Investigation on the Performance of Compact Polarimetry in SAR Interferometry

In this paper, we investigate the role and the performance of compact polarimetry in SAR interferometry. The considered SAR architecture is assumed to transmit either a circular polarized wave or a linear polarized one oriented at 45 degrees (pi/4), and to receive at horizontal and vertical polarization. Two polarimetric acquisitions are combined in an interferometric image, characterized by a polarimetric and interferometric covariance matrix. The expression of the PolInSAR covariance matrix for compact polarimetry is derived and discussed. The reconstruction algorithm of full polarimetry is developed and applied to PolInSAR simulated data, in order to assess the performance of the compact PolInSAR configuration. The simulated targets are forests, for which PolInSAR algorithms have found important applications. An assessment on the performance of compact polarimetry is carried out based on the comparison between the interferometric degree of coherence versus forest height observed by compact polarimetry and full polarimetry. The comparison shows a general good agreement between the two configurations.