Statistical chromaticity models for lip tracking with B-splines

Abstract

A method for lip tracking intended to support personal verification is presented in this paper. Lip contours are represented by means of quadratic B-splines. The lips are automatically localised in the original image and an elliptic B-spline is generated to start up tracking. Lip localisation exploits grey-level gradient projections as well as chromaticity models to find the lips in an automatically segmented region corresponding to the face area. Tracking proceeds by estimating new lip contour positions according to a statistical chromaticity model for the lips. The current tracker implementation follows a deterministic second order model for the spline motion based on a Lagrangian formulation of contour dynamics. The method has been tested on the M2VTS database[1]. Lips were accurately tracked on sequences consisting of more than hundred frames. localisation.