title: Ellipsoid-constrained robust fitting of quadrics with application to the 3D morphological characterization of articular surfaces.
abstract: This paper addresses the ellipsoid-type-specified fitting of quadratic surfaces, in the scope of model-based global feature extraction within scattered 3D point clouds. At characterizing articular bone surfaces, the quadrics estimated indicate useful overall-symmetry-related intrinsic centers and axes in joints. A constrained weighted least-squares minimization of algebraic residuals is used, with a robust and bias-corrected metric. With only one quadratic constraint involved, every step produces closed-form eigenvector solutions. To guarantee that an ellipsoid is output, we originally exploit a 2D representation called the Quadric Shape Map (QSM) by carrying out a visual study of the influence of shape constraints. The identified ellipsoid guarantee is needed to extract the center and axes in a wrist joint data stemming from 3D medical images.
authors.affiliation: Radiation Medicine Program, Princess Margaret Hospital, Uni. Health Network, 610 University Ave., Toronto, Ontario, Canada. stephane.allaire@enst-bretagne.fr
authors.forename: S
authors.initials: S
authors.lastname: Allaire
authors.forename: J J
authors.initials: JJ
authors.lastname: Jacq
authors.forename: V
authors.initials: V
authors.lastname: Burdin
authors.forename: Ch
authors.initials: Ch
authors.lastname: Roux
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007596:Joints / Q000033:anatomy & histology* / Q000502:physiology*; D008953:Models, Anatomic; D008954:Models, Biological