Politecnico Di Milano

Tele-Rilevamento Europa- T.r.e. S.r.l.

Alessio Rucci

Alessandro Ferretti

Alfio Fumagalli

Fabrizio Novali

Francesco De Zan

Stefano Tebaldini

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 &#x3b8;, here an unknown element, the functional: (formula) being R the operator which extracts the real part of a complex number, &#x3b3;the modulus of the element (n,m) of the coherence matrix, k a positive real number, &#x3c6;the phase of the element (n,m) of the coherence matrix, &#x3b8;n and &#x3b8;m the elements n and m of the unknown vector &#x3b8;. 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 &#x3b8;=0, and the phase values &#x3b8;thus obtained constitute the vector of the filtered phase values. 

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Cassina de' Pecchi, Italy

Alessio Rucci