Interference Circular SAR Three-Dimensional Imaging Method and Device for Complex Structure Buildings

Abstract

The present invention discloses an interferometric circular SAR three-dimensional imaging method and device for complex structure buildings. The method includes: obtaining a set of sub-aperture images corresponding to antenna phase centers, where the set of sub-aperture images is obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane; performing interferometric processing on the set of sub-aperture images to obtain a wrapped interferometric phase; determining multiple phase ambiguity numbers according to the wrapped interferometric phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase; calculating multiple three-dimensional positions under each sub-aperture according to the multiple phase ambiguity numbers by using the range-Doppler equation; selecting from the multiple three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm; and performing interferometric circular SAR three-dimensional imaging of the complex structure building according to the selection result. The present invention effectively reduces the data storage amount and the calculation amount and improves the imaging efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of interferometric circular SAR imaging, and particularly to an interferometric circular SAR three-dimensional imaging method and device for complex structure buildings. Background Art

[0002] This section aims to provide background or context for the embodiments of the present invention stated in the claims. The description herein is not admitted to be prior art merely because it is included in this section.

[0003] Circular synthetic aperture radar can obtain the scattering characteristics of a target in different azimuth directions through omnidirectional observation and has the ability of three-dimensional imaging. However, the circular SAR has very weak ability to obtain the height-direction scattering characteristics of strongly directional targets, and its three-dimensional resolution depends on the consistency of the target scattering direction.

[0004] The interferometric circular SAR three-dimensional imaging method proposes a new imaging mode, which combines the advantages of omnidirectional observation of circular SAR and the high ability of interferometric SAR to obtain height direction, and can improve the three-dimensional imaging ability. Interferometric SAR has high-precision inversion ability. It uses two antennas to perform repeated observations on the same area, makes full use of the phase information carried by the radar echo signal, and extracts the phase difference between the two echo signals corresponding to the same target. Therefore, for the problem that the three-dimensional resolution of circular SAR depends on the consistency of the target scattering direction, it can be improved by using the interferometric circular SAR three-dimensional imaging mode. However, for this new mode, the interferometric phase obtained by conjugate multiplication of the image pair is wrapped by the phase period 2π. For complex structure buildings, it is difficult to unwrap the interferometric phase and it is difficult to obtain the absolute phase. By using the omnidirectional SAR information, there is no need to solve the phase stacking and the interferometric phase ambiguity number can be directly obtained for three-dimensional imaging of complex structure buildings.

[0005] In the prior art, the interferometric circular SAR three-dimensional imaging mostly targets simple targets such as small vehicles, etc., performs tomographic imaging and uses dual-frequency interference to reduce the use of phase unwrapping technology. However, for complex structure buildings, the data storage amount and calculation amount for interferometric circular SAR three-dimensional imaging using the above method are huge, and the three-dimensional imaging efficiency is low.

[0006] Therefore, there is an urgent need for an interferometric circular SAR three-dimensional imaging scheme for complex structure buildings that can overcome the above problems. Summary of the Invention

[0007] An embodiment of the present invention provides an interferometric circular SAR three-dimensional imaging method for complex structure buildings, which is used for interferometric circular SAR three-dimensional imaging of complex structure buildings, effectively reduces the data storage amount and calculation amount, and improves the imaging efficiency. The method includes:

[0008] Obtain a set of sub-aperture images corresponding to the antenna phase centers, where the set of sub-aperture images is obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane;

[0009] Perform interference processing on the set of sub-aperture images to obtain a wrapped interference phase;

[0010] According to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase, determine multiple phase ambiguity numbers;

[0011] According to the multiple phase ambiguity numbers, use the range-Doppler equation to calculate multiple three-dimensional positions for each sub-aperture;

[0012] Use the correlation coefficient algorithm to select from the multiple three-dimensional positions for each sub-aperture;

[0013] According to the selection result, perform interferometric circular SAR three-dimensional imaging of complex-structured buildings.

