Wednesday, October 29, 20083:00 PM - 4:00 PMCNLS Conference Room (TA-3, Bldg 1690)|
IS&T Center Seminar Series: Acoustic Scene Analysis, Complex Modulations and a New Form of Filtering
Les AtlasElectrical Engineering Department, Washington University
Be it in a restaurant or other reverberant and noisy environment, normal hearing listeners segregate multiple sources, usually strongly overlapping in frequency, well beyond the capabilities expected by current beamforming approaches. What is it that we can learn from this common observation?
As is now commonly accepted, the differing dynamical modulation patterns of the sources are key to these powers of separation. But until recently, the theoretical underpinnings for the notion of dynamical modulation patterns have been lacking. We have taken a previously loosely defined concept, called “modulation frequency analysis,” and developed a theory which allows for distortion-free separation (filtering) of multiple sound sources with differing dynamics.
A key result is that previous assumptions of non-negative and real modulation are not sufficient and, instead, coherent separation approaches are needed to separate different modulation patterns. These results may have an impact in separation and representation of multiple simultaneous sound streams for speech, audio, hearing loss treatment, and underwater acoustic applications. This research also suggests exciting new and potentially important open theoretical questions for general nonstationary signal representations,extending beyond acoustic applications and potentially impating other areas of engineering and
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Host: John Hogden, Information Sciences (CCS-3)