| Scientific challenges ingame technology | | BIBA | Full-Text | 1 | |
| Mark Overmars | |||
| Computer games play an increasingly important role, both in entertainment
and in serious applications, like education, training, communication, decision
support, and marketing. Games use the most modern technology (both in hardware
and in software) and future games will greatly benefit from new developments in
such technology.
After an introduction into games and their future use, we will discuss the scientific challenges future games pose to researchers. Typical areas that will be treated are new modeling techniques, the design and behavior of virtual characters and avatars, simulating virtual worlds, and new interaction and interface techniques. | |||
| Real images for virtual reality | | BIBA | Full-Text | 2 | |
| Luc Robert | |||
| In most Virtual Reality applications, people try to achieve a high degree of
realism. Numerous techniques and approaches have been developed to achieve this
by using pictures and videos of the real world.
At REALVIZ, we have developed software products allowing digital content creators to acquire shape and motion from real images, using computer vision techniques. In this presentation I will give a snapshot of the current status of these technologies, and how they are used in various industries for VR- or AR-related applications. | |||
| Perceptual sensitivity to visual/kinesthetic discrepancy in hand speed, and why we might care | | BIBAK | Full-Text | 3-8 | |
| Eric Burns; Frederick P. Brooks | |||
| We investigated the ability of a user in a head-mounted display virtual
environment to detect a virtual hand avatar moving at a speed different than
that of the real hand. We measured discrepancy detection thresholds for each of
the six cardinal directions of 3-space (left, right, up, down, toward, and
away). For each of these six directions we measured two discrepancy detection
thresholds: one for when the avatar hand moved more quickly than the real hand
and one for when it moved more slowly. We found a trend that users are less
sensitive to increases in hand avatar speed than they are to decreases. The
amount the hand avatar speed can be increased without a user noticing is
surprisingly large. This information is useful for techniques that require
introducing hand-avatar motion discrepancy, such as a technique for recovering
from the position discrepancy introduced by simulated surface constraints. Keywords: intersensory discrepancy, perception, sensory conflict | |||
| Evaluating the effectiveness of occlusion reduction techniques for 3D virtual environments | | BIBAK | Full-Text | 9-18 | |
| Niklas Elmqvist; M. Eduard Tudoreanu | |||
| We present an empirical usability experiment studying the relative strengths
and weaknesses of three different occlusion reduction techniques for
discovering and accessing objects in information-rich 3D virtual environments.
More specifically, the study compares standard 3D navigation, generalized
fisheye techniques using object scaling and transparency, and the BalloonProbe
interactive 3D space distortion technique. Subjects are asked to complete a
number of different tasks, including counting, pattern recognition, and object
relation, in different kinds of environments with various properties. The
environments include a free-space abstract 3D environment and a virtual 3D
walkthrough application for a simple building floor. The study involved 16
subjects and was conducted in a three-sided CAVE environment. Our results
confirm the general guideline that each task calls for a specialized
interaction -- no single technique performed best across all tasks and worlds.
The results also indicate a clear trade-off between speed and accuracy; simple
navigation was the fastest but also most error-prone technique, whereas
spherical BalloonProbe proved the most accurate but required longer completion
time, making it suitable for applications where mistakes incur a high cost. Keywords: 3D space distortion, evaluation, interaction techniques, occlusion
management, occlusion reduction | |||
| Evaluating the effects of real world distraction on user performance in virtual environments | | BIBAK | Full-Text | 19-26 | |
| Yi Wang; Kunmi Otitoju; Tong Liu; Sijung Kim; Doug A. Bowman | |||
| Although many virtual environment (VE) technologies such as the four-screen
CAVE are described as immersive, users can still perceive distractions from the
real world. This exposure to real-world distraction may reduce users' sense of
presence, and if presence is correlated with performance as some have claimed,
the real-world distractions may also hinder performance. Thus, VE designers may
want to consider ways to reduce real-world distraction. This paper presents an
experiment to investigate the effect of reduced visual stimulus in the
peripheral area on user performance and the usability of an immersive VE. We
carefully designed three tasks that cause different levels of awareness of the
real-world distraction. Using these tasks, we evaluated users' performance and
preference in two conditions. The low-stimulus condition was created by hanging
a black cloth across the missing back wall of a CAVE. The high-stimulus
condition was created by projected animations and real human motion outside the
CAVE. The experiments show that reduced distraction may have a positive or
negative effect on user performance, depending on the specific tasks and
environments. Keywords: distraction, immersive virtual environments, low-stimulus area, user
performance | |||
| The benefits of third-person perspective in virtual and augmented reality? | | BIBAK | Full-Text | 27-30 | |
| Patrick Salamin; Daniel Thalmann; Frédéric Vexo | |||
| Instead of the reality in which you can see your own limbs, in virtual
reality simulations it is sometimes disturbing not to be able to see your own
body. It seems to create an issue in the proprio-perception of the user who
does not completely feel integrated in the environment. This perspective should
be beneficial for the users. We propose to give the possibility to the people
to use the first and the third-person perspective like in video games (e.g.
