BibSonomy publications for /user/jvrb_regulski/GRAPP2006Thu Dec 13 16:00:12 CET 2007Journal of Virtual Reality and BroadcastingSeptember{\tt urn:nbn:de:0009-6-11700}, ISSN 1860-20374Topologically Accurate Dual Isosurfacing Using Ray Intersection42007Peer_Reviewed Ray_Tracing JVRB 4.2007 Ray_Intersection DiPP [SLH07] Three-dimensional_Computer_Graphics Journal_of_Virtual_Reality_and_Broadcasting 4(2007)4 Trilinear_Interpolation Digital_Peer_Publishing_Initiative Computer_Graphics Open_Access Isosurface Dual_Contouring GRAPP2006 “Dual contouring” approaches provide an alternative to standard Marching Cubes (MC) method to extract and approximate an isosurface from trivariate data given on a volumetric mesh. These dual approaches solve some of the problems encountered by the MC methods. We present a simple method based on the MC method and the ray intersection technique to compute isosurface points in the cell interior. One of the advantages of our method is that it does not require us to use Hermite interpolation scheme, unlike other dual contouring methods. We perform a complete analysis of all possible configurations to generate a look-up table for all configurations. We use the look-up table to optimize the ray-intersection method to obtain minimum number of points necessarily sufficient for defining topologically correct isosurfaces in all possible configurations. Isosurface points are connected using a simple strategy.Thu Oct 25 12:08:05 CEST 2007Journal of Virtual Reality and BroadcastingsepISSN 1860-20372High-Level Modeling of Multimodal Interaction Techniques Using NiMMiT42007Multimodal_Interaction Interactive_Virtual_Environment Open_Access Interaction_Techniques 4(2007)2 Digital_Peer_Publishing_Initiative [DBVRC07] DiPP Journal_of_Virtual_Reality_and_Broadcasting GRAPP2006 Virtual_Environments Interaction_Metaphors JVRB Multimodal_System Peer_Reviewed Model-Based_Design 4.2007 The past few years, multimodal interaction has been gaining importance in virtual environments. Although multimodality renders interacting with an environment more natural and intuitive, the development cycle of such an application is often long and expensive. In our overall field of research, we investigate how model-based design can facilitate the development process by designing environments through the use of high-level diagrams. In this scope, we present ‘NiMMiT′, a graphical notation for expressing and evaluating multimodal user interaction; we elaborate on the NiMMiT primitives and demonstrate its use by means of a comprehensive example.Wed Oct 24 12:57:01 CEST 2007Journal of Virtual Reality and BroadcastingaugISSN 1860-203712High level methods for scene exploration32006Open_Access 3(2006)12 Peer_Reviewed JVRB [SP06] Journal_of_Virtual_Reality_and_Broadcasting Digital_Peer_Publishing_Initiative Scene_Understanding DiPP GRAPP2006 Automatic_Virtual_Camera Good_Point_of_View 3.2006 Virtual worlds exploration techniques are used in a wide variety of domains — from graph drawing to robot motion. This paper is dedicated to virtual world exploration techniques which have to help a human being to understand a 3D scene. An improved method of viewpoint quality estimation is presented in the paper, together with a new off-line method for automatic 3D scene exploration, based on a virtual camera. The automatic exploration method is working in two steps. In the first step, a set of “good” viewpoints is computed. The second step uses this set of points of view to compute a camera path around the scene. Finally, we define a notion of semantic distance between objects of the scene to improve the approach.Tue Oct 23 10:23:49 CEST 2007Journal of Virtual Reality and Broadcastingmayurn:nbn:de:0009-6-7774 ISSN 1860-20377System Architecture of a Mixed Reality Framework32006Mixed_Reality [SD06] DiPP GRAPP2006 Digital_Peer_Publishing_License Distributed_Systems Data-Flow_Management Peer-Reviewed JVRB Augmented_Reality 3(2006)7 3.2006 Journal_of_Virtual_Reality_and_Broadcasting In this paper the software architecture of a framework which simplifies the development of applications in the area of Virtual and Augmented Reality is presented. It is based on VRML/X3D to enable rendering of audio-visual information. We extended our VRML rendering system by a device management system that is based on the concept of a data-flow graph. The aim of the system is to create Mixed Reality (MR) applications simply by plugging together small prefabricated software components, instead of compiling monolithic C++ applications. The flexibility and the advantages of the presented framework are explained on the basis of an exemplary implementation of a classic Augmented Realityapplication and its extension to a collaborative remote expert scenario.Fri Mar 23 08:42:22 CET 2007Journal of Virtual Reality and BroadcastingDecemberISSN 1860-20374{V}iew-{D}ependent {E}xtraction of {C}ontours with {D}istance {T}ransforms for {A}daptive {P}olygonal {M}esh {S}implification32006Picture_and_Image_Generation Journal_of_Virtual_Reality_and_Broadcasting JVRB Three_Dimensional_Graphics_and_Realism 3(2006)4 Computer_Graphics 3.2006 Image_Processing DiPP Computational_Geometry Object_Modelling Algorithmic_Geometry Digital_Peer_Publishing_License GRAPP2006 Peer-Reviewed [MPR06] During decades Distance Transforms have proven to be useful for many image processing applications, and more recently, they have started to be used in computer graphics environments. The goal of this paper is to propose a new technique based on Distance Transforms for detecting mesh elements which are close to the objects' external contour (from a given point of view), and using this information for weighting the approximation error which will be tolerated during the mesh simplification process. The obtained results are evaluated in two ways: visually and using an objective metric that measures the geometrical difference between two polygonal meshes.Fri Feb 09 12:39:11 CET 2007urn:nbn:de:0009-6-7720Journal of Virtual Reality and BroadcastingDecemberISSN 1860-20375{E}xploring {U}rban {E}nvironments {U}sing {V}irtual and {A}ugmented {R}eality32006Virtual_Reality JVRB Urban_Environments Augmented_Reality Brujic-Okretic 3.2006 Wayfinding Liarokapis Papakonstantinou DiPP Peer-Reviewed Navigation Digital_Peer_Publishing_License [LBP06] Mobile_Computing GRAPP2006 3(2006)5 Journal_of_Virtual_Reality_and_Broadcasting Pathfinding In this paper, we propose the use of specific system architecture, based on mobile device, for navigation in urban environments. The aim of this work is to assess how virtual and augmented reality interface paradigms can provide enhanced location based services using real-time techniques in the context of these two different technologies. The virtual reality interface is based on faithful graphical representation of the localities of interest, coupled with sensory information on the location and orientation of the user, while the augmented reality interface uses computer vision techniques to capture patterns from the real environment and overlay additional way-finding information, aligned with real imagery, in real-time. The knowledge obtained from the evaluation of the virtual reality navigational experience has been used to inform the design of the augmented reality interface. Initial results of the user testing of the experimental augmented reality system for navigation are presented.