Anisotropy Scattering Detection From Multiaspect Signatures of Circular Polarimetric SAR

Circular synthetic aperture radar (CSAR) can provide distinctive multiaspect anisotropic scattering signatures. However, it is impossible to retain the anisotropic signatures in an SAR image that combines all the subapertures coherently or incoherently. In this letter, we propose a polarimetric CSAR anisotropic scattering detection framework to characterize multiaspect and fully polarimetric SAR signatures of pointlike and distributed targets. We applied this framework to quantify and rank media polarimetric scattering dissimilarity over all aspects and to determine whether the most different one shows anisotropy by the use of constant false-alarm rate (CFAR) detection. Furthermore, we demonstrated the monotonicity of CFAR detection function and incorporated this function to decrease the complexity of the anisotropic scattering test. Our algorithm was validated and applied to a set of airborne P-band fully polarimetric circular SAR data acquired by the Institute of Electronics, Chinese Academy of Science. The results indicate that the framework can retain anisotropic scattering and extract a series of new multiaspect polarimetric SAR signatures for terrain classification.