Classification of visual speech features
 
 
- Word=time sequence of visemes (mouth states) => temporal evolution of visual speech features is important for recognition:
- 
- need for dynamic classifiers, to model transitions between mouth states = model temporal evolution of data:
- HMM (Hidden Markov Models): the most frequently used: 
- 
- 
- 
- 
- TDNN (Time-Delayed Neural Networks): can perform recognition based on the temporal variation of visual speech features, not only static values.
 
Department of Informatics
Aristotle University of Thessaloniki