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Exploiting Redundancy of Speech Signals in Speech Enhancement and Blind Source Separation


Monday,January 29th 2007 -- Radu Balan
SPECIAL SEMINAR IN THE ECE DEPARTMENT

Siemens Corporate Research Princeton, NJ


Abstract:
 

Speech signals exhibit a huge redundancy from an information content point of view. In this talk I would like to present two problems where speech redundancy, and its dual concept, speech sparsity play a key role in solving them. A sparse representation allows one to hypothesis a strong disjointness of multiple speech signals. This key observation is further used to solve the blind source separation problem in degenerate cases (when more sources are present than the number of sensors). Another way of exploiting redundancy is by building prior stochastic models compatible with the sparse representation assumption. Then such prior knowledge can be used in a Bayesian framework to perform signal estimation. I will present some issues and results related to the noise reduction problem.


Bio:
 

Radu Balan graduated from Polytechnic Institute of Bucharest, and University of Bucharest, Romania, with Bachelor degrees in EE (Control Theory) 1992, and Physics (Theoretical Physics) 1994, respectively. Then he obtained his PhD degree from Princeton University (Applied and Computational Mathematics) in 1998. After one year of postdoc at IBM T.J.Watson and IMA (Minneapolis), he joined Siemens Corporate Research in Princeton, NJ, where he currently is a Senior Research Scientist, in the Department of Real-Time Vision and Modeling. At Siemens he has been responsible for audio and signal processing applications in hearing aids, mobile phones, and sensor fusion; he is also involved in analysis and control of WLAN systems. For the past two years he has been also an adjunct professor at Princeton University, teaching a graduate course in Wavelets and Time-Frequency Analysis.