A procedure for the identification and correction of Phase Unwrapping errors in redundant sequences of small baseline DlnSAR interferograms

Abstract:
We propose a solution to identify and correct Phase Unwrapping (PhU) errors, which can be applied to improve the resul ts obtained from multi-temporal DinSAR techniques based on the exploitation ofa redundant sequence ofsmall baseline interferograms. The whole procedure is divided into three main steps: in the first one, we extend the temporal coherence parameter, defined as a single value point-like quality factor of the PhU operation, by sampling it into a series of values, the local temporal coherence (LTc) time series, ir order to effectively select, for each pixel, a subset of the interferograms to be evaluated as possible PhU errors candidates. In the second step, such an interferogram subset is analyzed through an L-1 norm inversion to evaluate the phase residues that allow to sharply identify the interferograms affected by PhU errors. In the last step, we perform a guided scanning of the possible corrections to the recognized PhU errors, by means of a Genetic Algorithm, to identify the solution that maximizes the LTc.