National Research Council Canada

English

Article

Computer Animation and Virtual Worlds

2012

-

139281

21059283

surgical simulation; transnasal endoscopy; collision handling; haptics; virtual coupling

Simulation of endoscopic navigation in the narrow nasal cavity poses important challenges to the computation of adequate and near-realistic collision response and haptic feedback because extensive multidirectional contact and massive tissue deformations are inevitable. We present a virtual coupling algorithm that provides stable collision response as well as intuitive and smooth haptic interaction in all phases of the simulation. In each iteration, continuous collision detection between the point shell representing the surface of the virtual patient anatomy and the endoscope, represented by a cylinder, is performed. This allows for rolling back the instrument movement to the point in time the first collision occurred. Subsequently, a relaxation process locally optimizes the position and orientation of the instrument. A novel method of applying contact forces to colliding tissues and thus triggering appropriate deformations improves the fluency of navigation. This paper describes the algorithm and presents experimental results.