IPT/EGVE 2005: 9th International Workshop on Immersive Projection Technology, 11th Eurographics Workshop on Virtual Enviroments

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https://diglib.eg.org/handle/10.2312/372

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Using a single Spatial light modulator for stereoscopic images of high color quality and resolution
(The Eurographics Association, 2005) Hopp, Armin; Erik Kjems and Roland Blach
Since stereoscopy is a fundamental part of an immersive display, stereoscopic imaging has been part of many research papers and patents in the past. There have been different approaches developed to generate and transport the two images to the human eye. In general we can say that image generation may be done by one or two units and image encoding is done either by frequency, time or orientation. For image generation Projectors of CRT, LCD, LCOS and DLP Type are well known. Since 3D has gained more public interest, in the past different approaches have been undertaken to simplify setups for stereoscopy. Often two projectors are used to generate stereoscopic images. But these need more maintenance than a single projector system. For a single projector, frame interleaved stereoscopic Image generation is well known for 3Chip DLP Systems using three spatial light modulators to generate the image. In this paper we describe a solution producing frame interleaved output using a single chip spatial light modulator or digital micro mirror device (DMD) allowing combining high resolution and coloring quality.
Distributed Software-Based Volume Visualization in a Virtual Environment
(The Eurographics Association, 2005) Fuhrmann, A. L.; Splechtna, R. C.; Mroz, L.; Hauser, H.; Erik Kjems and Roland Blach
In this paper we present our integration of volume rendering into virtual reality, combining a fast and flexible software implementation of direct volume rendering with the intuitive manipulation and navigation techniques of a virtual environment. By distributing the visualization and interaction tasks to two low-end PCs we managed to realize a highly interactive, yet inexpensive set-up. The volume objects are seamlessly integrated into the polygonal virtual environment through image-based rendering. The interaction techniques include scalar parameterization of transfer functions, direct 3D selection, 3D highlighting of volume objects and clipping cubes and cutting planes. These methods combined with the interaction and display devices of virtual reality form a powerful yet intuitive environment for the investigation of volume data sets. As main application areas we propose training and education.
Augmented Reality Interaction for Semiautomatic Volume Classification
(The Eurographics Association, 2005) Río, A. del; Fischer, J.; Köbele, M.; Bartz, D.; Straßer, W.; Erik Kjems and Roland Blach
In the visualization of 3D medical data, the appropriateness of the achieved result is highly dependent on the application. Therefore, an intuitive interaction with the user is of utter importance in order to determine the particular aim of the visualization. In this paper, we present a novel approach for the visualization of 3D medical data with volume rendering combined with AR-based user interaction. The utilization of augmented reality (AR), with the assistance of a set of simple tools, allows the direct manipulation in 3D of the rendered data. The proposed method takes into account regions of interest defined by the user and employs this information to automatically generate an adequate transfer function. Machine learning techniques are utilized for the automatic creation of transfer functions, which are to be used during the classification stage of the rendering pipeline. The validity of the proposed approach for medical applications is illustrated.
Optical Tracking and Calibration of Tangible Interaction Devices
(The Eurographics Association, 2005) Rhijn, Arjen van; Mulder, Jurriaan D.; Erik Kjems and Roland Blach
In this paper, a novel optical tracking and object calibration system is presented for the recognition and pose estimation of tangible interaction devices for virtual and augmented reality systems. The calibration system allows a user to automatically generate models of the relative positions of point-shaped markers attached to interaction devices, simply by moving them in front of the cameras. There are virtually no constraints on the shape of interaction devices. The tracking method takes the calibrated models as input, and recognizes devices by subgraph matching. Both the calibration and tracking methods can handle partial occlusion. Results show the proposed techniques are efficient, accurate, and robust.
Reducing Fragmentation in Telecollaboration by Using IPT Interfaces
(The Eurographics Association, 2005) Roberts, D.; Al-Liabi, M.; Wolff, R.; Otto, O.; Al-Khalifah, A.; Erik Kjems and Roland Blach
Telecommunication systems, such as AccessGrid, allow collaboration across a distributed team. However, these systems typically introduce fragmentation into the view of the shared environment. Many have found that IPT systems offer several important advantages above other display technologies in supporting distance working. This study focuses on fragmentation, which has previously been shown to induce problems in efficient object referencing within a shared virtual environment accessed through desktop displays. We have attempted to repeat the experiment while varying the display type. The results reinforce previous studies by showing a significant improvement in task performance when the entire team uses IPT displays. We further show that the improvement is unlikely to come in this case from more natural interaction or navigation and thus postulate that it arises from more efficient mutual orientation towards objects of interest, arising from a reduction in fragmentation.
