Speaker Tracking for Hands-Free Continuous Speech Recognition in Noise Based on a Spectrum-Entropy Beamforming Method

George NOKAS  Evangelos DERMATAS  

IEICE TRANSACTIONS on Information and Systems   Vol.E86-D   No.4   pp.755-758
Publication Date: 2003/04/01
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: LETTER
Category: Speech and Hearing
speaker tracking,  microphone array,  spectrum entropy,  speech recognition,  speaker beam-former,  

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In this paper, we present a novel beam-former capable of tracking a rapidly moving speaker in a very noisy environment. The localization algorithm extracts a set of candidate direction-of-arrival (DOA) for the signal sources using array signal processing methods in the frequency domain. A minimum variance (MV) beam-former identifies the speech signal DOA in the direction where the signal's spectrum entropy is minimized. A fine tuning process detects the MV direction which is closest to the initial estimation using a smaller analysis window. Extended experiments, carried out in the range of 20-0 dB SNR, show significant improvement in the recognition rate of a moving speaker especially in very low SNRs (from 11.11% to 43.79% at 0 dB SNR in anechoic environment and from 9.9% to 30.51% in reverberant environment).