Localizing acoustic sources in non-line-of-sight scenarios using irregular-grid beamforming and first-order edge diffraction

Abstract

In this work, an algorithm that combines irregular-grid beamforming with first-order edge diffraction is proposed to localize acoustic sources in non-line-of-sight (NLOS) scenarios. The first-order edge diffraction impulse response is computed using the Biot–Tolstoy-Medwin method, which is then incorporated into the beamforming process to modify the steering vector. To improve performance, irregular grids are used to discretize the acoustic imaging area behind obstacles in the NLOS environment, minimizing main lobe deformation in the beamformer output. Simulation results demonstrate that the irregular-grid beamforming method enables precise acoustic source localization in NLOS environments. Unlike regular-grid beamforming, which exhibits significant main lobe deformation as the source position changes, the main lobe of the irregular-grid method remains nearly unaffected. Additionally, in the acoustic imaging area, the proposed algorithm achieves better resolution parallel to the edge of the obstacle compared to the resolution perpendicular to it. Experimental results confirm the validity of the simulation findings.