Towards Better Quality in Virtual Environments
(The Eurographics Association, 2005) Mannuß, F.; Hinkenjann, A.; Erik Kjems and Roland Blach
This paper describes the work done at our Lab to improve visual and other quality of Virtual Environments. To be able to achieve better quality we built a new Virtual Environments framework called basho. basho is a renderer independent VE framework. Although renderers are not limited to graphics renderers we first concentrated on improving visual quality. Independence is gained from designing basho to have a small kernel and several plugins.
Evaluation of Collaborative Construction in Mixed Reality
(The Eurographics Association, 2005) Boschker, Breght R.; Mulder, Jurriaan D.; Erik Kjems and Roland Blach
Collaborative virtual and augmented reality are an active area of research and many systems supporting collaboration have been presented. Just like there are many different systems for VR and AR, there are many different types of collaboration. In some cases, virtual reality is used to enhance an existing collaborative process. In other cases, it enables new types of collaboration that previously were not possible (e.g. distributed VR). Other systems support tasks that can be performed either individually as well as collaboratively. While these tasks may allow to be performed collaboratively, little has been said on what the benefit is in doing so. We present a user study of a collaborative construction task in a shared physical workspace virtual reality environment under various degrees of interaction in collaboration. Our results show that, for this type of task, a pair of subjects concurrently interacting can be significantly more effective, even though individual user performance decreases. Our results further show that there is no significant benefit in giving only verbal and non-verbal assistance over a single user performing the task.
Running Large VR Applications on a PC Cluster: the FlowVR Experience
(The Eurographics Association, 2005) Allard, Jérémie; Ménier, Clément; Boyer, Edmond; Raffin, Bruno; Erik Kjems and Roland Blach
In this paper, we present how FlowVR enables the development of modular and high performance VR applications running on a PC cluster. FlowVR is a middleware we specifically developed targeting distributed interactive applications. The goal of the FlowVR design is to favor the application modularity in an attempt to alleviate software engineering issues while taking advantage of this modularity to enable efficient executions on PC clusters. FlowVR relies on an extended data flow model that enables to implement complex message handling functions like collective communications, or bounding box based routing. After a short presentation of FlowVR, we describe a representative application that takes benefit of FlowVR to reach a real time performance running on a PC Cluster.
Modeling of Trees with 3D Gestures and Growth Simulation
(The Eurographics Association, 2005) Murakami, N.; Onishi, K.; Kitamura, Y.; Kishino, F.; Erik Kjems and Roland Blach
We propose a modeling system that enables users to create tree models with 3D gesture input. It generates tree models by using growth simulation based on the trunk or silhouette shapes of trees given by user gestures. The system carefully addresses the fragile balance and tradeoff between the freedom of user interaction and the autonomy of tree growth. Users intuitively and easily create tree models that have the exact features of branching structures or the silhouette shape of trees according to user intentions and imagination.
Enhanced Hand Manipulation for Efficient and Precise Positioning and Release
(The Eurographics Association, 2005) Osawa, N.; Erik Kjems and Roland Blach
Direct manipulation by hand is important in that it allows users to manipulate 3D virtual objects easily in an immersive virtual reality environment. Although direct hand manipulation is easy to understand and easy to use for approximate positioning, it has been considered unsuitable for making precise adjustments to virtual objects in an immersive environment because it is difficult to hold an unsupported hand in midair and then release an object at a fixed point. This paper therefore proposes automatic methods of adjustment to position and release virtual objects precisely. These methods are position adjustment, virtual hand size adjustment, viewpoint adjustment, and release adjustment. Combinations of these adjustments enable users to accurately manipulate virtual objects. Experimental evaluation revealed that release adjustment significantly increased the completion ratio for tasks and subjective preference for small targets.
