CN-115797648-B - Full-polarization scattering feature extraction method and device and computing equipment

CN115797648BCN 115797648 BCN115797648 BCN 115797648BCN-115797648-B

Abstract

The invention provides a method, a device and a computing device for extracting full-polarization scattering characteristics, wherein the method comprises the steps of obtaining an ISAR image of an object to be identified under a preset azimuth central angle; the ISAR images comprise sub-images corresponding to four polarization states, the method is carried out on each group of ISAR images, scattering center extraction is carried out on the sub-images in the ISAR images to obtain amplitude values of at least two scattering centers, an amplitude matrix corresponding to each scattering center is determined according to the amplitude values extracted by each group of ISAR images, the amplitude matrix comprises amplitude values of the scattering centers under a preset azimuth center angle, and polarization ratio distribution of the scattering centers is obtained according to the amplitude matrix. The full polarization scattering feature extraction method reduces the sensitivity of the polarization scattering matrix to radar sight angles and the dependence on scenes, and improves the accuracy of target identification.

Inventors

TIAN HE
REN HONGMEI
YIN HONGCHENG
DONG CHUNZHU
YUAN LI

Assignees

北京环境特性研究所

Dates

Publication Date: 20260512
Application Date: 20221130

Claims (9)

1. A method for extracting full polarization scattering features, comprising: an ISAR image of a target to be identified under a preset azimuth central angle is acquired, wherein the ISAR image comprises sub-images corresponding to four polarization states, and the ISAR image is obtained from broadband sweep frequency data; Extracting scattering centers from sub-images in the ISAR image to obtain amplitude values of at least two scattering centers, wherein the ISAR image comprises sub-images corresponding to HH, HV, VH, VV polarization states, H represents horizontal polarization, V represents vertical polarization, a front letter represents a transmitting state and a rear letter represents a receiving state; Determining an amplitude matrix corresponding to each scattering center according to the amplitude values extracted by each group of ISAR images, wherein the amplitude matrix comprises the amplitude values of the scattering centers under the preset azimuth center angle; Obtaining polarization ratio distribution of the scattering center according to the amplitude matrix; The determining an amplitude matrix corresponding to each scattering center according to the amplitude values extracted from the ISAR images comprises the following steps: classifying amplitude values extracted from each group of ISAR images according to the scattering centers to obtain amplitude value groups of each scattering center, wherein the amplitude value groups comprise amplitude values of the scattering centers corresponding to four polarization states under the preset azimuth center angle; taking the amplitude values in the amplitude value group as elements of the amplitude matrix to obtain the amplitude matrix; And obtaining the polarization ratio distribution of the scattering center according to the amplitude matrix, wherein the method comprises the following steps: for each of said scattering centers, performing: For each preset azimuth center angle, performing: acquiring an amplitude value of the scattering center under the preset azimuth center angle, wherein the amplitude value comprises a first amplitude value under an HH polarization state, a second amplitude value under an HV polarization state, a third amplitude value under the VH polarization state and a fourth amplitude value under a VV polarization state; obtaining a polarization ratio according to the first amplitude value, the second amplitude value, the third amplitude value and the fourth amplitude value; And arranging the polarization ratio of each preset azimuth center angle according to the azimuth direction of the preset azimuth center angle to obtain the polarization ratio distribution of the scattering center.
2. The method of claim 1, wherein the acquiring an ISAR image of the object to be identified at the preset azimuth center angle comprises: Acquiring broadband sweep frequency data of the target to be identified; dividing the broadband sweep frequency data into a plurality of sections of data along the azimuth direction, wherein the window length of the imaging accumulation angle of each section of data is the same, and the angle sliding window step sizes of the adjacent sections of data are the same; for each piece of data, performing: determining the azimuth center angle of the segment of data; performing two-dimensional imaging focusing processing on the data to obtain an ISAR image at the azimuth center angle; The preset azimuth center angle comprises an azimuth center angle of each piece of data.
3. The method of claim 2, wherein the step of determining the position of the substrate comprises, The number of segment data is determined by the following formula: ; Wherein, the The method comprises the steps of representing the number of segment data, representing the azimuth length of the broadband sweep data by L, representing the window length of the imaging accumulation angle by N, and representing the angle sliding window step length by M.
4. The method of claim 2, wherein the step of determining the position of the substrate comprises, And adopting a filtering back projection algorithm to perform two-dimensional imaging focusing processing.
5. The method of claim 1, wherein the polarization ratio comprises a first polarization ratio, a second polarization ratio, a third polarization ratio; The first polarization ratio is determined by the following formula: ; the second polarization ratio is determined by the following formula: ; The third polarization ratio is determined by the following formula: ; Wherein, the For characterizing the first polarization ratio; for characterizing the first amplitude value; For characterizing the fourth amplitude value; for characterizing the second polarization ratio; for characterizing the second amplitude value; For characterizing the third polarization ratio; The x m ,y m is used for representing the pixel point position of the scattering center m in the ISAR image; used for representing the ith preset azimuth center angle.
6. The method according to any one of claims 1 to 5, wherein, The extracting of scattering centers is performed on sub-images in the ISAR image to obtain amplitude values of at least two scattering centers, and the method comprises the following steps: and for each sub-image, performing separation and extraction on the sub-image by using prior information and a maximum peak method to obtain amplitude values of at least two scattering centers in a polarization state corresponding to the sub-image.
7. A full polarization scattering feature extraction device, for implementing the method of any one of claims 1 to 6, comprising: the device comprises an acquisition module, a detection module and a display module, wherein the acquisition module is used for acquiring an ISAR image of an object to be identified under a preset azimuth center angle, and the ISAR image comprises sub-images corresponding to four polarization states; The extraction module is used for extracting scattering centers of all sub-images in the ISAR images to obtain amplitude values of at least two scattering centers; the determining module is used for determining an amplitude matrix corresponding to each scattering center according to the amplitude values extracted by each group of ISAR images, wherein the amplitude matrix comprises the amplitude values of the scattering centers under the preset azimuth center angle; and the operation module is used for obtaining the polarization ratio distribution of the scattering center according to the amplitude matrix.
8. A computing device comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the method of any of claims 1-6 when the computer program is executed.
9. A computer readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform the method of any of claims 1-6.