[0014] An embodiment of the present invention provides an interferometric circular SAR three-dimensional imaging device for complex-structured buildings, which is used to perform interferometric circular SAR three-dimensional imaging of complex-structured buildings, effectively reducing the data storage amount and calculation amount, and improving the imaging efficiency. The device includes:

[0015] A sub-aperture image set acquisition module, configured to obtain a set of sub-aperture images corresponding to the antenna phase centers, where the set of sub-aperture images is obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane;

[0016] A sub-aperture image set interference processing module, configured to perform interference processing on the set of sub-aperture images to obtain a wrapped interference phase;

[0017] A phase ambiguity number determination module, configured to determine multiple phase ambiguity numbers according to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase;

[0018] A sub-aperture three-dimensional position calculation module, configured to calculate multiple three-dimensional positions for each sub-aperture according to the multiple phase ambiguity numbers by using the range-Doppler equation;

[0019] A sub-aperture three-dimensional position selection module, configured to select from the multiple three-dimensional positions for each sub-aperture by using the correlation coefficient algorithm;

[0020] An interferometric circular SAR three-dimensional imaging module, configured to perform interferometric circular SAR three-dimensional imaging of complex-structured buildings according to the selection result.

[0021] An embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the three-dimensional imaging method of the interferometric circular SAR for complex-structured buildings described above is implemented.

[0022] An embodiment of the present invention further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the three-dimensional imaging method of the interferometric circular SAR for complex-structured buildings described above is implemented.

[0023] An embodiment of the present invention further provides a computer program product. The computer program product includes a computer program. When the computer program is executed by a processor, the three-dimensional imaging method of the interferometric circular SAR for complex-structured buildings described above is implemented.

[0024] In an embodiment of the present invention, a set of sub-aperture image groups corresponding to antenna phase centers is obtained. The sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane; the sub-aperture image groups are subjected to interferometric processing to obtain wrapped interferometric phases; according to the wrapped interferometric phases, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase, a plurality of phase ambiguity numbers are determined; according to the plurality of phase ambiguity numbers, a plurality of three-dimensional positions under each sub-aperture are calculated using the range-Doppler equation; the correlation coefficient algorithm is used to select from the plurality of three-dimensional positions under each sub-aperture; according to the selected results, the three-dimensional imaging of the interferometric circular SAR for complex-structured buildings is performed. In an embodiment of the present invention, sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane, effectively utilizing the multi-angle information of each sub-aperture. The sub-aperture image groups are subjected to interferometric processing to obtain wrapped interferometric phases, without the need for dual-frequency interference or phase unwrapping. According to the wrapped interferometric phases, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase, a plurality of phase ambiguity numbers are determined, and a plurality of three-dimensional positions under each sub-aperture are calculated using the range-Doppler equation. Then, the correlation coefficient algorithm is used to select from the plurality of three-dimensional positions under each sub-aperture, thereby performing the three-dimensional imaging of the interferometric circular SAR for complex-structured buildings, effectively reducing the data storage amount and the calculation amount, and improving the imaging efficiency. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. In the drawings:

[0026] Figure 1 Schematic diagram of the interferometric circular SAR three-dimensional imaging method for complex-structure buildings in the embodiments of the present invention;

[0027] Figure 2 Schematic diagram of the interferometric circular SAR three-dimensional imaging method for another complex-structure building in the embodiments of the present invention;

[0028] Figure 3 Interferometric circular SAR geometric model in the embodiments of the present invention;

[0029] Figure 4 Schematic diagram of the interferometric circular SAR three-dimensional imaging method for another complex-structure building in the embodiments of the present invention;

[0030] Figure 5 Structural diagram of the interferometric circular SAR three-dimensional imaging device based on complex-structure buildings in the embodiments of the present invention. Detailed implementation manners

[0031] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer and more understandable, the following further describes the embodiments of the present invention in detail with reference to the accompanying drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.

