A method and device for three-dimensional reconstruction of artificial targets by polarization radar

Abstract

The present application relates to a method, device, computer equipment and storage medium for three-dimensional reconstruction of artificial targets by polarimetric radar. The method comprises: extracting targets from polarimetric radar data to obtain target strong scattering centers and polarimetric scattering matrices corresponding to target strong scattering centers; then using a scattering structure identification method to identify targets to obtain scattering structures; extracting target strong scattering points whose scattering structures are trihedral angles or flat plates to obtain target outer contours; deleting all outer contour strong scattering points in the target outer contour to obtain the circumscribed rectangle of the inner contour strong scattering points; obtaining the overlap distance based on the spacing between the circumscribed rectangle and the target outer contour; calculating the overlap distance and the radar incident angle by the highest peak method of the height histogram to obtain the height of each point of the outer contour; and reconstructing artificial targets in three dimensions based on the height of each point of the outer contour. The use of this method can improve the accuracy of three-dimensional reconstruction of targets.

Description

Technical Field

[0001] The present application relates to the field of radar data processing technology, and in particular to a method, device, computer equipment and storage medium for three-dimensional reconstruction of polarization radar artificial targets. Background Art

[0002] Conventional synthetic aperture radar (SAR) imaging systems project the target scattering coefficient of the radar's three-dimensional imaging space onto a two-dimensional imaging plane, and mainly obtain two-dimensional information of the target. Since two-dimensional SAR imaging systems generally have spatial blur, overlap, shadows and other phenomena, the application of target polarization scattering information in the field of classification and recognition is severely limited. Therefore, in order to meet the increasingly demanding target observation needs, it is necessary to develop technologies that use radar data to obtain three-dimensional target information.

[0003] However, in order to obtain the three-dimensional information of the target, there are currently two main approaches: one is to perform three-dimensional imaging of the target and develop new three-dimensional imaging technology; the other is to extract the three-dimensional structural information of the target from the two-dimensional SAR imaging results, and perform geometric structure inversion and three-dimensional reconstruction of the target. Three-dimensional imaging technology has been continuously developing in recent years, and some new imaging technologies and imaging modes have become favorable tools for obtaining three-dimensional information of the target, including interferometric SAR, tomographic SAR, array SAR, etc. However, tomographic SAR often requires multiple flight observations to obtain an image of a scene, the cost of obtaining information is very high, and the height dimension resolution capability is limited. Array SAR obtains height dimension resolution through the real aperture of the antenna array. Similarly, the cost and height dimension resolution of array SAR are still far from the expected goals.

[0004] On the other hand, considerable research has been conducted on the use of radar two-dimensional image sequences to reconstruct targets in three dimensions. However, due to the difficulty in matching feature points, the use of radar image sequences to reconstruct complex targets in three dimensions still faces major challenges. Polarization, as one of the most sensitive attributes of the target's scattering echo to the target's attitude, shape, size, and structure, contains rich information about the target. The target polarization scattering information obtained by polarimetric radar can accurately invert the target's structural information, which is of great significance for target three-dimensional reconstruction and can effectively solve the current problems of low accuracy, low computational efficiency, and high cost in target three-dimensional reconstruction. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, computer equipment and storage medium for three-dimensional reconstruction of artificial targets by polarization radar, which can improve the accuracy and computational efficiency of target three-dimensional reconstruction, in order to address the above technical problems.

[0006] A method for three-dimensional reconstruction of artificial targets by polarization radar, the method comprising:

[0007] Acquire polarimetric radar data;

[0008] Target extraction is performed on polarimetric radar data to obtain the target strong scattering center and the polarimetric scattering matrix corresponding to the target strong scattering center;

[0009] The scattering structure is obtained by identifying the polarization scattering matrix corresponding to the strong scattering center of the target and the scattering structure identification method; the scattering structure includes a trihedral angle or a flat plate;

[0010] Extract the strong scattering points of the target on the trihedral angle or flat plate to obtain the outer contour of the target;

[0011] All the strong scattering points of the outer contour of the target are deleted to obtain the circumscribed rectangle of the strong scattering points of the inner contour;

[0012] According to the distance between the circumscribed rectangle and the target outer contour, the overlap distance is obtained;

[0013] The overlap distance and radar incident angle are calculated by the highest peak method of the height histogram to obtain the height of each point of the outer contour;

[0014] The artificial target is reconstructed in three dimensions according to the height of each point of the outer contour.

