EGVE04: 10th Eurographics Symposium on Virtual Environments

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https://diglib7.eg.org/handle/10.2312/373

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Authoring of Mixed Reality Applications including Multi-Marker Calibration for Mobile Devices
(The Eurographics Association, 2004) Zauner, Jürgen; Haller, Michael; Sabine Coquillart and Martin Goebel
Creative and innovative people have good ideas for new kinds of Mixed Reality applications. Applications designed by artists for example enrich the exhibitions of modern museums. Developing such an MR application is a complex task, which nowadays is realized by software engineers. We have developed an authoring tool, which integrates a user-friendly and intuitive calibration tool for developing MR applications.
The DigiTracker, a Three Degrees of Freedom Pointing Device
(The Eurographics Association, 2004) Martinot, F.; Plénacoste, P.; Chaillou, C.; Sabine Coquillart and Martin Goebel
For a variety of reasons, only a few computer devices allow to achieve pointing, tracking and selecting tasks in a precise, fast and intuitive way in 3D workspaces. This article presents the ergonomic and technical principles that have conditioned the proposal of a desktop input device called "DigiTracker". The user controls the position of a virtual object by grasping an isotonic end-effector between the thumb and the forefinger while his forearm is laying on the desk. This equivalent to an absolute three degrees of freedom mouse is especially suitable for closed virtual workspaces. The low technological cost of this solution could provide a really worth alternative to complex VR tracking systems. Possible applications are remote positioning tasks or CAD in simultaneous use with a device dedicated to rotations control .
Foveated Stereoscopic Display for the Visualization of Detailed Virtual Environments
(The Eurographics Association, 2004) Godin, Guy; Massicotte, Philippe; Borgeat, Louis; Sabine Coquillart and Martin Goebel
We present a new method for the stereoscopic display of complex virtual environments using a foveated arrangement of four images. The system runs on four rendering nodes and four projectors, for the fovea and periphery in each eye view. The use of high-resolution insets in a foveated configuration is well known. However, its extension to projector-based stereoscopic displays raises a specific issue: the visible boundary between fovea and periphery present in each eye creates a stereoscopic cue that may conflict with the perceived depth of the underlying scene. A previous solution to this problem displaces the boundary in the images to ensure that it is always positioned over stereoscopically corresponding scene locations. The new method proposed here addresses the same problem, but by relaxing the stereo matching criteria and reformulating the problem as one of spatial partitioning, all computations are performed locally on each node, and require a small and fixed amount of post-rendering processing, independent of scene complexity. We discuss this solution and present an OpenGL implementation; we also discuss acceleration techniques using culling and fragments, and illustrate the use of the method on a complex 3D textured model of a Byzantine crypt built using laser range imaging and digital photography.
ENVIRON - Visualization of CAD Models In a Virtual Reality Environment
(The Eurographics Association, 2004) Corseuil, Eduardo T. L.; Raposo, Alberto B.; Silva, Romano J. M. da; Pinto, Marcio H. G.; Wagner, Gustavo N.; Gattass, Marcelo; Sabine Coquillart and Martin Goebel
This paper presents ENVIRON (ENvironment for VIRtual Objects Navigation), an application that was developed motivated by the necessity of using Virtual Reality in large industrial engineering models coming from CAD (Computer Aided Design) tools. This work analyzes the main problems related to the production of a VR model, derived from the CAD model.
An Experimental Comparison of Three Optical Trackers for Model Based Pose Determination in Virtual Reality
(The Eurographics Association, 2004) Liere, R. van; Rhijn, A. van; Sabine Coquillart and Martin Goebel
In recent years many optical trackers have been proposed for usage in Virtual Environments. In this paper, we compare three model based optical tracking algorithms for pose determination of input devices. In particular, we study the behavior of these algorithms when applied to two-handed manipulation tasks. We experimentally show how critical parameters influence the relative accuracy, latency and robustness of each algorithm. Although the study has been performed in a specific near-field virtual environment, the results can be applied to other virtual environments such as workbenches and CAVEs.
