Localization of multiple speakers based on a two step acoustic map analysis

An interface for distant-talking control of home devices requires the possibility of identifying the positions of multiple users. Acoustic maps, based either on global coherence field (GCF) or oriented global coherence field (OGCF), have already been exploited successfully to determine position and head orientation of a single speaker. This paper proposes a new method using acoustic maps to deal with the case of two simultaneous speakers. The method is based on a two step analysis of a coherence map: first the dominant speaker is localized; then the map is modified by compensating for the effects due to the first speaker and the position of the second speaker is detected. Simulations were carried out to show how an appropriate analysis of OGCF and GCF maps allows one to localize both speakers. Experiments proved the effectiveness of the proposed solution in a linear microphone array set up.