Description

Full-polarization scattering feature extraction method and device and computing equipment Technical Field The present invention relates to the field of radar technologies, and in particular, to a method and an apparatus for extracting full polarization scattering features, and a computing device. Background With the continuous development of radar technology, researchers want to obtain more effective information of targets for classification and identification of targets, and target identification is a difficult problem of aerospace defense. Polarization domain information in radar target echo signals is another important feature for target recognition, which follows time domain, frequency domain, etc. The mapping relation exists between the target polarization characteristics and physical properties such as the target structure and materials, but under the narrow-band condition, due to the superposition effect of each scattering center, the narrow-band polarization characteristics have strong gesture sensitivity, have strong dependence on actual application scenes, and cannot reflect the regular mapping of the target structure properties and the polarization characteristics, so that the identification accuracy of the existing space defense targets is still low. Disclosure of Invention The invention provides a full-polarization scattering feature extraction method, a full-polarization scattering feature extraction device and computing equipment. In a first aspect, an embodiment of the present invention provides a method for extracting a full polarization scattering feature, including: Obtaining an ISAR image of an object to be identified under a preset azimuth center angle, wherein the ISAR image comprises sub-images corresponding to four polarization states; extracting scattering centers from sub-images in the ISAR images to obtain amplitude values of at least two scattering centers; Determining an amplitude matrix corresponding to each scattering center according to the amplitude values extracted by each group of ISAR images, wherein the amplitude matrix comprises the amplitude values of the scattering centers under the preset azimuth center angle; and obtaining the polarization ratio distribution of the scattering center according to the amplitude matrix. Optionally, the acquiring an ISAR image of the object to be identified under the preset azimuth center angle includes: Acquiring broadband sweep frequency data of the target to be identified; dividing the broadband sweep frequency data into a plurality of sections of data along the azimuth direction, wherein the window length of the imaging accumulation angle of each section of data is the same, and the angle sliding window step sizes of the adjacent sections of data are the same; for each piece of data, performing: determining the azimuth center angle of the segment of data; performing two-dimensional imaging focusing processing on the data to obtain an ISAR image at the azimuth center angle; The preset azimuth center angle comprises an azimuth center angle of each piece of data. Optionally, the number of segment data is determined by the following formula: ; Wherein Q is used for representing the number of the segment data, L is used for representing the azimuth length of the broadband sweep frequency data, N is used for representing the window length of the imaging accumulation angle, and M is used for representing the angle sliding window step length. Optionally, a filtered backprojection algorithm is used for the two-dimensional imaging focusing process. Optionally, the ISAR image comprises sub-images corresponding to HH, HV, VH, VV polarization states, wherein H represents horizontal polarization, V represents vertical polarization, the front letter represents a transmitting state, and the rear letter represents a receiving state. Optionally, the obtaining the polarization ratio distribution of the scattering center according to the amplitude matrix includes: for each of said scattering centers, performing: For each preset azimuth center angle, performing: acquiring an amplitude value of the scattering center under the preset azimuth center angle, wherein the amplitude value comprises a first amplitude value under an HH polarization state, a second amplitude value under an HV polarization state, a third amplitude value under the VH polarization state and a fourth amplitude value under a VV polarization state; obtaining a polarization ratio according to the first amplitude value, the second amplitude value, the third amplitude value and the fourth amplitude value; And arranging the polarization ratio of each preset azimuth center angle according to the azimuth direction of the preset azimuth center angle to obtain the polarization ratio distribution of the scattering center. Optionally, the polarization ratio includes a first polarization ratio, a second polarization ratio, and a third polarization ratio; The first polarization ratio is determined