Pseudoautomatic Lip Contour Detection Based on Edge Direction Patterns

Detection and tracking of the lip contour is an important issue in speechreading. While there are solutions for lip tracking once a good contour initialization in the first frame is available, the problem of finding such a good initialization is not yet solved automatically, but done manually. Solutions based on edge detection and tracking have failed when applied on real world mouth images. In this paper we propose a solution to the lip contour detection that minimize the user interaction. A minimal number of points to be manually marked on the mouth image is required. The method is based on the examination of gradient direction patterns in the lips area, and makes use of the local direction constancy along the lip contours, as opposed to the other regions of the mouth image that are characterized by random edge directions.