摘要
受到海面整体运动、海面后向散射系数相对低以及海况的影响,海洋锋特征在SAR图像中表现较弱,给后续的应用带来困难,亟需开展海洋锋特征增强方法的研究。SAR海面回波可以分解成Bragg散射分量和非极化分量,本文提出了一种基于非极化分量的SAR图像海洋锋特征增强方法。首先对双极化(VV和HH极化)数据进行辐射定标,为解决非极化分量提取过程中噪声增强的问题,对定标结果进行滤波;然后计算Bragg散射极化比;最后借助于极化差和极化比提取非极化分量,实现海洋锋特征增强。本文使用ALOSPALSAR数据进行处理验证,并通过计算峰值-背景比(PBR)和等效视数(ENL)进行定量分析。实验结果表明,经过本文方法处理后PBR较双极化图像可以提升15%以上,ENL较双极化图像可以提升30%以上。实验结果证明了方法的有效性,为后续的应用奠定基础。
Owing to the sea surface motion,relatively low NRCS of the sea surface,and influence of the sea state,the oceanic front features in SAR images tend to be weak;this causes difficulties in subsequent applications.Therefore,it is imperative to develop methods for enhancing oceanic front features.The sea surface echoes received by SAR can be decomposed into Bragg scattering components and nonpolarized components.This paper proposes a method for enhancing oceanic front features based on these nonpolar⁃ized components.First,dual co-polarization(VV and HH)radar data are calibrated.To address the prob⁃lem of noise enhancement during the extraction of nonpolarized components,the calibrated results are fil⁃tered.Subsequently,we calculate the Bragg model polarization ratio.Finally,the nonpolarized compo⁃nents are extracted based on the polarization difference and polarization ratio to enhance the oceanic front features.In this study,the ALOS PALSAR data are processed.Quantitative analyses are performed by calculating the peak-to-background ratio(PBR)and the equivalent number of looks(ENL).The experi⁃mental results indicate that the PBR increased by more than 15%and the ENL increased by more than 30%,as compared with those for dual-polarization images.These experimental results prove the effective⁃ness of the proposed method,serving as the basis for subsequent applications.
作者
赵亚威
孙凯
种劲松
ZHAO Ya-wei;SUN Kai;CHONG Jin-song(Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China;National Key Laboratory of Microwave Imaging Technology,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2021年第6期1440-1447,共8页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.41276185)。
关键词
海洋锋
非极化分量
特征增强
oceanic front
nonpolarized components
features enhancement
作者简介
赵亚威(1995-),男,山东曲阜人,博士研究生,2017年于中国矿业大学获得学士学位,主要从事SAR海洋成像、极化SAR等方面的研究。E-mail:zhaoyawei17@mails.ucas.ac.cn;通讯作者:种劲松(1969-),女,北京人,研究员,博士生导师,1991年于吉林大学获得学士学位,2000年于北京航空航天大学获得硕士学位,2003年于中国科学院研究生院获得博士学位,主要从事合成孔径雷达图像海洋信息提取、海洋目标探测等方面的研究。E-mail:iecas_chong@163.com。
