The Assessment of Equivalence and Rotation Angle Ambiguity of Four-Component Scattering PowerDecomposition Algorithm with Rotation of Coherency and Covariance Matrices in SAR Polarimetry

Abstract

The present study shows an assessment of the equivalence between the four-component scattering power decomposition (4-CSPD) algorithms based on rotation of covariance matrix and coherency matrix, and the ambiguity in the rotation of these matrices. Theoretically, the 4-CSPD algorithms with rotation of the two matrices should be identical. In this paper, an experimental proof is presented to show the actual equivalence of the two algorithms using polarimetric synthetic aperture radar (POLSAR) data acquired by Phased Array L-band SAR (PALSAR) on board Advanced Land Observing Satellite (ALOS).
An obscure point in the previous publications was also made clear. That is, there is ambiguity in minimizing the cross-polarized term in order to enhance the double-bounce scattering component by the rotation of polarimetric matrices. We analyzed how the results would be different if this ambiguity remains. The removal of this ambiguity optimally enhances the double-bounce scattering component.