Interfaces for Cloning in Immersive Virtual Environments
(The Eurographics Association, 2004) Chen, Jian; Bowman, Doug A.; Lucas, John F.; Wingrave, Chadwick A.; Sabine Coquillart and Martin Goebel
Three-dimensional objects in many applications domains, such as architecture and construction, can be extremely complex and can consist of a large number of components. However, many of these complex objects also contain a great deal of repetition. Therefore, cloning techniques, which generate multiple spatially distributed copies of an object to form a repeated pattern, can be used to model these objects more efficiently. Such techniques are important and useful in desktop three-dimensional modeling systems, but we are not aware of any cloning techniques designed for immersive virtual environments (VEs). In this paper, we present an initial effort toward the design and development of such interfaces. We define the design space of the cloning task, and present five novel VE interfaces for cloning, then articulate the design rationale. We have also performed a usability study intended to elicit subjective responses with regard to affordances, feedback, attention, perceived usefulness, ease of use, and ease of learning in these interfaces. The study resulted in four major conclusions. First, slider widgets are better suited for discrete than for continuous numeric input. Second, the attentional requirements of the interface increase with increased degrees-of-freedom associated with widgets. Third, users prefer constrained widget movement, although more degrees-of-freedom allow more efficient parameter setting. Finally, appropriate feedback can reduce the cognitive load. The lessons we learned will influence our continuing design of cloning techniques, and these techniques will ultimately be applied to VE applications for design, construction, and prototyping
Effect of visual cues on human performance in navigating through a virtual maze
(The Eurographics Association, 2004) Vembar, D.; Iyengar, N.; Duchowski, A.; Clark, K.; Hewitt, J.; Pauls, K.; Sabine Coquillart and Martin Goebel
Navigation in Virtual Environments (VEs) requires users to develop spatial knowledge of the environment primarily through visual cues provided to the user. Thus, the design and display of visual navigation cues is important for efficient navigation in a VE. In this paper, we report the results of an experiment in which three different visual cues were tested for their benefit toward users' navigation in a 3D virtual maze. The experiment varied the form of visual cue: a 2D map, a 2D map with a directionally ambiguous cue, and a 2D map with a directional cue. Eye tracking data was collected and analyzed to examine the correlation between the type of visual cue presented and the navigational efficiency of the user through the virtual maze. It was observed that the cue type affected performance of the participant in the 3D maze. The directional cue was most effective in the time taken by users to reach the center of the maze. Results of this study have implications for VE design as well as for game development.
A Real-Time System for Full Body Interaction with Virtual Worlds
(The Eurographics Association, 2004) Hasenfratz, J-M.; Lapierre, M.; Sillion, F.; Sabine Coquillart and Martin Goebel
Real-time video acquisition is becoming a reality with the most recent camera technology. Three-dimensional models can be reconstructed from multiple views using visual hull carving techniques. However the combination of these approaches to obtain a moving 3D model from simultaneous video captures remains a technological challenge. In this paper we demonstrate a complete system architecture allowing the real-time (>
Optical Tracking using Line Pencil Fiducials
(The Eurographics Association, 2004) Rhijn, Arjen van; Mulder, Jurriaan D.; Sabine Coquillart and Martin Goebel
In this paper, a new pattern based optical tracking method is presented for the recognition and pose estimation of input devices for virtual or augmented reality environments. The method is based on pencils of linefiducials, which reduces occlusion problems and allows for single camera pattern recognition and orientation estimation. Pattern recognition is accomplished using a projective invariant property of line pencils: the cross ratio. Orientation is derived from single camera line-plane correspondences, and position estimation is achieved using multiple cameras. The method is evaluated against a related point based tracking approach. Results show our method has lower latency and comparable accuracy, and is less sensitive to occlusion.