[0032] As described above, the existing interferometric circular SAR three-dimensional imaging uses dual-frequency interference to reduce the use of phase unwrapping technology, so that the angle information is not well utilized, and tomographic imaging is no longer applicable to complex structures. When this method is used in large scenes, it will cause problems of excessive calculation amount and excessive memory.

[0033] To perform interferometric circular SAR three-dimensional imaging of complex-structure buildings, effectively reduce the data storage amount and calculation amount, and improve the imaging efficiency, the embodiments of the present invention provide an interferometric circular SAR three-dimensional imaging method for complex-structure buildings. As Figure 1 shown, the method may include:

[0034] Step 101: Obtain a group of sub-aperture image groups corresponding to the antenna phase centers, where the sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane;

[0035] Step 102: Perform interference processing on the sub-aperture image groups to obtain a wrapped interference phase;

[0036] Step 103: Determine a plurality of phase ambiguity numbers according to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase;

[0037] Step 104: Calculate a plurality of three-dimensional positions under each sub-aperture according to the plurality of phase ambiguity numbers by using the range-Doppler equation.

[0038] Step 105: Select from the multiple three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm;

[0039] Step 106: Perform interferometric circular SAR three-dimensional imaging of the complex structure building according to the selection result.

[0040] As can be seen from Figure 1 shown, in the embodiment of the present invention, a set of sub-aperture image groups corresponding to the antenna phase centers is obtained. The sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on the reference height plane; perform interferometric processing on the sub-aperture image groups to obtain the wrapped interferometric phase; determine a plurality of phase ambiguity numbers according to the wrapped interferometric phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase; calculate the multiple three-dimensional positions under each sub-aperture according to the plurality of phase ambiguity numbers by using the range-Doppler equation; select from the multiple three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm; perform interferometric circular SAR three-dimensional imaging of the complex structure building according to the selection result. In the embodiment of the present invention, a set of sub-aperture image groups is obtained by imaging the sub-aperture data of each antenna phase center on the reference height plane, effectively utilizing the multi-angle information of each sub-aperture. Perform interferometric processing on the sub-aperture image groups to obtain the wrapped interferometric phase, without the need for dual-frequency interference or phase unwrapping. Determine a plurality of phase ambiguity numbers according to the wrapped interferometric phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase, calculate the multiple three-dimensional positions under each sub-aperture by using the range-Doppler equation, and then select from the multiple three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm, so as to perform interferometric circular SAR three-dimensional imaging of the complex structure building, effectively reducing the data storage amount and the calculation amount, and improving the imaging efficiency.

[0041] In step 101, a set of sub-aperture image groups corresponding to the antenna phase centers is obtained. The sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on the reference height plane.

[0042] In one embodiment, as Figure 2 shown, a set of sub-aperture image groups corresponding to the antenna phase centers is obtained in the following manner:

[0043] Step 201: Divide the circular apertures of at least two antenna phase centers to obtain the sub-aperture data of each antenna phase center;

[0044] Step 202: Image the sub-aperture data of each antenna phase center on the reference height plane to obtain a set of sub-aperture image groups corresponding to the antenna phase centers.

[0045] Figure 3 This is the geometric model of the interferometric circular SAR in the embodiments of the present invention. The radar platform includes two cross-track antenna phase centers: antenna phase center 1 and antenna phase center 2. That is, the line connecting the two antenna phase centers is perpendicular to the track direction of the radar platform. The line connecting the two antenna phase centers is called the baseline, with a length of B. The angle between the baseline and the horizontal plane is β. The radar platform makes a 360° circular motion around the area of interest. θ ∈ [0, 2π) is the azimuth angle, H is the height of the radar platform from the ground, and R is the trajectory radius of antenna phase center 1. The two independent circular apertures obtained from the two interferometric antenna phase centers are divided into M sub-apertures. Generally, each sub-aperture is 1°, and 360 sub-apertures can be divided. The sub-aperture data collected are respectively imaged on the reference height plane. h0 is the reference height, generally taken as the ground plane height. The obtained images are S 1i (x, y), S 2i (x, y). Represent the coordinates of the pixels. The subscripts 1 and 2 respectively represent antenna phase center 1 and antenna phase center 2, and represents the sub-aperture serial number, = 1, 2, …, M.