GTA). As the gamers prefer to use the third-person perspective for moving
actions and the first-person view for the thin operations, we will verify this
comportment is extendable to simulations in augmented and virtual reality. Keywords: distance evaluation, exocentric perspective, immersion, presence,
proprio-perception | |||
| Mixed reality: are two hands better than one? | | BIBAK | Full-Text | 31-34 | |
| Aaron Kotranza; John Quarles; Benjamin Lok | |||
| For simulating hands-on tasks, the ease of enabling two-handed interaction
with virtual objects gives Mixed Reality (MR) an expected advantage over
Virtual Reality (VR). A user study examined whether two-handed interaction is
critical for simulating hands-on tasks in MR. The study explored the effect of
one- and two-handed interaction on task performance in a MR assembly task. When
presented with a MR system, most users chose to interact with two hands. This
choice was not affected by a user's past VR experience or the quantity and
complexity of the real objects with which users interacted. Although two-handed
interaction did not yield a significant performance improvement, two hands
allowed subjects to perform the virtual assembly task similarly to the
real-world task. Subjects using only one hand performed the task fundamentally
differently, showing that affording two-handed interaction is critical for
training systems. Keywords: mixed reality, two-handed interaction, virtual reality | |||
| Development of a tracking method for augmented reality applied to NPP maintenance work and its experimental evaluation | | BIBAK | Full-Text | 35-44 | |
| Zhiqiang Bian; Hirotake Ishii; Masanori Izumi; Hiroshi Shimoda; Hidekazu Yoshikawa; Yoshitsugu Morishita; Yoshiki Kanehira | |||
| Nuclear power plants (NPP) must be maintained periodically. The maintenance
efficiency must be improved and human error must be reduced simultaneously to
improve NPPs' competitive capability in electricity markets. Although Augmented
Reality (AR) offers great possibilities to support NPP maintenance work, some
difficulties exist for application of AR to actual work support because current
AR systems cannot be implemented in NPP environments without technical
improvement. Problems exist such as recognition distance, tracking accuracy,
and a complex working environment when applying AR to NPP field work support.
