Reconstruction of scatterers with four different boundary conditions by T-matrix method

This paper introduces a general inversion method to simultaneously reconstruct scatterers with different boundary conditions such as Dirichlet, Neumann, Robin, and transmission boundaries without a priori information on their locations, shapes, or physical properties. The forward scattering of mixed scatterers is modeled by a unified framework of T-matrix method, while the objective function considered in the inverse problem is solved by a subspace-based optimization method. The unknowns are T-matrix coefficients, from which the types of boundary conditions of scatterers are identified. Numerical examples show that this method is able to recover not only the shapes of scatterers but also their physical properties and parameters.