Medical Augmented Reality based on Commercial Image Guided Surgery
(The Eurographics Association, 2004) Fischer, J.; Neff, M.; Freudenstein, D.; Bartz, D.; Sabine Coquillart and Martin Goebel
Utilizing augmented reality for applications in medicine has been a topic of intense research for several years. A number of challenging tasks need to be addressed when designing a medical AR system. These include the import and management of medical datasets and preoperatively created planning data, the registration of the patient with respect to a global coordinate system, and accurate tracking of the camera used in the AR setup as well as the respective surgical instruments. Most research systems rely on specialized hardware or algorithms for realizing augmented reality in medicine. Such base technologies can be expensive or very time-consuming to implement. In this paper, we propose an alternative approach of building a surgical AR system by harnessing existing, commercially available equipment for image guided surgery (IGS). We describe the prototype of an augmented reality application, which receives all necessary information from a device for intraoperative navigation.
Image-based Techniques for the Creation and Display of Photorealistic Interactive Virtual Environments
(The Eurographics Association, 2004) Drettakis, George; Roussou, Maria; Tsingos, Nicolas; Reche, Alex; Gallo, Emmanuel; Sabine Coquillart and Martin Goebel
In this paper we introduce an image-based 3D capture process for the creation and display of photorealistic virtual environments (VEs). The resulting VEs aim to realistically recreate existing real-world scenes that can be displayed in a range of immersive VR systems using a high-quality, view-dependent algorithm and further enhanced using advanced vegetation, shadow display algorithms and 3D sound. The scenes, an archaeological site and an urban environment, were chosen according to real-world applications in the areas of urban planning/architecture and cultural heritage education. The users in each case are able to reconstruct or manipulate elements of the VEs according to their needs, as these have been specified through a detailed user requirements survey. Furthermore, a user task analysis and scenario-based approach has been adopted for the design of the virtual prototypes and the evaluation, which is currently underway. This work is being developed in the context of the EU-funded research project CREATE and the first examples of the prototype system in use are described and demonstrated in this paper.
A Tele-immersive System Based On Binocular View Interpolation
(The Eurographics Association, 2004) Boulanger, Pierre; Benitez, Martha; Wong, Winston; Sabine Coquillart and Martin Goebel
The main idea behind tele-immersive environment is to create an immersive virtual environment that connect people across networks and enable them to interact not only with each other, but also with various other forms of shared digital data (video, 3D models, images, text, etc.). Tele-immersive environments may eventually replace current video and telephone conferencing, and enable for a better and more intuitive way to communicate between people and computer systems. To accomplish this, participants to a meeting has to be represented digitally with a high degree of accuracy in order to keep a sense of immersion. Tele-immersive environments should have the same "feel" as a real meeting. Interactions among people should be natural. In other to create such a system, we need to solve the key problem of how to create in real-time new views from a fixed network of cameras that will correspond to new viewpoints. We also need to do this for two virtual cameras corresponding to the inter-ocular distance of each participant. In this paper, we will describe a new binocular view interpolation method based on a re-projection technique using calibrated cameras. We will discuss the various aspects of this new algorithm and of the hardware systems necessary to perform these operations in real-time. We will also present early experimental results illustrating the various advantages of this algorithm.
Digital Mock-up database simplification with the help of view and application dependent criteria for industrial Virtual Reality application
(The Eurographics Association, 2004) Chevaldonné, Marc; Neveu, Marc; Mérienne, Frédéric; Dureigne, Michel; Chevassus, Nicolas; Guillaume, François; Sabine Coquillart and Martin Goebel
Aircraft cockpits are advanced interfaces dedicated to the interaction and exchange of observations and commands between the pilot and the flying system. The design process of cockpits is benefiting from the use of Virtual Reality technologies: early ergonomics and layout analysis through the exploration of numerous alternatives, availability all along the cockpit life cycle of a virtual product ready for experimentation, reduced usage of costly physical mock-ups. Nevertheless, the construction of a virtual cockpit with the adequate performances is very complex. Due to the fact that the CAD based digital mock-up used for setting up the virtual cockpit is very large, one challenge is to achieve interactivity while maintaining the quality of rendering. The reduction of the information contained in the CAD database shall achieve a sufficient frame rate without degradation of the geometrical visual quality of the virtual cockpit which would alleviate the relevance of ergonomics and layout studies. This paper proposes to control the simplification process by using objective criteria based on considerations about the cockpit application and the visual performances of human beings. First, it presents the results of studies on the characteristics of the Human Visual System linked to virtual reality and visualization applications. Illustrated by first results, it establishes how to control simplifications in a rational and automatic way.
