Three-dimensional GTD scattering center modeling method and device for complex target

Abstract

The invention discloses a three-dimensional GTD scattering center modeling method and device for a complex target, and belongs to the field of scattering center modeling. The method comprises the following steps: decomposing a target geometric model into a plurality of component modules; performing ray tracing on the target geometric model by using a bounce ray technology, and determining a plurality of ray subsets based on the bounce times of each ray and the part module where the small surface element of each bounce effect is located; for each ray subset, generating a component three-dimensional ISAR image corresponding to the current ray subset by adopting an image domain ray integration mode under a single view angle and utilizing an image domain range frame capable of covering a component module corresponding to the current ray subset; and sequentially extracting a scattering center in the three-dimensional ISAR image of each component by using a CLEAN algorithm so as to construct a three-dimensional GTD scattering center model of the target. According to the scheme, memory occupation can be reduced, and the model precision can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of scattering center modeling, and in particular to a three-dimensional GTD scattering center modeling method and device for complex targets. Background Art

[0002] In the high frequency region, the backscattered echo of a radar target can be approximated as the sum of the responses of multiple scattering centers of the target. The scattering center model can provide a concise and physically relevant description of the echo signal of a radar target, and is therefore widely used in data compression and generation, and automatic target recognition.

[0003] In the prior art, a three-dimensional ideal point scattering center model can be quickly extracted from the target geometric model by using the bouncing ray technique (SBR), and a three-dimensional ISAR image of the complete target is generated by image domain ray integration. The three-dimensional position and amplitude of the scattering center are extracted from the three-dimensional ISAR image by using the CLEAN algorithm, and then the ideal point scattering center model is introduced to obtain the ideal point scattering center model of the target. Although this method can quickly construct a three-dimensional ideal point scattering center model of the target, the ideal point scattering center model cannot describe the relationship between the change of electromagnetic characteristics with frequency, and for large-sized and complex-shaped targets, when generating a three-dimensional ISAR image of the complete target by image domain ray integration, the image domain range frame is a cuboid or a cube, which needs to cover the complete target, which will result in many useless image intervals in the generated three-dimensional ISAR image, and in order to ensure the high accuracy of the model, sufficient sampling points are required, that is, the sampling step size is reduced, which will bring huge memory usage for large-sized targets. In addition, since various mechanisms are coupled and superimposed in the process of generating three-dimensional ISAR images, the extracted scattering center may be the result of the combined action of various mechanisms, which reduces the extraction accuracy of the scattering center. Therefore, the existing modeling methods occupy a large amount of memory when processing large-scale complex targets, and the model accuracy is not high.

[0004] Therefore, there is an urgent need for a three-dimensional GTD scattering center modeling method and device for complex targets. Summary of the invention

[0005] The present invention provides a three-dimensional GTD scattering center modeling method and device for complex targets, which can solve the problems of large memory usage and low model accuracy in the existing modeling methods when processing large-size complex targets. The technical solution is as follows:

[0006] In one aspect, a three-dimensional GTD scattering center modeling method for a complex target is provided, the method comprising:

[0007] Decompose the target geometric model into several component modules;

[0008] Performing ray tracing on the target geometric model using a bouncing ray technology, and determining a plurality of ray subsets based on the number of bounces of each ray and the component module in which the small facet acted by each bounce is located; wherein the ray subsets include a ray subset that acts only on a single component module and a ray subset that acts on multiple component modules;

[0009] For each ray subset, the image domain ray integration method under a single viewing angle is adopted, and the image domain range frame that can cover the component module corresponding to the current ray subset is used to generate the three-dimensional ISAR image of the component corresponding to the current ray subset;

[0010] The CLEAN algorithm is used to extract the scattering center in each of the three-dimensional ISAR images of the component in turn to construct a three-dimensional GTD scattering center model of the target.