[0015] In one embodiment, target extraction is performed on polarization radar data to obtain a target strong scattering center and a polarization scattering matrix corresponding to the target strong scattering center, including:

[0016] Presetting the minimum interval between target strong scattering centers and the number of target strong scattering centers;

[0017] Traverse each point in the polarimetric radar data with the minimum interval, and calculate the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point;

[0018] The point with the maximum total energy of the scattering matrix is ​​selected as the strong scattering center.

[0019] In one embodiment, traversing each point in the polarization radar data at a minimum interval and calculating the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point includes:

[0020] Traversing each point in the polarization radar data with the minimum interval, the scattering matrix of each point is obtained as follows: Where S HV is the backscatter coefficient for vertically polarized transmission and horizontally polarized reception, S VH is the backscatter coefficient for horizontally polarized transmission and vertically polarized reception, S VV is the backscatter coefficient of vertical polarization transmission and vertical polarization reception, S HH is the backscatter coefficient for horizontal polarization transmission and horizontal polarization reception;

[0021] According to the scattering matrix of each point, the total energy of the scattering matrix corresponding to each point is calculated as SPAN = |S HH | 2 +|S HV | 2 +|S VH | 2 +|S VV | 2 .

[0022] In one embodiment, the target strong scattering points of the trihedral angle or the flat plate are extracted to obtain the target outer contour, including:

[0023] Extract the strong scattering points of the trihedral angle or the plate and map their coordinates to a binary image;

[0024] Setting the expansion template corresponding to the scattering structure type and the expansion width of a single pixel of the expansion template;

[0025] The binary image is expanded according to the expansion template and the expansion width to obtain the connected area of ​​the binary image;

[0026] Mark the connected area to obtain the mark of the connected area;

[0027] According to the markings of the connected regions, the scattering centers in the connected regions are divided into different categories, and the category with the largest number of scattering centers is selected as the target outer contour.

[0028] In one embodiment, the process of setting the expansion width includes:

[0029] The distance between any two scattering centers is defined as d ij ,j=1...N c , j≠i, then the minimum distance between the i-th scattering center and the remaining scattering centers is

[0030] According to the minimum spacing, the expansion width is set to

[0031] In one embodiment, obtaining the overlap distance according to the distance between the circumscribed rectangle and the target outer contour includes:

[0032] Connect any point on the target's outer contour with the midpoint of the circumscribed rectangle to obtain the intersection of any point on the target's outer contour and the circumscribed rectangle;

[0033] The distance between any point on the target outer contour and the line segment between the intersection point is the overlap distance.

[0034] In one embodiment, the overlap distance and the radar incident angle are calculated by the highest peak value method of the height histogram to obtain the height of each point of the outer contour, including:

[0035] The overlap distance and radar incident angle are calculated by the highest peak method of the height histogram, and the height of each point of the outer contour is obtained as follows: Where φ represents the radar incident angle, l h Indicates the overlap distance.

[0036] A polarization radar artificial target three-dimensional reconstruction device, the device comprising:

[0037] The target extraction module is used to obtain polarization radar data; perform target extraction on the polarization radar data to obtain the target strong scattering center and the polarization scattering matrix corresponding to the target strong scattering center;

[0038] A structure identification module is used to identify the target strong scattering center according to the polarization scattering matrix and the scattering structure identification method to obtain the scattering structure; the scattering structure includes a trihedral angle or a flat plate;

[0039] The inner and outer contour extraction module is used to extract the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour; delete all the outer contour strong scattering points in the target outer contour to obtain the circumscribed rectangle of the inner contour strong scattering points;

[0040] The artificial target three-dimensional reconstruction module is used to obtain the overlap distance based on the distance between the circumscribed rectangle and the target outer contour; calculate the overlap distance and the radar incident angle through the highest peak method of the height histogram to obtain the height of each point of the outer contour; and reconstruct the artificial target in three dimensions based on the height of each point of the outer contour.

