Process for filtering interferograms obtained from sar images acquired on the same area

Abstract

A process for filtering interferograms obtained from SAR images, acquired on the same area by synthetic aperture radars, comprising the following steps: a) acquiring a series of N radar images (Al . . . AN) by means of a SAR sensor on a same area with acquisition geometries such as to allow re-sampling of the data on a common grid; b) after re-sampling on a common grid, selecting a pixel from the common grid; c) calculating the coherence matrix of the selected pixel, that is estimating the complex coherence values for each possible pair of available images; d) maximizing, with respect of the source vector θ, here an unknown element, the functional: (formula) being R the operator which extracts the real part of a complex number, γthe modulus of the element (n,m) of the coherence matrix, k a positive real number, φthe phase of the element (n,m) of the coherence matrix, θn and θm the elements n and m of the unknown vector θ. Given that only phase differences appear in the functional T, the values of the unknown factor are estimated less an additive constant, which can be fixed by setting for example θ=0, and the phase values θthus obtained constitute the vector of the filtered phase values.