Acousto-Optic Reconstruction of Exterior Sound Field Based on Concentric Circle Sampling With Circular Harmonic Expansion

Acousto-optic sensing provides an alternative approach to traditional microphone arrays by shedding light on the interaction of light with an acoustic field. Sound-field reconstruction is a fascinating and advanced technique used in acousto-optic sensing. Current challenges in sound-field reconstruction methods pertain to scenarios, in which the sound source is located within the reconstruction area, known as the exterior problem. Existing reconstruction algorithms, primarily designed for interior scenarios, often exhibit suboptimal performance when applied to exterior cases. This article introduces a novel technique for exterior sound-field reconstruction. The proposed method leverages concentric circle sampling and a 2-D exterior sound-field reconstruction approach based on circular harmonic extensions. To evaluate the efficacy of this approach, both numerical simulations and practical experiments are conducted. The results highlight the superior accuracy of the proposed method when compared to conventional reconstruction methods, all while utilizing a minimal amount of measured projection data.