Improved Global Soft Decision Incorporating Second-Order Conditional MAP in Speech Enhancement

Jong-Mo KUM  Joon-Hyuk CHANG  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E93-D   No.6   pp.1652-1655
Publication Date: 2010/06/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E93.D.1652
Print ISSN: 0916-8532
Type of Manuscript: LETTER
Category: Speech and Hearing
Keyword: 
speech enhancement,  global soft decision,  conditional MAP,  

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Summary: 
In this paper, we propose a novel method based on the second-order conditional maximum a posteriori (CMAP) to improve the performance of the global soft decision in speech enhancement. The conventional global soft decision scheme is found through investigation to have a disadvantage in that the global speech absence probability (GSAP) in that scheme is adjusted by a fixed parameter, which could be a restrictive assumption in the consecutive occurrences of speech frames. To address this problem, we devise a method to incorporate the second-order CMAP in determining the GSAP, which is clearly different from the previous approach in that not only current observation but also the speech activity decisions of the previous two frames are exploited. Performances of the proposed method are evaluated by a number of tests in various environments and show better results than previous work.