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VRST Tables of Contents: 979899000102030405060708091012131415

Proceedings of the 2009 ACM Symposium on Virtual Reality Software and Technology

Fullname:VRST'09 ACM Symposium on Virtual Reality Software and Technology
Editors:Steven N. Spencer; Yoshifumi Kitamura; Haruo Takemura; Kiyoshi Kiyokawa; Benjamin Lok; Daniel Thalmann
Location:Kyoto, Japan
Dates:2009-Nov-18 to 2009-Nov-20
Standard No:ISBN: 1-60558-869-5, 978-1-60558-869-8; ACM DL: Table of Contents hcibib: VRST09
Links:Conference Home Page
  1. Keynote abstracts
  2. Devices
  3. Performance analysis
  4. Haptics & multi-modality
  5. Rendering
  6. Augmented reality
  7. Interaction
  8. Cyberspace & virtual human
  9. Poster abstracts

Keynote abstracts

Light control and 3D video: building blocks for telepresence of the future BIBAFull-Text 8
  Markus Gross
The understanding and the conception of systems for telepresence has been a long-standing problem in research and development. In order to convey a true sense of presence, a variety of technical and perceptual factors have to be considered including visual, auditory, and tactile cues. While there has been significant progress in the design of telepresence systems in recent years, we are still far from our ultimate goal of the "holodeck experience." Yet, there are two distinct technological building blocks for enabling telepresence in a controlled environment: The first one relates to the ability to control light on surfaces, either through intelligent projection or through active surface imaging. The second one comprises holographic video, that is, a fully 3-dimensional representation of a remote scene in realtime. The proliferation of increasingly low-cost, small, and high quality digital video cameras, time-of-flight sensors, and projectors constitutes an important infrastructure to implement these building blocks.
   In this talk I will discuss the variety of technical challenges underlying simultaneous display and acquisition, such as synchronization, calibration, 3D reconstruction, recognition, modeling, rendering. I will summarize our own experiences in system design from monolithic projection theatres, such as blue-c, towards modular, lightweight setups. I will illustrate how projector-camera modules can be utilized for 3D video acquisition, displays on demand, spatial light control, tabletop surface computing, interactive visual tracking, and recalibration. I will present my vision for telepresence of the future and introduce to the ETH program for Research and Understanding of Telepresence.
Dive into the movie: an instant casting and immersive experience in the story BIBAFull-Text 9
  Shigeo Morishima
Our research project, Dive into Movie (DIM) aims to build a new genre of interactive entertainment which enables anyone to easily participate in a movie by assuming a role and enjoying an embodied, first-hand theater experience. This is specifically accomplished by replacing the original roles of the precreated traditional movie with user created, high-realism, 3-D CG characters. DIM movie is in some sense a hybrid entertainment form, somewhere between a game and storytelling. We hope that DIM movies might enhance interaction and offer more dramatic presence, engagement, and fun for the audience. In DIM movie, audiences can experience high-realism 3-D CG character action with individualized facial characteristics, expression, gait and voice. The DIM system has two key features: First, it can full-automatically create a CG character in a few minutes from capturing the face, body, gait and voice feature of a user and generating her/his corresponding CG animation, to inserting the individualized CG character into the movie in real-time which do not cause any discomfort to the participant; Second, the DIM system makes it possible for multiple participants to take part in a movie at the same time in different roles, such as a family, a circle of friends, etc. And also DIM project proposes a panoramic image capture/projection system and 3D sound field capture/playback system from performer, Äôs view and standing point.
A taxonomy of (real and virtual world) display and control interactions BIBAFull-Text 10
  Paul Milgram
Interactions between a human operator and objects in his/her world afford a wide range of possible viewing and control options, which can vary with respect to time, space, proximity, and frame of reference. Whereas it is conventionally recognised that essentially any kind of interaction metaphor can in principle be simulated in a virtual environment, modern image processing technology now permits greatly increased flexibility also for real world interactions with indirect viewing, Äî as the common video camera has gone beyond being a simple eye on the (remote) real world to being an instrument that is able to integrate and interpolate real world images spatially and temporally, in real time.
   In the talk, I shall propose a framework for classifying viewing and manipulation interactions for any task where visual feed back is provided.
   The framework involves identifying key components of the environment that are central to the interaction, in terms of the multidimensional couplings among the components, where the configuration and characteristics of the couplings determine the nature of the visual and manual control interactions experienced by the operator. The framework is domain independent, and is intended to be used both to classify current display-control interactions and to identify future areas of research.


Wearable imaging system for capturing omnidirectional movies from a first-person perspective BIBAKFull-Text 11-18
  Kazuaki Kondo; Yasuhiro Mukaigawa; Yasushi Yagi
We propose a novel wearable imaging system that can capture omnidirectional movies from the viewpoint of the camera wearer. The imaging system solves the problems of resolution uniformity and gaze matching that conventional approaches do not address. We combine cameras with curved mirrors that control the projection of the imaging system to produce uniform resolution. Use of the mirrors also enables the viewpoint to be moved closer to the eyes of the camera wearer, thus reducing gaze mismatching. The optics, including the curved mirror, have been designed to form an objective projection. The capability of the designed optics is evaluated with respect to resolution, aberration, and gaze matching. We have developed a prototype based on the designed optics for practical use. Capability of the prototype and effectiveness of first-person perspective omnidirectional movies were demonstrated through quantitative evaluations and presentation experiments to ordinary people, respectively.
Keywords: first-person perspective, omnidirectional imaging system, wearable camera
A wide-view parallax-free eye-mark recorder with a hyperboloidal half-silvered mirror BIBAKFull-Text 19-22
  Erika Sumiya; Tomohiro Mashita; Kiyoshi Kiyokawa; Haruo Takemura
In this paper, we propose a wide-view parallax-free eye-mark recorder with a hyperboloidal half-silvered mirror. Our eye-mark recorder provides a wide field-of-view (FOV) video recording of the user's exact view by positioning the focal point of the mirror at the user's viewpoint. The vertical view angle of the prototype is 122 [deg] (elevation and depression angles are 38 and 84 [deg], respectively) and its horizontal view angle is 116 [deg] (nasal and temporal view angles are 38 and 78 [deg], respectively). We have implemented and evaluated a gaze estimation method for our eyemark recorder. Experimental results have verified that our eye-mark recorder successfully captures a wide FOV of a user and estimates a rough gaze direction.
Keywords: eye-mark recorder, gaze estimation, half-silvered hyperboloidal mirror, head-mounted camera
Study on design of controllable particle display using water drops suitable for light environment BIBAKFull-Text 23-26
  Shin-ichiro Eitoku; Kunihiro Nishimura; Tomohiro Tanikawa; Michitaka Hirose
Controllable particle display has been proposed, that controls the position and blinking patterns to yield a visual representation and the representation to touch these particles. Additionally, as an example of its implementation, a controllable particle display using water drops as the particles was proposed. In this system, objects are represented by projecting images upward onto falling water drops designed to form a plane surface, depending on the positions of the water drops. However, this method has a problem in terms of the brightness of the object. In this paper, we propose a method by which images are projected onto falling water drops at an angle, and users observe the images from in front of a projector.
Keywords: public space, volumetric display, water drop
Tearable: haptic display that presents a sense of tearing real paper BIBAKFull-Text 27-30
  Takuya Maekawa; Yuichi Itoh; Keisuke Takamoto; Kiyotaka Tamada; Takashi Maeda; Yoshifumi Kitamura; Fumio Kishino
We propose a novel interface called Tearable that allows users to continuously experience the real sense of tearing paper. To provide such a real sense, we measured the actual vibration data of tearing a piece of real paper and analyzed them. Based on this data, we utilized hook-and-loop fasteners and a DC motor for representing the sense of tearing. We compared the force given by Tearable with that by a piece of real paper and recommended its reproducibility and usability. In addition, we evaluated Tearable with questionnaires after user experiences.
Keywords: haptic display
Camera-based OBDP locomotion system BIBAKFull-Text 31-34
  Minghadi Suryajaya; Tim Lambert; Chris Fowler
In virtual reality, locomotion is a key factor in making a simulation immersive. Actually walking is the most intuitive way for people to move about, providing a better sense of presence than walking-in-place or flying [Usoh et al. 1999]. We have built a locomotion system with a ball-bearing platform that allows the user to walk in a natural fashion in any direction. The user's leg motion is tracked with two cameras and turned into locomotion in the simulation. We also track upper body motion and use this to animate the user's avatar.
   Our approach is less expensive than systems that involve complex mechanical arrangements, such as an omnidirectional treadmill [Darken et al. 1997], and more immersive than simple switch mechanisms such as the Walking-Pad [Bouguila et al. 2004]. Our system delivers real-time performance on mid-tier hardware computer and webcams.
Keywords: locomotion interface, meanshift algorithm, stereo camera, virtual reality, walking