[0046] In step 102, the sub-aperture image group is subjected to interferometric processing to obtain the wrapped interferometric phase.

[0047] Specifically, when implemented, the sub-aperture image pair corresponding to the two antenna phase centers is subjected to interferometric processing to obtain the wrapped interferometric phase where the symbol * represents conjugation.

[0048] In step 103, according to the wrapped interferometric phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase, a plurality of phase ambiguity numbers are determined.

[0049] In one embodiment, the relationship between the height difference and the wrapped interferometric phase is pre-established according to the following formula:

[0050]

[0051] where Δh i,k (x, y) is the height difference, c is the speed of light, φ i,k (x, y) is the wrapped interferometric phase, R p1 is the distance from the sub-aperture antenna phase center to the pixel point (x, y, h0), f c is the center frequency of the antenna transmitted signal, B is the baseline length, ψ is the pitch angle of the radar relative to this pixel point, β is the angle between the baseline and the horizontal plane, and k is the phase ambiguity number.

[0052] Specifically, when implemented, φ i,k (x, y) is the absolute phase, that is, φ i,k (x, y) = φ i(x, y) + 2π·k, where k is the phase ambiguity number. According to the known scene height range, determine the possible phase ambiguity numbers k. There are a total of K phase ambiguity numbers, which are positive integers. The phase ambiguity numbers can be calculated based on the wrapped interferometric phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interferometric phase. The relationship between the height difference and the wrapped interferometric phase is derived and established as follows:

[0053] First, calculate the height difference to obtain K possible height differences between the target and the reference height through the slant range difference. The relationship between the slant range difference and the wrapped interferometric phase is:

[0054]

[0055] where c is the speed of light, and f c represents the center frequency of the antenna transmitting signal.

[0056] Then, calculate the K possible height differences:

[0057]

[0058] where R p1 is the distance from the phase center of the sub-aperture antenna 1 to the pixel point (x, y, h0), and ψ is the pitch angle of the radar relative to this pixel point.

[0059] Furthermore, the relationship between the height difference and the wrapped interferometric phase can be obtained:

[0060]

[0061] where Δh i,k (x, y) is the height difference, c is the speed of light, φ i,k (x, y) is the wrapped interferometric phase, R p1 is the distance from the phase center of the sub-aperture antenna to the pixel point (x, y, h0), f c is the center frequency of the antenna transmitting signal, B is the baseline length, ψ is the pitch angle of the radar relative to this pixel point, β is the angle between the baseline and the horizontal plane, and k is the phase ambiguity number.

[0062] In step 104, according to the multiple phase ambiguity numbers, use the range-Doppler equation to calculate the multiple three-dimensional positions under each sub-aperture.

[0063] Specifically, when implementing, solve the K three-dimensional positions under the i-th sub-aperture through the range-Doppler (RD) equation.

[0064] Let the sub-aperture radar platform velocity vector be The center of the sub-aperture is D i . The pixel coordinates on the sub-aperture projection plane are (x, y, h0) i , denoted as Pi ; The three-dimensional coordinates of K are (x k , y k , h k ), denoted as P i , and set as P i, ′ k , where h k = h0 + Δh i,k . The RD equation is as follows:

[0065]

[0066] Among them, the symbol · represents the inner product.

[0067] In step 105, the correlation coefficient algorithm is used to select from the multiple three-dimensional positions under each sub-aperture.

