"Evaluation of a Rigidity Penalty Term for Nonrigid Registration"
Marius Staring, Stefan Klein and Josien P.W. Pluim
Nonrigid registration of medical images usually does not model properties of different tissue types. This results for example in nonrigid deformations of structures that are rigid. In this work we address this problem by employing a local rigidity penalty term. We illustrate this approach on a 2D synthetic image, and evaluate it on clinical 2D DSA image sequences, and on 3D CT follow-up data of the thorax of patients suffering from lung tumours. The results show that the rigidity penalty term does indeed penalise nonrigid deformations of rigid structures, whereas the standard nonrigid registration algorithm compresses those.