全极化SAR数据提供了更多的地物极化散射信息,目前被广泛地应用于海上船舶检测的应用研究。提出改进的Notch滤波方法,实现全极化SAR数据的海上船舶检测。该方法结合目标的极化散射特性与能量双重特点,设计针对海面、方位向模糊、相干斑噪的不同滤波,消除虚警,通过功率(SPAN)能量因子降低由于散射机制相同而造成的漏检。利用RADATSAT-2全极化精细扫描数据对本文方法进行验证,并与极化白化滤波(PWF)和SPAN方法进行对比分析,实验结果表明,本文方法能从海面上有效检测出各种大小的船舶,同时能抑制方位向模糊、相干斑噪以及船舶的旁瓣造成的虚警。

Polarimetric SAR data provide more information about objects' scattering properties and they have been widely used in the research of ship detection in the ocean.In this paper, an improved notch filter method is proposed, which uses both the polarimetric scattering mechanisms and the backscattering power of the target.By devising the projection subspace of the sea, azimuth ambiguities and coherent noises, a lower coherency of all those targets in the image can be reached, thus eliminating false alarms caused by them.What's more, a power related factor, the SPAN, is added to the detector in order to separate ships that have the similar scattering mechanism as the sea.The proposed method has been applied on RADARSAT-2 Fine Quad Mode data to validate its efficiency. Comparing to Polarimetric whitening filter(PWF) and SPAN method, the proposed method shows higher detection ability with low false alarms caused by azimuth ambiguities and coherent noises.