[0011] On the other hand, a three-dimensional GTD scattering center modeling device for a complex target is provided, the device comprising:

[0012] A decomposition unit, used for decomposing the target geometric model into several component modules;

[0013] A diversity unit is used to perform ray tracing on the target geometric model using a bouncing ray technology, and determine a plurality of ray subsets based on the number of bounces of each ray and in which component module the small facet acted by each bounce is located; wherein the ray subsets include a ray subset that acts only on a single component module and a ray subset that acts on multiple component modules;

[0014] An imaging unit is used for generating a three-dimensional ISAR image of the component corresponding to the current ray subset by using an image domain range frame that can cover the component module corresponding to the current ray subset, for each ray subset, by using an image domain ray integration method under a single viewing angle;

[0015] The modeling unit is used to extract the scattering center in each of the three-dimensional ISAR images of the component in turn by using the CLEAN algorithm to construct a three-dimensional GTD scattering center model of the target.

[0016] On the other hand, a computer device is provided, which includes a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of the above-mentioned method.

[0017] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned method are implemented.

[0018] On the other hand, a computer program product is provided, comprising a computer program, wherein the computer program implements the steps of the above method when executed by a processor.

[0019] The technical solution provided by the present invention can at least bring the following beneficial effects:

[0020] The scattering center modeling method of bouncing ray technology is combined with the component decomposition technology to decompose the modeling problem of complex targets into the modeling problem of multiple groups of component modules. After the complex targets are decomposed into components and the ray subsets are divided in the calculation process, the mutual coupling and superposition between different scattering mechanisms can be reduced to a certain extent, and the extraction accuracy of the scattering center can be improved. At the same time, after the complex targets are decomposed into components, in the process of generating the three-dimensional ISAR image of the components, the image domain range frame can be set according to the shape and size of the component module. Compared with the traditional imaging method that does not perform component decomposition and needs to use a rectangular or cube-shaped image domain range frame to cover the complete target, it can effectively remove the redundant image intervals that do not belong to the target area, thereby reducing the memory usage in the calculation process. In addition, the traditional modeling method constructs an ideal point scattering center model, while this scheme constructs a GTD scattering center parameterized model, which can effectively characterize the relationship between the change of electromagnetic characteristics with frequency. Therefore, this scheme can not only reduce memory usage, but also improve model accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a flow chart of a three-dimensional GTD scattering center modeling method for a complex target provided by an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of an exploded view of a target component provided by an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of memory usage of a modeling method without component decomposition in the prior art;

[0025] Figure 4 is a schematic diagram of memory usage provided by an embodiment of the present invention;

[0026] Figure 5 It is a structural diagram of a three-dimensional GTD scattering center modeling device for a complex target provided by an embodiment of the present invention;

[0027] Figure 6 It is a hardware architecture diagram of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] The specific implementation of the above concept is described below.

[0030] Please refer to Figure 1 , an embodiment of the present invention provides a three-dimensional GTD scattering center modeling method for a complex target, the method comprising:

[0031] Step 100, decomposing the target geometric model into a plurality of component modules;

[0032] Step 102, using the bouncing ray technology to perform ray tracing on the target geometric model, and determining a plurality of ray subsets based on the number of bounces of each ray and the component module in which the small facet acted by each bounce is located; wherein the ray subsets include ray subsets that act only on a single component module and ray subsets that act on multiple component modules;

[0033] Step 104, for each ray subset, an image domain ray integration method under a single viewing angle is adopted, and an image domain range frame that can cover the component module corresponding to the current ray subset is used to generate a three-dimensional ISAR image of the component corresponding to the current ray subset;

[0034] Step 106: Use the CLEAN algorithm to extract the scattering center of each component in the three-dimensional ISAR image in turn to construct a three-dimensional GTD scattering center model of the target.