Interacting with Molecular Structures: User Performance versus System Complexity
(The Eurographics Association, 2005) Liere, R. van; Martens, J.-B. O. S.; Kok, A. J. F.; Tienen, M. H. A. V. van; Erik Kjems and Roland Blach
Effective interaction in a virtual environment requires that the user can adequately judge the spatial relationships between the objects in a 3D scene. In order to accomplish adequate depth perception, existing virtual environments create useful perceptual cues through stereoscopy, motion parallax and (active or passive) haptic feedback. Specific hardware, such as high-end monitors with stereoscopic glasses, head-mounted tracking and mirrors are required to accomplish this. Many potential VR users however refuse to wear cumbersome devices and to adjust to an imposed work environment, especially for longer periods of time. It is therefore important to quantify the repercussions of dropping one or more of the above technologies. These repercussions are likely to depend on the application area, so that comparisons should be performed on tasks that are important and/or occur frequently in the application field of interest. In this paper, we report on a formal experiment in which the effects of different hardware components on the speed and accuracy of three-dimensional (3D) interaction tasks are established. The tasks that have been selected for the experiment are inspired by interactions and complexities, as they typically occur when exploring molecular structures. From the experimental data, we develop linear regression models to predict the speed and accuracy of the interaction tasks. Our findings show that hardware supported depth cues have a significant positive effect on task speed and accuracy, while software supported depth cues, such as shadows and perspective cues, have a negative effect on trial time. The task trial times are smaller in a simple fish-tank like desktop environment than in a more complex co-location enabled environment, sometimes at the cost of reduced accuracy.
Applications of Augmented Reality for Maintenance Training
(The Eurographics Association, 2005) Weng, Dongdong; Wang, Yongtian; Liu, Yue; Erik Kjems and Roland Blach
An Augmented Reality system that is designed for maintenance training is introduced. The proposed system adopts a projector to display the augmented video of the components to be repaired. With the augmented video, students can observe not only the real video of the components to be repaired, but also the additional information about the components such as contour, name and inner structure of the key parts etc. In order to accurately track the spatial relationship between the camera and the repaired components, several markers (small infrared LED) are attached with the components to be repaired, which ensure the dependability of the proposed system.
Towards a general concept for distributed visualisation of simulations in Virtual Reality environments
(The Eurographics Association, 2005) J.Metze,; Neidhold, B.; Wacker, M.; Erik Kjems and Roland Blach
We present a concept for Virtual Reality-Systems that allows easy design and implementation of applications in virtual environments as well as fast integration of new hardware and software components into an existing system of this type. Starting from an abstract module based approach for distributed systems we provide a guidance for specifying and designing components for VR-Applications with focus on the communication, administration and visualisation. Finally we have implemented a proof-of-concept for a cab simulator to demonstrate the effectiveness of our approach.
Dynamic Bounding Volume Hierarchies for Occlusion Culling
(The Eurographics Association, 2005) Kovalcík, Vít; Tobola, Petr; Erik Kjems and Roland Blach
We present an algorithm for rendering complex scenes using occlusion queries to resolve visibility. To organize objects in the scene, the algorithm uses a ternary tree which is dynamically modified according to the current view and positions of the objects in the scene. Aside from using heuristic techniques to estimate unnecessary queries, the algorithm uses several new features to estimate the set of visible objects more precisely while still retaining the conservativeness. The algorithm is suitable for both static and dynamic scenes with huge number of moving objects.
Language Learning in Virtual Environments: Bobo and Apples
(The Eurographics Association, 2005) Holmen, H.; Nielsen, F.; Erik Kjems and Roland Blach
Bobo and Apples is one of the prototype games within SAME4KIDS (Speech-based,Animated, Multilingual,Educational games for Kids, http://same4kids.sourceforge.net/ ), a multi-language and multi-purpose games project for young kids of age 3-5 years. The main goal of SAME4KIDS is to expose young learners to multi-module games in various available platforms. In the prototype of Bobo and Apples , the game is designed to teach multiple languages and simple math within a frame of virtual environment, using mainly visual images, animation and sound. In this paper we introduce the main design concept and architecture for the prototype, as well as the envisioned VR conversion of the game, based on the Animarium system.