[0068] In one embodiment, as Figure 4 shown, using the correlation coefficient algorithm to select from the multiple three-dimensional positions under each sub-aperture includes:

[0069] Step 401: Project the multiple three-dimensional positions under each sub-aperture onto an imaging plane at a preset angle;

[0070] Step 402: Determine the window data correlation coefficient according to the projection result and the preset window using the correlation coefficient algorithm;

[0071] Step 403: Select the phase ambiguity number estimate value from the multiple phase ambiguity numbers according to the maximum value in the window data correlation coefficient;

[0072] Step 404: Select the target three-dimensional true coordinates from the multiple three-dimensional positions under each sub-aperture according to the phase ambiguity number estimate value.

[0073] Specifically, when implementing, project P i, ′ k at the i-th angle to the imaging plane at the (i + m)-th angle using the RD projection relationship, and there is Generally, m is taken as 5. Select a 3×3 or 5×5 window, and calculate the correlation coefficient ρ 1i (x, y) of the window data at the position of P i and the window data of the complex image S 1i+m (x, y) at position, and take the k corresponding to the maximum correlation coefficient as the finally estimated ambiguity number, that is i,k (x, y), and the corresponding is the most likely three-dimensional true coordinate of the target, realizing the ambiguity resolution using the azimuth angle. The correlation coefficient ρ is as follows: i,k As follows:

[0074]

[0075] Among them, n is the window size, and I i is the complex image S 1i (x, y) is the window data of P i at the position, and I i+m the complex image S 1i+m (x, y) at the position of the window data, and is the average value of the window data.

[0076] In step 106, according to the selected result, the interferometric circular SAR three-dimensional imaging of the complex structure building is performed.

[0077] Specifically, when the above steps are performed on all M sub-apertures, the three-dimensional point clouds at M angles obtained are merged, and there is that is, the omnidirectional three-dimensional point cloud is obtained.

[0078] The embodiment of the present invention adopts three-dimensional point cloud imaging. First, a three-dimensional point cloud is established with the interferometric SAR data at a certain angle to reduce the data storage amount and calculation amount. Then, the phase ambiguity number is obtained by using multi-angle data without phase unwrapping. Finally, the point clouds at each angle are assembled to form an omnidirectional three-dimensional point cloud.

[0079] The interferometric circular SAR three-dimensional imaging method for complex structure buildings provided by the embodiment of the present invention has the following advantages:

[0080] 1. It makes better use of multi-angle information without dual-frequency interference or phase unwrapping;

[0081] 2. It improves the problems of large calculation amount and much memory occupation when the interferometric circular SAR performs three-dimensional imaging on complex structure buildings, making its three-dimensional imaging efficiency higher.

[0082] Based on the same inventive concept, the embodiment of the present invention also provides an interferometric circular SAR three-dimensional imaging device for complex structure buildings, as described in the following embodiments. Since the principles of solving problems are similar to those of the interferometric circular SAR three-dimensional imaging method for complex structure buildings, the implementation of the interferometric circular SAR three-dimensional imaging device for complex structure buildings can refer to the implementation of the method, and the repeated parts will not be elaborated.

[0083] Figure 5 is the structural diagram of the interferometric circular SAR three-dimensional imaging device for complex structure buildings in the embodiment of the present invention, as Figure 5 shown. The interferometric circular SAR three-dimensional imaging device for complex structure buildings includes:

[0084] The sub-aperture image group acquisition module 501 is configured to acquire a group of sub-aperture images corresponding to a group of antenna phase centers, where the group of sub-aperture images is obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane;

[0085] The sub-aperture image group interference processing module 502 is configured to perform interference processing on the group of sub-aperture images to obtain a wrapped interference phase;

[0086] The phase ambiguity number determination module 503 is configured to determine a plurality of phase ambiguity numbers according to the wrapped interference phase, the scene height range, and a pre-established relationship between the height difference and the wrapped interference phase;

[0087] The sub-aperture three-dimensional position calculation module 504 is configured to calculate a plurality of three-dimensional positions under each sub-aperture according to the plurality of phase ambiguity numbers by using the range-Doppler equation;

[0088] The sub-aperture three-dimensional position selection module 505 is configured to perform selection from the plurality of three-dimensional positions under each sub-aperture by using a correlation coefficient algorithm;

[0089] The interferometric circular SAR three-dimensional imaging module 506 is configured to perform interferometric circular SAR three-dimensional imaging of complex structure buildings according to the selection result.

