Complex topology 3-D objects segmentation

Adaptive topology surfaces can be used to put the segmenting problem of fitting that type of surface (modelized by spline tensorial products) with the edges of an object detected with low- level operators. The advantage of this method is that continuity degrees can give an appropriate solution to missing datas and surface parametrization ensures global coherence to detected edges. Moreover, this method is by nature adaptative: it is easy to control the number of B-spline used to represent the frontier, which makes it possible to improve progressively the result of the segmentation. A priori knowledge can easily be taken into account if provided under the form of a CAD model of the object to segment. Some topological problems may appear: surfaces topologically equivalent to spheres may have to be transformed into more complex topology surfaces (torus for instance). We propose a method to solve that problem.