Recognition Performance Improvement of Unsupervised Limabeam Algorithm using Post Filtering Technique

Title
Recognition Performance Improvement of Unsupervised Limabeam Algorithm using Post Filtering Technique
Author(s)
정현열구엔딘쿵최숙남
Keywords
Robust speech recognition; Microphone array processing; Beamforming; Limabeam; hidden markov model; HM-Net; Post filtering; Feature Weighted Malahanobis Distance.
Issue Date
201308
Publisher
대한임베디드공학회
Citation
대한임베디드공학회논문지, v.8, no.4, pp.185 - 194
Abstract
In distant-talking environments, speech recognition performance degrades significantly due to noise and reverberation. Recent work of Michael L. Selzer shows that in microphone array speech recognition, the word error rate can be significantly reduced by adapting the beamformer weights to generate a sequence of features which maximizes the likelihood of the correct hypothesis. In this approach, called Likelihood Maximizing Beamforming algorithm (Limabeam), one of the method to implement this Limabeam is an UnSupervised Limabeam(USL) that can improve recognition performance in any situation of environment. From our investigation for this USL, we could see that because the performance of optimization depends strongly on the transcription output of the first recognition step, the output become unstable and this may lead lower performance. In order to improve recognition performance of USL, some post-filter techniques can be employed to obtain more correct transcription output of the first step. In this work, as a post-filtering technique for first recognition step of USL, we propose to add a Wiener-Filter combined with Feature Weighted Malahanobis Distance to improve recognition performance. We also suggest an alternative way to implement Limabeam algorithm for Hidden Markov Network (HM-Net) speech recognizer for efficient implementation. Speech recognition experiments performed in real distant-talking environment confirm the efficacy of Limabeam algorithm in HM-Net speech recognition system and also confirm the improved performance by the proposed method.
URI
http://hdl.handle.net/YU.REPOSITORY/29154
ISSN
1975-5066
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공과대학 > 모바일정보통신공학과 > Articles
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