IPT/EGVE 2005: 9th International Workshop on Immersive Projection Technology, 11th Eurographics Workshop on Virtual Enviroments
Permanent URI for this collection
Browse
Browsing IPT/EGVE 2005: 9th International Workshop on Immersive Projection Technology, 11th Eurographics Workshop on Virtual Enviroments by Title
Now showing 1 - 20 of 29
Results Per Page
Sort Options
Item Applications of Augmented Reality for Maintenance Training(The Eurographics Association, 2005) Weng, Dongdong; Wang, Yongtian; Liu, Yue; Erik Kjems and Roland BlachAn 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.Item Attribute Correlations between Haptic and Auditory Modalities(The Eurographics Association, 2005) Baird, Bridget; Izmirli, Özgür; Heacock, Bradford; Blevins, Donald; Erik Kjems and Roland BlachCorrelations 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.Item 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 BlachIn 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.Item Binaural Acoustics For CAVE-like Environments Without Headphones(The Eurographics Association, 2005) Assenmacher, I.; Kuhlen, T.; Lentz, T.; Erik Kjems and Roland BlachThe human auditory system, in contrast to the human visual system, can perceive input from all directions and has no limited field of view. As such, it provides valuable cues for navigation and orientation in virtual environments. However, audio stimuli are not that common in today s Virtual Reality applications, and this might result from the lack of middleware or user acceptance due to the need for specialized or costly hardware. Surprisingly, the lack of headphone-less near body acoustics is widely accepted, and simple intensity panning approaches that enable plausible spatial audio are used. This paper describes a networked environment for sophisticated binaural synthesis-based audio rendering in visual VR applications for a freely moving listener in a CAVE-like environment without the use of headphones. It describes the binaural acoustics rendering technique and a dynamic crosstalk cancellation system for four loudspeakers. In addition to that, synchronization issues and network coupling together with performance measurements that proof the applicability of the system in interactive Virtual Environments are discussed.Item Colosseum3D Authoring framework for Virtual Environments(The Eurographics Association, 2005) Backman, Anders; Erik Kjems and Roland BlachThis paper describes an authoring environment for real time 3D environments, Colosseum3D. The framework makes it possible to easily create rich virtual environments with rigid-body dynamics, advanced rendering using OpenGL Shaders, 3D sound and human avatars. The creative process of building complex simulators is supported by allowing several authoring paths such as a low level C++ API, an expressive high level file format and a scripting layer.Item 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 BlachIn 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.Item Dynamic Bounding Volume Hierarchies for Occlusion Culling(The Eurographics Association, 2005) Kovalcík, Vít; Tobola, Petr; Erik Kjems and Roland BlachWe 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.Item Enhanced Hand Manipulation for Efficient and Precise Positioning and Release(The Eurographics Association, 2005) Osawa, N.; Erik Kjems and Roland BlachDirect 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.Item Evaluation of Collaborative Construction in Mixed Reality(The Eurographics Association, 2005) Boschker, Breght R.; Mulder, Jurriaan D.; Erik Kjems and Roland BlachCollaborative 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.Item Experience of a Hybrid Information Space between an Outdoor Field and an Immersive Virtual World(The Eurographics Association, 2005) Ogi, T.; Fujise, T.; Erik Kjems and Roland BlachThis paper proposes the concept of the hybrid information space that integrates the information seamlessly between the real world and the virtual world, and the prototype system was developed in which the immersive virtual world was constructed from the photograph images that were taken in the outdoor field. In this system, the user can go and come between the real world and the virtual world by using his own cellular phone as an interface device. This system was applied to relive travel experiences.Item 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 BlachFeature 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.Item 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 BlachIn 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.Item Imperceptible Projection Blanking for Reliable Segmentation within Mixed Reality Applications(The Eurographics Association, 2005) Kuechler, M.; Kunz, A.; Erik Kjems and Roland BlachApplications 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.Item IntenSelect: Using Dynamic Object Rating for Assisting 3D Object Selection(The Eurographics Association, 2005) Haan, Gerwin de; Koutek, Michal; Post, Frits H.; Erik Kjems and Roland BlachWe present IntenSelect, a novel selection technique that dynamically assists the user in the selection of 3D objects in Virtual Environments. Ray-casting selection is commonly used, although it has limited accuracy and can be problematic in more difficult situations where the intended selection object is occluded or moving. Selection-byvolume techniques, which extend normal ray-casting, provide error tolerance to cope with the limited accuracy. However, these extensions generally are not usable in the more complex selection situations.We have devised a new selection-by-volume technique to create a more flexible selection technique which can be used in these situations. To achieve this, we use a new scoring function to calculate the score of objects, which fall within a user controlled, conic selection volume. By accumulating these scores for the objects, we obtain a dynamic, time-dependent, object ranking. The highest ranking object, or active object, is indicated by bending the otherwise straight selection ray towards it. As the selection ray is effectively snapped to the object, the user can now select the object more easily. Our user tests indicate that IntenSelect can improve the selection performance over ray-casting, especially in the more difficult cases of small objects. Furthermore, the introduced time-dependent object ranking proves especially useful when objects are moving, occluded and/or cluttered. Our simple scoring scheme can be easily extended for special purpose interaction such as widget or application specific interaction functionality, which creates new possibilities for complex interaction behavior.Item 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 BlachEffective 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.Item Language Learning in Virtual Environments: Bobo and Apples(The Eurographics Association, 2005) Holmen, H.; Nielsen, F.; Erik Kjems and Roland BlachBobo 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.Item Low-Cost, Portable, Multi-Wall Virtual Reality(The Eurographics Association, 2005) Miller, Samuel A.; Misch, Noah J.; Dalton, Aaron J.; Erik Kjems and Roland BlachVirtual reality systems make compelling outreach displays, but some systems highly suitable for outreach, notably the CAVE, have design features that make using them for that purpose inconvenient. In the case of the CAVE, the equipment is difficult to disassemble, transport, and reassemble, and typically only large-budget research facilities can afford such a system. We implemented a system like the CAVE that costs less than $30,000, weighs about 500 pounds, and fits into a fifteen-passenger van. A team of six people have unpacked, assembled, and calibrated the system in less than two hours. This cost reduction versus similar virtual reality systems stems from the unique approach we took to stereoscopic projection. We used an assembly of optical chopper wheels and commodity LCD projectors to create true active stereo at less than a fifth of the cost of comparable active stereo technologies. The screen and frame design also harbor portability optimizations; the frame assembles in minutes with only two fasteners, and both pack into small bundles for easy and secure shipment.Item 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 BlachWe 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.Item Näprä - Affordable Fingertip Tracking with Ultrasound(The Eurographics Association, 2005) Reunanen, M.; Palovuori, K.; Ilmonen, T.; Mäkelä, W.; Erik Kjems and Roland BlachIn this paper we present Näprä, a novel tracking device suitable for fine motor interaction. The motivation for building the device was the need to track users' fingertips in an immersive free-hand drawing environment. Such tracking offers significant benefits for fine-grained artwork. Out of the numerous tracking methods ultrasound was chosen because of its affordability and low computational requirements. The design and implementation of both the hardware and software are discussed in detail in their respective sections. The device was evaluated in practice by two user tests, the first involving ten professional artists and the latter seven ordinary users. The results obtained in the tests are presented to reader as well as some directions for future work.Item Optical Tracking and Calibration of Tangible Interaction Devices(The Eurographics Association, 2005) Rhijn, Arjen van; Mulder, Jurriaan D.; Erik Kjems and Roland BlachIn 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.