In this work, a novel approach is proposed to recognize some facial expressions from time-sequential depth videos. Local Directional Pattern (LDP) features are extracted from the time-sequential depth faces that are followed by Linear Discriminant Analysis (LDA) to make the features more robust. Finally, the robust local features are applied with Hidden Markov Models (HMMs) for facial expressio...

[1] K. S. Fu, Sequential Methods in Pattern Recognition and Machine Learning. (Mathematics in Science and Engineering Series, vol. 52) New York: Academic, 1968, second printing 1970 (Russian translation, 1971, Nauka, Moscow, third printing 1978). [2] K. S. Fu, Syntactic Methods in Pattern Recognition. New York: Academic, 1974, second printing 1976 (Russian translation, Mir Press, Moscow, 1976)....

In the latest decades, machine learning approaches have been intensively experimented for natural language processing. Most of the time, systems rely on using statistics within the system, by analyzing texts at the token level and, for labelling tasks, categorizing each among possible classes. One may notice that previous symbolic approaches (e.g. transducers) where designed to delimit pieces o...