Fourier-Based Invariant Shape Prior for Snakes

A novel method of parametric active contours with geometric shape prior is presented in this paper. The main idea of the method consists in minimizing an energy functional that includes an additional information on a shape reference called "template" or "prototype". Prior shape knowledge is introduced throw a complete family of Euclidean invariants, computed from the Fourier descriptors of the evolving contour and the prototype. It enhances the model robustness to noise and occlusion, and allows it to evolve in highly concave boundaries. The variational formulation of the proposed approach is described in details. Experimental results on both synthetic and real images are presented and discussed