A biomimetic system for localization and separation of multiple sound sources

We present a system for sound source localization and separation inspired by the auditory mechanisms of biological systems. The system consists of three omni-directional microphones, banks of band-pass filters and a personal computer with a digital signal processor (DSP). Each microphone is set at a vertex of an equilateral triangle with a side length of 13.5 cm. First temporal disparities between microphones are detected by each band-pass filtered signal with some time duration (e.g. 30 sec.). It uses the onsets of a signal which are not corrupted with other sound sources including sound reflected by walls, etc. From the estimated azimuth of sound sources, we can calculate the time differences of sound arriving from different microphones. Each sound source is separated from each microphone signal using an inverse filter designed with this time difference. Experiments were carried out in an anechoic chamber and an empty room using two sound sources located with azimuth offset of 38 deg. We used a radio weather forecast by a male announcer and a radio talk show by a male and a female hosts as our sound sources. We localized each sound source with an error of less than 3 deg. and the separation of each sound source had a quality of 25 dB attenuation of each original sound