Surface Deformation Analysis of Facial Expressions Using Stereo Digital Image Correlation

Facial expression is an important way to reflect human emotions. Analyzing facial movements is an effective means of understanding expressions. In this paper, a classic optical measuring method called stereo digital image correlation (stereo-DIC or 3D-DIC) is employed to analyze the deformation of facial expressions. The forming processes of six basic facial expressions of certain experimental subject are analyzed through the strain calculated by 3D-DIC. Based on the calculated results, a novel deformation analysis strategy is introduced to dissect the details of facial expressions. The observations especially deal with the areas that deform first and the strain variation of the most active areas on the human face in the expressions. The presented investigations demonstrate the superior performance of 3D-DIC in the quantitative analysis of facial expressions. Such measuring method and analytical strategy might have potential value to further reveal the underlying human emotional fluctuation.