Patent ID: 7464034
Filing Date: 2008-12-09
Classification: G10L

Abstract:
1. An apparatus for temporally aligning a sequence of phonemes of a target voice represented by a time-series of frames with a sequence of phonemes of an input voice represented by a time-series of frames, the apparatus comprising: a target storage section that stores a sequence of phonemes contained in the target voice, the sequence of the phonemes being obtained by provisionally analyzing the time-series of the frames of the target voice; a phoneme storage section that stores a code book containing characteristic vectors representing characteristic parameters typical to phonemes, the characteristic vector being clustered into a number of symbols in the code book, and that stores a probability of a state transition from a first state to a second state of each phoneme and an observation probability of each symbol; a quantizing section that analyzes the time-series of the frames of the input voice to extract therefrom the characteristic parameters, and that quantizes the characteristic parameters into observed code vectors which represent observed symbols of the input voice according to the code book stored in the phoneme storage section; a state forming section that applies a hidden Markov model to the sequence of the phonemes of the target voice stored in the target storage section so as to estimate therefrom a time-series of states of the phonemes of the target voice based on the probability of the state transition from the first state to the second state of each phoneme and the observation probability of each symbol stored in the phoneme storage section; a transition determining section that determines transitions of states occurring in the sequence of the phonemes of the input voice by a Viterbi algorithm based on the observed symbols of the input voice and the estimated time-series of the states of the phonemes of the target voice; and an aligning section that aligns the sequence of the phonemes of the target voice and the sequence of the phonemes of the input voice with each other according to the determined state transitions of the input voice.