No abstract

Real-time surgical simulation often requires computing the deformations of visco-elastic human-body tissue and generating both graphic and haptic renderings. As human users are more sensitive to small haptic discrepancies than visual ones, good force rendering requires a refresh rate of 500Hz or more, which is far beyond the capabilities of current simulators. Moreover, if the simulator runs on a remote server, limited bandwidth, network latency and variance further compromise the quality of haptic rendering. To address these problems, a new interpolation-extrapolation data structure -called the forcegrid -is proposed, which makes it possible to approximate forces at rates greater than 500Hz, regardless of the complexity of the simulated object. The forcegrid is designed for haptic interaction with continuous contact. It is a regular grid defined over the virtual workspace, in which every vertex contains a force. An extrapolation algorithm updates this force at every simulation cycle (~30Hz), while an interpolation algorithm computes the force to be rendered on the haptic device at the desired rate (~500Hz). The forcegrid has been successfully tested on various virtual deformable objects.

En dix ans, la plate-forme BlaBlaCar, le leader mondial du covoiturage longue distance, est devenue une alternative de transport à part entière véhiculant plus de trois fois le volume de voyageurs de l’Eurostar à travers l’Europe, et au-delà. Lorsque l’idée m’est venue d’optimiser l’énorme gâchis que représentaient des millions de voitures roulant quasiment à vide, et de mettre en réseau des passagers souhaitant effectuer un trajet avec des conducteurs allant dans la même direction qu’eux, j’étais motivé par la faisabilité d’une solution permettant une telle optimisation de nos ressources. J’ignorais, cependant, qu’allait naître un service qui bouleverserait profondément les usages de l’automobile et notre façon de nous déplacer.

This paper details the construction of a high resolution, stereoscopic rear-projection display specially optimized for collaborative, computer-based surgical planning. The projection display was designed to address a number of drawbacks that exist in the use of other, more general-purpose projection displays for this task