Assessing the Fidelity of Haptically Rendered Deformable Objects

A central element of surgical simulators is the generation of appropriate haptic feedback. Several factors influence this rendering process, which could potentially degrade the feedback quality. In this context, our current research aims at assessing, how well haptic sensations encountered during interaction with real objects, can actually be approximated in a virtual environment. Since finding appropriate soft tissue deformation models for real time interaction is a complex task in itself, we limited the investigations in this pilot study to simple linear-elastic silicone objects. A model of a virtual deformable object was adapted and parameters selected to approximate a real silicone sample within a specific hardware setup. A comparative study was performed, in which 13 subjects had to discriminate between the categories of real and virtual objects. We found that subjects could discern between the categories with a mean accuracy of 63% with no significant bias towards assuming the presence of either real or virtual objects. While being above chance level, the results indicate that we were able to approximate haptic feedback of a real object with high fidelity in our specific hardware setup.