EURASIP Journal on Applied Signal Processing 
Volume 2003 (2003), Issue 11, Pages 1147-1156
doi:10.1155/S1110865703305025

Multichannel Direction-Independent Speech Enhancement Using Spectral Amplitude Estimation

Thomas Lotter,1 Christian Benien,2 and Peter Vary1

 1Institute of Communication Systems and Data Processing, Aachen University (RWTH), Templergraben 55, Aachen D-52056, Germany
2Philips Research Center, Aachen, Weißhausstraße 2, Aachen D-52066, Germany
Received 25 November 2002; Revised 12 March 2003

Abstract

This paper introduces two short-time spectral amplitude estimators for speech enhancement with multiple microphones. Based on joint Gaussian models of speech and noise Fourier coefficients, the clean speech amplitudes are estimated with respect to the MMSE or the MAP criterion. The estimators outperform single microphone minimum mean square amplitude estimators when the speech components are highly correlated and the noise components are sufficiently uncorrelated. Whereas the first MMSE estimator also requires knowledge of the direction of arrival, the second MAP estimator performs a direction-independent noise reduction. The estimators are generalizations of the well-known single channel MMSE estimator derived by Ephraim and Malah (1984) and the MAP estimator derived by Wolfe and Godsill (2001), respectively.