Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization
Moving ship refocusing is challenging because the target motion parameters are unknown. Moreover, moving ships in squint synthetic aperture radar (SAR) images obtained by the back-projection (BP) algorithm usually suffer from geometric deformation and spectrum winding. Therefore, a spectrum-orthogon...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-07-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/14/2807 |
| _version_ | 1827686913971060736 |
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| author | Xuyao Tong Min Bao Guangcai Sun Liang Han Yu Zhang Mengdao Xing |
| author_facet | Xuyao Tong Min Bao Guangcai Sun Liang Han Yu Zhang Mengdao Xing |
| author_sort | Xuyao Tong |
| collection | DOAJ |
| description | Moving ship refocusing is challenging because the target motion parameters are unknown. Moreover, moving ships in squint synthetic aperture radar (SAR) images obtained by the back-projection (BP) algorithm usually suffer from geometric deformation and spectrum winding. Therefore, a spectrum-orthogonalization algorithm that refocuses moving ships in squint SAR images is presented. First, “squint minimization” is introduced to correct the spectrum by two spectrum compression functions: one to align the spectrum centers and another to translate the inclined spectrum into orthogonalized form. Then, the precise analytic function of the two-dimensional (2D) wavenumber spectrum is derived to obtain the phase error. Finally, motion compensation is performed in the two-dimensional wavenumber domain after the motion parameter is estimated by maximizing the image sharpness. This method has low computational complexity because it lacks interpolation and can be implemented by the inverse fast Fourier translation (IFFT) and fast Fourier translation (FFT). Processing results of simulation experiments and the GaoFen-3 squint SAR data validate the effectiveness of this method. |
| first_indexed | 2024-03-10T09:24:23Z |
| format | Article |
| id | doaj.art-1c687819f46b42999419fb4c651c9b43 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T09:24:23Z |
| publishDate | 2021-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-1c687819f46b42999419fb4c651c9b432023-11-22T04:52:43ZengMDPI AGRemote Sensing2072-42922021-07-011314280710.3390/rs13142807Refocusing of Moving Ships in Squint SAR Images Based on Spectrum OrthogonalizationXuyao Tong0Min Bao1Guangcai Sun2Liang Han3Yu Zhang4Mengdao Xing5National Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, ChinaSchool of Electronic Engineering, Xidian University, Xi’an 710071, ChinaNational Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, ChinaSchool of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071, ChinaSchool of Electronic Engineering, Xidian University, Xi’an 710071, ChinaNational Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, ChinaMoving ship refocusing is challenging because the target motion parameters are unknown. Moreover, moving ships in squint synthetic aperture radar (SAR) images obtained by the back-projection (BP) algorithm usually suffer from geometric deformation and spectrum winding. Therefore, a spectrum-orthogonalization algorithm that refocuses moving ships in squint SAR images is presented. First, “squint minimization” is introduced to correct the spectrum by two spectrum compression functions: one to align the spectrum centers and another to translate the inclined spectrum into orthogonalized form. Then, the precise analytic function of the two-dimensional (2D) wavenumber spectrum is derived to obtain the phase error. Finally, motion compensation is performed in the two-dimensional wavenumber domain after the motion parameter is estimated by maximizing the image sharpness. This method has low computational complexity because it lacks interpolation and can be implemented by the inverse fast Fourier translation (IFFT) and fast Fourier translation (FFT). Processing results of simulation experiments and the GaoFen-3 squint SAR data validate the effectiveness of this method.https://www.mdpi.com/2072-4292/13/14/2807squint synthetic aperture radar (SAR)back-projection (BP) algorithmmoving ship refocusingspectrum orthogonalizationsquint minimization |
| spellingShingle | Xuyao Tong Min Bao Guangcai Sun Liang Han Yu Zhang Mengdao Xing Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization Remote Sensing squint synthetic aperture radar (SAR) back-projection (BP) algorithm moving ship refocusing spectrum orthogonalization squint minimization |
| title | Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization |
| title_full | Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization |
| title_fullStr | Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization |
| title_full_unstemmed | Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization |
| title_short | Refocusing of Moving Ships in Squint SAR Images Based on Spectrum Orthogonalization |
| title_sort | refocusing of moving ships in squint sar images based on spectrum orthogonalization |
| topic | squint synthetic aperture radar (SAR) back-projection (BP) algorithm moving ship refocusing spectrum orthogonalization squint minimization |
| url | https://www.mdpi.com/2072-4292/13/14/2807 |
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