Analysis and improvement of direct sampling method in the mono-static configuration

TL;DR

This paper analyzes why the direct sampling method (DSM) fails in mono-static configurations for inverse scattering problems, provides an analytical explanation, and proposes a modified DSM to improve imaging performance, supported by numerical validation.

Contribution

The paper offers the first analytical explanation for DSM failure in mono-static setups and introduces a modified DSM to enhance imaging accuracy.

Findings

Analytical expression of DSM indicator function in 2D scalar case.

Identification of the theoretical reason for DSM failure in mono-static configuration.

Numerical validation demonstrating improved imaging with the modified DSM.

Abstract

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.