specifically, the hemispherical iron frame 31 and the water storage container 32 are detachably connected to facilitate module installation and maintenance. The inner surface of the hemispherical iron frame 31 is provided with a positioning structure for precisely fixing the positions of the first laser 11, the first CCD detector 17, the second laser 21, and the second CCD detector 25. The bubbler 33 is driven by an external air pump or compressed air device to control the bubble generation rate. This is a prior art technique and will not be described in detail here.

[0032] The standard block 14 generally refers to a three-dimensional block with a regular shape, such as a cube. In order to clearly describe the standard block 14, the edges of its bottom surface and the directions related thereto are defined. The edges of the standard block 14 are defined as follows: the first edge is an edge on the bottom surface; the second edge is another edge on the bottom surface that is perpendicular to the first edge; the third edge is an edge perpendicular to the bottom surface, and together with the first two edges, it forms a three-dimensional rectangular coordinate system. The size of the target 22 to be reconstructed in the target surface reconstruction module 2 is not restricted, but it is necessary to ensure that the Mueller matrix of the incident light and the reflected light wake bubble in the target surface reconstruction module 2 are equal, and to ensure that the Mueller matrix of the incident light and the reflected light wake bubble in the Mueller matrix measurement module 1 are equal. For ease of understanding, in this embodiment, the target 22 to be reconstructed is a cube of the same size and shape as the standard block 14. The standard block 14 and the target to be reconstructed 22 are symmetrically arranged at the center point of the inner bottom surface of the water storage container 32, and the center point of the inner bottom surface of the water storage container 32 is defined as the intersection of the horizontal bisector and the vertical bisector, wherein the standard block 14 is located in the first quadrant with the center point as the origin, its first side coincides with the horizontal bisector, and its second side coincides with the vertical bisector; the target to be reconstructed 22 is located in the third quadrant with the center point as the origin, its first side coincides with the horizontal bisector, and its second side coincides with the vertical bisector, and the vertices of the standard block 14 and the target to be reconstructed 22 coincide at the center point, so that the optical path of the Mueller matrix measurement module 1 and the target surface reconstruction module 2 are equal.

[0033] If the target to be reconstructed 22 is an irregular shape, it is necessary to ensure that the upper surface of the target to be reconstructed 22 is at the same height as the upper surface of the standard block 14, and to ensure that the distance between the intersection of the incident light emitted by the second laser 21 and the upper surface of the target to be reconstructed 22 and the midpoint of the lower surface of the water storage container 32 as viewed from a top view is equal to the distance from the midpoint of the upper surface of the standard block 14 to the midpoint of the lower surface of the water storage container 32.

[0034] The first laser 11 and the first CCD detector 17 in the Mueller matrix measurement module 1 are placed at the same height. From a top view, the standard block 14 is placed exactly at the midpoint of the optical path of the Mueller matrix measurement module 1, and the incident light and the reflected light in the Mueller matrix measurement module 1 intersect at the center of the upper surface of the standard block 14, so as to ensure that the Mueller matrix of the incident light wake bubble environment and the Mueller matrix of the reflected light wake bubble environment in the Mueller matrix measurement module 1 are equal.

[0035] The second laser 21 and the second CCD detector 25 in the target surface reconstruction module 2 are placed at the same height. From the top view, it can be seen that the target to be reconstructed 22 is placed exactly at the midpoint of the optical path of the target surface reconstruction module 2, and the incident light and the reflected light intersect at the center of the upper surface of the target to be reconstructed 22, which is used to ensure that the Mueller matrix of the incident light wake bubble environment and the Mueller matrix of the reflected light wake bubble environment in the target surface reconstruction module 2 are equal.

