Eric Bouvier

A Large Scale Interactive Holographic Display

Our work focuses on the development of interactive multi-user holographic displays that allow freely moving naked eye participants to share a three dimensional scene with fully continuous, observer independent, parallax. Our approach is based on a scalable design that exploits a specially arranged array of projectors and a holographic screen. The feasibility of such an approach has already been demonstrated with a working hardware and software 7.4M pixel prototype driven at 10-15Hz by two DVI streams. In this short contribution, we illustrate our progress, presenting a 50M pixel display prototype driven by a dedicated cluster hosting multiple consumer level graphic cards.

Crowd simulation in immersive space management

We present here an immersive application specifically oriented to the visualisation of urban space dedicated to transportation. To the “usual” constraint of urban / architecture walkthrough, we add the dimension of rapid transit of large numbers of people and vehicles, which we manage by a dedicated tool of “crowd simulation”, using statistical algorithms such as are used in the realm of physics. This enables us to have a fast and realistic simulation of a complex environment, to be used for urban assessment and planning, on a dedicated graphics-accelerated PC based workstation “Elysium”.

A Scalable Hardware and Software System for the Holographic Display of Interactive Graphics Applications

We present a scalable holographic system design targeting multi-user interactive computer graphics applications. The display uses a specially arranged array of micro-displays and a holographic screen. Each point of the holographic screen emits light beams of different color and intensity to the various directions, in a controlled manner. The light beams are generated through a light modulation system arranged in a specic geometry and the holographic screen makes the necessary optical transformation to compose these beams into a perfectly continuous 3D view. With proper software control, the light beams leaving the various pixels can be made to propagate in multiple directions, as if they were emitted from physical objects at xed spatial locations. The display is driven by DVI streams generated by multiple consumer level graphics boards and decoded in real-time by image processing units that feed the optical modules at high refresh rates. An OpenGL compliant library running on a client PC redenes the OpenGL behavior to multicast graphics commands to server PCs, where they are re-interpreted for implementing holographic rendering. The feasibility of the approach has been successfully evaluated with a working hardware and software 7.4M pixel prototype driven at 10-15Hz by three DVI streams.

Time-critical multiresolution rendering of large complex models

Very large and geometrically complex scenes, exceeding millions of polygons and hundreds of objects, arise naturally in many areas of interactive computer graphics. Time-critical rendering of such scenes requires the ability to trade visual quality with speed. Previous work has shown that this can be done by representing individual scene components as multiresolution triangle meshes, and performing at each frame a convex constrained optimization to choose the mesh resolutions that maximize image quality while meeting timing constraints. The authors demonstrate that the nonlinear optimization problem with linear constraints associated to a large class of quality estimation heuristics is efficiently solved using an active-set strategy. By exploiting the problem structure, Lagrange multiplier estimates and equality-constrained problem solutions are computed in linear time. Results show that our algorithms and data structures provide low memory overhead, smooth level-of-detail control, and guarantee, within acceptable limits, a uniform, bounded frame rate even for widely changing viewing conditions. Implementation details are presented along with the results of tests for memory needs, algorithm timing, and efficacy

TOM: TOTALLY ORDERED MESH A MULTIRESOLUTION STRUCTURE FOR TIME CRITICAL GRAPHICS APPLICATIONS

Tridimensional interactive applications are confronted to situations where very large databases have to be animated, transmitted and displayed in very short bounded times. As it is generally impossible to handle the complete graphics description while meeting timing constraint, techniques enabling the extraction and manipulation of a significant part of the geometric database have been the focus of many research works in the field of computer graphics. Multiresolution representations of 3D models provide access to 3D objects at arbitrary resolutions while minimizing appearance degradation. We describe the TOM (Totally Ordered Mesh), a multiresolution triangle mesh structure tailored to the support of time-critical adaptive rendering. The structure grants high speed access to the continuous levels of detail of a mesh and allows very fast traversal of the list of triangles at arbitrary resolution so that bottlenecks in the graphic pipeline are avoided. Moreover, and without specific compression, the memory footprint of the TOM is small (about 108% of the single resolution object in face-vertex form) so that large scenes can be handled effectively. The TOM structure also supports storage per vertex (or per corner of triangle) attributes such as colors, normals, texture coordinates or dynamic properties. Implementation details are presented along with the results of tests for memory needs, approximation quality, timing and efficacy.

An interactive multi-user holographic environment

We present an interactive multi-user holographic environment that allows freely moving naked eye participants to share a large 3D scene with fully continuous, observer independent, parallax.