Voice Individuality, i.e. speaker characteristic, is detailed explained and the research history on this topic is also illustrated.
Voice individuality, in particular, is important not only because it helps us identify the person to whom we are talking, but also because it enriches our daily life with variety. However, for most speaker-independent speech recognition tasks, voice individuality is simply an obstacle that must be overcome, and speaker normalization and adaptation are methods that have been developed for that purpose.
What is voice individuality?
community the speaker belongs to
sound or timbre
Acoustic characteristics of voice individuality:
1) voice source:
the average pitch frequency;
the time-frequency pattern of pitch (the pitch contour);
the pitch frequency fluctuation
the glottal wave shape
2) vocal tract resonance:
the shape of spectral envelope and spectral tilt;
the absolute values of formant frequencies;
the time-frequency pattern of formant frequencies (formant trajectories)
the long-term average speech spectrum
the formant bandwidth
Spectral conversion algorithms:
1) Code book mapping
2) Speaker difference vector inter/extra-polation
3) Frequency scaling
4) Multi-speaker inter/extra-polation
5) Unsupervised conversion
Three stages of the mapping methods:
1) parametric representation of acoustic characteristics;
2) mapping algorithms;
3) speech corpus development to train the weights on the mappings.