A point-selection algorithm based on spatial-stiffness analysis of rigid registration

Abstract

Objective: We propose a model of shape-based registration that leads to a task-specific algorithm for preoperatively selecting a set of model registration points.

Materials and Methods: We performed five sets of computer simulations using registration points generated by our algorithm and two noise amplification index (NAI) algorithms on the basis of the research of Simon . We used several different bone surface models (distal radius, proximal femur and tibia) computed from CT images of patient volunteers. The number of registration points used varied between 6 and 30.

Results: Our algorithm was faster than the NAI-based algorithms by factors of approximately 4 and 200. It had equal or better performance in terms of target registration error (TRE) when compared with the other algorithms. Our simulations also showed that point selection can have a large effect on TRE behavior; in particular, poor point selection does not necessarily decrease TRE as more registration points are added.

Conclusions: Our point-selection algorithm produces model registration points with similar or better TRE behavior than the NAI-based algorithms we tested, and it does so with significantly less computation time.

• Orthopaedic surgery
• point selection
• rigid registration
• spatial stiffness
• target registration error