1. Jia, X., Wen, C.C., Bao, X.Y.: Expression recognition based on dynamic image sequence. J. Beijing Univ. Technol. 9, 1360–1365 (2013)
2. Wang, L., Liu, J., Fu, X.: Facial expression recognition integrating local features and depth belief network. Laser Optoelectron. Prog. 1, 198–206 (2018)
3. Zhao, J., Mao, X., Zhang, J.: Learning deep facial expression features from image and optical flow sequences using 3D CNN. Visual Comput. 34, 1–15 (2018)
4. Li, H., Roivainen, P., Forcheimer, R.: 3-D motion estimation in model-based facial image coding. IEEE Trans. Pattern Anal. Mach. Intell. 15(6), 545–555 (1993)
5. Lecture Notes in Computer Science (Lecture Notes in Artificial Intelligence);A Seal,2014