Tangible 3D: Hand Gesture Interaction for Immersive 3D Modeling
(The Eurographics Association, 2005) Kim, Hyosun; Albuquerque, Georgia; Havemann, Sven; Fellner, Dieter W.; Erik Kjems and Roland Blach
Most of all interaction tasks relevant for a general three-dimensional virtual environment can be supported by 6DOF control and grab/select input. Obviously a very efficient method is direct manipulation with bare hands, like in real environment. This paper shows the possibility to perform non-trivial tasks using only a few well-known hand gestures, so that almost no training is necessary to interact with 3D-softwares. Using this gesture interaction we have built an immersive 3D modeling system with 3D model representation based on a mesh library, which is optimized not only for real-time rendering but also accommodates for changes of both vertex positions and mesh connectivity in real-time. For performing the gesture interaction, the user s hand is marked with just four fingertipthimbles made of inexpensive material as simple as white paper. Within our scenario, the recognized hand gestures are used to select, create, manipulate and deform the meshes in a spontaneous and intuitive way. All modeling tasks are performed wirelessly through a camera/vision tracking method for the head and hand interaction.
Imperceptible Projection Blanking for Reliable Segmentation within Mixed Reality Applications
(The Eurographics Association, 2005) Kuechler, M.; Kunz, A.; Erik Kjems and Roland Blach
Applications that run in a projection-based mixed reality environment frequently require simultaneous image acquisition of the user by a camera. For later processing, very often a segmentation of the user s image is required, but along with the user, the camera captures the projected dynamic image in the background of the scene. This dynamic background complicates the later segmentation of the user in real-time. To ease segmentation, we introduce methods allowing to imperceptible blank the projected image for the camera. Four different methods are tested and compared. Acquired video streams are recorded and a successful segmentation of a user in front of a dynamic background is demonstrated. The paper concludes with an outlook on possible applications.
A Game Engine-based Multi-Projection Virtual Environment with System-Level Synchronization
(The Eurographics Association, 2005) Hashimoto, Naoki; Ishida, Yoshihiko; Sato, Makoto; Erik Kjems and Roland Blach
In multi-projector displays, which surround users with high-resolution images, a PC-Cluster is often used for realistic and real-time image generation. However, developing applications that support parallel processing on the PC-Cluster is quite troublesome. It is also difficult to acquire sufficient rendering performance because of the limited bandwidth of the PC-Cluster. Therefore, we aim to achieve affordable and accessible software environments for the multi-projector displays. In this paper, we describe a self-distributing software environment for inheriting existent game engines which provide basic functions of realizing virtual environments. This environment achieves minimum data communication based on a master-slave model. The communication mechanism is automatically applied to target applications by intercepting APIs. Hence we can directly exploit high-capability of the existing game engines on the multi-projector displays.
Feature Tracking in VR for Cumulus Cloud Life-Cycle Studies
(The Eurographics Association, 2005) Griffith, E. J.; Post, F. H.; Koutek, M.; Heus, T.; Jonker, H. J. J.; Erik Kjems and Roland Blach
Feature tracking in large data sets is traditionally an off-line, batch processing operation while virtual reality typically focuses on highly interactive tasks and applications. This paper presents an approach that uses a combination of off-line preprocessing and interactive visualization in VR to simplify and speed up the identification of interesting features for further study. We couch the discussion in terms of our collaborative research on using virtual reality for cumulus cloud life-cycle studies, where selecting suitable clouds for study is simple for the skilled observer but difficult to formalize. The preprocessing involves identifying individual clouds within the data set through a 4D connected components algorithm, and then saving isosurface, bounding box, and volume information. This information is then interactively visualized in our VR Cloud Explorer with various tools and information displays to identify the most interesting clouds. In a small pilot study, reasonable performance, both in the preprocessing phase and the visualization phase, has been measured.
Attribute Correlations between Haptic and Auditory Modalities
(The Eurographics Association, 2005) Baird, Bridget; Izmirli, Özgür; Heacock, Bradford; Blevins, Donald; Erik Kjems and Roland Blach
Correlations between attributes in the haptic domain and those in the auditory will assist in multimodal applications. This paper looks at the auditory attributes of pitch and reverberation and the haptic attributes of vibration, size and viscosity and seeks to correlate changes in one of the modalities with changes in the other. A total of 4 pairs of experiments were performed. The results indicate significant correlations in 3 of the pairs: pitch/vibration, pitch/viscosity, reverberation/size. There was no significant correlation found between reverberation and viscosity. These results have significance for designers of multimodal interfaces in virtual environments.

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