Reconstruction of 3-D dielectric objects from measured data

We developed a combined BIM-DTA (the Born iterative method with the diagonal tensor approximation) and DBIM-BCGS (the distorted Born iterative method with the stabilized biconjugate gradient fast Fourier transform) method for 3D image reconstruction in layered media. The DTA is a high-order scattering approximation method that does not require a large matrix inversion in the forward solver. So the inversion results with BIM-DTA gives a better reconstruction object than the conventional Born approximation. Thus, when the BIM-DTA inversion result is used as the initial solution in the follow-up DBIM-BCGS method, the convergence of the inversion iteration will be accelerated. The combined inverse scattering method has been applied to the inversion of experimental data for microwave biomedical imaging applications. In this work, we use the DBIM-BCGS method for the 3D dielectric object reconstruction from experimental data collected by Institut Fresnel (Marseille, France) for targets in a homogeneous air background. Our inversion procedure allows arbitrarily-polarized sources, including electrical and magnetic dipoles and plane waves; the measured field components can be arbitrary.