Acoustic Beamforming in Front of a Reflective Plane

Abstract

In this paper, we consider the problem of beamforming with a planar microphone array placed in front of a wall of the room, so that the microphone array plane is perpendicular to that of the wall. While this situation is very likely to occur in a real life problem, the reflections introduced by the adjacent wall can be the cause of a serious mismatch between the actual acoustic paths and the traditionally employed free-field propagation model. We present an adaptation from the free-field to the so-called reflection-aware propagation model, that exploits an in-situ estimation of the complex and frequency-dependent wall reflectivity. Results presented in a real environment demonstrate that the proposed approach may bring significant improvements to the beamforming process compared to the free-field propagation model, as well as compared to other reflection-aware models that have been recently proposed.