Joint Use of Scattered and Received Wave Polarization Information for Target Characterization and Scattering Power Decomposition

This manuscript was submitted on 31 December 2019 to IEEE Transactions on Geoscience and Remote Sensing.

Abstract: Incoherent target decomposition techniques provide unique scattering information from polarimetric SAR data either by fitting appropriate scattering models or by optimizing the ``received" wave intensity through the diagonalization of the coherency (or covariance) matrix. Hence, the information provided by the ``scattered" wave might be neglected. This scattered wave information can be well utilized to gain complete polarimetric information for numerous applications. In this study, a new roll-invariant scattering-type parameter is introduced, which jointly uses the degree of polarization as the ``scattered" wave information and the elements of the covariance matrix as the ``received" wave information from both full-polarimetric (FP) and compact-polarimetric (CP) SAR data. This scattering-type parameter, which is comparable to that of the Cloude $\alpha$ for FP SAR data and the ellipticity parameter $\chi$ for CP SAR data, can be well utilized to characterize various targets. Furthermore, this new scattering-type parameter is adequately utilized to obtain a non-model based three-component scattering power decomposition technique. The double-bounce and the odd-bounce scattering powers are obtained by modulating the total polarized power by a proper geometrical factor easily derived using the new scattering-type parameter for both FP and CP SAR data. Moreover, due to its natural and direct formulation, the decomposition scattering powers are non-negative and roll-invariant while the total power is conserved. The proposed method is qualitatively and quantitatively assessed utilizing the L-band ALOS-2 and C-band Radarsat-2 FP and the associated simulated CP SAR data.