Performance analysis

Judgment of natural perspective projections in head-mounted display environments BIBAKFull-Text 35-42
  Frank Steinicke; Gerd Bruder; Klaus Hinrichs; Scott Kuhl; Markus Lappe; Pete Willemsen
The display units integrated in todays head-mounted displays (HMDs) provide only a limited field of view (FOV) to the virtual world. In order to present an undistorted view to the virtual environment (VE), the perspective projection used to render the VE has to be adjusted to the limitations caused by the HMD characteristics. In particular, the geometric field of view (GFOV), which defines the virtual aperture angle used for rendering of the 3D scene, is set up according to the display's field of view. A discrepancy between these two fields of view distorts the geometry of the VE in a way that either minifies or magnifies the imagery displayed to the user. Discrepancies between the geometric and physical FOV causes the imagery to be minified or magnified. This distortion has the potential to negatively or positively affect a user's perception of the virtual space, sense of presence, and performance on visual search tasks.
   In this paper we analyze if a user is consciously aware of perspective distortions of the VE displayed in the HMD. We introduce a psychophysical calibration method to determine the HMD's actual field of view, which may vary from the nominal values specified by the manufacturer. Furthermore, we conducted an experiment to identify perspective projections for HMDs which are identified as natural by subjects -- even if these perspectives deviate from the perspectives that are inherently defined by the display's field of view. We found that subjects evaluate a field of view as natural when it is larger than the actual field of view of the HMD -- in some cases up to 50%.
Keywords: field of view, head-mounted displays, virtual reality
Gaze behavior and visual attention model when turning in virtual environments BIBAKFull-Text 43-50
  Sébastien Hillaire; Anatole Lécuyer; Gaspard Breton; Tony Regia Corte
In this paper we analyze and try to predict the gaze behavior of users navigating in virtual environments. We focus on first-person navigation in virtual environments which involves forward and backward motions on a ground-surface with turns toward the left or right. We found that gaze behavior in virtual reality, with input devices like mice and keyboards, is similar to the one observed in real life. Participants anticipated turns as in real life conditions, i.e. when they can actually move their body and head. We also found influences of visual occlusions and optic flow similar to the ones reported in existing literature on real navigations. Then, we propose three simple gaze prediction models taking as input: (1) the motion of the user as given by the rotation velocity of the camera on the yaw axis (considered here as the virtual heading direction), and/or (2) the optic flow on screen. These models were tested with data collected in various virtual environments. Results show that these models can significantly improve the prediction of gaze position on screen, especially when turning, in the virtual environment. The model based on rotation velocity of the camera seems to be the best trade-off between simplicity and efficiency. We suggest that these models could be used in several interactive applications using gaze point as input. They could also be used as a new top-down component in any existing visual attention model.
Keywords: first-person navigation, gaze behavior, gaze tracking, perception model, visual attention
Influence of degrees of freedom's manipulation on performances during orientation tasks in virtual reality environments BIBAKFull-Text 51-58
  Manuel Veit; Antonio Capobianco; Dominique Bechmann
In this paper we investigate the influence of the integration and separation of the Degrees Of Freedom (DOF) on the users' performances during 3-D orientation tasks. For this purpose, we compare the performances and the level of DOF's coordination users reached using two interaction techniques, one integrating and the other separating the task's DOF. To evaluate the degree of coordination, we propose a new behavioural measurement (called Magnitude of Degrees of Freedom's Separation), which provides the number of DOF simultaneously manipulated during an orientation task. The results of our study suggest that users are not able to integrate the manipulation of all the DOF during the whole task even using a direct manipulation technique. Moreover, if the interaction eases the task's decomposition, its use can lead to significant improvements regarding the achievement times. This result suggests that the simultaneous manipulation of all the DOF does not necessary lead to the best performances.
Keywords: degrees of freedom, human-computer interaction, interaction technique, measurements, rotation, virtual reality
Analyzing the effect of a virtual avatar's geometric and motion fidelity on ego-centric spatial perception in immersive virtual environments BIBAKFull-Text 59-66
  Brian Ries; Victoria Interrante; Michael Kaeding; Lane Phillips
Previous work has shown that giving a user a first-person virtual avatar can increase the accuracy of their egocentric distance judgments in an immersive virtual environment (IVE). This result provides one of the rare examples of a manipulation that can enable improved spatial task performance in a virtual environment without potentially compromising the ability for accurate information transfer to the real world. However, many open questions about the scope and limitations of the effectiveness of IVE avatar self-embodiment remain. In this paper, we report the results of a series of four experiments, involving a total of 40 participants, that explore the importance, to the desired outcome of enabling enhanced spatial perception accuracy, of providing a high level of geometric and motion fidelity in the avatar representation. In these studies, we assess participants' abilities to estimate egocentric distances in a novel virtual environment under four different conditions of avatar self-embodiment: a) no avatar; b) a fully tracked, custom-fitted, high fidelity avatar, represented using a textured triangle mesh; c) the same avatar as in b) but implemented with single point rather than full body tracking; and d) a fully tracked but simplified avatar, represented by a collection of small spheres at the raw tracking marker locations. The goal of these investigations is to attain insight into what specific characteristics of a virtual avatar representation are most important to facilitating accurate spatial perception, and what cost-saving measures in the avatar implementation might be possible. Our results indicate that each of the simplified avatar implementations we tested is significantly less effective than the full avatar in facilitating accurate distance estimation; in fact, the participants who were given the simplified avatar representations performed only marginally (but not significantly) more accurately than the participants who were given no avatar at all. These findings suggest that the beneficial impact of providing users with a high fidelity avatar self-representation may stem less directly from the low-level size and motion cues that the avatar embodiment makes available to them than from the cognitive sense of presence that the self-embodiment supports.
Keywords: head mounted displays, immersive virtual environments, presence, spatial perception, virtual avatars

