Bitstream-based feature extraction method for a front-end speech recognizer
AssigneeAT&T Corp.
InventorsRichard Vandervoort Cox, Hong Kook Kim
Life of this patent
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Abstract
A feature extraction process for use in a wireless communication system provides automatic speech recognition based on both spectral envelope and voicing information. The shape of the spectral envelope is used to determine the LSPs of the incoming bitstream and the adaptive gain coefficients and fixed gain coefficients are used to generate the “voiced” and “unvoiced” feature parameter information.
Claims13
An automatic speech recognition system for receiving as an input a coded bitstream speech signal and generating therefrom feature recognition parameters, said recognition system including
- a spectral envelope detection arrangement for generating features derived from line spectrum pair (LSP) information from the encoded bitstream;
- and
- an excitation signal extraction arrangement for generating features derived from adaptive codebook gain and fixed codebook gain information related to voiced and unvoiced information, respectively.
A method of performing feature extraction on a continuous bitstream of encoded speech, the method comprising the steps of:
- determining the line spectrum product coefficients from a predetermined set of bits in each frame in the continuous bitstream;
- converting the coefficients into spectral envelope information;
- determining adaptive codebook gain coefficients and fixed codebook gain coefficients from another set of bits in each frame of said continuous bitstream;
- and
- calculating voiced and unvoiced feature information from the adaptive and fixed codebook gain coefficients.
Dependencies are inferred from the claim text.