Patent ID: 8711029

Claim:
A process for filtering interferograms obtained from SAR images, acquired on the same area by synthetic aperture radars, the process 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 common grid; b) after re-sampling on common grid, selecting a pixel from the common grid; c) calculating, using a microprocessor, 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 unknown element, the functional: T = ⁢ { ∑ n = 1 N ⁢ ∑ m = 1 N ⁢ γ n ⁢ ⁢ m k · ⅇ ⅈϕ n ⁢ ⁢ m ⁢ ⅇ - ⅈ ⁡ ( θ n - θ m ) } being the operator which extracts the real part of a complex number, γ nm the module of the element (n,m) of the coherence matrix, k a positive real number, φ nm the phase of the element (n,m) of the coherence matrix, θ n and θ m the elements n and m of the unknown vector θ, the values of the unknown factor being estimated unless an additive constant and the phase values θ n thus obtained constituting the vector of the filtered phase values.