[0036] The optical paths of the Mueller matrix measurement module 1 and the target surface reconstruction module 2 when passing through the wake bubble environment are symmetrical and equivalent. From the top view, it can be observed that the Mueller matrix measurement module 1 and the target surface reconstruction module 2 are symmetrically placed about the diagonal line of the water storage container 32 in the wake bubble environment simulation module 3, ensuring that the Mueller matrix of the incident light and the reflected light wake bubble environment in the Mueller matrix measurement module 1 and the Mueller matrix of the incident light and the reflected light wake bubble environment in the target surface reconstruction module 2 are equal.

[0037] The first laser 11 in the Mueller matrix measurement module 1 and the second laser 21 in the target surface reconstruction module 2 are placed at the same height, and the standard block 14 and the target to be reconstructed 22 are centrally symmetrically distributed with respect to the diagonal line of the internal space of the water storage container 32 in the wake bubble environment simulation module 3; and the outgoing light path of the first laser 11 and the outgoing light path of the second laser 21 are precisely aligned with the geometric center of the upper surface of the standard block 14 and the geometric center of the upper surface of the target to be reconstructed 22 respectively; the symmetrical distribution relationship between the standard block 14 and the target to be reconstructed 22 satisfies the following conditions: The incident light path of the matrix measurement module 1 and the incident light path of the target surface reconstruction module 2 have equivalent optical transmission characteristics in the wake bubble environment, thereby ensuring that the Mueller matrices of the incident light of the two modules in the wake bubble environment are equal; accordingly, the surface reflection characteristics of the standard block 14 and the target to be reconstructed 22 are configured as follows: the reflected light of the Mueller matrix measurement module 1 and the reflected light of the target surface reconstruction module 2 have equivalent polarization modulation characteristics in the wake bubble environment, thereby achieving the equality of the Mueller matrices of the reflected light in the wake bubble environment of the Mueller matrix measurement module 1 and the target surface reconstruction module 2.

[0038] The computer processing module 4 obtains the Mueller matrix of the wake bubble according to the light intensity pattern, and reconstructs the surface of the target to be reconstructed according to the polarization image.

[0039] The specific implementation steps of the target surface reconstruction system based on the symmetrical arrangement of the wake scattering removal are as follows:

[0040] Step 1: Turn on the first laser 11 in the Mueller matrix measurement module 1, remove the first quarter-wave plate 13, and adjust the first linear polarizer 12 to generate 0-degree linear polarized light;

[0041] Step 2: Adjust the optical path in the Mueller matrix measurement module 1 so that the incident light accurately hits the midpoint of the upper surface of the standard block 14, thereby making the optical paths of the incident light and the reflected light equal;

[0042] Step 3: Turn on the second laser 21 in the target surface reconstruction module 2 and adjust the optical path in the target surface reconstruction module 2 so that the incident light accurately hits the midpoint of the upper surface of the target to be reconstructed 22, thereby making the optical paths of the incident light and the reflected light equal;

[0043] Step 4: Turn on the bubbler 33 in the wake bubble environment simulation module 3 to simulate various wake bubble environments. Wait until the bubbles fill the water storage container 32 and are evenly distributed to ensure a uniform medium environment.

[0044] Step 5: Adjust the second quarter-wave plate 15 and the second linear polarizer 16 in the Mueller matrix measurement module 1 to sequentially detect the light intensity patterns of 0-degree linear polarized light, 90-degree linear polarized light, +45-degree linear polarized light, -45-degree linear polarized light, left-handed circularly polarized light, and right-handed circularly polarized light, and the first CCD detector 17 sequentially records the current six light intensity patterns;

[0045] Step 6: Adjust the angles of the first linear polarizer 12 and the first quarter-wave plate 13 in the Mueller matrix measurement module 1 to generate 90-degree, +45-degree, and -45-degree linear polarization light as well as left-handed and right-handed circular polarization light in sequence; adjust the angle between the second quarter-wave plate 15 and the second linear polarizer 16 in the Mueller matrix measurement module 1 so that the camera receives polarization images of 0-degree linear polarization light, 45-degree linear polarization light, -45-degree linear polarization light, 90-degree linear polarization light, left-handed circular polarization light, and right-handed circular polarization light, for a total of thirty sets of light intensity patterns;