[0041] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0042] Acquire polarimetric radar data;

[0043] Target extraction is performed on polarimetric radar data to obtain the target strong scattering center and the polarimetric scattering matrix corresponding to the target strong scattering center;

[0044] The scattering structure is obtained by identifying the polarization scattering matrix corresponding to the strong scattering center of the target and the scattering structure identification method; the scattering structure includes a trihedral angle or a flat plate;

[0045] Extract the strong scattering points of the target on the trihedral angle or flat plate to obtain the outer contour of the target;

[0046] All the strong scattering points of the outer contour of the target are deleted to obtain the circumscribed rectangle of the strong scattering points of the inner contour;

[0047] According to the distance between the circumscribed rectangle and the target outer contour, the overlap distance is obtained;

[0048] The overlap distance and radar incident angle are calculated by the highest peak method of the height histogram to obtain the height of each point of the outer contour;

[0049] The artificial target is reconstructed in three dimensions according to the height of each point of the outer contour.

[0050] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the following steps:

[0051] Acquire polarimetric radar data;

[0052] Target extraction is performed on polarimetric radar data to obtain the target strong scattering center and the polarimetric scattering matrix corresponding to the target strong scattering center;

[0053] The scattering structure is obtained by identifying the polarization scattering matrix corresponding to the strong scattering center of the target and the scattering structure identification method; the scattering structure includes a trihedral angle or a flat plate;

[0054] Extract the strong scattering points of the target on the trihedral angle or flat plate to obtain the outer contour of the target;

[0055] All the strong scattering points of the outer contour of the target are deleted to obtain the circumscribed rectangle of the strong scattering points of the inner contour;

[0056] According to the distance between the circumscribed rectangle and the target outer contour, the overlap distance is obtained;

[0057] The overlap distance and radar incident angle are calculated by the highest peak method of the height histogram to obtain the height of each point of the outer contour;

[0058] The artificial target is reconstructed in three dimensions according to the height of each point of the outer contour.

[0059] The above-mentioned method, device, computer equipment and storage medium for three-dimensional reconstruction of artificial targets by polarimetric radar first perform target extraction on polarimetric radar data to obtain the target strong scattering center and the polarimetric scattering matrix corresponding to the target strong scattering center, extract the strong scattering points whose scattering structure is a trihedral angle or a flat plate, and obtain the outer contour of the target. All strong scattering points of the outer contour are removed to obtain the circumscribed rectangle of the strong scattering points of the inner contour, and the overlapping distance of each point of the outer contour is obtained according to the spacing between the inner and outer contours. The height of each point of the outer contour is obtained using the overlapping distance and the radar incident angle, and the three-dimensional reconstruction result of the target is obtained according to the height of the outer contour. The present application extracts the target strong scattering points and their polarimetric scattering matrix, and uses the polarimetric radar artificial target scattering structure identification method to invert the target geometric structure information from the two-dimensional radar image, extract the contour information of different geometric structures of the target, and obtain the three-dimensional height information of the target according to the radar imaging geometry, thereby realizing the three-dimensional reconstruction of the target. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic flow chart of a method for three-dimensional reconstruction of an artificial target by polarization radar in one embodiment;

[0061] Figure 2 is a schematic diagram of a polarization radar image of a vehicle target obtained in one embodiment;

[0062] Figure 3 A schematic diagram of a target strong scattering point extraction result and a scattering structure identification result in one embodiment;

[0063] Figure 4 A schematic flow chart of the results of the geometric structure polarization inversion of a strong scattering point of a trihedral angle or a flat plate in another embodiment;

[0064] Figure 5 A schematic diagram of an extraction result of an inscribed rectangle of a strong scattering point of an inner contour of a target in another embodiment;

