Which model for inversions? The case of strong scatterers.

We analyze the performances of a Physical Optics (PO) based shape reconstruction algorithm for the retrieval of strong metallic scatterers in a subsurface measurement configuration. For the sake of shape reconstruction and when the impinging field is provided by current filaments, we can regard the PO algorithm as one of assuming the magnetic field on the illuminated side, after normalization to unessential factors, as linear in phase and growing with the square root of the frequency in amplitude, as far as the dependence on the frequency is concerned. Therefore, we numerically analyze, with reference to the case of circular cylindrical strong scatterers, the limits of validity of such a model for inversion purposes and we validate an inversion algorithm based on the Singular Value Decomposition approach on synthetic data.