[0090] In one embodiment, the sub-aperture image group acquisition module 501 is further configured to acquire a group of sub-aperture images corresponding to a group of antenna phase centers in the following manner:

[0091] Divide the circular apertures of at least two antenna phase centers to obtain the sub-aperture data of each antenna phase center;

[0092] Image the sub-aperture data of each antenna phase center on a reference height plane to obtain a group of sub-aperture images corresponding to a group of antenna phase centers.

[0093] In one embodiment, the sub-aperture three-dimensional position selection module 505 is further configured to:

[0094] Project the plurality of three-dimensional positions under each sub-aperture onto an imaging plane at a preset angle;

[0095] Determine the window data correlation coefficient by using the correlation coefficient algorithm according to the projection result and a preset window;

[0096] Select an estimated value of the phase ambiguity number from the plurality of phase ambiguity numbers according to the maximum value in the window data correlation coefficient;

[0097] Select the target three-dimensional true coordinates from the plurality of three-dimensional positions under each sub-aperture according to the estimated value of the phase ambiguity number.

[0098] Based on the foregoing inventive concept, an embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the three-dimensional imaging method of the interferometric circular SAR for complex structure buildings described above is implemented.

[0099] Based on the foregoing inventive concept, an embodiment of the present invention further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the three-dimensional imaging method of the interferometric circular SAR for complex structure buildings described above is implemented.

[0100] An embodiment of the present invention further provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the three-dimensional imaging method of the interferometric circular SAR for complex structure buildings described above is implemented.

[0101] In an embodiment of the present invention, a set of sub-aperture image groups corresponding to antenna phase centers is obtained. The sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane; the sub-aperture image groups are subjected to interference processing to obtain a wrapped interference phase; according to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase, a plurality of phase ambiguity numbers are determined; according to the plurality of phase ambiguity numbers, a plurality of three-dimensional positions under each sub-aperture are calculated using the range-Doppler equation; the correlation coefficient algorithm is used to select from the plurality of three-dimensional positions under each sub-aperture; according to the selected results, the three-dimensional imaging of the interferometric circular SAR for complex structure buildings is performed. In the embodiment of the present invention, sub-aperture image groups are obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane, effectively utilizing the multi-angle information of each sub-aperture. The sub-aperture image groups are subjected to interference processing to obtain a wrapped interference phase, without the need for dual-frequency interference or phase unwrapping. According to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase, a plurality of phase ambiguity numbers are determined, and the range-Doppler equation is used to calculate a plurality of three-dimensional positions under each sub-aperture, and then the correlation coefficient algorithm is used to select from the plurality of three-dimensional positions under each sub-aperture, so as to perform the three-dimensional imaging of the interferometric circular SAR for complex structure buildings, effectively reducing the data storage amount and the calculation amount, and improving the imaging efficiency.

[0102] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0103] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0104] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, such that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0106] The specific embodiments described above further elaborate on the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An interference circular SAR three-dimensional imaging method for complex structure buildings, characterized in that, Including: Obtaining a set of sub-aperture images corresponding to a group of antenna phase centers, where the set of sub-aperture images is obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane; Performing interference processing on the set of sub-aperture images to obtain a wrapped interference phase; Determining a plurality of phase ambiguity numbers according to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase; Calculating a plurality of three-dimensional positions under each sub-aperture according to the plurality of phase ambiguity numbers by using the range-Doppler equation; Selecting from the plurality of three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm; Performing interferometric circular SAR three-dimensional imaging of a complex structure building according to the selected result.

2. The interference circular SAR three-dimensional imaging method for complex structure buildings according to claim 1, characterized in that, Obtaining a set of sub-aperture images corresponding to a group of antenna phase centers in the following manner: Dividing the circular apertures of at least two antenna phase centers to obtain the sub-aperture data of each antenna phase center; Imaging the sub-aperture data of each antenna phase center on a reference height plane to obtain a set of sub-aperture images corresponding to a group of antenna phase centers.

