Fully automatic 3D facial expression recognition using polytypic multi-block local binary patterns

3D facial expression recognition has been greatly promoted for overcoming the inherent drawbacks of 2D facial expression recognition and has achieved superior recognition accuracy to the 2D. In this paper, a novel holistic, full-automatic approach for 3D facial expression recognition is proposed. First, 3D face models are represented in 2D-image-like structure which makes it possible to take advantage of the wealth of 2D methods to analyze 3D models. Then an enhanced facial representation, namely polytypic multi-block local binary patterns (P-MLBP), is proposed. The P-MLBP involves both the feature-based irregular divisions to depict the facial expressions accurately and the fusion of depth and texture information of 3D models to enhance the facial feature. Based on the BU-3DFE database, three kinds of classifiers are employed to conduct 3D facial expression recognition for evaluation. Their experimental results outperform the state of the art and show the effectiveness of P-MLBP for 3D facial expression recognition. Therefore, the proposed strategy is validated for 3D facial expression recognition; and its simplicity opens a promising direction for fully automatic 3D facial expression recognition.