Moment invariants are invariant under shifting, scaling and rotation. They are widely used in pattern recognition because of their discrimination power and robustness. HMM method is a natural and highly reliable way of recognition. In this paper, we have proposed a method of using moment invariants as features and HMM as recognition method in facial expression recognition. Sequences of four universal expressions, i.e. anger, disgust, happiness and surprise, are recognized. We were able to attain an accuracy as high as 96.77%. Ó 2002 Elsevier Science B.V. All rights reserved.
Y. Zhu, Liyanage C. De Silva, Chi Chung Ko