[0035] In the embodiment of the present invention, the scattering center modeling method of the bouncing ray technology is combined with the component decomposition technology, and the modeling problem of the complex target is decomposed into the modeling problem of multiple groups of component modules. After the complex target is decomposed into components and the ray subsets are divided in the calculation process, the mutual coupling superposition between different scattering mechanisms can be reduced to a certain extent, and the extraction accuracy of the scattering center can be improved. At the same time, after the complex target is decomposed into components, in the process of generating the three-dimensional ISAR image of the component, the image domain range frame can be set according to the shape and size of the component module. Compared with the traditional imaging method that does not perform component decomposition and needs to cover the complete target with an image domain range frame in the shape of a rectangular or cube, it can effectively remove the redundant image interval that does not belong to the target area, thereby reducing the memory usage in the calculation process. In addition, the traditional modeling method constructs an ideal point scattering center model, while the present solution constructs a GTD scattering center parameterized model, which can effectively characterize the relationship between the change of electromagnetic characteristics with frequency. Therefore, the present solution can not only reduce memory usage, but also improve model accuracy.

[0036] Described below Figure 1 How the various steps are performed.

[0037] For step 100:

[0038] In this embodiment, the target geometric model can be imported into the Hypermesh software, and the components with relatively concentrated spatial distribution on the complex target can be classified into a component module according to the spatial distribution of the target components. Figure 2 , the component decomposition results of the ship are given, where different colors represent different component modules obtained by decomposition.

[0039] Regarding step 102:

[0040] For example, assuming that the target is decomposed into three component modules, namely component module 1, component module 2 and component module 3, then according to the component modules acted upon by the rays multiple times of bouncing, a ray subset acting only on component module 1, a ray subset acting only on component module 2 and a ray subset acting only on component module 3 can be generated. In addition, the rays may bounce multiple times and act upon multiple component modules, and the ray subsets also include a ray subset acting on component module 1 and component module 2 at the same time, a ray subset acting on component module 1 and component module 3 at the same time, a ray subset acting on component module 2 and component module 3 at the same time, and a ray subset acting on component module 1, component module 2 and component module 3 at the same time.

[0041] Regarding step 104:

[0042] In some implementations, step 104 may include:

[0043] For each subset of rays, perform:

[0044] According to the closed expression of the image domain ray integral under a single viewing angle and the image domain range frame that can cover the component module corresponding to the current ray subset, the image domain ray integral result of each ray in the current ray subset is determined in turn;

[0045] The image domain ray integration results of all rays in the previous ray subset are superimposed to obtain the three-dimensional ISAR image of the component corresponding to the current ray subset.

[0046] In this embodiment, according to the closed expression of the image domain ray integral under a single viewing angle, the image domain ray integral result calculation formula of the i-th ray in each ray subset is:

[0047] Image3Di(x,y,z)=E i ·h(xx i ,yy i ,zz i )

[0048]

[0049] Among them, Image3Di(x,y,z) is the image domain ray integration result of the i-th ray, (x i ,y i ,z i ) is the equivalent three-dimensional position of the i-th ray in the radar coordinate system, (x, y, z) is the position of any point in the image domain range box of the component module corresponding to the current ray subset, E i is the scattering field of the i-th ray, h() is an intermediate function with no real meaning, k0 is the electromagnetic wave number, Δk is the wave number width, Δθ is the pitch angle width, Δφ is the azimuth angle width, and j is an imaginary number.

[0050] After calculating the image domain ray integration results of each ray in the ray subset, the image domain ray integration results of all rays are superimposed to obtain the 3D ISAR image of the component corresponding to the current ray subset:

[0051]

[0052] Where p is the number of rays in the ray subset.

[0053] It should be noted that if the ray subset is a ray subset that only acts on a single component module, then the obtained component three-dimensional ISAR image only contains this component module; if the ray subset is a ray subset that acts on multiple component modules, then the obtained component three-dimensional ISAR image contains these component modules.