[0065] Figure 6 It is a schematic diagram of calculating the overlap distance of a point P on the outer contour according to the spacing between the inner and outer contours in another embodiment;

[0066] Figure 7 A schematic diagram of a height value histogram of each point of an outer contour and target height selection in another embodiment;

[0067] Figure 8 is a schematic diagram of models and three-dimensional reconstruction results of ten types of vehicle targets in another embodiment;

[0068] Fig. 9 It is a structural block diagram of a polarization radar artificial target three-dimensional reconstruction device in one embodiment;

[0069] Fig.10FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0071] In one embodiment, Figure 1 As shown, a method for three-dimensional reconstruction of artificial targets by polarization radar is provided, comprising the following steps:

[0072] Step 102, obtaining polarization radar data; performing target extraction on the polarization radar data to obtain the target strong scattering center and the polarization scattering matrix corresponding to the target strong scattering center.

[0073] Target extraction refers to calculating the total energy of the scattering matrix of each point based on the scattering matrix of each point in the polarization radar data, taking the point corresponding to the largest scattering matrix total energy as the strong scattering point of the target, and using the polarization scattering matrix corresponding to the strong scattering point of the target to calculate its scattering structure.

[0074] Step 104, performing identification according to the polarization scattering matrix corresponding to the target strong scattering center and the scattering structure identification method to obtain the scattering structure; the scattering structure includes a trihedral or a flat plate.

[0075] Scattering structure identification is generally achieved by using specific methods such as Cameron decomposition, that is, the type of scattering structure is determined by the polarization scattering matrix of the strong scattering point. This is a prior art and will not be described in detail in this application. Figure 3 As shown, the scattering structure types in the identification results include ten scattering structures, including trihedral or flat plate, dihedral or hat-shaped structure, cylinder, narrow dihedral, 1 / 4 wave device, horizontal dipole, vertical dipole, left spiral and right spiral scattering structures;

[0076] Step 106, extract the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour; delete all the outer contour strong scattering points in the target outer contour to obtain the circumscribed rectangle of the inner contour strong scattering points.

[0077] In SAR radar images, due to the overlap phenomenon, vehicles and other targets with a certain height and a relatively flat top will form two layers of contours. The outer contour is the top of the target, which is generally odd scattering (i.e., trihedral angle and flat plate). Therefore, the strong scattering points of the trihedral angle or flat plate can be extracted to construct the outer contour of the target. Through the identification of the target scattering structure, the target geometric structure information is inverted from the two-dimensional radar image, and the contour information of different geometric structures of the target is extracted, such as Figure 4(a) shows the geometric structure discrimination result of the trihedral strong scattering point. Figure 4 (b) is the target outer contour result obtained by extraction; Figure 5 (a) is the result of extracting the circumscribed rectangle of the inner contour, and (b) is the result after correcting the strong scattering points of the inner and outer contours of the target.

[0078] Step 108, obtaining the overlap distance according to the distance between the circumscribed rectangle and the target outer contour; calculating the overlap distance and the radar incident angle by the highest peak method of the height histogram to obtain the height of each point of the outer contour; and reconstructing the artificial target in three dimensions according to the height of each point of the outer contour.

[0079] The target after artificial 3D target reconstruction based on the height information of each point of the outer contour and the inner contour of the target is displayed in a 3D visualization diagram, such as Figure 8 shown.

[0080] In the above-mentioned method for three-dimensional reconstruction of artificial targets by polarization radar, firstly, target extraction is performed on polarization radar data to obtain the target strong scattering center and the polarization scattering matrix corresponding to the target strong scattering center, and the strong scattering points whose scattering structure is a trihedral angle or a flat plate are extracted to obtain the outer contour of the target. All strong scattering points of the outer contour are removed to obtain the circumscribed rectangle of the strong scattering points of the inner contour, and the overlapping distance of each point of the outer contour is obtained according to the spacing between the inner and outer contours. The overlapping distance and the radar incident angle are used to obtain the height of each point of the outer contour, and the three-dimensional reconstruction result of the target is obtained according to the height of the outer contour. The present application extracts the target strong scattering points and their polarization scattering matrix, and uses the polarization radar artificial target scattering structure identification method to invert the target geometric structure information from the two-dimensional radar image, extract the contour information of different geometric structures of the target, and obtain the three-dimensional height information of the target according to the radar imaging geometry, thereby realizing the three-dimensional reconstruction of the target.