Using Saccadic Suppression to Hide Graphic Updates
(The Eurographics Association, 2004) Schumacher, J.; Allison, R. S.; Herpers, R.; Sabine Coquillart and Martin Goebel
In interactive graphics it is often necessary to introduce large changes in the image in response to updated information about the state of the system. Updating the local state immediately would lead to a sudden transient change in the image, which could be perceptually disruptive. However, introducing the correction gradually using smoothing operations increases latency and degrades precision. It would be beneficial to be able to introduce graphic updates immediately if they were not perceptible. In the paper the use of saccade-contingent updates is exploited to hide graphic updates during the period of visual suppression that accompanies a rapid, or saccadic, eye movement. Sensitivity to many visual stimuli is known to be reduced during a change in fixation compared to when the eye is still. For example, motion of a small object is harder to detect during a rapid eye movement (saccade) than during a fixation. To evaluate if these findings generalize to large scene changes in a virtual environment, gaze behavior in a 180 degree hemispherical display was recorded and analyzed. This data was used to develop a saccade detection algorithm adapted to virtual environments. The detectability of trans-saccadic scene changes was evaluated using images of high resolution real world scenes. The images were translated by 0.4, 0.8 or 1.2 degrees of visual angle during horizontal saccades. The scene updates were rarely noticeable for saccades with a duration greater than 58 ms. The detection rate for the smallest translation was just 6.25%. Qualitatively, even when trans-saccadic scene changes were detectible, they were much less disturbing than equivalent changes in the absence of a saccade.
Changes in Navigational Behaviour Produced by a Wide Field of View and a High Fidelity Visual Scene
(The Eurographics Association, 2004) Lessels, S.; Ruddle, R. A.; Sabine Coquillart and Martin Goebel
The difficulties people frequently have navigating in virtual environments (VEs) are well known. Usually these difficulties are quantified in terms of performance (e.g., time taken or number of errors made in following a path), with these data used to compare navigation in VEs to equivalent real-world settings. However, an important cause of any performance differences is changes in people s navigational behaviour. This paper reports a study that investigated the effect of visual scene fidelity and field of view (FOV) on participants behaviour in a navigational search task, to help identify the thresholds of fidelity that are required for efficient VE navigation. With a wide FOV (144 degrees), participants spent significantly larger proportion of their time travelling through the VE, whereas participants who used a normal FOV (48 degrees) spent significantly longer standing in one place planning where to travel. Also, participants who used a wide FOV and a high fidelity scene came significantly closer to conducting the search "perfectly" (visiting each place once). In an earlier real-world study, participants completed 93% of their searches perfectly and planned where to travel while they moved. Thus, navigating a high fidelity VE with a wide FOV increased the similarity between VE and real-world navigational behaviour, which has important implications for both VE design and understanding human navigation. Detailed analysis of the errors that participants made during their non-perfect searches highlighted a dramatic difference between the two FOVs. With a narrow FOV participants often travelled right past a target without it appearing on the display, whereas with the wide FOV targets that were displayed towards the sides of participants overall FOV were often not searched, indicating a problem with the demands made by such a wide FOV display on human visual attention.
