Qualitative methods are widely used for the solution of inverse obstacle problems.They allow one to retrieve the morphological properties of the unknown targets from the scattered field by avoiding dealing with the problem in its full non-linearity and considering a persol 3195 simplified mathematical model with a lower computational burden.Very many qualitative approaches have been proposed in the literature.In this paper, a comparison is performed in terms of performance amongst three different qualitative methods, i.e.
, the linear sampling method, the orthogonality flybar bumper car wheel replacement sampling method, and a recently introduced method based on joint sparsity and equivalence principles.In particular, the analysis is focused on the inversion of experimental data and considers a wide range of (distinct) working frequencies and different kinds of scattering experiments.