Extraction and tracking of the eyelids

Facial analysis is used in a number of applications like face recognition systems, human-computer interaction through head movements or facial expressions, or model based coding. In all these applications a very precise extraction of the feature points corresponding to the eyes is necessary. In this paper we present a method for automatic extraction and tracking of the eyelids. First the images are filtered in order to enhance the interesting features. Then a dynamic programming algorithm is applied to extract the precise shape of the eyelids. Although restrictions are applied on the possible shapes, they are not modeled as ellipse arcs. This allows extracting the corner of the eyes with higher precision. Once the eyelids are extracted for the first image, a new robust tracking algorithm based on snakes is applied to track them along the sequence, which allows large motion of the eyes and rotation and zooming of the head.