Determining ITDs Using Two Microphones on a Flat Panel During Onset Intervals With a Biologically Inspired Spike-Based Technique

Abstract

Using a mockup of a flat panel display, with two omnidirectional microphones we have used intermicrophone time difference (ITD) to determine the azimuthal direction of a sound source (speaker). The speaker is in a noise field in an office-type environment. Bandpass filtering followed by a biologically inspired low latency onset detector (which can cope with a considerable dynamic range) determines the intervals and spectral locations in which an onset is occurring. Direction determination during these onset intervals enables discovery of the onsetting sound's azimuthal angle even in the presence of competing sounds. We compare the results from cross-correlation and novel spike based techniques for determining azimuthal angle during these onset intervals. We note that the system is suitable for real-time implementation.