A New External Force for Snakes Based on the IGGVF

An improved generalized gradient vector force for active contour model, named IGGVF is presented in this paper. For the diffusion of GGVF force field virtually depends on Laplace operation and it can be decomposed in the tangent and normal directions and the diffusion in the normal direction plays the major role while the tangent direction has little effect. So the tangent component can be thrown out and only the normal component be maintained and its counterpart coefficient be doubled to speed up its diffusion velocity. In GGVF, it only takes consideration of the gradient information of the image which might be considered as a drawback. So a slightly modified GGVF function is presented in this paper. Experiments results reveal that it has larger capture range, bigger time step and can expedite force active contours into concave regions.