Speech spectrum non-stationarity detection based on line spectrum frequencies and related applications
Ertan, Ali Erdem
Çetin, A. Enis
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In this thesis, two new speech variation measures for speech spectrum nonstationarity detection are proposed. These measures are based on the Line Spectrum Frequencies (LSF) and the spectral values at the LSF locations. They are formulated to be subjectively meaningful, mathematically tractable, and also have low computational complexity property. In order to demonstrate the usefulness of the non-stationarity detector, two applications are presented: The first application is an implicit speech segmentation system which detects non-stationary regions in speech signal and obtains the boundaries of the speech segments. The other application is a Variable Bit-Rate Mixed Excitation Linear Predictive (VBR-MELP) vocoder utilizing a novel voice activity detector to detect silent regions in the speech. This voice activity detector is designed to be robust to non-stationary background noise and provides efficient coding of silent sections and unvoiced utterances to decrease the bit-rate. Simulation results are also presented.
KeywordsSpeech variation measure,
Spectrum non-stationarity detection
Line Spectrum Frequencies (LSF)
Mixed Excitation Linear Predictive coding (MELP)
Variable bit-rate vocoder
Voice activity detector
TK7882.S65 E78 1998
Speech processing systems.