Haptics & multi-modality

Multi-modal exploration of small artifacts: an exhibition at the Gold Museum in Bogota BIBAKFull-Text 67-74
  Pablo Figueroa; Mauricio Coral; Pierre Boulanger; Juan Borda; Eduardo Londoño; Felipe Vega; Flavio Prieto; Diego Restrepo
We present the iterative development and initial evaluation of a multi-modal platform for interacting with precious small artifacts from the Gold Museum in Bogota. By using a commercial haptic interface, loud speakers, and stereo displays, one can allow visitors to touch, hear, and observe in stereo those precious artifacts. We use this multi-modal interface in a novel way and in a novel context in order to provide virtual replicas that can be weighed, cleaned, and explored as if they were close to a visitor's hand. This platform is currently open to the public, and some of the lessons learned are reported in terms of usability in a real-world museum application.
Keywords: Museo del Oro Colombia, haptics, multimodal booth, virtual heritage
Haptic interaction with one-dimensional structures BIBAKFull-Text 75-78
  Ugo Bonanni; Petr Kmoch; Nadia Magnenat-Thalmann
One-dimensional structures are very important for simulating a variety of slender objects such as ropes, hair, wires, cables or tubes. Because of their practical relevance, an increasing number of dynamic simulation methods have been proposed during the last years. However, interaction techniques have not followed this evolution. Hence, we propose to combine the recent advances in the computation of physically plausible rod dynamics with dedicated force rendering methods. We present a novel approach for computing the haptic interaction with slender objects in a virtual environment. Our interaction framework allows for an enhanced control over the rod by taking into account user-induced torques in the dynamics equations. Interaction forces are computed according to the rod's bending stiffness and frictional properties. Our force rendering method can thus be applied to a variety of simulation models based on the Cosserat Theory of Elastic Rods. The results of this paper are relevant for including haptic feedback within applications involving 1D-rods, such as virtual hair modeling systems for the digital effects industry, or assembly simulation environments in the automotive industry using flexible parts such as wire harnesses and hoses.
Keywords: force feedback, haptics, multimodal interaction
Profiling the behaviour of 3D selection tasks on movement time when using natural haptic pointing gestures BIBAFull-Text 79-82
  Vijay M. Pawar; Anthony Steed
In this paper we profiled the performance of two types of 3D selections tasks: selection of one target and the selection of two targets. We designed an Immersive Virtual Environment (IVE) to evaluate any differences that may exist, and understand the underlying human behaviour by recording the hand movements' participants made when asked to select a series of 3D objects. To do this, we implemented a natural virtual hand-like interaction technique that participants could control using a large-scale force-feedback device placed into a CAVE™-like IVE system. We also investigated the interaction of no, soft and hard haptic force-feedback responses in addition to three target sizes on user performance. From the results obtained, we show distinct differences in the movement time taken when participants used their right hand to select one target in comparison to the selection of two targets.
Haptic augmented reality interface using the real force response of an object BIBAKFull-Text 83-86
  Yuichi Kurita; Atsutoshi Ikeda; Takeshi Tamaki; Tsukasa Ogasawara; Kazuyuki Nagata
This paper presents the haptic interface system that consists of a base object and a haptic device. The desired force response is achieved by the combination of the real force response of the base object and the virtual force exerted by the haptic device. The proposed haptic augmented reality (AR) system can easily generate the force response of a visco-elastic object with a cheap haptic device and a base object that has the similar visco-elastic property to the target object. In the demonstration, the force response of the target object was generated by using a haptic device only (VR) and using both a haptic device and a base object (AR), respectively. The evaluation experiments by participants show that the AR method has better performance than the VR method. This result indicates the potential of the proposed haptic AR interface.
Keywords: augmented reality, haptic interface
Improving perceived hardness of haptic rendering via stiffness shifting: an initial study BIBAKFull-Text 87-90
  Gabjong Han; Seokhee Jeon; Seungmoon Choi
Rendering a stiff virtual surface using a force-feedback haptic interface has been one of the most classic and important research issues in haptics. In this paper, we present an initial study for a novel haptic rendering technique, named stiffness shifting, which greatly increases the perceived hardness of a virtual surface. The key idea of stiffness shifting is to use a stiffness profile that includes an instantaneous increment shortly after a contact. The algorithm is very simple, and can be easily integrated into existing haptic rendering algorithms for 3D objects. Furthermore, the perceptual performance of the algorithm is impressive; a virtual wall rendered using stiffness shifting is perceived as hard as one rendered using the common linear spring model with 2.5 times higher stiffness. This result demonstrates a great potential of stiffness shifting to be a general means for improving the perceptual quality of haptic rendering.
Keywords: haptic rendering, hardness perception, stiffness
Virtual bone drilling for dental implant surgery training BIBAKFull-Text 91-94
  Kimin Kim; Jinah Park
Mechanical removal of bone material is the most critical procedure during dental implant surgery because it can jeopardize patient safety in several ways such as damage in the mandibular canal and piercing of the maxillary sinus. With recognition of the effectiveness in virtual training, many simulators with haptic feedback have been proposed. Although there are many varieties in drill bits, most of previously developed simulators consider only a spherically shaped tool due to its simplicity in tool-bone interaction. In this paper, we propose a new simulation method that can handle any arbitrarily shaped tools with multiple contacts between the tool and the bone. The tool is represented by a signed-distance field, and the bone is represented as voxels surrounded by a point shell. Upon chipping away bone elements, the point shell is updated reflecting the deformation of bone in real-time, while the collision detection and the reflected force is efficiently and accurately computed from the distance field encoded in the tool. We also present the experimental results with 12 dental implantologists to evaluate realism of the proposed simulator.
Keywords: dental implant surgery, haptics, virtual drilling


