Deformable Model Acquisition and Validation

Objects deform in response to contact forces exerted on them. The deformation depends on material properties, the geometry of the object and external forces. This thesis develops a robotic system for automatically acquiring observations of a deforming object and for estimating a model of the deformation from these observations. Models of deformable objects are in wide-spread use in simulation, computer graphics and virtual reality. Deformation, impact and fitting simulation aid manufacturing. In computer graphics deformable objects are designed and animated. Medical simulators incorporating physical models of organs and tissue are a significant emerging virtual reality application. The material properties of deformable models are often assigned based on mechanical (and other) testing of material samples. Material samples do not represent commonly simulated objects well if there is a high variability in the material of the object, e.g., due to mixed material, unknown material, or material with imperfections. In contrast to material sampling, this thesis develops a method to scan the deformation behavior of a complete object. The scanning is analogous to the scanning of the visual appearance of an object. The scan captures the individual response of a complete object to contact forces. The result of the scan is not only a deformable model but also data which serves to validate the model. This validation step gives a qualitative and sometimes quantitative assessment of the suitability of a model.