Intelligent interactive image outlining using spline snakes

Abstract

Outlining 20 shapes and image regions is often required in image manipulation and analysis. Most polygon and curve drawing tools in gmphics do not use the knowledge o f image intensities and its derivatives in guiding the outlining process, and hence am quite tedious and error prone. This paper presents a fast interactive drawing tool based on a parametric spline formulation of snakes that exploits the underlying image intensities. Specifically, interactivelyspecified contours are naturally attracted to strong image edges in the vicinity because spline snakes are designed to migrate to significant ridges in the gradient magnitude image. Furthermore, allowable stretching and bending can be controlled b y minimizing explicitly the bending and stretching energies of the curve. Parameterization of spline snakes in terms of a limited number of control points yields a fast minimization solution thus enabling interactive rubber banding of the cutwe on the screen. This feedback allows users to quickly guide the snake on the desired path.