A generic real-time rendering approach for structural colors BIBAKFull-Text 95-102
  Masataka Imura; Osamu Oshiro; Masahiko Saeki; Yoshitsugu Manabe; Kunihiro Chihara; Yoshihiro Yasumuro
Colors in nature can be classified into two categories: pigment colors and structural colors. Structural colors, which are caused by optical path differences of reflected rays in microstructures, change depending on viewing angle and lighting conditions. In the present paper, we propose a generic approach for rendering structural colors in real-time. The proposed method uses optical path differences as common parameters to allow unified treatment of various types of microstructures, such as thin films, multilayer films, and diffraction gratings. To achieve real-time rendering, we store pre-computed information related to specific microstructure and lighting conditions on several kinds of textures. The textures are used as a look-up table in the rendering process. The proposed method can be applied to objects that have arbitrary shape and enables rendering from any viewing direction and under any lighting conditions.
Keywords: optical path difference, real-time rendering, structural color, texture representation
GPU acceleration of stereoscopic and multi-view rendering for virtual reality applications BIBAKFull-Text 103-110
  Jonathan Marbach
Stereo and Multi-View rendering of three-dimensional virtual environments can be accelerated using modern GPU features such as geometry shaders and layered rendering, allowing multiple images to be generated in a single geometry pass. These same capabilities can be used to generate the multiple views necessary for co-present multi-user projection environments. Previous work has demonstrated the feasibility of applying such techniques, but has not shown under what circumstances these techniques provide increased or decreased rendering performance. This paper provides a detailed analysis of the performance of single-pass stereo and multi-view generation techniques and provides guidelines for when their application is beneficial to rendering performance.
Keywords: geometry shader, layered rendering, multi-viewer images, stereoscopic rendering, virtual reality
A particle-based method for viscoelastic fluids animation BIBAKFull-Text 111-117
  Yuanzhang Chang; Kai Bao; Youquan Liu; Jian Zhu; Enhua Wu
We present a particle-based method for viscoelastic fluids simulation. In the method, based on the traditional Navier-Stokes equation, an additional elastic stress term is introduced to achieve viscoelastic flow behaviors, which have both fluid and solid features. Benefiting from the Lagrangian nature of Smoothed Particle Hydrodynamics, large flow deformation can be handled more easily and naturally. And also, by changing the viscosity and elastic stress coefficient of the particles according to the temperature variation, the melting and flowing phenomena, such as lava flow and wax melting, are achieved. The temperature evolution is determined with the heat diffusion equation. The method is effective and efficient, and has good controllability. Different kinds of viscoelastic fluid behaviors can be obtained easily by adjusting the very few experimental parameters.
Keywords: heat diffusion, melting, smoothed particle hydrodynamics, viscoelastic fluids
The virtual magic lantern: an interaction metaphor for enhanced medical data inspection BIBAKFull-Text 119-122
  Eva Monclús; José Díaz; Isabel Navazo; Pere-Pau Vázquez
In Volume Rendering, it is difficult to simultaneously visualize interior and exterior structures. Several approaches have been developed to solve this problem, such as cut-away or exploded views. Nevertheless, in most cases, those algorithms usually require either a preprocess of the data, or an accurate determination of the region of interest, previous to data inspection.
   In this paper we present the Virtual Magic Lantern (VML), an interaction tool tailored to facilitate volumetric data inspection. It behaves like a lantern whose virtual illumination cone provides the focal region which is visualized using a secondary transfer function or different rendering style. This may be used for simple visual inspection, surgery planning, or injure diagnosis. The VML is a particularly friendly and intuitive interaction tool suitable for an immersive Virtual Reality setup with a large screen, where the user moves a Wanda device, like a lantern pointing to the model. We show that this inspection metaphor can be efficiently and easily adapted to a GPU ray casting volume visualization algorithm. We also present the Virtual Magic Window (VMW) metaphor as an efficient collateral implementation of the VML, that can be seen as a restricted case where the lantern illuminates following the viewing direction, through a virtual window created as the intersection of the virtual lantern (guided by the Wanda device) and the bounding box of the volume.
Keywords: interaction, medical models, virtual reality
Sizing avatars from skin weights BIBAKFull-Text 123-126
  Mustafa Kasap; Nadia Magnenat-Thalmann
In current computer games and simulation environments, individuality of virtual character bodies are mainly constructed using different textures and accessories. However, this type of modeling generates anthropometrically similar shapes due to the reliance on a single or few body models. Alternatively, using large variety of body size models require larger storage resources and design efforts. We present an efficient method for generating and storing variety of body size models derived from a skinned template. Our method doesn't require additional design efforts and uses the existing skinning data that are already attached to the template model. Algorithm used for sizing the model is based on anthropometric body measurement standards that are used in ergonomic design application. Resulting new body size models use the same skinning information for animation by adapting the underlying skeleton according to the anthropometric parameters. Our developed system is useful in CAD applications from ergonomic design of cloths to parametrically resizing avatars.
Keywords: anthropometry, deformation, multi-scale models, virtual human

Augmented reality

Relocalization using virtual keyframes for online environment map construction BIBAKFull-Text 127-134
  Sehwan Kim; Christopher Coffin; Tobias Höllerer
The acquisition of surround-view panoramas using a single hand-held or head-worn camera relies on robust real-time camera orientation tracking. In absence of robust tracking recovery methods, the complete acquisition process has to be re-started when tracking fails. This paper presents methodology for camera orientation relocalization, using virtual keyframes for online environment map construction. Instead of relying on real keyframes from incoming video, the proposed approach enables camera orientation relocalization by employing virtual keyframes which are distributed strategically within an environment map. We discuss our insights about a suitable number and distribution of virtual keyframes, as suggested by our experiments on virtual keyframe generation and orientation relocalization. After a shading correction step, we relocalize camera orientation in real-time by comparing the current camera frame to virtual keyframes. While expanding the captured environment map, we continue to simultaneously generate virtual keyframes within the completed portion of the map, as descriptors to estimate camera orientation. We implemented our camera orientation relocalizer with the help of a GPU fragment shader for real-time application, and evaluated the speed and accuracy of the proposed approach.
Keywords: camera pose relocalization, environment map, virtual key frame, vision-based tracking
SparseSPOT: using a priori 3-D tracking for real-time multi-person voxel reconstruction BIBAFull-Text 135-138
  Anuraag Sridhar; Arcot Sowmya
Voxel reconstruction has received increasing interest in recent times, driven by the need for efficient reconstructions of real world scenes from video images. The voxel model has proven useful for activity recognition and motion capture technologies. However most current voxel reconstruction algorithms operate on a fairly small 3-D real world volume and only allow for a single person to be reconstructed. In this paper we present SparseSPOT, an extension of the SPOT voxel reconstruction algorithm, that enables real-time reconstruction of multiple humans within a large environment. We compare SparseSPOT to SPOT and show (by extensive experimental evaluation) that the former achieves superior real time performance.
Standalone edge-based markerless tracking of fully 3-dimensional objects for handheld augmented reality BIBAKFull-Text 139-142
  João P. Lima; Veronica Teichrieb; Judith Kelner; Robert W. Lindeman
This paper presents a markerless tracking technique targeted to the Windows Mobile Pocket PC platform. The primary aim of this work is to allow the development of standalone augmented reality applications for handheld devices based on natural feature tracking of fully 3-Dimensional objects. In order to achieve this goal, a model-based tracking approach that relies on edge information was adopted. Since it does not require high processing power, it is suitable for constrained devices such as handhelds. The OpenGL ES graphics library was used to detect the visible edges in a given frame, taking advantage of graphics hardware acceleration when available. In addition, a subset of two computer vision libraries was ported to the Pocket PC platform in order to provide some required algorithms to the markerless mobile solution. They were also adapted to use fixed-point math, with the purpose of improving the overall performance of the routines. The port of these libraries opens up the possibility of having other computer-vision tasks being executed on mobile platforms. An augmented reality application was created using the implemented technique and evaluations were done regarding tracking performance, accuracy and robustness. In most of the tests, the frame rates obtained are suitable for handheld augmented reality and a reasonable estimation of the object pose was provided.
Keywords: augmented reality, computer vision, handheld, markerless tracking, mobile
Freeze-Set-Go interaction method for handheld mobile augmented reality environments BIBAKFull-Text 143-146
  Gun A. Lee; Ungyeon Yang; Yongwan Kim; Dongsik Jo; Ki-Hong Kim; Jae Ha Kim; Jin Sung Choi
Mobile computing devices are getting popular as a platform for augmented reality (AR) application, and efficient interaction methods for mobile AR environments are considered necessary. Recently, touch interfaces are getting popular and drawing attention as a future standard interface on mobile computing devices. However, accurate touch interactions are not that easy in mobile AR environments where users tend to move and viewpoints easily get shaky. In this paper, the authors suggest a new interaction method for handheld mobile AR environments, named 'Freeze-Set-Go'. The proposed interaction method lets users to 'freeze' the real world view tentatively, and continue to manipulate virtual entities within the AR scene. According to the user experiment, the proposed method turns out to be helping users to interact with mobile AR environments using touch interfaces in a more accurate and comfortable way.
Keywords: augmented reality, handheld interface, touch interaction
Robustness enhancement of a localization system using interior decoration with coded pattern BIBAKFull-Text 147-150
  Shinya Nishizaka; Atsushi Hiyama; Tomohiro Tanikawa; Michitaka Hirose
Several indoor positioning systems have been studied to offer a public service based on one's location information. We have studied an indoor localization system using original fiducial markers. The original markers can be designed freely by users; therefore, they can be used for interior decoration. Using this system, you can obtain the three-dimensional position and pose of your camera by capturing the image of the markers arranged on the floor. However, there are some problems associated with the use of this system in a public space, such as a decline in the marker recognition rate by a change in the surrounding light condition and an instability in the marker recognition rate depending on the type of marker used and the camera angle. In this study, we enhanced the robustness of an indoor localization system used in a public space and increased the number of recognizable markers.
Keywords: AR, fiducial marker, indoor position tracking, neural network, p-type Fourier descriptor
Evaluating the effects of tracker reliability and field of view on a target following task in augmented reality BIBAKFull-Text 151-154
  Jonathan Ventura; Marcus Jang; Tyler Crain; Tobias Höllerer; Doug Bowman
We examine the effect of varying levels of immersion on the performance of a target following task in augmented reality (AR) X-ray vision. We do this using virtual reality (VR) based simulation. We analyze participant performance while varying the field of view of the AR display, as well as the reliability of the head tracking sensor as our components of immersion. In low reliability conditions, we simulate sensor dropouts by disabling the augmented view of the scene for brief time periods. Our study gives insight into the effect of tracking sensor reliability, as well as the relationship between sensor reliability and field of view on user performance in a target following task in a simulated AR system.
Keywords: augmented reality, immersion, simulation, user study


