Analysis and improvement of direct sampling method in the mono-static configuration
For researchers in inverse scattering, this work provides a theoretical explanation and a practical fix for a known limitation of DSM in mono-static setups.
The paper identifies why the direct sampling method (DSM) fails in mono-static configuration for inverse scattering problems, deriving an analytical expression that reveals the limitation, and proposes a modified DSM that improves performance, validated with synthetic data.
The recently introduced non-iterative imaging method entitled \enquote{direct sampling method} (DSM) is known to be fast, robust, and effective for inverse scattering problems in the multi-static configuration but fails when applied to the mono-static one. To the best of our knowledge no explanation of this failure has been provided yet. Thanks to the framework of the asymptotic and the far-field hypothesis in the 2D scalar configuration an analytical expression of the DSM indicator function in terms of the Bessel function of order zero and sizes, shapes and permittivities of the inhomogeneities is obtained and the theoretical reason of the limitation identified. A modified version of DSM is then proposed in order to improve the imaging method. The theoretical results are supported by numerical results using synthetic data.