Steered beamforming approaches for acoustic source localization

Abstract

Multiple microphone devices aimed at hands-free capabilities and speech recognition via acoustic beamforming require reliable estimates of the position of the acoustic source. Two-stage approaches based on the timedifference- of-arrival (TDOA) are computationally simple but lack robustness in practical environments. This chapter presents a family of broadband source localization algorithms based on parameterized spatiotemporal correlation, including the popular and robust steered response power (SRP) algorithm. Before forming the conventional spatial correlation matrix, the vector of microphone signals is time-aligned with respect to a hypothesized source location. It is shown that this parametrization easily generalizes classical narrowband techniques to the broadband setting. Methods based on minimum information entropy and temporally constrained minimum variance are developed. In order to ease the high computational demands imposed by a location parameterized scheme, a sparse representation of the parameterized spatial correlation matrix is proposed.