基于香农熵的极化SAR相干矩阵信息量评价  

Information Measure of Polarimetric SAR Coherence Matrix based on A Shannon Entropy

作　　者：李姣姣 刘玉 陈锟山 Li Jiaojiao;Liu Yu;Chen Kunshan(State Key Laboratory of Remote Sensing Science,Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences,Beijing,100101,China;University of Chinese Academy of Sciences,Beijing,100049,China)

机构地区：[1]中国科学院遥感与数字地球研究所遥感科学国家重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《遥感技术与应用》2018年第5期842-849,共8页Remote Sensing Technology and Application

基　　金：国家自然科学基金重点项目"同轨集合SAR-Scatterometer的新型微波多维探测理论与模式研究"(41531175)

摘　　要：极化SAR(Synthetic Aperture Radar)非相干分解是获取地物目标特性的重要手段。针对目前非相干分解所使用的极化相干矩阵包含的信息量尚未定量估计的问题,引入信息论中的香农熵(Shannon Entropy),系统分析了不同地物包括海洋、植被和建筑物在不同时段和波段下极化相干矩阵信息量随窗口大小的变化规律。研究发现,不同地物类型的极化相干矩阵包含的信息量差异较大。其中建筑物平均相干矩阵的信息量较低,且随窗口增加信息量呈现近线性增加,而海洋、植被的极化相干矩阵信息量偏高,且随窗口增加信息量先快速增加后趋于稳定。同种地物在不同波段及时段下,平均相干矩阵的信息量随窗口大小的变化规律相近。研究表明:基于香农熵的相干矩阵信息量评价方法,可以简单有效地定量评估相干矩阵包含的信息量,同时也可为计算极化相干矩阵滑动窗口的选择提供重要理论依据和指标参考,有助于后续进行极化目标分解和对目标散射机制的理解。The incoherent target decomposition of fully polarimetric SAR based on an average coherence ma- trix is a powerful means to characterize the targets.The objective of this study is to measure the informa- tion content contained in the average coherence matrix,which is usually not quantitatively estimated.In so doing,the Shannon entropy is used to assess the information content during the course of estimating the coherence matrix by applying the proper window size so that information loss may be minimized. Experi- mental results show that the average coherence matrix of different targets has different information content.For example,the information content for the Buildings is relatively low,under the same window size, and the increases almost linearly as the window size increases, while for ocean and vegetative area are com- paratively high and the amount of information content increase rapidly at first, then become stable with the increasing of window size. The dependence of the information content on the window size remains quite similar for different time and frequency.It demonstrates that the Shannon entropy based information measure is robust and yet effective to quantitatively evaluate the target information content in average coherence matrix estimated,and thus it offers a fair criteria for determining the optimum window size to preserve maximum information content when estimating the average coherence matrix in SAR.

关 键 词：全极化SAR 相干矩阵 香农熵 信息量 

分 类 号：TP237[自动化与计算机技术—检测技术与自动化装置]