Abstract:
The design, implementation, and performance of a low-cost, real-time DSP system for source location is discussed. The system consists of an eight-element electret microphone array connected to a Signalogic DSP daughterboard hosted by a PC. The system determines the location of a speaker in the audience in an irregularly shaped auditorium. The auditorium presents a nonideal acoustical environment; some of the walls are acoustically treated but there still exist significant reverberation and a large amount of low-frequency noise from fans in the ceiling. The source location algorithm is implemented in a two-step process: The first step determines time delay of arrival (TDOA) for select microphone pairs. A modified version of the cross-power spectrum phase method [M. Omologo and P. Svaizer, Proceedings of IEEE ICASSP 1994 (IEEE, New York, 1994), pp. II273--II276] is used to compute TDOAs and is implemented on the DSP daughterboard. The second step uses the computed TDOAs in a least-mean-square gradient descent search algorithm implemented on the PC to compute a location estimate. [Work supported by a contract with Bell Communications Research.]