[0081] In one embodiment, target extraction is performed on polarization radar data to obtain a target strong scattering center and a polarization scattering matrix corresponding to the target strong scattering center, including:

[0082] Presetting the minimum interval between target strong scattering centers and the number of target strong scattering centers;

[0083] Traverse each point in the polarimetric radar data with the minimum interval, and calculate the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point;

[0084] The point with the maximum total energy of the scattering matrix is ​​selected as the strong scattering center.

[0085] In one embodiment, traversing each point in the polarization radar data at a minimum interval and calculating the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point includes:

[0086] Traversing each point in the polarization radar data with the minimum interval, the scattering matrix of each point is obtained as follows: Where S HV is the backscatter coefficient for vertically polarized transmission and horizontally polarized reception, S VH is the backscatter coefficient for horizontally polarized transmission and vertically polarized reception, S VV is the backscatter coefficient of vertical polarization transmission and vertical polarization reception, S HH is the backscatter coefficient for horizontal polarization transmission and horizontal polarization reception;

[0087] According to the scattering matrix of each point, the total energy of the scattering matrix corresponding to each point is calculated as SPAN = |S HH | 2 +|S HV | 2 +|S VH | 2 +|S VV | 2 .

[0088] In one embodiment, the target strong scattering points of the trihedral angle or the flat plate are extracted to obtain the target outer contour, including:

[0089] Extract the strong scattering points of the trihedral angle or the plate and map their coordinates to a binary image;

[0090] Setting the expansion template corresponding to the scattering structure type and the expansion width of a single pixel of the expansion template;

[0091] The binary image is expanded according to the expansion template and the expansion width to obtain the connected area of ​​the binary image;

[0092] Mark the connected area to obtain the mark of the connected area;

[0093] According to the markings of the connected regions, the scattering centers in the connected regions are divided into different categories, and the category with the largest number of scattering centers is selected as the target outer contour.

[0094] like Figure 2 As shown in the figure, due to the existence of overlapping phenomenon, the vehicle target is composed of two circles of contours, of which the outer contour is mainly due to the echo reflected by the roof reaching the radar receiving end first, and in the imaging result, it is closer to the outside than the inner contour where the wheel is located. In the scattering structure identification results, the outer contours of the four vehicles are trihedral / flat plates. The scattering structure of the inner contour is relatively complex, and the differences between different vehicles are large.

[0095] In one embodiment, the process of setting the expansion width includes:

[0096] The distance between any two scattering centers is defined as d ij ,j=1...Nc , j≠i, then the minimum distance between the i-th scattering center and the remaining scattering centers is

[0097] According to the minimum spacing, the expansion width is set to

[0098] In one embodiment, obtaining the overlap distance according to the distance between the circumscribed rectangle and the target outer contour includes:

[0099] Connect any point on the target's outer contour with the midpoint of the circumscribed rectangle to obtain the intersection of any point on the target's outer contour and the circumscribed rectangle;

[0100] The distance between any point on the target outer contour and the line segment between the intersection point is the overlap distance.

[0101] like Figure 6 As shown in the figure, assume that P is a point on the outer contour and o is the center of the circumscribed rectangle of the inner contour. The intersection point of the circumscribed rectangle connecting point P and point o is B. E . Then the overlap distance l h That is, point P and point B E The distance between the line segments

[0102] In one embodiment, the overlap distance and the radar incident angle are calculated by the highest peak value method of the height histogram to obtain the height of each point of the outer contour, including:

[0103] The overlap distance and radar incident angle are calculated by the highest peak method of the height histogram, and the height of each point of the outer contour is obtained as follows: Where φ represents the radar incident angle, l h Indicates the overlap distance.

[0104] Figure 7 The histogram is calculated for the height of each point of the outer contour, and the height of the target is calculated to be h = 1.54 meters.