[0054] In addition, you can refer to Figure 3and Figure 4 , Figure 3 It is a schematic diagram of memory usage of a modeling method that does not use component decomposition in the prior art. Figure 3 The yellow range frame in the figure is the image domain range frame when generating a 3D ISAR image of a complete target. It needs to cover the complete target, which will result in many useless image intervals in the generated 3D ISAR image. Figure 4 FIG. 1 is a schematic diagram of the image domain range of each component module when the component modules are sequentially imaged with a component 3D ISAR image after the ship is decomposed into components in an embodiment of the present invention. It can be seen that compared with Figure 3 The modeling method that does not adopt component decomposition can effectively remove redundant image intervals that do not belong to the target area, thereby reducing memory usage during the calculation process.

[0055] Regarding step 106:

[0056] In some embodiments, the step of “using the CLEAN algorithm to sequentially extract the scattering center in the three-dimensional ISAR image of each component” includes:

[0057] For each component 3D ISAR image, execute:

[0058] S1, determining whether the amplitude of the strongest point in the three-dimensional ISAR image of the current component is less than a set threshold value;

[0059] S2, if yes, stop the extraction and output the positions and amplitudes of all the extracted scattering centers;

[0060] S3, if not, then take the strongest point in the three-dimensional ISAR image of the current component as the scattering center extracted in this cycle, then subtract the integral result of the scattering center in the image domain from the three-dimensional ISAR image of the current component to obtain a residual image, and use the residual image as the new three-dimensional ISAR image of the current component, and jump to execute step S1.

[0061] In this embodiment, it is assumed that the component 3D ISAR image is formed by Q independent point scattering centers, each scattering center is represented by an amplitude parameter SA i and three-dimensional position parameters (Sx i ,Sy i ,Sz i ) characterization, then the three-dimensional ISAR image of the component can also be obtained by superposition approximation after the scattering center is integrated in the image domain. The formula for obtaining the three-dimensional ISAR image of the component by superposition approximation is:

[0062]

[0063] Compared with formula 1 in step 104, the strongest point in the current component three-dimensional ISAR image, that is, the point with the largest value in the component three-dimensional ISAR image matrix calculated in step 104, can be used as the scattering center extracted in this cycle, that is, the position of the scattering center (Sx i ,Sy i ,Sz i ) and amplitude SA i .

[0064] For the i-th cycle, the formula for calculating the residual image using the CLEAN algorithm is:

[0065] (Image3D) i+1 =(Image3D) i -SA i ·h(x-Sx i ,y-Sy i ,z-Sz i )

[0066] Where, (Image3D) i+1 is the residual image, (Image3D) i is the 3D ISAR image of the current component, SA i ·h(x-Sx i ,y-Sy i ,z-Sz i ) is the integration result of the scattering center in the image domain after taking the strongest point in the 3D ISAR image of the current component as the scattering center.

[0067] Therefore, in this embodiment, in each cycle, the strongest point of the three-dimensional ISAR image of the current component is used as the extracted scattering center. Then, before the amplitude of the strongest point is less than the set threshold value, a scattering center is extracted in each cycle, and the scattering center of the three-dimensional ISAR image of the current component is obtained through multiple cycles.

[0068] It should be noted that in the traditional scattering center modeling method, after the scattering centers in the three-dimensional ISAR image of the complete target are extracted using the CLEAN algorithm, since the ideal point scattering center model form only requires amplitude and position parameters, the amplitude and position parameters of the scattering center can be directly used to model the ideal point scattering center.

[0069] In this embodiment, in order to reduce the computer memory usage, the number of pixels in the component three-dimensional ISAR image cannot be too many, which limits the accuracy of the initial parameters of the scattering center extracted by the CLEAN algorithm. Since electromagnetic waves are coherent waves, the position parameters of the scattering center directly affect the phase of its scattering field. Therefore, the error of the position parameters of the scattering center will cause the coherence relationship between the scattering centers to be inaccurate in the process of reconstructing the total scattering field of the target by the scattering center parameterized model, thereby causing a large error in the reconstructed scattering field. Therefore, after the step of "using the CLEAN algorithm to extract the scattering center in each component three-dimensional ISAR image in turn", before the step of "constructing the three-dimensional GTD scattering center model of the target", the position parameters of the extracted scattering center can also be corrected to improve the model accuracy.

