Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images
The image intensities of low-backscattering areas in synthetic aperture radar (SAR) images are often seriously contaminated by the system noise floor and azimuthal ambiguity signal from adjacent high-backscattering areas. Hence, the image intensity of low-backscattering areas does not correctly refl...
| Main Authors: | , , , , |
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| Format: | Article |
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MDPI AG
2017-02-01
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| Series: | Remote Sensing |
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| Online Access: | http://www.mdpi.com/2072-4292/9/3/219 |
| _version_ | 1818958305344618496 |
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| author | Hui Meng Xiaoqing Wang Jinsong Chong Xiangfei Wei Weiya Kong |
| author_facet | Hui Meng Xiaoqing Wang Jinsong Chong Xiangfei Wei Weiya Kong |
| author_sort | Hui Meng |
| collection | DOAJ |
| description | The image intensities of low-backscattering areas in synthetic aperture radar (SAR) images are often seriously contaminated by the system noise floor and azimuthal ambiguity signal from adjacent high-backscattering areas. Hence, the image intensity of low-backscattering areas does not correctly reflect the backscattering intensity, which causes confusion in subsequent image processing or interpretation. In this paper, a method is proposed to estimate the normalized radar cross-section (NRCS) of low-backscattering area by utilizing the differences between noise, azimuthal ambiguity, and signal in the Doppler frequency domain of single-look SAR images; the aim is to eliminate the effect of system noise and azimuthal ambiguity. Analysis shows that, for a spaceborne SAR with a noise equivalent sigma zero (NESZ) of −25 dB and a single-look pixel of 8 m × 5 m, the NRCS-estimation precision of this method can reach −38 dB at a resolution of 96 m × 100 m. Three examples are given to validate the advantages of this method in estimating the low NRCS and the filtering of the azimuthal ambiguity. |
| first_indexed | 2024-12-20T11:23:38Z |
| format | Article |
| id | doaj.art-49b2bb076d9c4b6187bd0db30649406c |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-12-20T11:23:38Z |
| publishDate | 2017-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-49b2bb076d9c4b6187bd0db30649406c2022-12-21T19:42:26ZengMDPI AGRemote Sensing2072-42922017-02-019321910.3390/rs9030219rs9030219Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR ImagesHui Meng0Xiaoqing Wang1Jinsong Chong2Xiangfei Wei3Weiya Kong4National Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, ChinaInstitute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, ChinaNational Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, ChinaNational Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, ChinaNational Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, ChinaThe image intensities of low-backscattering areas in synthetic aperture radar (SAR) images are often seriously contaminated by the system noise floor and azimuthal ambiguity signal from adjacent high-backscattering areas. Hence, the image intensity of low-backscattering areas does not correctly reflect the backscattering intensity, which causes confusion in subsequent image processing or interpretation. In this paper, a method is proposed to estimate the normalized radar cross-section (NRCS) of low-backscattering area by utilizing the differences between noise, azimuthal ambiguity, and signal in the Doppler frequency domain of single-look SAR images; the aim is to eliminate the effect of system noise and azimuthal ambiguity. Analysis shows that, for a spaceborne SAR with a noise equivalent sigma zero (NESZ) of −25 dB and a single-look pixel of 8 m × 5 m, the NRCS-estimation precision of this method can reach −38 dB at a resolution of 96 m × 100 m. Three examples are given to validate the advantages of this method in estimating the low NRCS and the filtering of the azimuthal ambiguity.http://www.mdpi.com/2072-4292/9/3/219SARoceanNRCSDoppler spectrumazimuthal ambiguity |
| spellingShingle | Hui Meng Xiaoqing Wang Jinsong Chong Xiangfei Wei Weiya Kong Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images Remote Sensing SAR ocean NRCS Doppler spectrum azimuthal ambiguity |
| title | Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images |
| title_full | Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images |
| title_fullStr | Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images |
| title_full_unstemmed | Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images |
| title_short | Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images |
| title_sort | doppler spectrum based nrcs estimation method for low scattering areas in ocean sar images |
| topic | SAR ocean NRCS Doppler spectrum azimuthal ambiguity |
| url | http://www.mdpi.com/2072-4292/9/3/219 |
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