Multi-source localization in reverberant environments

The very large relative bandwidth of acoustic sources, coupled with the high number of reflections of a typical listening room, makes localization a challenging task, since all basic assumptions of classical array processing algorithms constitute at the best viable approximations in real-world environments. In this work, a novel decentralized approach for acoustic localization in reverberant environment is presented. It is based on a two-stage strategy. First, candidate source positions are found by a Time-Delay-Of-Arrivals (TDOA) analysis of signals received by colocated pairs of microphones. Differential delays are estimated by a robust ROOT-MUSIC based technique, applied to the sample cross-spectrum of whitened signals recorded from each microphone pair. A subsequent clustering stage in the spatial coordinates validates the raw TDOA estimates, eliminating most of false detections. The new algorithm is capable of tracking multiple speakers at the same time, exhibits a very good consistency of location estimates, and compares favourably with previous approaches.