A Variable Step Size Algorithm for Speech Noise Reduction Method Based on Noise Reconstruction System

Masatoshi WATANABE
Yoshio ITOH
Kensaku FUJII

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E92-A    No.1    pp.244-251
Publication Date: 2009/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E92.A.244
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Digital Signal Processing
noise reduction,  adaptive filter,  system identification,  NLMS algorithm,  variable step size,  

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We have proposed a noise reduction method based on a noise reconstruction system (NRS). The NRS uses a linear prediction error filter (LPEF) and a noise reconstruction filter (NRF) which estimates background noise by system identification. In case a fixed step size for updating tap coefficients of the NRF is used, it is difficult to reduce background noise while maintaining the high quality of enhanced speech. In order to solve the problem, a variable step size is proposed. It makes use of cross-correlation between an input signal and an enhanced speech signal. In a speech section, a variable step size becomes small so as not to estimate speech, on the other hand, large to track the background noise in a non-speech section.