Fitting of iso-surfaces using superquadrics and free-form deformations

Recovery of 3D data with simple parametric models has been the subject of many studies over the last ten years. Many have used the notion of superquadrics introduced for graphics by Barr (1981). Different improvements were introduced to make the model a better representation of the data (Boult and Gross, 1987; Ferrie et al., 1989; Solina and Bajcsy 1990; Terzopoulos and Metaxas, 1991). The authors describe a two-steps method to fit a parametric deformable surface to 3D points. They suppose that a 3D image has been segmented to get a set of 3D points. The first step consists in their version of a superquadric fit with global tapering, similar to the method proposed by Boult and Gross (1987). The authors then make use of the technique of free-form deformations, as introduced by Sederberg and Parry (1986) in computer graphics. They present experimental results with synthetic and real 3D medical images