[0070] Next, the method of correcting the scattering center position parameters will be described.

[0071] In some embodiments, before the step of “constructing a three-dimensional GTD scattering center model of the target” and after the step of “using the CLEAN algorithm to sequentially extract the scattering center in the three-dimensional ISAR image of each component”, the method further includes:

[0072] For each scattering center extracted, execute:

[0073] Determine a set of rays forming the current scattering center based on the position of the current scattering center and the equivalent three-dimensional position of each ray in the ray subset corresponding to the current scattering center;

[0074] Using the predetermined frequency constraint, two adjacent frequency points f1 and f2 are selected to calculate the reconstructed scattering field of the current scattering center at these two frequency points respectively. and And the scattering field of the corresponding ray set at these two frequency points and

[0075] Calculate the reconstructed scattered field separately and The phase of the scattering field of the ray set corresponding to the current scattering center at these two frequency points and The phase of the scattering center is corrected using the position correction formula.

[0076] In this embodiment, the rays in the ray subset whose equivalent positions are within the position range of the scattering center are classified into the ray set of the current scattering center. After the two adjacent frequency points f1 and f2 have been determined, the scattering field of the ray set corresponding to the current scattering center at these two frequency points can be directly calculated. and , these two scattered fields and is the accurate electric field. Therefore, if the extracted scattering center is accurate, the reconstructed scattering field of the current scattering center at these two frequency points should be satisfied. and Respectively and Since the position parameter directly determines the phase of the scattered field, the scattered field can be reconstructed through the scattering center. and With accurate scattered field and The phase difference is used to correct the position parameters.

[0077] Assumptions and The phases are and , and The phases are and ,in and The relationship with the position parameters is as follows:

[0078]

[0079] Where c is the speed of light, m1 and n1 are phase ambiguity integers; Sz i is the radial position of the current scattering center extracted using the CLEAN algorithm.

[0080] Assume that the exact radial position of the scattering center is FSz i , then the phase of the reconstructed scattered field should be the accurate phase, that is, the following relationship exists:

[0081]

[0082] Where m2 and n2 are also phase ambiguity integers. Combining equations (2) and (3), the position correction formula can be determined as:

[0083]

[0084] In the formula, FSz i is the corrected radial position of the current scattering center, Sz i is the radial position of the current scattering center extracted by the CLEAN algorithm, c is the speed of light, f1 and f2 are two adjacent frequency points selected, and They are the scattering fields of the ray set corresponding to the current scattering center at these two frequency points. and The phase of and are the reconstructed scattering fields of the current scattering center and The phase, p and q are integer parameters, p = (m2-m1), q = (n2-n1).

[0085] F i Should be with Sz i Located in the same pixel unit, then

[0086] |FSz i -Sz i |<z c

[0087] where z c is the pixel unit length. Assuming f2<f1, if the equation group (4) is to have a unique solution, it is required that there is only one intersection point for all positions that meet the phase condition within the radial distance ambiguity range, that is, the frequency constraint condition is:

[0088]

[0089] When the two frequency points f1 and f2 satisfy the frequency constraint conditions in equation (5), p and q in equation (4) can be uniquely determined, thereby solving the exact position FSz of the scattering center. i Therefore, in the correction method of the scattering center position parameters, the ray set of the current scattering center is first determined, and then the frequency constraint condition shown in formula (5) is used to select two adjacent frequency points f1 and f2. Then, the reconstructed scattering field of the current scattering center at these two frequency points can be calculated. and , and the scattering field of the corresponding ray set at these two frequency points and , then the reconstructed scattered field can be determined respectively and The phase of the scattering field of the ray set corresponding to the current scattering center at these two frequency points and The phase of and Phase and , the scattering field of the corresponding ray set at these two frequency points and Phase and Substituting into the position correction formula (4), the unique p and q can be determined, thereby solving the exact position FSz of the scattering center i , and obtain the corrected position of the current scattering center.

[0090] Since the GTD scattering center model includes three parameters: the position, amplitude and frequency dependence factor of the scattering center, after completing the position correction of each scattering center, it is also necessary to determine the frequency dependence parameter to obtain the three-dimensional GTD scattering center model of the target.

[0091] In some embodiments, constructing a three-dimensional GTD scattering center model of the target includes:

[0092] For each scattering center extracted, execute:

[0093] According to the scattering field of the ray set corresponding to the current scattering center at two frequency points f1 and f2 and , estimate the frequency-dependent parameters of the current scattering center;

[0094] The amplitude, corrected position and frequency-dependent parameters of the current scattering center are brought into the GTD scattering center model expression to construct a three-dimensional GTD scattering center model of the target.

[0095] Specifically, the frequency-dependent parameters of the scattering center can be estimated by the following formula:

[0096]

[0097] In the formula, α is the frequency dependence, f1 and f2 are two adjacent frequency points selected, and are the scattering fields of the ray set corresponding to the scattering center at frequencies f1 and f2 respectively.

[0098] Since the frequency-dependent parameters in the GTD model can only take finite half-integer values, and the set of half-integer values ​​in the GTD model is Therefore, the half-integer value of the frequency dependence calculation result closest to the above formula in the half-integer value set of the GTD model can be used as the final frequency-dependent parameter of the current scattering center. When the amplitude, corrected position and frequency-dependent parameters of all scattering centers are determined, they are brought into the GTD scattering center model expression to construct the three-dimensional GTD scattering center model of the target.

[0099] Please refer to Figure 5 The embodiment of the present invention provides a three-dimensional GTD scattering center modeling device for a complex target, the device comprising:

[0100] A decomposition unit 501 is used to decompose the target geometric model into a plurality of component modules;

[0101] A diversity unit 502 is used to perform ray tracing on the target geometric model using a bouncing ray technology, and determine a plurality of ray subsets based on the number of bounces of each ray and the component module in which the small facet acted by each bounce is located; wherein the ray subsets include ray subsets that act only on a single component module and ray subsets that act on multiple component modules;

[0102] An imaging unit 503 is used to generate a three-dimensional ISAR image of the component corresponding to the current ray subset by using an image domain range frame that can cover the component module corresponding to the current ray subset, for each ray subset, by using an image domain ray integration method under a single viewing angle;

[0103] The modeling unit 504 is used to extract the scattering center in the three-dimensional ISAR image of each component in turn by using the CLEAN algorithm to construct a three-dimensional GTD scattering center model of the target.

[0104] In one embodiment of the present invention, the imaging unit 503 is used to perform:

[0105] For each subset of rays, perform:

[0106] According to the closed expression of the image domain ray integral under a single viewing angle and the image domain range frame that can cover the component module corresponding to the current ray subset, the image domain ray integral result of each ray in the current ray subset is determined in turn;

[0107] The image domain ray integration results of all rays in the previous ray subset are superimposed to obtain the three-dimensional ISAR image of the component corresponding to the current ray subset.

[0108] In one embodiment of the present invention, when the modeling unit 504 sequentially extracts the scattering center in the three-dimensional ISAR image of each component using the CLEAN algorithm, it is used to:

[0109] For each component 3D ISAR image, execute:

[0110] S1, determining whether the amplitude of the strongest point in the three-dimensional ISAR image of the current component is less than a set threshold value;

[0111] S2, if yes, stop the extraction and output the positions and amplitudes of all the extracted scattering centers;

[0112] S3, if not, then take the strongest point in the three-dimensional ISAR image of the current component as the scattering center extracted in this cycle, then subtract the integral result of the scattering center in the image domain from the three-dimensional ISAR image of the current component to obtain a residual image, and use the residual image as the new three-dimensional ISAR image of the current component, and jump to execute step S1.

[0113] In one embodiment of the present invention, before executing the construction of the three-dimensional GTD scattering center model of the target, and after sequentially extracting the scattering centers in the three-dimensional ISAR image of each component using the CLEAN algorithm, the modeling unit 504 is further configured to:

[0114] For each scattering center extracted, execute:

[0115] Determine a set of rays forming the current scattering center based on the position of the current scattering center and the equivalent three-dimensional position of each ray in the ray subset corresponding to the current scattering center;

[0116] Using the predetermined frequency constraint, two adjacent frequency points f1 and f2 are selected to calculate the reconstructed scattering field of the current scattering center at these two frequency points respectively. and And the scattering field of the corresponding ray set at these two frequency points and

[0117] Calculate the reconstructed scattered field separately and The phase of the scattering field of the ray set corresponding to the current scattering center at these two frequency points and The phase of the scattering center can be corrected using the position correction formula.

[0118] In one embodiment of the present invention, the position correction formula in the modeling unit 504 is:

[0119]

[0120] In the formula, FSz i is the corrected radial position of the current scattering center, Sz i is the radial position of the current scattering center extracted by the CLEAN algorithm, c is the speed of light, f1 and f2 are two adjacent frequency points selected, and They are the scattering fields of the ray set corresponding to the current scattering center at these two frequency points. and The phase of and are the reconstructed scattering fields of the current scattering center and The phase of , p and q are integer parameters.

[0121] In one embodiment of the present invention, when executing the construction of the three-dimensional GTD scattering center model of the target, the modeling unit 504 is used to:

[0122] For each scattering center extracted, execute:

[0123] According to the scattering field of the ray set corresponding to the current scattering center at two frequency points f1 and f2 and Estimate frequency-dependent parameters of the current scattering center;

[0124] The amplitude, corrected position and frequency-dependent parameters of the current scattering center are brought into the GTD scattering center model expression to construct a three-dimensional GTD scattering center model of the target.

[0125] It should be noted that the three-dimensional GTD scattering center modeling device for complex targets provided in the above embodiment is only illustrated by the division of the above functional units. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device is divided into different functional units to complete all or part of the functions described above. In addition, the above device embodiment and the method embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0126] The embodiment of the present application also provides a computer device, please refer to Figure 6 The computer device includes a processor and a memory, in which at least one instruction, at least one program, code set or instruction set is stored, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the three-dimensional GTD scattering center modeling method for complex targets provided by the above-mentioned method embodiments.

[0127] An embodiment of the present application also provides a computer-readable storage medium, on which is stored at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by a processor to implement the three-dimensional GTD scattering center modeling method for complex targets provided in the above-mentioned method embodiments.

[0128] An embodiment of the present application also provides a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the three-dimensional GTD scattering center modeling method for complex targets described in any of the above embodiments.

[0129] For the convenience of description, the above system or device is described by dividing it into various modules or units according to its functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0130] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0131] Finally, it should be noted that, in this article, relational terms such as first, second, third and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0132] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A three-dimensional GTD scattering center modeling method for complex targets, characterized in that: include: Decompose the target geometric model into several component modules; Performing ray tracing on the target geometric model using a bouncing ray technology, and determining a plurality of ray subsets based on the number of bounces of each ray and the component module in which the small facet acted by each bounce is located; wherein the ray subsets include a ray subset that acts only on a single component module and a ray subset that acts on multiple component modules; For each ray subset, the image domain ray integration method under a single viewing angle is adopted, and the image domain range frame that can cover the component module corresponding to the current ray subset is used to generate the three-dimensional ISAR image of the component corresponding to the current ray subset; The CLEAN algorithm is used to extract the scattering center in each of the three-dimensional ISAR images of the component in turn to construct a three-dimensional GTD scattering center model of the target.