3. The interference circular SAR three-dimensional imaging method for complex structure buildings according to claim 1, characterized in that, Pre-establishing the relationship between the height difference and the wrapped interference phase according to the following formula: Among them, for the i-th sub-aperture, Δh i,k (x, y) is the height difference, c is the speed of light, φ i,k (x, y) is the wrapped interference phase, R p1 is the distance from the phase center of the sub-aperture antenna to the pixel point (x, y, h0), f c is the center frequency of the antenna transmitting signal, B is the baseline length, ψ is the elevation angle of the radar relative to this pixel point, β is the angle between the baseline and the horizontal plane, and k is the phase ambiguity number.

4. The interference circular SAR three-dimensional imaging method for complex structure buildings according to claim 1, wherein Selecting from the plurality of three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm, including: Projecting the plurality of three-dimensional positions under each sub-aperture onto an imaging plane at a preset angle; Determining the window data correlation coefficient by using the correlation coefficient algorithm according to the projection result and a preset window; Selecting an estimated value of the phase ambiguity number from the plurality of phase ambiguity numbers according to the maximum value in the window data correlation coefficient; Selecting the target three-dimensional true coordinates from the plurality of three-dimensional positions under each sub-aperture according to the estimated value of the phase ambiguity number.

5. An interference circular SAR three-dimensional imaging device for a complex structure building, characterized in that, Including: A sub-aperture image group obtaining module, configured to obtain a set of sub-aperture images corresponding to a group of antenna phase centers, where the set of sub-aperture images is obtained by imaging the sub-aperture data of each antenna phase center on a reference height plane; A sub-aperture image group interference processing module, configured to perform interference processing on the set of sub-aperture images to obtain a wrapped interference phase; A phase ambiguity number determining module, configured to determine a plurality of phase ambiguity numbers according to the wrapped interference phase, the scene height range, and the pre-established relationship between the height difference and the wrapped interference phase; A sub-aperture three-dimensional position calculating module, configured to calculate a plurality of three-dimensional positions under each sub-aperture according to the plurality of phase ambiguity numbers by using the range-Doppler equation; A sub-aperture three-dimensional position selecting module, configured to select from the plurality of three-dimensional positions under each sub-aperture by using the correlation coefficient algorithm; An interferometric circular SAR three-dimensional imaging module, configured to perform interferometric circular SAR three-dimensional imaging of a complex structure building according to the selected result.

6. The interferometric circular SAR three-dimensional imaging device for complex structure buildings according to claim 5, characterized in that, The sub-aperture image group obtaining module is further configured to obtain a set of sub-aperture images corresponding to a group of antenna phase centers in the following manner: Dividing the circular apertures of at least two antenna phase centers to obtain the sub-aperture data of each antenna phase center; Imaging the sub-aperture data of each antenna phase center on a reference height plane to obtain a set of sub-aperture images corresponding to a group of antenna phase centers.

7. The interference circular SAR three-dimensional imaging device for complex structure buildings according to claim 5, characterized in that The sub-aperture three-dimensional position selection module is further configured to: Project multiple three-dimensional positions under each sub-aperture onto an imaging plane at a preset angle; Determine the window data correlation coefficient according to the projection result and a preset window by using the correlation coefficient algorithm; Select an estimated value of the phase ambiguity number from multiple phase ambiguity numbers according to the maximum value in the window data correlation coefficient; Select the target three-dimensional true coordinates from the multiple three-dimensional positions under each sub-aperture according to the estimated value of the phase ambiguity number.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the method according to any one of claims 1 to 4 is implemented.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the method according to any one of claims 1 to 4 is implemented.

10. A computer program product, characterized in that, The computer program product includes a computer program, and when the computer program is executed by the processor, the method according to any one of claims 1 to 4 is implemented.

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