  This paper addresses the electro-sensing problem for weakly electric fish in
the case of inhomogeneous targets. It aims at providing a shape
descriptor-based classification for inhomogeneous targets from measurements of
the potentials on the skin of the fish. The approach is based on new invariants
for the contracted generalized polarization tensors associated with
inhomogeneous objects. The numerical simulations show that by comparing these
invariants with those in a dictionary of precomputed homogeneous and
inhomogeneous targets, one can successfully classify the inhomogeneous target.
