A Feasibility Study for a Hand-Held Acoustic Imaging Camera

Abstract

Acoustic imaging systems construct spatial maps of sound sources and have potential in various applications, but large, cumbersome form factors limit their adoption. This paper investigates methodologies to miniaturize acoustic camera systems for improved mobility. Our approach optimizes planar microphone array design to achieve directional sensing capabilities on significantly reduced footprints compared to benchmarks. The current prototype utilizes a 128−microphone, 50 × 50 cm2 array with beamforming algorithms to visualize acoustic fields in real time but its stationary bulk hampers portability. We propose minimizing the physical aperture by carefully selecting microphone positions and quantities with tailored spatial filter synthesis. This irregular array geometry concentrates sensitivity toward target directions while avoiding aliasing artefacts. Simulations demonstrate a 32−element, ≈20 × 20 cm2 array optimized this way can outperform the previous array in directivity and noise suppression in a sub-range of frequencies below 4 kHz, supporting a 4× surface factor reduction with acceptable trade-offs. Ongoing work involves building and testing miniature arrays to validate performance predictions and address hardware challenges. The improved mobility of compact acoustic cameras could expand applications in car monitoring, urban noise mapping and other industrial fields limited by current large systems.

Keywords

• acoustic imaging
• microphone arrays
• robust super directive beamforming
• array processing
• miniaturization
• aperiodic sparse planar arrays