The magic barrier tape: a novel metaphor for infinite navigation in virtual worlds with a restricted walking workspace BIBAKFull-Text 155-162
  Gabriel Cirio; Maud Marchal; Tony Regia-Corte; Anatole Lécuyer
In most virtual reality simulations the virtual world is larger than the real walking workspace. The workspace is often bounded by the tracking area or the display devices. This paper describes a novel interaction metaphor called the Magic Barrier Tape, which allows a user to navigate in a potentially infinite virtual scene while confined to a restricted walking workspace. The technique relies on the barrier tape metaphor and its "do not cross" implicit message by surrounding the walking workspace with a virtual barrier tape in the scene. Therefore, the technique informs the user about the boundaries of his walking workspace, providing an environment safe from collisions and tracking problems. It uses a hybrid position/rate control mechanism to enable real walking inside the workspace and rate control navigation to move beyond the boundaries by "pushing" on the virtual barrier tape. It provides an easy, intuitive and safe way of navigating in a virtual scene, without break of immersion. Two experiments were conducted in order to evaluate the Magic Barrier Tape by comparing it to two state-of-the-art navigation techniques. Results showed that the Magic Barrier Tape was faster and more appreciated than the compared techniques, while being more natural and less tiring. Considering it can be used in many different virtual reality systems, it is an interaction metaphor suitable for many different applications, from the entertainment field to training simulations scenarios.
Keywords: 3D interaction, hybrid position/rate control, interaction metaphor, navigation, walking workspace
Visual feedback techniques for virtual pointing on stereoscopic displays BIBAKFull-Text 163-170
  Ferran Argelaguet; Carlos Andujar
The act of pointing to graphical elements is one of the fundamental tasks in Human-Computer Interaction. In this paper we analyze visual feedback techniques for accurate pointing on stereoscopic displays. Virtual feedback techniques must provide precise information about the pointing tool and its spatial relationship with potential targets. We show both analytically and empirically that current approaches provide poor feedback on stereoscopic displays, resulting in low user performance when accurate pointing is required. We propose a new feedback technique following a camera viewfinder metaphor. The key idea is to locally flatten the scene objects around the pointing direction to facilitate their selection. We present the results of a user study comparing cursor-based and ray-based visual feedback techniques with our approach. Our user studies indicate that our viewfinder metaphor clearly outperforms competing techniques in terms of user performance and binocular fusion.
Keywords: image-plane selection, raycasting, virtual pointer
3D object arrangement for novice users: the effectiveness of combining a first-person and a map view BIBAKFull-Text 171-178
  Luca Chittaro; Roberto Ranon; Lucio Ieronutti
Arranging 3D objects in Virtual Environments can be a complex, error prone and time consuming task, especially for users who are not familiar with interfaces for 3D navigation and object manipulation. In this paper, we analyze and compare novice users' performance on 3D object arrangement tasks using three interfaces that differ in the views of the 3D environment they provide: the first one is based only on a first-person view; the second one combines the first-person view and a map view in which the zoom level is manually controlled by the user; the third one extends the second with automated assistance in controlling the map zoom level during object manipulation. Our study shows that users without prior experience in 3D object arrangement prefer and actually benefit from having a map view in addition to a first person view in object arrangement tasks.
Keywords: 3D manipulation, experimental evaluation, user study, virtual environments
D3: an immersive aided design deformation method BIBAKFull-Text 179-182
  Vincent Meyrueis; Alexis Paljic; Philippe Fuchs
In this paper, we introduce a new deformation method adapted to immersive design. The use of Virtual Reality (VR) in the design process implies a physical displacement of project actors and data between the virtual reality facilities and the design office. The decisions taken in the immersive environment are manually reflected on the Computed Aided Design (CAD) system. This increases the design time and breaks the continuity of data workflow. On this basis, there is a clear demand among the industry for tools adapted to immersive design. But few methods exist that encompass CAD problematic in VR. For this purpose, we propose a new method, called D3, for "Draw, Deform and Design", based on a 2 step manipulation paradigm, consisting with 1) area selection and 2) path drawing, and a final refining and fitting phase. Our method is discussed on the basis of a set of CAD deformation scenarios.
Keywords: computer-aided design (CAD), immersive environment, real-time 3D object deformation, virtual reality
Facilitating system control in ray-based interaction tasks BIBAKFull-Text 183-186
  André Kunert; Alexander Kulik; Christopher Lux; Bernd Fröhlich
This paper investigates the usability of tracked wands equipped with additional input sensors for system control tasks in 3D interaction scenarios. We integrated a thumb-operated circular touchpad into a hand-held wand and compared the performance of our input device to common ray-based interaction in a menu selection and parameter adjustment task. The results show that both interfaces can be highly efficient, but ray-based interaction is only competitive if large-sized graphical interface representations are provided. In contrast, touchpad input performs well independent of the size of the graphical elements due to proprioceptive and tactile feedback.
Keywords: 3D input device, 3D pointing, system control
Crafting memorable VR experiences using experiential fidelity BIBAKFull-Text 187-190
  Robert W. Lindeman; Steffi Beckhaus
Much of Virtual Reality (VR) is about creating virtual worlds that are believable. But though the visual and audio experiences we provide today technically approach the limits of human sensory systems, there is still something lacking; something beyond sensory fidelity hinders us from fully buying into the worlds we experience through VR technology.
   We introduce the notion of Experiential Fidelity, which is an attempt to create a deeper sense of presence by carefully designing the user experience. We suggest to guide the user's frame of mind in a way that their expectations, attitude, and attention are aligned with the actual VR experience, and that the user's own imagination is stimulated to complete the experience. We propose to do this by structuring the time prior to exposure to increase anticipation, expectation, and the like.
Keywords: experience design, presence, user experience, virtual reality

