Passive array imaging in random media

TL;DR

This paper introduces a new algorithm for high-resolution imaging of sound sources in random media, improving upon existing methods by resolving sources too close for traditional techniques, with demonstrated numerical success.

Contribution

The paper develops a modified CINT-based algorithm that enhances resolution in array imaging within random scattering media, extending the capabilities of existing coherent interferometry methods.

Findings

The algorithm achieves higher resolution than standard CINT.

Numerical simulations confirm improved source distinguishability.

The method effectively handles wavefront distortions in random media.

Abstract

We present a novel algorithm for high resolution coherent imaging of sound sources in random scattering media using time resolved measurements of the acoustic pressure at an array of receivers. The sound waves travel a long distance between the sources and receivers so that they are significantly affected by scattering in the random medium. We model the scattering effects by large random wavefront distortions, but the results extend to stronger effects, as long as the waves retain some coherence i.e., before the onset of wave diffusion. It is known that scattering in random media can be mitigated in imaging using coherent interferometry (CINT). This method introduces a statistical stabilization in the image formation, at the cost of image blur. We show how to modify the CINT method in order to image wave sources that are too close to each other to be distinguished by CINT alone. We introduce the algorithm from first principles and demonstrate its performance with numerical simulations.