{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T02:36:45Z","timestamp":1782873405005,"version":"3.54.5"},"reference-count":23,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2017,2,28]],"date-time":"2017-02-28T00:00:00Z","timestamp":1488240000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41276185"],"award-info":[{"award-number":["41276185"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>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 \u221225 dB and a single-look pixel of 8 m \u00d7 5 m, the NRCS-estimation precision of this method can reach \u221238 dB at a resolution of 96 m \u00d7 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.<\/jats:p>","DOI":"10.3390\/rs9030219","type":"journal-article","created":{"date-parts":[[2017,2,28]],"date-time":"2017-02-28T10:57:52Z","timestamp":1488279472000},"page":"219","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images"],"prefix":"10.3390","volume":"9","author":[{"given":"Hui","family":"Meng","sequence":"first","affiliation":[{"name":"National Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, China"},{"name":"Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoqing","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinsong","family":"Chong","sequence":"additional","affiliation":[{"name":"National Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, China"},{"name":"Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiangfei","family":"Wei","sequence":"additional","affiliation":[{"name":"National Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, China"},{"name":"Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weiya","family":"Kong","sequence":"additional","affiliation":[{"name":"National Key Laboratory of Science and Technology on Microwave Imaging, Beijing 100190, China"},{"name":"Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2017,2,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1109\/JOE.2005.857505","article-title":"SAR-derived coastal and marine applications: From research to operational products","volume":"30","author":"Kerbaol","year":"2005","journal-title":"IEEE J. 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