title: Localization of multiple sound sources with two microphones.
abstract: This paper presents a two-microphone technique for localization of multiple sound sources. Its fundamental structure is adopted from a binaural signal-processing scheme employed in biological systems for the localization of sources using interaural time differences (ITD). The two input signals are transformed to the frequency domain and analyzed for coincidences along left/right-channel delay-line pairs. The coincidence information is enhanced by a nonlinear operation followed by a temporal integration. The azimuths of the sound sources are estimated by integrating the coincidence locations across the broadband of frequencies in speech signals (the "direct" method). Further improvement is achieved by using a novel "stencil" filter pattern recognition procedure. This includes coincidences due to phase delays of greater than 2pi, which are generally regarded as ambiguous information. It is demonstrated that the stencil method can greatly enhance localization of lateral sources over the direct method. Also discussed and analyzed are two limitations involved in both methods, namely missed and artifactual sound sources. Anechoic chamber tests as well as computer simulation experiments showed that the signal-processing system generally worked well in detecting the spatial azimuths of four or six simultaneously competing sound sources.
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign 61801, USA.
authors.forename: C
authors.initials: C
authors.lastname: Liu
authors.forename: B C
authors.initials: BC
authors.lastname: Wheeler
authors.forename: W D
authors.initials: WD
authors.lastname: O'Brien
authors.forename: R C
authors.initials: RC
authors.lastname: Bilger
authors.forename: C R
authors.initials: CR
authors.lastname: Lansing
authors.forename: A S
authors.initials: AS
authors.lastname: Feng
mesh_terms: D000328:Adult; D000465:Algorithms; D001288:Attention; D003198:Computer Simulation; D004007:Dichotic Listening Tests; D005260:Female; D006801:Humans; D008297:Male; D010470:Perceptual Masking; D013017:Sound Localization; D013018:Sound Spectrography; D013067:Speech Perception