Cyberspace & virtual human

A semantic environment model for crowd simulation in multilayered complex environment BIBAKFull-Text 191-198
  Hao Jiang; Wenbin Xu; Tianlu Mao; Chunpeng Li; Shihong Xia; Zhaoqi Wang
Simulating crowds in complex environment is fascinating and challenging, however, modeling of the environment is always neglected in the past, which is one of the essential problems in crowd simulation especially for multilayered complex environment. This paper presents a semantic model for representing the complex environment, where the semantic information is described with a three-tier framework: a geometric level, a semantic level and an application level. Each level contains different maps for different purposes and our approach greatly facilitates the interactions between individuals and virtual environment. And then a modified continuum crowd method is designed to fit the proposed virtual environment model so that realistic behaviors of large dense crowds could be simulated in multilayered complex environments such as buildings and subway stations. Finally, we implement this method and test it in two complex synthetic urban spaces. The experiment results demonstrate that the semantic environment model can provide sufficient and accurate information for crowd simulation in multilayered complex environment.
Keywords: continuum crowd, crowd simulation, environment representation, semantic environment model
A saliency-based method of simulating visual attention in virtual scenes BIBAKFull-Text 199-206
  Oyewole Oyekoya; William Steptoe; Anthony Steed
Complex interactions occur in virtual reality systems, requiring the modelling of next-generation attention models to obtain believable virtual human animations. This paper presents a saliency model that is neither domain nor task specific, which is used to animate the gaze of virtual characters. A critical question is addressed: What types of saliency attract attention in virtual environments and how can they be weighted to drive an avatar's gaze? Saliency effects were measured as a function of their total frequency. Scores were then generated for each object in the field of view within each frame to determine the most salient object within the virtual environment. This paper compares the resulting saliency gaze model to tracked gaze, in which avatars' eyes are controlled by head-mounted mobile eye-trackers worn by human subjects, random gaze model informed by head-orientation for saccade generation, and static gaze featuring non-moving centered eyes. Results from the evaluation experiment and graphical analysis demonstrate a promising saliency gaze model that is not just believable and realistic but also target-relevant and adaptable to varying tasks. Furthermore, the saliency model does not use any prior knowledge of the content or description of the virtual scene.
Keywords: behavioural realism, character animation, facial animation, gaze modeling, target saliency, visual attention
Indexing and retrieval of human motion data by a hierarchical tree BIBAKFull-Text 207-214
  Shuangyuan Wu; Zhaoqi Wang; Shihong Xia
For the convenient reuse of large-scale 3D motion capture data, browsing and searching methods for the data should be explored. In this paper, an efficient indexing and retrieval approach for human motion data is presented based on a novel similarity metric. We divide the human character model into three partitions to reduce the spatial complexity and measure the temporal similarity of each partition by self-organizing map and Smith-Waterman algorithm. The overall similarity between two motion clips can be achieved by integrating the similarities of the separate body partitions. Then the hierarchical clustering method is implemented, which can not only cluster the motion data accurately, but also discover the relationships between different motion types by a binary tree structure. With our typical cluster locating algorithm and motion motif mining method, fast and accurate retrieval can be performed. The experiment results show the effectiveness of our approach.
Keywords: Smith-Waterman algorithm, hierarchical clustering, indexing, motion capture, retrieval, self-organizing map
A location aware P2P voice communication protocol for networked virtual environments BIBAKFull-Text 215-222
  Gabor Papp; Chris GauthierDickey
Multiparty voice communication, where multiple people can communicate in a group, is an important component of networked virtual environments (NVEs), especially in many types of online games. In this paper, we present a new peer-to-peer protocol that uses Gabriel graphs, a subgraph of Delaunay triangulations, to provide scalable multiparty voice communication. In addition, our protocol uses positional information so that voice data can be accurately modeled to listeners to increase the immersiveness of their experience. Our simulations show that the algorithms scale well even in densely populated areas, while prioritizing the sending of voice packets to the closest listeners of a speaker first, thus behaving as users expect.
Keywords: Delaunay triangulation, Gabriel graph, P2P, location awareness, virtual environment, voice communication
Searching for the metaverse BIBAKFull-Text 223-226
  Joshua Eno; Susan Gauch; Craig Thompson
We present a system for collecting content from 3D multi-user virtual worlds for use in a cross-world search engine, an enabling technology for linking virtual worlds to the wider web. We use an intelligent agent crawler designed to collect user-generated content without relying on access to private internal server databases. The agents navigate autonomously through the world and interact with content to discover regions, parcels of land within regions, user-created objects, other avatars, and user associations. The experiments we performed are the first which focus on the content within a large virtual world. Our results show that virtual worlds can be effectively crawled using autonomous agent crawlers that emulate normal user behavior. Additionally, we find that the collection of interactive content enhances our ability to identify dynamic, immersive environments within the world.
Keywords: 3D web, search engine, virtual worlds

