Formant tracking based on phoneme information

A system for selecting formant trajectories based on speech corresponding to text data, the system comprising:

• a spectral analyzer receiving the speech as input and producing as output one or more formant candidates for each of a plurality of time frames;
• a segmentor receiving the text data as input and producing a sequence of phonemes as output, each phoneme being temporally aligned with a corresponding segment of the input speech, and having nominal formant frequencies associated with a center point;
• a target formant generator receiving the nominal formant frequencies and center points as input and generating a target formant trajectory for each time frame according to an interpolation of the nominal formant frequencies;
• and
• a selector receiving for each time frame the target formant trajectory and the at least one formant candidate and identifying a particular formant candidate which is closest to the corresponding target formant trajectory in accordance with at least one cost factor.

A method of selecting formant trajectories based on input speech and corresponding to text data, the method comprising the steps of:

• segmenting the text data comprising the substeps of;
• converting text data into a phonemic sequence;
• aligning temporally the input speech into a plurality of time frames with the phonemic sequence to form individual phonemes divided by phoneme boundaries;
• calculating center points between the phoneme boundaries;
• and
• assigning nominal formant frequencies to the center points of each phoneme in the phoneme sequence;
• interpolating the nominal formant frequencies over the plurality of time frames to generate a plurality of target formant trajectories;
• calculating a plurality of formant candidates for each time frame from the input speech by applying Linear predictive coding techniques;
• and
• selecting a particular formant candidate from the plurality of formant candidates for each time frame which is closest to the corresponding target formant trajectories in accordance with the minimum of at least one cost factor.