Inversion of multi-frequency experimental data for imaging complex objects by a DTA–CSI method

Abstract

This paper deals with image reconstruction from measured multi-frequency scattering data for 2D inhomogeneous targets by using a technique combining the diagonal tensor approximation (DTA) and contrast source inversion (CSI) methods. In this algorithm, the diagonal tensor approximation is applied as a nonlinear approximation of the 2D domain integral equation for an inverse scattering problem, and is used as an initial guess for the nonlinear contrast source inversion. Taking advantage of the properties of fast convergence of the DTA operator and stable convergence of the CSI method, the combined technique makes image reconstructions more effective. Using this combined approach, the multi-frequency experimental data from Institut Fresnel have been processed, and excellent reconstruction results have been obtained for inhomogeneous targets.