A space-time minimum cost flow phase unwrapping algorithm for the generation of persistent scatterers deformation time-series

We have investigated the phase retrieval capability of the Extended Minimum Cost Flow (EMCF) phase unwrapping (PhU) approach in the framework of the Persistent Scatterers Interferometry (PSI) algorithms for the generation of deformation time-series. The presented technique exploits an appropriate selection of full resolution interferograms obtained via a triangulation step carried out in the Temporal/Perpendicular baseline plane, where the available SAR image sequence is represented. Moreover, the phase unwrapping procedure is implemented via the cascade of two steps, based on the conventional Minimum Cost Flow (MCF) algorithm, that allows us to exploit both the spatial characteristics and the temporal relationships among the produced interferograms. The presented experiments, carried out by analyzing a set of 43 ERS SAR images relevant to an area of the city of Rome (Italy), confirm the effectiveness of the exploited PhU approach.