Speech Enhancement by Overweighting Gain with Nonlinear Structure in Wavelet Packet Transform

Sung-il JUNG
Younghun KWON
Sung-il YANG

Publication
IEICE TRANSACTIONS on Communications   Vol.E90-B    No.8    pp.2147-2150
Publication Date: 2007/08/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.8.2147
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories for Communications
Keyword: 
speech enhancement,  wavelet packet transform,  modified spectral subtraction,  noise estimation,  overweighting gain per subband with nonlinear structure,  

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Summary: 
A speech enhancement method is proposed that can be implemented efficiently due to its use of wavelet packet transform. The proposed method uses a modified spectral subtraction with noise estimation by a least-squares line method and with an overweighting gain per subband with nonlinear structure, where the overweighting gain is used for suppressing the residue of musical noise and the subband is used for applying the weighted values according to the change of signals. The enhanced speech by our method has the following properties: 1) the speech intelligibility can be assured reliably; 2) the musical noise can be reduced efficiently. Various assessments confirmed that the performance of the proposed method was better than that of the compared methods in various noise-level conditions. Especially, the proposed method showed good results even at low SNR.