Lips contour detection and tracking using watershed region-based active contour model and modified H_∞

In this paper, a region-based active contour model (ACM) with local information using watershed segmentation is proposed for lips contour detection. Compared to the ACM with global energy terms, the proposed system provides a more precise lips contour convergence under the circumstances where the lips are difficult to distinguish using global statistics. Furthermore, since the ACM is sensitive to the initial contour position, a modified H_∞ based on Lyapunov stability theory is proposed to provide better tracking of the subsequent lips feature points as the ACM initialization. The integration of the proposed ACM and modified H_∞ has revealed an improvement of the overall lips contour detection.