Facial expression analysis FaceReader is the most reliable software tool for facial expression analysis (source). FaceReader is the most robust automated system for the recognition of a number of specific properties in facial images, including the six basic or universal expressions: happy, sad, angry, surprised, scared, and disgusted.
Pattern Recognition, Facial Expression Analysis, Research Needs, Multimodal System; Facial Expression Analysis for Estimating Learner's Emotional State In Intelligent .
PDF | Computer analysis of human face images includes detection of faces, identification of people, and understanding of expression. Among these three tasks, facial expression has been the least.