[0046] The Mueller matrix M of the wake bubble medium of Mueller matrix measurement module 1 is obtained based on the thirty-six light intensity patterns. 总 , Mueller matrix M 总 for:

[0047]

[0048] Wherein the first number in the subscript of I represents the polarization state of the polarized light when the incident light in the Mueller matrix measurement module 1 passes through the first linear polarizer 12 and the first quarter-wave plate 13 but does not enter the standard block 14, and the second number in the subscript of I represents the polarization state of the reflected light when the reflected light in the Mueller matrix measurement module 1 passes through the second quarter-wave plate 15 and the second linear polarizer 16; the number 0 represents 0-degree linear polarization light, the number 1 represents 90-degree linear polarization light, the number 2 represents +45-degree linear polarization light, the number 3 represents -45-degree linear polarization light, the number 4 represents left-handed circularly polarized light, and the number 5 represents right-handed circularly polarized light;

[0049] Step 7: Based on the propagation path of the incident light in the Mueller matrix measurement module 1, the Stokes vector is used to establish the formula S out =M 入射 AM 反射 S in , where A is the Mueller matrix of standard block 14, S in is the Stokes vector of the incident light emitted by the first laser 11, M 入射 and M 反射are the Mueller matrices of the incident light wake bubble environment and the Mueller matrices of the reflected light wake bubble environment in the Mueller matrix measurement module 1 respectively; because the optical path of the incident light wake bubble is equal to the optical path of the reflected light wake bubble, and the heights of the first laser 11 and the first CCD detector 17 are equal, the standard block 14 is placed at the midpoint of the Mueller matrix measurement module 1, so M 入射 and M 反射 Equal, and then the formula can be simplified to S out =MAMS in ; According to the outgoing Stokes vector S out and Mueller matrix measurement module 1 Mueller matrix M of the wake bubble environment 总 Formula S can be determined out =M 总 S in , according to the two known formulas, we can get the formula M 总 =MAM, and the Mueller matrix of the incident light and reflected light wake bubble in the Mueller matrix measurement module 1 is obtained from this formula;

[0050] Step 8: Adjust the angle between the third quarter wave plate 23 and the third linear polarizer 24 in the target surface reconstruction module 2, so that the second CCD detector 25 captures polarization images of 0 degree linear polarization light, 45 degree linear polarization light, 90 degree linear polarization light, 135 degree linear polarization light, left-handed circular polarization light, and right-handed circular polarization light, and obtain the light intensity information I0, I 45 , I 90 , I 135 , I L and I R ;

[0051] where S′ out It can be obtained according to the following formula:

[0052]

[0053] Step 9: Based on the propagation path of the incident light in the target surface reconstruction module 2, the Stokes vector can be used to establish the formula S′ out =M′ 入射 BM′ 反射 S′ in , where B is the Mueller matrix of the target 22 to be reconstructed, S′ in is the Stokes vector of the incident light emitted by the second laser 21, M′ 入射 and M′ 反射are the Mueller matrices of the incident light wake bubble environment and the Mueller matrix of the reflected light wake bubble environment in the target surface reconstruction module 2, respectively; because the optical path of the incident light wake bubble is equal to the optical path of the reflected light wake bubble, and the heights of the second laser 21 and the second CCD detector 25 are equal, the target to be reconstructed 22 is placed at the midpoint of the target surface reconstruction module 2, so M′ 入射 and M′ 反射 Equal, the formula can be simplified to S′ out =M′BM′S′ in Since the wake bubble Mueller matrix in the Mueller matrix measurement module 1 is equal to the wake bubble Mueller matrix in the target surface reconstruction module 2, the formula can be changed to S′ out =MBMS′ in , where M is the wake bubble Mueller matrix in the Mueller matrix measurement module 1 calculated in step 7, and the Mueller matrix B of the target to be reconstructed 22 is obtained;

