title: Model-based geometric calibration for medical x-ray systems.
abstract: OBJECTIVE
  Currently applied calibration approaches lead to satisfying 3D roadmapping overlay and 3D reconstruction accuracies; however, the required calibration times are extensive. The aim of this paper is the introduction of a novel model-based approach for geometric system calibrations, leading to a significant reduction of calibration times.
  
  
  METHODS
  By using physical insight into the system, a physical model is derived which can be exploited to predict geometric calibrations parameters. Model-parameters are estimated using a limited set of phantom-based measurement data. Effectively, the calibration procedure is recast to a parameter identification experiment.
  
  
  RESULTS
  The potential of the proposed approach is illustrated by virtue of a benchmark object, successful reconstruction of a clinical phantom, and comparison to phantom-based accuracies.
  
  
  CONCLUSIONS
  Accurate models are required to achieve the desired accuracies. Based on the results in this work, the approach seems to be feasible for practical applications; however, to achieve all the desired specifications, future research should focus on enhanced modeling techniques.
authors.affiliation: Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands.
authors.forename: Rick
authors.initials: R
authors.lastname: van der Maas
authors.affiliation: Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands.
authors.forename: Bram
authors.initials: B
authors.lastname: de Jager
authors.affiliation: Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: Steinbuch
authors.affiliation: Philips Healthcare, iXR Innovation, P.O. Box 10000, Best 5680 DA, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Dries
mesh_terms: D000465:Algorithms; D002138:Calibration / Q000592:standards; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000592:standards; D038622:Internationality; D011856:Radiographic Image Enhancement / Q000379:methods* / Q000592:standards; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards