title: Groupwise rigid registration of wrist bones.
abstract: We present an extension of the symmetric ICP algorithm that is unbiased for an arbitrary number (N > or = 2) of shapes, using rigid transformations and scaling. The method does not require the selection of a reference shape or registration order and hence it is unbiased towards any of the registered shapes. The functional to be minimized is non-linear in the transformation parameters and thus computationally complex. We therefore propose a first order approximation that estimates the transformation parameters in a closed form, with computational complexity (see text for symbol)(N2). Using a set of wrist bones, we show that the least-squares minimization and the proposed approximation converge to the same solution. Experiments also show that the proposed algorithms lead to smaller registration errors than algorithms that select a reference shape or register to an evolving mean shape. The low computational cost and trivial parallelization enable the alignment of large numbers of bones.
authors.affiliation: Quantitative Imaging Group, Delft University of Technology, The Netherlands. m.vandegiessen@lumc.nl
authors.forename: Martijn
authors.initials: M
authors.lastname: van de Giessen
authors.forename: Frans M
authors.initials: FM
authors.lastname: Vos
authors.forename: Cornelis A
authors.initials: CA
authors.lastname: Grimbergen
authors.forename: Lucas J
authors.initials: LJ
authors.lastname: van Vliet
authors.forename: Geert J
authors.initials: GJ
authors.lastname: Streekstra
mesh_terms: D000465:Algorithms; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014955:Wrist Joint / Q000000981:diagnostic imaging*