[0105] The height information of the target's outer contour and the target's inner contour are combined and displayed in a three-dimensional visualization, such as Figure 8As shown, the vehicle models and 3D reconstruction results used in the CVDomes electromagnetic simulation data, among which, (a) is the model and 3D reconstruction result of the mid-size sedan Camry, (b) is the model and 3D reconstruction result of the small sedan Honda Civicdr, (c) is the model and 3D reconstruction result of the large sedan Maxima, (d) is the model and 3D reconstruction result of the mid-size van Mitsubishi, (e) is the model and 3D reconstruction result of the small sedan Sentra, (f) is the model and 3D reconstruction result of the mid-size sedan Toyota Avalon, (g) is the model and 3D reconstruction result of the multi-purpose commercial vehicle Jeep 93, (h) is the model and 3D reconstruction result of the multi-purpose commercial vehicle Jeep 99, (i) is the model and 3D reconstruction result of the multi-purpose station wagon Mazda MPV, and (j) is the model and 3D reconstruction result of the large truck Toyota Tacoma.

[0106] The electromagnetic simulation data includes 10 common vehicles, including sedans, SUVs, trucks, station wagons, vans, etc. This experiment selects 4 representative vehicle data for analysis, namely Camry (mid-size sedan), Maxima (large sedan), Sentra (small sedan) and Mazda MPV (multi-purpose station wagon). The main simulation parameters of CVDomes data are shown in Table 1.

[0107] Table 1 Main parameters of CVDomes data

[0108]

[0109] From the results of 3D reconstruction, we can see that the reconstruction results of different vehicles are closely related to the vehicle model, and there are significant differences in the reconstruction results of different vehicles. Among them, the reconstruction results of Honda Civic 4dr, Camry, Sentra and other small cars are relatively similar, but the differences in the body structure of different cars can still be distinguished through the 3D reconstruction results.

[0110] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0111] In one embodiment, Fig. 9 As shown, a polarimetric radar artificial target 3D reconstruction device is provided, comprising: a target extraction module 902, a structure recognition module 904, an inner and outer contour extraction module 906 and an artificial target 3D reconstruction module 908, wherein:

[0112] The target extraction module 902 is used to obtain polarization radar data; perform target extraction on the polarization radar data to obtain the target strong scattering center and the polarization scattering matrix corresponding to the target strong scattering center;

[0113] The structure identification module 904 is used to identify the target strong scattering center according to the polarization scattering matrix and the scattering structure identification method to obtain the scattering structure; the scattering structure includes a trihedral or a flat plate;

[0114] The inner and outer contour extraction module 906 is used to extract the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour; delete all the outer contour strong scattering points in the target outer contour to obtain the circumscribed rectangle of the inner contour strong scattering points;

[0115] The artificial target three-dimensional reconstruction module 908 is used to obtain the overlap distance based on the distance between the circumscribed rectangle and the target outer contour; calculate the overlap distance and the radar incident angle by the highest peak method of the height histogram to obtain the height of each point of the outer contour; and reconstruct the artificial target in three dimensions based on the height of each point of the outer contour.

[0116] In one embodiment, the target extraction module 902 is further used to perform target extraction on the polarization radar data to obtain the target strong scattering center and the polarization scattering matrix corresponding to the target strong scattering center, including:

[0117] Presetting the minimum interval between target strong scattering centers and the number of target strong scattering centers;

[0118] Traverse each point in the polarimetric radar data with the minimum interval, and calculate the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point;

[0119] The point with the maximum total energy of the scattering matrix is ​​selected as the strong scattering center.

[0120] In one embodiment, the target extraction module 902 is further configured to traverse each point in the polarization radar data at a minimum interval, and calculate the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point, including:

[0121] Traversing each point in the polarization radar data with the minimum interval, the scattering matrix of each point is obtained as follows: Where S HV is the backscatter coefficient for vertically polarized transmission and horizontally polarized reception, S VH is the backscatter coefficient for horizontally polarized transmission and vertically polarized reception, S VV is the backscatter coefficient of vertical polarization transmission and vertical polarization reception, S HH is the backscatter coefficient for horizontal polarization transmission and horizontal polarization reception;

[0122] According to the scattering matrix of each point, the total energy of the scattering matrix corresponding to each point is calculated as SPAN = |S HH | 2 +|S HV | 2 +|S VH | 2 +|S VV | 2 .

