Snakes. From active contours to active surfaces.
Ricard Delgado Gonzalo, EPFL STI LIB

Seminar • 06 February 2012

Abstract
Snakes are effective tools for image segmentation. Within a 2D image, a snake is a 1D curve that evolves from an initial position, which is usually specified by a user, toward the boundary of an object. Within a 3D image, a snake is represented by a 2D surface. In the literature, these methods are also known as active contours or active surfaces. The snake evolution is formulated as a minimization problem. The associated cost function is called a snake energy. Snakes have become popular because it is possible for the user to interact with them, not only when specifying their initial position, but also during the segmentation process. This is often achieved by allowing the user to specify anchor points the curve or surface should go through. In this talk we will show a framework for the design of 2D and 3D snakes that are parameterized by a set of control points. We will mainly discuss the importance of a good parameterization and its impact in the computational performance of the final algorithm. From the practical side, awe will present a user interface for ICY that features numerous possibilities for user interaction through a mouse-based manipulation of control points in synchronized 2D and 3D views. High-quality data rendering is performed thanks to VTK. Moreover, the snake surface can be overlaid to the original data during the optimization process.