Examination of the phase and log magnitude measurement projections and the implications for tomographic image reconstruction behavior

We examine the log magnitude and phase projections of simple circular objects in a 2D microwave tomography setting. Because of the inherent insight visible with these log transformed quantities, we can explore the forward and associated inverse scattering characteristics. For these situations, it is clear that the reconstructions for the cases where the target properties are higher than that of the background take more iterations and the convergence behavior is more uneven. Interestingly this corresponds to the situation where the composite pattern from the antenna/target combination produces a crudely focused beam with corresponding side nulls and lobes. We speculate that these features are somewhat confounding and ultimately prove more challenging for the reconstruction algorithm than for when the target properties are less than the background.