A dual active contour for head boundary extraction

The position of a head in an image is germane to automatic face recognition. Several techniques have been proposed to extract an approximation to the head boundary. This paper presents a new approach to improve robustness of face contour extraction by extending active contour techniques. The main problems with the basic snake technique (Kass et al., 1988) include sensitivity to initialisation and obstruction of evolution by insignificant is localised features. In deployment, these factors can force selection of an initial contour which is close to the target. By combining an expanding contour with a shrinkage one, in a dual active contour, we can reduce sensitivity to initialisation, effectively by constraining the space in which the target contour is expected to lie