Stable dynamic 3D shape models

Shape models used for the segmentation of 3D image data often suffer from high instability of shape. Current approaches to avoid this instability often result in models with high computation times and few possibilities for interaction and modelling. We present a 3D mass-spring model which has been extended by torsion forces and the capability of explicit rotation. These models are stable with respect to shape collapse and contortion. Stability is achieved even if the model is only sparsely connected. This makes the computation efficient enough for real-time interaction. The extended model has been successfully applied to the segmentation of the left ventricle of the human heart in 3D SPECT data.