Research Activities

Over the last decade Visual Computing has established itself as a core discipline within computer science and information technology. Its research scope covers the design of computational and mathematical methods and interactive systems for geometric and physics-based modeling, image acquisition and synthesis, scientic visualization, as well as virtual reality. As a result, visual computing research is providing enabling technology for a broad spectrum of applications in all of CRS4 thematic areas. The Visual Computing Group has been founded in 1996, and has developed remarkable skills in visual computing technology, gaining a national and international visibility.

Current projects range from desktop 3D tools to immersive virtual environments with haptic feedback. Representative examples of current active research domains are the following:

  • Rendering and streaming of terrains and urban environments. We develop multi-resolution out-of-core techniques for rapid high-quality visualization of textured digital terrain models and high resolution urban environments. For terrain rendering, we developed the Batched Dynamic Adaptive Meshes Framework (BDAM). The framework introduced one of the first methods for rapidly generating seamless variable resolution surfaces by assembling precomputed patches (BDAM - Eurographics 2003). It exploits GPU programmability for ensuring submetric accuracy on full planet visualization (P-BDAM - IEEE Visualization 2003). Coupled with a two-stage wavelet based near lossless compression scheme, the method supports data compression with maximum error metric (C-BDAM - Eurographics 2006). The efficiency of the approach has been demonstrated on a number of local and global test cases, and is at the core of successfully deployed internet geoviewers. For urban model rendering and streaming, we introduced a GPU-friendly technique that efficiently exploits the highly structured nature of urban environments to ensure rendering quality and interactive performance of city exploration tasks (BlockMap - Eurographics 2007). Central to our approach is a novel discrete representation for the efficient encoding and rendering of a small set of textured buildings far from the viewer. Work done in collaboration with ISTI-CNR.
  • Processing, distribution, and rendering of massive dense 3D meshes and point clouds. We look at techniques for supporting inspection of surface models characterized by a high sample density, such as those generated by laser scanning. Our main result is the introduction of a coarse grained multiresolution model based on hierarchical volumetric decomposition, that lead to the first GPU bound high quality technique for large scale meshes (2004). Introduced optimized representation that exploits the properties of a conformal hierarchy of tetrahedra (Adaptive TetraPuzzles, SIGGRAPH 2004) and a general framework based on an extension of the Multi-Triangulation (GPU-MT, IEEE Visualization 2005). We also introduced the first coarse-grained multiresolution point hierarchy (LPC, Computers and Graphics 2004). Demonstrated on a number of test cases, including all Digital Michelangelo models. Work done in collaboration with ISTI-CNR.
  • Processing, distribution, and rendering of huge complex 3D models. We focus on methods able to support very large arbitrary surface models with high topological genus, highly variable depth complexity, fine geometric detail, "Bad" tessellations. Models of this kind arise from numerical simulation and computer aided design. Our main result is the introduction of a volumetric method based on multi-scale modeling of appearance rather than geometry with tight integration of visibility and LOD construction (Far Voxels, SIGGRAPH 2005). The method exploits GPU programmability for accelerated rendering and has been demonstrated on a number of test cases, ranging from laser scans, to isosurfaces, to extremely large CAD models, including the full Boeing 777 model. Fully interactive performance even for large windows on current single processor PCs.
  • Massive volume rendering. We focus on methods able to render models of potentially unlimited size on current GPU platform. Our methods are based on adaptive out-of-core multiresolution techniques with visibility feedback realized within a single-pass GPU raycasting framework. Specialized techniques have been created both within an OpenGL shading framework (Visual Computer 2008) and NVIDIA CUDA (Visual Computer 2009). Illustrative techniques have been realized to increase volume understanding. Fully interactive performance has been demonstrated on datasets of many GVoxels.
  • Interactive visualization on novel light field displays. We focus on developing efficient techniques for harnessing the power of novel 3D display design. We work with Holografika (Hungary), that develops a 3D display combining a specially arranged array of projectors and a holographic screen. By properly controlling image generation, rendered objects appear floating in space to multiple naked eye viewers. Sustaining interactive rates is a challenging tasks, since hundreds of views per frame have to be generated. We develop specialized surface and volume rendering techniques for both single processor and network parallel rendering. By dynamically adapting resolution to spatial display capabilities, we have demonstrated the capability to sustain interaction for huge models on a 50Mpixel display (SIGGRAPH 2006 Etech). We have subsequently designed and produced specialized interactive rendering systems both for meshes and volumetric data (Eurographics 2008, Visual Computer 2009, 2010).
  • Real-time surgical simulation with visual and haptic feedback. We develop enabling technology to support surgical training through simulation. Our results so far include a multiresolution volumetric model for simulating bone burring, simplified models for contrast agent transport in human vessels, real-time techniques for phacoemulsification simulation. Some of our simulation and rendering modules have been integrated in industrial systems for surgical training.

Check our projects, publications, and multimedia pages for more information on our activities.