[0123] In one embodiment, the inner and outer contour extraction module 906 is further used to extract the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour, including:

[0124] Extract the strong scattering points of the trihedral angle or the plate and map their coordinates to a binary image;

[0125] Setting the expansion template corresponding to the scattering structure type and the expansion width of a single pixel of the expansion template;

[0126] The binary image is expanded according to the expansion template and the expansion width to obtain the connected area of ​​the binary image;

[0127] Mark the connected area to obtain the mark of the connected area;

[0128] According to the markings of the connected regions, the scattering centers in the connected regions are divided into different categories, and the category with the largest number of scattering centers is selected as the target outer contour.

[0129] In one embodiment, the process of setting the expansion width includes:

[0130] The distance between any two scattering centers is defined as d ij ,j=1...N c , j≠i, then the minimum distance between the i-th scattering center and the remaining scattering centers is

[0131] According to the minimum spacing, the expansion width is set to

[0132] In one embodiment, the artificial target 3D reconstruction module 908 is further configured to obtain an overlap distance according to a distance between a circumscribed rectangle and an outer contour of the target, including:

[0133] Connect any point on the target's outer contour with the midpoint of the circumscribed rectangle to obtain the intersection of any point on the target's outer contour and the circumscribed rectangle;

[0134] The distance between any point on the target outer contour and the line segment between the intersection point is the overlap distance.

[0135] In one embodiment, the artificial target 3D reconstruction module 908 is further used to calculate the overlap distance and the radar incident angle by using the highest peak value method of the height histogram to obtain the height of each point of the outer contour, including:

[0136] The overlap distance and radar incident angle are calculated by the highest peak method of the height histogram, and the height of each point of the outer contour is obtained as follows: Where φ represents the radar incident angle, l h Indicates the overlap distance.

[0137] For the specific definition of a polarization radar artificial target three-dimensional reconstruction device, please refer to the definition of a polarization radar artificial target three-dimensional reconstruction method above, which will not be repeated here. Each module in the above-mentioned polarization radar artificial target three-dimensional reconstruction device can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0138] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig.10As shown. The computer device includes a processor, a memory, a network interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for three-dimensional reconstruction of artificial targets by polarization radar is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse, etc.

[0139] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0140] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method in the above embodiment when executing the computer program.

[0141] In one embodiment, a computer storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method in the above embodiment are implemented.

[0142] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0143] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for 3D reconstruction of artificial targets using polarimetric radar. It is characterized in that The method comprises: Acquire polarimetric radar data; Performing target extraction on the polarization radar data to obtain a target strong scattering center and a polarization scattering matrix corresponding to the target strong scattering center; Identify the strong scattering center according to the polarization scattering matrix and the scattering structure identification method to obtain the scattering structure; the scattering structure includes a trihedral or a flat plate; Extracting the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour; Deleting all the strong scattering points of the outer contour of the target to obtain a circumscribed rectangle of the strong scattering points of the inner contour; Obtaining an overlap distance according to a distance between the circumscribed rectangle and the target outer contour; The overlap distance and the radar incident angle are calculated by using the highest peak value method of the height histogram to obtain the height of each point of the outer contour; Performing three-dimensional reconstruction of the artificial target according to the height of each point of the outer contour; Obtaining the overlap distance according to the distance between the circumscribed rectangle and the target outer contour includes: Connecting any point on the outer contour of the target with the midpoint of the circumscribed rectangle to obtain an intersection point between any point on the outer contour of the target and the circumscribed rectangle; The distance between any point on the outer contour of the target and the line segment between the intersection point is the overlap distance; The overlap distance and the radar incident angle are calculated by the highest peak value method of the height histogram to obtain the height of each point of the outer contour, including: The overlap distance and radar incident angle are calculated by the highest peak value method of the height histogram, and the height of each point of the outer contour is obtained as follows: Where φ represents the radar incident angle, l h Indicates the overlap distance.

