SPEECH SIGNAL SECTION ESTIMATING DEVICE, METHOD THEREOF, PROGRAM THEREOF, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide speech signal section estimation technique capable of estimating a speech signal section with high precision by accurately grasping state transition of a signal in spite of an unsteady noise such that statistical property of the noise signal changes with time. SOLUTION: A sound signal analyzer 10 extracts sound feature quantities by frames obtained by cutting an input signal in constant section units. Using a probability model (GMM) of a clean speech signal and a soundless signal, a forward estimating unit 30 and a backward estimating unit 40 estimate noise model parameters not only forward, but also backward along the time base through parallel processings by a plurality of normal distributions included in the GMM. Based upon the estimated noise model parameters, a speech/non-speech output probability and a noise state transition probability are calculated. A state probability ratio calculator 60 calculates ratios of speech probabilities to non-speech state probabilities by the frames and a speech signal section estimating unit 70 compares the calculated probability ratios with a threshold to decide a speech state or a non-speech state for each frame. COPYRIGHT: (C)2008,JPO&INPIT