POLARIMETRIC SAR DISTORTIONS INDUCED BY TOPOGRAPHY: AN ANALYTICAL FORMULATION FOR COMPENSATION IN THE IMAGING DOMAIN

A novel look-angle function based formulation of the topography-induced backscattering matrix rotation is proposed in this paper. The proposed formulation is obtained by relying on a suitable cylindrical coordinate system and a suitable parametric representation of the illuminated surface. A concise functional form for the polarization orientation angle shifts, whose expression is given uniquely in terms of the partial derivative of the look-angle function along the azimuthal (or along track) direction, is derived. As a result, a unifying analytical approach for the calibration of polarimetric SAR data, which incorporates consistently within a common formalism both area-stretching radiometric compensation and polarization orientation angle shifts compensation, is developed. The validity of the proposed method is demonstrated by using real polarimetric SAR data.