Inner Lip Segmentation by Combining Active Contours and Parametric Models

Abstract

Lip reading applications require accurate information about lip movement and shape, and both outer and inner contours are useful. In this paper, we introduce a new method for inner lip segmentation. From the outer lip contour given by a preexisting algorithm, we use some key points to initialize an active contour called "jumping snake". According to some optimal information of luminance and chrominance gradient, this active contour fits the position of two parametric models; a first one composed of two cubic curves and a broken line in case of a closed mouth, and a second one composed of four cubic curves in case of an open mouth. These parametric models give a flexible and accurate final inner lip contour. Finally, we present several experimental results demonstrating the effectiveness of the proposed algorithm.