Imperial College London > Talks@ee.imperial > COMMSP Seminar > Multichannel Eigenspace Beamforming in a Reverberant Noise Environment with Multiple Interfering Speech Signals

Multichannel Eigenspace Beamforming in a Reverberant Noise Environment with Multiple Interfering Speech Signals

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In many practical environments we wish to extract several desired speech signals, which are contaminated by nonstationary and stationary interfering signals. The desired signals may also be subject to distortion imposed by the acoustic Room Impulse Responses (RIRs). In this work, a Linearly Constrained Minimum Variance (LCMV) beamformer is designed for extracting the desired signals from multi-microphone measurements. The beamformer satisfies two sets of linear constraints. One set is dedicated to maintaining the desired signals, while the other set is chosen to mitigate both the stationary and non-stationary interferences. Unlike classical beamformers, which approximate the RIRs as delay-only filters, we take into account the entire RIR . We show that Relative Transfer Functions (RTFs), which relate the speech sources and the microphones, and a basis for the interference subspace suffice for constructing the beamformer. The RTFs are estimated by applying the Generalized Eigenvalue Decomposition (GEVD) procedure to the Power Spectrum Density (PSD) matrices of the received signals and the stationary noise. A basis for the interference subspace is estimated by collecting eigenvectors, calculated in segments where non-stationary interfering sources are active and the desired sources are inactive. The rank of the basis is then reduced by the application the Orthogonal Triangular Decomposition (QRD). This procedure relaxes the common requirement for non-overlapping activity periods of the interference sources. A comprehensive experimental study in both simulated and real environments demonstrates the performance of the proposed beamformer.

Bioagraphy Sharon Gannot received his B.Sc. degree (summa cum laude) from the Technion – Israel Institute of Technology, Haifa, Israel in 1986 and the M.Sc. (cum laude) and Ph.D. degrees from Tel-Aviv University, Israel in 1995 and 2000 respectively, all in electrical engineering. In the year 2001 he held a post-doctoral position at the department of Electrical Engineering (SISTA) at K.U.Leuven, Belgium. From 2002 to 2003 he held a research and teaching position at the Faculty of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel. Currently, he is a Senior Lecturer at the School of Engineering, Bar-Ilan University, Israel. Dr. Gannot is an Associate Editor of IEEE trans. on Speech, Audio and Language processing and of the EURASIP Journal of Applied signal Processing. Dr. Gannot is general co-chair of the International Workshop on Acoustic Echo and Noise Control (IWAENC) to be held at Tel-Aviv, Israel in August 2010. His research interests include parameter estimation, statistical signal processing and speech processing using either single- or multi-microphone arrays.

This talk is part of the COMMSP Seminar series.

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