The GrImage Platform: A Mixed Reality Environment for Interactions

In this paper, we present a scalable architecture to compute, visualize and interact with 3D dynamic models of real scenes. This architecture is designed for mixed reality applications requiring such dynamic models, tele-immersion for instance. Our system consists in 3 main parts: the acquisition, based on standard firewire cameras; the computation, based on a distribution scheme over a cluster of PC and using a recent shape-from-silhouette algorithm which leads to optimally precise 3D models; the visualization, which is achieved on a multiple display wall. The proposed distribution scheme ensures scalability of the system and hereby allows control over the number of cameras used for acquisition, the frame-rate, or the number of projectors used for high resolution visualization. To our knowledge this is the first completely scalable vision architecture for real time 3D modeling, from acquisition to visualization through computation. Experimental results show that this framework is very promising for real time 3D interactions.