2. The method according to claim 1, It is characterized in that Performing target extraction on the polarization radar data to obtain a target strong scattering center and a polarization scattering matrix corresponding to the target strong scattering center includes: Preset the minimum interval between target strong scattering centers and the number of target strong scattering centers; Traversing each point in the polarization radar data at the minimum interval, and calculating the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point; The point with the maximum total energy of the scattering matrix is ​​selected as the strong scattering center.

3. The method according to claim 2, It is characterized in that Traversing each point in the polarization radar data at the minimum interval, and calculating the total energy of the scattering matrix corresponding to each point according to the scattering matrix of each point, including: Traversing each point in the polarization radar data with the minimum interval, the scattering matrix of each point is obtained as Where S HV is the backscatter coefficient for vertically polarized transmission and horizontally polarized reception, S VH is the backscatter coefficient for horizontally polarized transmission and vertically polarized reception, S VV is the backscatter coefficient of vertical polarization transmission and vertical polarization reception, S HH is the backscatter coefficient for horizontal polarization transmission and horizontal polarization reception; According to the scattering matrix of each point, the total energy of the scattering matrix corresponding to each point is calculated as SPAN = |S HH | 2 +|S HV | 2 +|S VH | 2 +|S VV | 2 .

4. The method according to any one of claims 1 to 3, It is characterized in that Extracting the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour includes: Extract the strong scattering points of the trihedral angle or the plate and map their coordinates to a binary image; Setting the expansion template corresponding to the scattering structure type and the expansion width of a single pixel of the expansion template; Performing expansion processing on the binary image according to the expansion template and the expansion width to obtain a connected area of ​​the binary image; Marking the connected area to obtain a mark of the connected area; According to the labels of the connected regions, the scattering centers in the connected regions are divided into different categories, and the category with the largest number of scattering centers is selected as the target outer contour.

5. The method according to claim 4, It is characterized in that The process of setting the expansion width includes: The distance between any two scattering centers is defined as d ij ,j=1...N c , j≠i, then the minimum distance between the i-th scattering center and the remaining scattering centers is The expansion width is set according to the minimum spacing.

6. A three-dimensional reconstruction device for artificial targets using polarimetric radar. It is characterized in that The device comprises: A target extraction module is used to obtain polarization radar data; perform target extraction on the polarization radar data to obtain a target strong scattering center and a polarization scattering matrix corresponding to the target strong scattering center; A structure identification module, used to identify the strong scattering center according to the polarization scattering matrix and the scattering structure identification method to obtain the scattering structure; the scattering structure includes a trihedral or a flat plate; The inner and outer contour extraction module is used to extract the target strong scattering points of the trihedral angle or the flat plate to obtain the target outer contour; delete all the outer contour strong scattering points in the target outer contour to obtain the circumscribed rectangle of the inner contour strong scattering points; The artificial target three-dimensional reconstruction module is used to obtain the overlap distance according to the distance between the circumscribed rectangle and the target outer contour; calculate the overlap distance and the radar incident angle by the highest peak method of the height histogram to obtain the height of each point of the outer contour; and perform three-dimensional reconstruction of the artificial target according to the height of each point of the outer contour; wherein, obtaining the overlap distance according to the distance between the circumscribed rectangle and the target outer contour includes: Connect any point on the target outer contour with the midpoint of the circumscribed rectangle to obtain the intersection of any point on the target outer contour and the circumscribed rectangle; the distance between the line segment of any point on the target outer contour and the intersection is the overlap distance; The overlapping distance and the radar incident angle are calculated by the highest peak method of the height histogram to obtain the height of each point of the outer contour, including: the overlapping distance and the radar incident angle are calculated by the highest peak method of the height histogram to obtain the height of each point of the outer contour. Where φ represents the radar incident angle, l h Indicates the overlap distance.

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