Poster abstracts

3D positioning techniques for multi-touch displays BIBAKFull-Text 227-228
  Anthony Martinet; Géry Casiez; Laurent Grisoni
Multi-touch displays represent a promising technology for the display and manipulation of 3D data. To fully exploit their capabilities, appropriate interaction techniques must be designed. In this paper, we explore the design of free 3D positioning techniques for multi-touch displays to exploit the additional degrees of freedom provided by this technology. We present a first interaction technique to extend the standard four viewports technique found in commercial CAD applications and a second technique designed to allow free 3D positioning with a single view of the scene.
Keywords: 3D positioning task, direct manipulation, multi-touch displays
Compression of massive models by efficiently exploiting repeated patterns BIBAKFull-Text 229-230
  Kangying Cai; Yu Jin; Wencheng Wang; QuQing Chen; Zhibo Chen; Jun Teng
We propose a new compression algorithm for massive models, which consist of a large number of small to medium sized connected components. It is by efficiently exploiting repetitive patterns in the input model. Compared with the similar work by finding repetitive patterns, our new algorithm is more efficient on detecting repeated components by recognizing instances repeating in various scalings. We also propose an efficient compression scheme for transformation data. As a result, it can achieve a considerably higher compression ratio.
Keywords: automatic discovery, compression, repeated pattern
Crime scene robot and sensor simulation BIBAKFull-Text 231-232
  Robert Codd-Downey; Michael Jenkin
Virtual reality has been proposed as a training regime for a large number of tasks from surgery rehearsal (cf. [Robb et al. 1996], to combat simulation (cf. [U. S. Congress, Office of Technology Assessment 1994]) to assisting in basic design (cf. [Fa et al. 1992]). Virtual reality provides a novel and effective training medium for applications in which training "in the real world" is dangerous or expensive. Here we describe the C2SM simulator system -- a virtual reality-based training system that provides an accurate simulation of the CBRNE Crime Scene Modeller System (see [Topol et al. 2008]). The training system provides a simulation of both the underlying robotic platform and the C2SM sensor suite, and allows training of the system to take place without physically deploying the robot or the simulation of chemical and radiological agents that might be present. This paper describes the basic structure of the C2SM simulator and the software components that were used to construct it.
Keywords: bomb disposal simulation, crime scene simulation, virtual reality
Doppler effects without equations BIBAKFull-Text 233-234
  Peter Brinkmann; Michael Gogins
We present a fast and robust method for approximating sound propagation in situations where audio and video frame rates may differ significantly and positions of sound sources and listeners are only known at discrete times, so that numerically stable velocities are not available. Typical applications include 3D scenes in virtual environments where positions of sources and listeners are determined in real time by user interaction. Our method employs a computationally inexpensive heuristic that converges to the exact solution for constant speeds and achieves convincing Doppler shifts in general.
Keywords: Doppler effects, VR audio, sound propagation
Dynamic light amplification for head mounted displays BIBAKFull-Text 235-236
  Andrei Sherstyuk; Anton Treskunov
Two common limitations of modern Head Mounted Displays (HMD): the narrow field of view and limited dynamic range, call for rendering techniques that can circumvent or even take advantage of these factors. We describe a simple practical method of enhancing visual response from HMDs by using view-dependent control over lighting. One example is provided for simulating blinding lights in dark environments.
Keywords: real-time light control, simulated lighting effects
Estimation of thinking states in cyberspace using multiple physiological parameters BIBAKFull-Text 237-238
  Hiromu Miyashita; Ryo Segawa; Ken-ichi Okada
Thinking states are very important factors in the evaluation of and interaction with virtual spaces. Physiological information is often used to estimate thinking states objectively. However, it is difficult to estimate complex feelings numerically from limited physiological information. In this paper, we propose a method for the evaluation of thinking states in cyberspace using multiple physiological parameters. We developed a mapping matrix that converted physiological data into a composite of thinking states. In experiments, we found that with one mapping matrix the thinking states of different subjects for the same task could be derived. In addition, we investigated the similarities and differences between six estimated thinking states by using the mapping matrix.
Keywords: feelings, presence, psychology
Event-related de-synchronization and synchronization (ERD/ERS) of EEG for controlling a brain-computer-interface driving simulator BIBAKFull-Text 239-240
  Junichi Toyama; Jun Ando; Michiteru Kitazaki
The purpose of this study was to investigate ERD/ERS during hand movements and their imagery for developing ERD/ERS-utilized speed control on the brain-computer-interface driving simulator. We found clear ERD in contra-lateral cortex after 9-days learning of motor imagery. We developed a driving simulator equipped with ERD speed control, and showed a driver could control the speed of car.
Keywords: brain computer interface, driving simulator, speed control, vision
Experiments for developing touchable online shopping system BIBAKFull-Text 241-242
  Kenji Funahashi; Masahisa Ichino; Mototoshi Teshigahara
The touchable online shopping system we propose enables users can touch a virtual commodity with their own hands. One purpose of our proposal is to evaluate whether it is easy to measure the size and weight of the commodity intuitively only with small-scale size and low-price elements. Another is to make a general-purpose system only with them for general applications. With such virtual reality, we used a data-glove with vibrators and a simple force feedback device to cover any impressions such as interface interference during use. We evaluated whether users can measure the size and weight of a virtual commodity. Using this system, we found that users could measure them similar to the use of real ones.
Keywords: haptic and force feedback, online shopping, virtual reality
HardBorders: a new haptic approach for selection tasks in 3D menus BIBAKFull-Text 243-244
  Caroline Essert-Villard; Antonio Capobianco
In this paper, we introduce a 3D menu with a new technique of haptic guidance, for virtual environments. The 3D menu consists in a thin polyhedral shape, with the items at the corners. The HardBorders technique haptically simulates the collisions of the pointer with the borders of the polyhedron, making it glide towards the items of the menu. A comparison with 2 reference modalities has been performed, showing a clear advantage of our HardBorders technique.
Keywords: 3D interaction, computer-human interfaces, force feedback devices, haptic interfaces, menus, virtual reality
High resolution insets for stereoscopic immersive displays: a method for 3D content dependent inset boundaries BIBAKFull-Text 245-246
  Alexis Paljic; Caroline de Bossoreille; Philippe Fuchs; Gabriel Soubies
This poster presents a novel approach for integrating, as insets, high resolution stereoscopic areas within a wider low resolution stereoscopic image. The objective is to propose ways to increase local resolution in virtual reality systems, with the use of a small number of additional projectors. Our novel approach consists of inserting high resolution areas whose shape depends on the geometry of 3D objects. For comparison purposes, an existing method is implemented, it consists of setting a rectangular high resolution inset. Both methods are implemented in a large screen VR system with active stereoscopy and head tracking. A user study meant to check for shape perception discrepancies between the two methods was performed. Results show that the novel technique does not introduce any perception distortion in shape size.
Keywords: immersive display, occlusion, seamless high resolution inset, stereoscopy
Importance masks for revealing occluded objects in augmented reality BIBAKFull-Text 247-248
  Erick Mendez; Dieter Schmalstieg
When simulating "X-ray vision" in Augmented Reality, a critical aspect is ensuring correct perception of the occluded objects position. Naïve overlay rendering of occluded objects on top of real-world occluders can lead to a misunderstanding of the visual scene and a poor perception of the depth. We present a simple technique to enhance the perception of the spatial arrangements in the scene. An importance mask associated with occluders informs the rendering what information can be overlaid and what should be preserved. This technique is independent of scene properties such as illumination and surface properties, which may be unknown. The proposed solution is computed efficiently in a single-pass fragment shaders on the GPU.
Keywords: augmented reality, focus and context, importance masks, x-ray vision
Influence of event-based haptic on the manipulation of rigid objects in degraded virtual environments BIBAKFull-Text 249-250
  Mathieu Gautier; Jean Sreng; Claude Andriot
In this paper, we propose to evaluate the benefits of event-based haptic rendering in virtual environments subject to high damping or low contact stiffness. In such context, the degraded perception of contact impairs the manipulation performance and the overall user's experience. Haptic rendering techniques known as event-based (or open-loop) rendering have been proposed to improve the realism of contacts in such contexts.
   We conducted a preliminary experiment to investigate the effect in terms of performance of haptic event-based technique on virtual environments using different parameters of damping and stiffness. The first results suggest that event-based haptic can improve the perception of contact for such environments (particularly with high damping and/or low stiffness).
Keywords: contact, event-based haptic, haptic feedback, open loop haptic
Interactive high dynamic range rendering for virtual reality applications BIBAKFull-Text 251-252
  Josselin Petit; Roland Brémond