Integrating Real-time Binaural Acoustics into VR Applications
(The Eurographics Association, 2004) Assenmacher, I.; Kuhlen, T.; Lentz, T.; Vorländer, M.; Sabine Coquillart and Martin Goebel
Common research in the field of Virtual Reality (VR) considers acoustic stimulation as a highly important necessity for enhanced immersion into virtual scenes. However, most common VR toolkits do only marginally support the integration of sound for the application programmer. Furthermore, the quality of stimulation that is provided usually ranges from system sounds (e.g. beeps while selecting a menu) to simple 3D panning. In the latter case, these approaches do only allow the user to correctly detect sounds that are at quite a distance from his current position. Binaural synthesis is an interesting way to allow the spatial auditory representation by using few loudspeakers or headphones. This paper describes a system that combines the efforts of creating a binaural representation for the listener who is interacting in a common visual VR application in real-time, thus allowing the research on interaction between visual and auditory human perception systems. It will describe the theoretical background to establishing a binaural representation of a sound and the necessary hardware set-up for this. Afterwards, the infrastructure and software interface which will allow the connection of the audio renderer to a visual VR toolkit is discusse
Lateral Head Tracking in Desktop Virtual Reality
(The Eurographics Association, 2004) Boschker, B. R.; Mulder, J. D.; Sabine Coquillart and Martin Goebel
Head coupled perspective is often considered to be an essential aspect of stereoscopic desktop virtual reality (VR) systems. Such systems use a tracking device to determine the user's head pose in up to six degrees of freedom (DOF). Users of desktop VR systems perform their task while sitting down and therefore the extent of head movements is limited. This paper investigates the validity of using a head tracking system for desktop VR that only tracks lateral head movement. Users performed a depth estimation task under full (six DOF) head tracking, lateral head tracking, and disabled head tracking. Furthermore, we considered stereoscopic and monoscopic viewing. Our results show that user performance was not significantly affected when incorporating only lateral head motion. Both lateral and full head tracking performed better than the disabled head tracking case.
Multi-Finger Haptic Rendering of Deformable Objects
(The Eurographics Association, 2004) Maciel, Anderson; Sarni, Sofiane; Buchwalder, Olivier; Boulic, Ronan; Thalmann, Daniel; Sabine Coquillart and Martin Goebel
The present paper describes the integration of a multi-finger haptic device with deformable objects in an interactive environment. Repulsive forces are synthesized and rendered independently for each finger of a user wearing a Cybergrasp force-feedback glove. Deformation and contact models are based on mass-spring systems, and the issue of the user independence is dealt with through a geometric calibration phase. Motivated by the knowledge that human hand plays a very important role in the somatosensory system, we focused on the potential of the Cybergrasp device to improve perception in Virtual Reality worlds. We especially explored whether it is possible to distinguish objects with different elasticities. Results of performance and perception tests are encouraging despite current technical and computational limitations.
MANDALA: A Reconfigurable VR Environment for Studying Spatial Navigation in Humans Using EEG
(The Eurographics Association, 2004) Boulanger, Pierre; Torres, Daniel; Bischof, Walter; Sabine Coquillart and Martin Goebel
This paper describes a reconfigurable VR environment and a markup language for creating experiments aimed at understanding human spatial navigation. It permits the creation of high-quality virtual environments and the recording of behavioral and brain activity measures while observers navigate these environments. The system is used in studies where the electroencephalographic activity is recorded while observers navigate virtual environments. The results of the study reported here confirmed previous finding that theta oscillations (electroencephalographic activity in the 4-8 Hz band) are linked to the difficulty of spatial navigation. Further, it showed that this activity is likely to occur at points where new rooms come into view, or after navigational mistakes have been realized and are being corrected. This indicates that theta oscillations in humans are related to the encoding and retrieval of spatial information.
Live Tuning of Virtual Environments: The VR-Tuner
(The Eurographics Association, 2004) Conrad, Stefan; Krüger, Hans Peter; Haringer, Matthias; Sabine Coquillart and Martin Goebel
This paper describes a solution for the modification of virtual environment (VE) applications while being immersed in the application scenario inside of an immersive projection environment. We propose an infrastructure which enables developers to adjust object properties and change the structure of the scene graph and data flow between nodes using a tablet PC. The interface consists of a two dimensional graphical user interface (2D GUI) brought on a spacial aware touch screen computer, accompanied by a mixer console with motor faders. We discuss the usability of the combination of different interaction modalities for the task of tuning of VE applications.

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