[0054] Step 10: According to the outgoing Stokes vector S′ out The Stokes vector S″ before light transmission is determined by the Mueller matrix M″ of the wake bubble environment in , the formula is S′ out =M″S″ in , where M″=MBM, represents the Mueller matrix of the wake bubble environment of the target surface reconstruction module 2. Then, the normal zenith angle and azimuth angle of the target to be reconstructed 22 are determined, and a normal gradient field is established based on the obtained normal zenith angle and azimuth angle; and three-dimensional reconstruction of the target to be reconstructed is performed based on the normal gradient field. The above is the existing technology and will not be described in detail.

[0055] In summary, the symmetrically arranged de-wake scattering target surface reconstruction system provided by the present invention aims to solve the problem of the influence of wake bubbles on the target surface reconstruction in actual underwater applications. It adopts a wake bubble environment simulation method to prepare a real underwater wake bubble medium, and adopts a Mueller matrix measurement method to measure the Mueller matrix of the wake bubble environment. The polarization Stokes vector under the influence of the wake bubbles is measured through the target surface reconstruction module 2, and a mapping relationship is established between it and the Mueller matrix. The normal zenith angle and azimuth angle of the object to be measured are further solved, and the normal gradient field is established. Finally, the surface of the target to be reconstructed 22 is reconstructed.

Claims

1. A symmetrically arranged target surface reconstruction system with wake scatter removal is characterized by: It includes a Mueller matrix measurement module (1), a target surface reconstruction module (2), a wake bubble environment simulation module (3) and a computer processing module (4); The wake bubble environment simulation module (3) comprises a water storage container (32) and a bubbler (33), wherein the water storage container (32) is a cube structure, and the bubbler (33) is arranged in the water storage container (32) and is used to generate bubbles in the water storage container (32) to simulate the wake bubble environment; The standard block (14) in the Mueller matrix measurement module (1) is arranged on a propagation path of collimated light emitted by a light source of the Mueller matrix measurement module (1); the standard block (14) is configured to receive incident light and reflect the incident light, and the incident light and the reflected light intersect at the center of an upper surface of the standard block (14); the optical paths of the incident light and the reflected light of the Mueller matrix measurement module (1) are equal; and the Mueller matrix of the standard block (14) is known; The target to be reconstructed (22) in the target surface reconstruction module (2) is arranged on a propagation path of collimated light emitted by a light source of the target surface reconstruction module (2), the target to be reconstructed (22) is configured to receive incident light and reflect the incident light, and the incident light and the reflected light intersect at the center of the upper surface of the target to be reconstructed (22), and the optical paths of the incident light and the reflected light of the target surface reconstruction module (2) are equal; The standard block (14) and the target to be reconstructed (22) are symmetrically arranged on the inner bottom surface of the water storage container (32), the center point of the inner bottom surface of the water storage container (32) is defined as the intersection of the horizontal bisector and the vertical bisector, the standard block (14) is located in the first quadrant with the center point as the origin, and the target to be reconstructed (22) is located in the third quadrant with the center point as the origin, the vertices of the standard block (14) and the target to be reconstructed (22) coincide with the center point of the inner bottom surface, the upper surface of the target to be reconstructed (22) and the upper surface of the standard block (14) are at the same height, and the distance between the center of the upper surface of the target to be reconstructed (22) and the midpoint of the lower surface of the water storage container (32) is equal to the distance between the midpoint of the upper surface of the standard block (14) and the midpoint of the lower surface of the water storage container (32), thereby ensuring that the Mueller matrix of the incident light and the reflected light measured by the Mueller matrix measurement module (1) and the target surface reconstruction module (2) are consistent in the wake bubble environment; The Mueller matrix measurement module (1) and the target surface reconstruction module (2) are respectively connected to a computer processing module (4), and the computer processing module (4) is used to obtain the Mueller matrix of the wake bubble according to the light intensity pattern, and to reconstruct it according to the polarization image to complete the surface reconstruction of the target to be reconstructed (22); The Mueller matrix measurement module (1) is composed of a first laser (11), a first linear polarizer (12), a first quarter wave plate (13), a standard block (14), a second quarter wave plate (15), a second linear polarizer (16) and a first CCD detector (17). The first laser (11) and the first CCD detector (17) are arranged at the same height. The first laser (11) serves as the light source of the Mueller matrix measurement module (1) and is used to emit laser light. The first linear polarizer (12) and the first quarter wave plate (13) are sequentially arranged on the output light path of the first laser (11), and the first quarter wave plate (13) can be moved in or out. The output light path of the first laser (11) cooperates with the first linear polarizer (12) to generate 0-degree linear polarized light, 90-degree linear polarized light, +45-degree linear polarized light, -45-degree linear polarized light, left-handed circular polarized light, and right-handed circular polarized light; the polarized light is transmitted to the standard block (14); after being reflected by the standard block (14), the reflected light passes through the second quarter-wave plate (15) and the second linear polarizer (16) in sequence and then enters the first CCD detector (17); the first CCD detector (17) is connected to the computer processing module (4), and the computer processing module (4) calculates the Mueller matrix of the wake bubble according to the signal received by the first CCD detector (17); The target surface reconstruction module (2) is composed of a second laser (21), a target to be reconstructed (22), a third quarter-wave plate (23), a third linear polarizer (24) and a second CCD detector (25). The second laser (21) and the second CCD detector (25) are arranged at the same height. After the laser light emitted by the second laser (21) is reflected by the target to be reconstructed (22), the reflected light passes through the third quarter-wave plate (23) and the third linear polarizer (24) in sequence and is received by the second CCD detector (25) to generate a polarization image. The polarization image is sent to a computer processing module (4) for realizing surface reconstruction of the target to be reconstructed (22). The first laser (11) in the Mueller matrix measurement module (1) and the second laser (21) in the target surface reconstruction module (2) are arranged at the same height; the first CCD detector (17) and the second CCD detector (25) in the Mueller matrix measurement module (1) are arranged at the same height.