Realistic images can be computed at interactive frame rates for Virtual Reality applications. Meanwhile, High Dynamic Range (HDR) rendering has a growing success in video games and virtual reality, as it improves the image quality and the player's immersion feeling. We propose a new method, based on a simplified physical model of light propagation, to compute in real time a HDR illumination in a Virtual Environment (VE). Our method allows to re-use existing Low Dynamic Range (LDR) Virtual Databases as input in order to compute the HDR images. Then, from these HDR images, displayable 8-bit images are rendered with a Tone Mapping Operator (TMO) and displayed on a standard display device. The HDR computation and the TMO are implemented in OpenSceneGraph (OSG), working in real time with pixel shaders. The method is illustrated with a practical application where the Dynamic Range is a key rendering issue: driving at night. The VE includes light sources such as road lighting and car headlights.
Keywords: high dynamic range, pixel shader, virtual reality
Physically based grasping and manipulation method using pre-contact grasping quality measure BIBAKFull-Text 253-254
  Yongwan Kim; Jinseong Choi; Jinah Park
While the human hand is the most natural tool for interacting with objects, hand interaction with virtual objects is still a challenging research field. We recognize that common hand interaction involves two separate stages with different aspects: One is the robustness of grasping, and the other is the dexterity of manipulation after grasping a virtual object. In this paper, we address virtual hand interaction by decoupling these two aspects and propose strategic simulation algorithms for two different stages. As for the initial grasping, a quality measure-based grasping algorithm is applied for robustness, and the manipulation is simulated by physically based methods to meet the requirements of dexterity. We conducted experiments to evaluate the effectiveness of our proposed method under different display environments -- monoscopic and stereoscopic. From the 2-way ANOVA test, we were able to show that the proposed scheme that separates a pre-contact grasping phase and a post-contact manipulation phase gives us the robustness of grasping quality and dexterity of tool operation. Furthermore, we demonstrate various assembly manipulations of the relatively complex models using our interaction scheme.
Keywords: grasping, hand interaction, manipulation
Realization of a vibro-tactile glove type mouse BIBAKFull-Text 255-256
  Jun-Hyung Park; Hyun Suk Lee; Ju Seok Jeong; Tae-Jeong Jang
In this paper, we suggested a glove type mouse using a gyroscope sensor, an acceleration sensor, and six pin-type vibro-tactile modules. It was designed as a USB HID (human interface device) so that it can be automatically recognized and installed as a general mouse when it is plugged in PC USB socket. This mouse recognizes a user's wrist movement by the gyroscope sensor and the acceleration sensor in the glove and transmits coordinate value to the PC through wireless Bluetooth. This vibro-tactile glove type mouse accommodates all circuits and devices in the glove, implementing a wearable system. A user can use general spatial mouse without any driver or application program. However, since tactile devices are not included in the USB HID, we made an application program for vibro-tactile display so that a PC program can transmit specific vibro-tactile information to the user to represent gray scale of pictures, braille codes, directions to go, and so on.
Keywords: HID (human interface device), glove type mouse, haptics, vibro-tactile display
Reconstructing chat history for avatar agents using spatio-temporal features of virtual space BIBAKFull-Text 257-258
  Seung-Hyun Ji; Tae-Jin Yoon; Hwan-Gue Cho
One of the crucial issues in Internet chat is how to manage the corresponding pairs of questions and answers in a sequence of conversations. This paper addresses the problems of ambiguous dialogue logs, lack of a social interaction network of chat agents, and the rupture of the turn sequence in the plain chat room. Therefore we can resolve the ambiguity in rupturing connections between turns and replies. Also, our system supports a graphical visualization interface for tracking the chat dialogue using Chat Flow Graph (CFG) [Park et al. 2008a]. In this paper, we improve our previous work and construct a social network between avatar agents. Our experiment shows that our system is highly effective in a virtual chat environment.
Keywords: chat program, communication, virtual reality
A study of multimodal feedback to support collaborative manipulation tasks in virtual worlds BIBAKFull-Text 259-260
  Arturo S. García; José P. Molina; Pascual González; Diego Martínez; Jonatan Martínez
In the research community, developers of Collaborative Virtual Environments (CVEs) usually refer to the terms awareness and feedback as something necessary to maintain a fluent collaboration when highly interactive tasks have to be performed. However, it is remarkable that few studies address the effect that including special kinds of feedback has on user awareness and task performance. This work follows a preliminary experiment where we already studied awareness in CVEs, evaluating the effect of visual cues in the performance of collaborative tasks and showing that users tend to make more mistakes when such feedback is not provided, that is, they are less aware. These early results were promising and encouraged us to continue investigating the benefit of improving awareness in tasks that require close collaboration between users, but this time analyzing more types of awareness and experimenting with visual, audio and vibrotactile feedback cues.
Keywords: CSCW, awareness, collaborative virtual environments, feedback
Thermal display for scientific haptization of numerical simulations BIBAKFull-Text 261-262
  Yuichi Tamura; Hiroaki Nakamura
Thermal display is a useful device for representing the haptic sense; however most such devices are used in a sitting position. We have used an immersive projection technology (IPT) display for scientific visualization, which is very useful for comprehending complex phenomena. However, in the IPT, the observer generally watches and controls 3D objects in standing position. Therefore it is necessary to develop a thermal display that can be used in a standing position. In addition, in scientific visualization, the response time is very important for observing physical phenomena, especially in dynamic numerical simulation results. One solution is to provide two types of thermal information: information about the rate of thermal change, and information about the real temperature. Using the two types of information, the observer can recognize the change and the real thermal value immediately.
Keywords: immersive projection display, numerical simulation, thermal display, virtual reality
Toolkit-independent interaction specification for VR-based visualization BIBAKFull-Text 263-264
  Irene Tedjo-Palczynski; Bernd Hentschel; Marc Wolter; Thomas Beer; Torsten Kuhlen
The application of virtual environments to scientific visualization provides the user with an intuitive interface to interact with the data to be analyzed. We present an approach that leverages the utilization of 3D interaction techniques to directly interact with scientific data. First, we propose an abstraction of VR-based interaction by decoupling the low-level interaction groundwork from high-level declarations of interaction behaviors. Second, we describe how recurring interaction patterns in scientific visualizations can be distilled into 3D widgets, exhibiting reusability for diverse participants in the development of interactive visualization. The benefits which follow from this approach are exchangeability of VR-toolkits and devices, faster development cycles and better code maintainability.
Keywords: 3D interaction, scientific visualization, virtual reality
User-centered design of a maxillo-facial surgery training platform BIBAKFull-Text 265-266
  Christine Mégard; Florian Gosselin; Sylvain Bouchigny; Fabien Ferlay; Farid Taha
The paper describes the requirements specification process involved in the design of a Virtual Reality trainer for Epker maxillo-facial surgery. This surgery is considered as very delicate and difficult to teach. Vision guided movements are very limited and haptic sense is largely used. The user-centered methodology and the first experiments designed to develop the training platform are presented. Finally the Virtual training platform is sketched out.
Keywords: multimodal, skills, surgery, task analysis, training
A virtual performance system and its application on a Noh stage BIBAKFull-Text 267-268
  Masahito Shiba; Asako Soga; Jonah Salz
We have developed a virtual performance system that projects visual images and controls them in a theater easily. This system manages videos and 3D models, and users can control the projected image in real-time. We used the system on a Noh stage. We displayed virtual actors and had them act with the real actors. As a result of evaluations by the audience, we verified that using virtual actors acting with real actors can provide effective stage presentations.
Keywords: Noh, live performance, virtual actor
Visualization of virtual weld beads BIBAKFull-Text 269-270
  Dongsik Jo; Yongwan Kim; Ungyeon Yang; Gun A. Lee; Jin Sung Choi
In this paper, we present a visualization method of weld beads for a welding training under virtual environments. To represent virtual beads, a bead shape is defined according to the datasets which consist of bead width, height, angle, penetration acquired from real welding operations. A curve equation of bead's sectional shape is mathematical modeled, and a height map is generated according to this numerical equation, which is used for generating the bead's mesh data using its height information. Finally, virtual weld beads are visualized in real-time according to the accurately simulated results from user's input motion.
Keywords: bead, training, virtual reality, visualization, welding
Weathering fur simulation BIBAKFull-Text 271-272
  Shaohui Jiao; Gang Yang; Enhua Wu
The paper presents a novel approach for simulating the weathering fur. Dusty effects on fur is generated by volumetric γ-ton tracing method and the geometry deformation is modeled through a dynamic PBS. The proposed approach can efficiently simulate the weathering effects of fur.
Keywords: γ-ton, PBS, fur texel, weathering simulation