Patent ID: 8280738
Filing Date: 2012-10-02
Classification: G10L

Abstract:
1. A voice quality conversion apparatus that converts voice quality of an input speech, said apparatus comprising: a fundamental frequency converting unit configured to calculate a weighted sum of a fundamental frequency of an input sound source waveform and a fundamental frequency of a target sound source waveform at a predetermined conversion ratio as a resulting fundamental frequency, the input sound source waveform representing sound source information of an input speech waveform, and the target sound source waveform representing sound source information of a target speech waveform; a low-frequency spectrum calculating unit configured to calculate a low-frequency sound source spectrum by mixing a level of a harmonic of the input sound source waveform and a level of a harmonic of the target sound source waveform at the predetermined conversion ratio for each order of harmonics including fundamental, using an input sound source spectrum and a target sound source spectrum in a frequency range equal to or lower than a boundary frequency determined depending on the resulting fundamental frequency calculated by said fundamental frequency converting unit, the low-frequency sound source spectrum having levels of harmonics in which the resulting fundamental frequency is set to a fundamental frequency of the low-frequency sound source spectrum, the input sound source spectrum being a sound source spectrum of an input speech, and the target sound source spectrum being a sound source spectrum of a target speech; a high-frequency spectrum calculating unit configured to calculate a high-frequency sound source spectrum by mixing the input sound source spectrum and the target sound source spectrum at the predetermined conversion ratio in a frequency range larger than the boundary frequency; a spectrum combining unit configured to combine the low-frequency sound source spectrum with the high-frequency sound source spectrum at the boundary frequency to generate a sound source spectrum for an entire frequency range; and a synthesis unit configured to generate a synthesized speech waveform using the sound source spectrum for the entire frequency range.