2. The symmetrically arranged target surface reconstruction system according to claim 1 is characterized in that: The combination of the first linear polarizer (12) and the first quarter-wave plate (13) is configured as follows: When the first quarter-wave plate (13) is moved out of the light path, the first linear polarizer (12) alone generates 0-degree or 90-degree linear polarized light; When the first quarter-wave plate (13) is moved into the optical path and the fast axis direction is ±45 degrees, it cooperates with the first linear polarizer (12) to generate left-handed or right-handed circularly polarized light; When the first quarter-wave plate (13) is moved into the optical path and the fast axis direction is 0 degrees or 90 degrees, it cooperates with the first linear polarizer (12) to generate ±45-degree linear polarized light.

3. The symmetrically arranged target surface reconstruction system according to claim 1 is characterized in that: The standard block (14) is made of a gold-plated titanium alloy, and the surface of the standard block (14) is ion-beam polished and covered with a silicon dioxide waterproof layer.

4. The target surface reconstruction system based on symmetrical arrangement without wake scattering according to claim 1, characterized in that: The wake bubble environment simulation module (3) further comprises a hemispherical iron frame (31), which is a hemispherical structure. The hemispherical iron frame (31) is used to fix the first laser (11), the first linear polarizer (12), the first quarter-wave plate (13), the second quarter-wave plate (15), the second linear polarizer (16), the first CCD detector (17), the second laser (21), the third quarter-wave plate (23), the third linear polarizer (24) and the second CCD detector (25). The diameter of the hemispherical iron frame (31) is greater than the side length of the water storage container (32), and the centers of the water storage container (32) and the hemispherical iron frame (31) are arranged to coincide with each other.

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