Open Access

An Integrated Real-Time Beamforming and Postfiltering System for Nonstationary Noise Environments

EURASIP Journal on Advances in Signal Processing20032003:936861

https://doi.org/10.1155/S1110865703305050

Received: 1 September 2002

Published: 5 October 2003

Abstract

We present a novel approach for real-time multichannel speech enhancement in environments of nonstationary noise and time-varying acoustical transfer functions (ATFs). The proposed system integrates adaptive beamforming, ATF identification, soft signal detection, and multichannel postfiltering. The noise canceller branch of the beamformer and the ATF identification are adaptively updated online, based on hypothesis test results. The noise canceller is updated only during stationary noise frames, and the ATF identification is carried out only when desired source components have been detected. The hypothesis testing is based on the nonstationarity of the signals and the transient power ratio between the beamformer primary output and its reference noise signals. Following the beamforming and the hypothesis testing, estimates for the signal presence probability and for the noise power spectral density are derived. Subsequently, an optimal spectral gain function that minimizes the mean square error of the log-spectral amplitude (LSA) is applied. Experimental results demonstrate the usefulness of the proposed system in nonstationary noise environments.

Keywords

array signal processing signal detection acoustic noise measurement speech enhancement spectral analysis adaptive signal processing

Authors’ Affiliations

(1)
Department of Electrical Engineering, Technion – Israel Institute of Technology
(2)
School of Engineering, Bar-Ilan University
(3)
Lamar Signal Processing, Ltd., Andrea Electronics Corp.

Copyright

© Copyright © 2003 Hindawi Publishing Corporation 2003