2. The method according to claim 1, characterized in that For each ray subset, the image domain ray integration method under a single viewing angle is adopted, and the image domain range frame that can cover the component module corresponding to the current ray subset is used to generate a three-dimensional ISAR image of the component corresponding to the current ray subset, including: For each subset of rays, perform: According to the closed expression of the image domain ray integral under a single viewing angle and the image domain range frame that can cover the component module corresponding to the current ray subset, the image domain ray integral result of each ray in the current ray subset is determined in turn; The image domain ray integration results of all rays in the previous ray subset are superimposed to obtain the three-dimensional ISAR image of the component corresponding to the current ray subset.

3. The method according to claim 2, characterized in that The step of sequentially extracting the scattering center in each of the three-dimensional ISAR images of the component using the CLEAN algorithm includes: For each of the three-dimensional ISAR images of the component, the following steps are performed: S1, determining whether the amplitude of the strongest point in the three-dimensional ISAR image of the current component is less than a set threshold value; S2, if yes, stop the extraction and output the positions and amplitudes of all the extracted scattering centers; S3, if not, then take the strongest point in the three-dimensional ISAR image of the current component as the scattering center extracted in this cycle, then subtract the integral result of the scattering center in the image domain from the three-dimensional ISAR image of the current component to obtain a residual image, and use the residual image as the new three-dimensional ISAR image of the current component, and jump to execute step S1.

4. The method according to claim 1, characterized in that Before constructing the three-dimensional GTD scattering center model of the target, after sequentially extracting the scattering center in each three-dimensional ISAR image of the component using the CLEAN algorithm, the method further includes: For each scattering center extracted, execute: Determine a set of rays forming the current scattering center based on the position of the current scattering center and the equivalent three-dimensional position of each ray in the ray subset corresponding to the current scattering center; Using the predetermined frequency constraint, two adjacent frequency points f1 and f2 are selected to calculate the reconstructed scattering field of the current scattering center at these two frequency points respectively. and And the scattering field of the corresponding ray set at these two frequency points and Calculate the reconstructed scattered field separately and The phase of the scattering field of the ray set corresponding to the current scattering center at these two frequency points and The phase of the scattering center can be corrected using the position correction formula.

5. The method according to claim 4, characterized in that The position correction formula is: In the formula, FSz i is the corrected radial position of the current scattering center, Sz i is the radial position of the current scattering center extracted by the CLEAN algorithm, c is the speed of light, f1 and f2 are two adjacent frequency points selected, and They are the scattering fields of the ray set corresponding to the current scattering center at these two frequency points. and The phase of and are the reconstructed scattering fields of the current scattering center and The phase of , p and q are integer parameters.

6. The method according to claim 4, characterized in that The three-dimensional GTD scattering center model of the target is constructed, comprising: For each scattering center extracted, execute: The scattering field of the ray set corresponding to the current scattering center at two frequency points f1 and f2 and Estimate frequency-dependent parameters of the current scattering center; The amplitude, corrected position and frequency-dependent parameters of the current scattering center are brought into the GTD scattering center model expression to construct a three-dimensional GTD scattering center model of the target.

7. A three-dimensional GTD scattering center modeling device for complex targets, characterized in that: include: A decomposition unit, used for decomposing the target geometric model into several component modules; A diversity unit is used to perform ray tracing on the target geometric model using a bouncing ray technology, and determine a plurality of ray subsets based on the number of bounces of each ray and in which component module the small facet acted by each bounce is located; wherein the ray subsets include a ray subset that acts only on a single component module and a ray subset that acts on multiple component modules; An imaging unit is used for generating a three-dimensional ISAR image of the component corresponding to the current ray subset by using an image domain range frame that can cover the component module corresponding to the current ray subset, for each ray subset, by using an image domain ray integration method under a single viewing angle; The modeling unit is used to extract the scattering center in each of the three-dimensional ISAR images of the component in turn by using the CLEAN algorithm to construct a three-dimensional GTD scattering center model of the target.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of any one of the methods described in claims 1-6.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The method comprises a computer program, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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