【华为云技术分享】人脸情感模型简介
人脸情感模型主要分为三类:
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离散分类模型 categorical model
二十世纪,Ekman和Friesen定义了6种基本情感,生气anger, 厌恶disgust, 害怕fear, 开心happiness, 伤心sadness, 和 惊奇surprise [1]。之后轻蔑contempt被加入到基本情感中[2]。
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连续维度模型 dimensional model
如下图是二维的valence和arousal脸部表情示意图。其中valence表示表情的积极或者消极,arousal表示表情的兴奋或者平静。
3. 脸部动作编码系统模型 Facial Action Coding System (FACS) model
FACS模型并不直接描述脸部表情,而是描述脸部动作,其中脸部动作用动作单位(Action Units,AUs)描述,例如AU1代表内部眉毛上升、AU6表示脸颊上升。每个脸部动作可以有5种强度。存在一些方法将动作单位转换到情感空间中。比如EMFACS认为AU6和AU12的共同出现代表开心。具体的人脸动作可以参考维基百科Facial Action Coding System。
[1] P. Ekman and W. V. Friesen, “Constants across cultures in the face and emotion.” Journal of personality and social psychology, vol. 17, no. 2,
pp. 124–129, 1971.
[2] D. Matsumoto, “More evidence for the universality of a contempt expression,” Motivation and Emotion, vol. 16, no. 4, pp. 363–368, 1992.
[3] Mollahosseini, Ali, Behzad Hasani, and Mohammad H. Mahoor. "Affectnet: A database for facial expression, valence, and arousal computing in the wild." IEEE Transactions on Affective Computing 10.1 (2017): 18-31.
[4] Li, Shan, and Weihong Deng. "Deep facial expression recognition: A survey." arXiv preprint arXiv:1804.08348 (2018).
作者:冰糖柠萌