Patent ID: 8010362

Claim:
An apparatus for converting a source speaker's speech to a target speaker's speech, comprising: a speech unit generation section configured to acquire speech units of the source speaker by segmenting the source speaker's speech; a parameter calculation section configured to calculate spectral parameter vectors of each time in a speech unit, the each time being a predetermined time between a start time and an end time of the speech unit; a conversion rule memory configured to store voice conversion rules and rule selection parameters each corresponding to a voice conversion rule, the voice conversion rule converting a spectral parameter vector of the source speaker to a spectral parameter vector of the target speaker, a rule selection parameter representing a feature of the spectral parameter vector of the source speaker; a rule selection section configured to select a first voice conversion rule corresponding to a first rule selection parameter and a second voice conversion rule corresponding to a second rule selection parameter from the conversion rule memory, the first rule selection parameter being matched with a first spectral parameter vector of the start time, the second rule selection parameter vector being matched with a second spectral parameter of the end time; an interpolation coefficient decision section configured to determine interpolation coefficients each corresponding to a third spectral parameter vector of the each time in the speech unit based on the first voice conversion rule and the second voice conversion rule; a conversion rule generation section configured to generate third voice conversion rules each corresponding to the third spectral parameter vector of the each time in the speech unit by interpolating the first voice conversion rule and the second conversion rule with each of the interpolation coefficients; a spectral parameter conversion section configured to respectively convert the third spectral parameter vector of the each time to a spectral parameter vector of the target speaker based on each of the third voice conversion rules; a spectral compensation section configured to compensate a spectrum acquired from the converted spectral parameter of the target speaker by a spectral compensation filter or power ratio; and a speech waveform generation section configured to generate a speech waveform from the compensated spectrum.