Microphone Arrays and Beamforming

Abstract

In this chapter, the authors study the question of how sound pickup in a noisy and reverberant environment can be improved by adding spatial diversity to the signal acquisition front-end. Spatially distributed receivers, i.e., microphone arrays, and multichannel signal processing and machine learning techniques allow the exploitation of spatial, temporal and spectral features of signals. They achieve a performance, which surpasses that of single microphone systems. Array technology has been used in radar and sonar systems for quite some time. The authors consider microphone arrays and their properties for stationary environments, i.e. with fixed beam patterns. They also explain typical design procedures for beamformers, where they assume that the direction of incidence of the source signal is given and that the sound field is stationary. Finally, the authors briefly discuss postfilter techniques and adaptive beamforming approaches.

Authors 2

1. Peter Vary Aachen Institute of Communication Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Institute of Communication Systems, Aachen, Germany

2. Rainer Martin

   Ruhr University Bochum

   Affiliation as printed

   Ruhr-Universität Bochum, Institute of Communication Acoustics, Bochum, Germany