Considerable extension of tracking distance and improvement of accuracy are
particularly desired because NPPs are large-scale indoor environments. This
study designed a linecode marker, a new type of paper-based marker, along with
recognition and tracking algorithms for it to resolve these problems. In
contrast to conventional paper-based markers, such as square markers and circle
markers, the linecode marker is not merely easier to set up in complex
industrial environments: it also enables the use of AR in industrial plants
because of its considerable tracking-performance improvement. To evaluate
tracking accuracy, the trackable distance, and the tracking speed of the
proposed tracking method, an evaluation experiment was conducted in a large
room. The experiment results show that the tracking distance is extended
extremely over that of the traditional marker-based tracking method: tracking
accuracy improved to 20 cm in 10 m distance. The running speed can be as fast
as 15 frames per second with a laptop. Keywords: augmented reality, linecode marker, maintenance, nuclear power plant,
tracking method | |||
| Sceptre: an infrared laser tracking system for virtual environments | | BIBAK | Full-Text | 45-50 | |
| Christian Wienss; Igor Nikitin; Gernot Goebbels; Klaus Troche; Martin Göbel; Lialia Nikitina; Stefan Müller | |||
| In this paper a 3D tracking system for Virtual Environments is presented
which utilizes infrared (IR) laser technology. Invisible laser patterns are
projected from the user(s) to the screen via the input device Sceptre or the
appending headtracking device. IR-sensible cameras which are placed near the
projectors in a backprojection setup recognize the pattern. That way position
and orientation of the input devices is reconstructed. The infrared laser is
not seen by human eye and therefore does not disturb the immersion. Keywords: 3D-reconstruction, IR-laser, laser pattern, tracking | |||
| Spatial input device structure and bimanual object manipulation in virtual environments | | BIBAK | Full-Text | 51-60 | |
| Arjen van Rhijn; Jurriaan D. Mulder | |||
| Complex 3D interaction tasks require the manipulation of a large number of
input parameters. Spatial input devices can be constructed such that their
structure reflects the task at hand. As such, somatosensory cues that a user
receives during device manipulation, as well as a users expectations, are
consistent with visual cues from the virtual environment. Intuitively, such a
match between the device's spatial structure and the task at hand would seem to
allow for more natural and direct interaction. However, the exact effects on
aspects like task performance, intuitiveness, and user comfort, are yet
unknown.
The goal of this work is to study the effects of input device structure for complex interaction tasks on user performance. Two factors are investigated: the relation between the frame of reference of a user's actions and the frame of reference of the virtual object being manipulated, and the relation between the type of motion a user performs with the input device and the type of motion of the virtual object. These factors are addressed by performing a user study using different input device structures. Subjects are asked to perform a task that entails translating a virtual object over an axis, where the structure of the input device reflects this task to different degrees. First, the action subjects need to perform to translate the object is either a translation or a rotation. Second, the action is performed in the same frame of reference of the virtual object, or in a fixed, separately located, frame of reference. Results show that task completion times are lowest when the input device allows a user to make the same type of motion in the same coordinate system as the virtual object. In case either factor does not match, task completion times increase significantly. Therefore, it may be advantageous to structure an input device such that the relation between its frame of reference and the type of action matches the corresponding frame of reference and motion type of the virtual object being manipulated. Keywords: configurable input device, direct manipulation, multi-dimensional control,
virtual reality | |||
| Interactive modelling and tracking for mixed and augmented reality | | BIBAK | Full-Text | 61-64 | |
| R. Freeman; A. Steed | |||
| Some tasks vital to many mixed and augmented reality systems are either too
time consuming or complex to be carried out whilst the system is active. 3D
scene modelling and labelling are two such tasks commonly performed by skilled
operators in an off-line initialisation phase. Because this phase sometimes
needs specialist software and/or expertise it can be a considerable limiting
factor for new mixed reality system developers. If a mixed reality system is to
operate in real-time, where artificial graphics are woven into real world live
images, the way in which these off-line processes are tackled is critical. In
this paper we propose a flexible new approach that reduces the time spent
during the off-line initialisation phase by adopting an on-line interactive
primitive modelling technique. Our solution combines two existing and freely
available packages, the Augmented Reality Toolkit Plus (ARToolKitPlus) and the
Mixed Reality Toolkit (MRT), to enable rapid interactive modelling over live
video using a freely moving camera. As a demonstration we show how these can be
used to rapidly seed an object appearance-based tracking algorithm. Keywords: augmented reality, image based modelling, mixed reality, model based
tracking | |||
| Traversal fields for ray tracing dynamic scenes | | BIBAK | Full-Text | 65-74 | |
| Peijie Huang; Wencheng Wang; Gang Yang; Enhua Wu | |||
| This paper presents a novel scheme for accelerating ray traversal
computation in ray tracing. By the scheme, a pre-computed stage is applied to
constructing what is called a traversal field for each rigid object that
records the destinations for all possible incoming rays. The field data, which
could be efficiently compressed offline, is stored in a small number of big
rectangles called ray-relays that enclose each approximate convex segment of an
object. In the ray-tracing stage, the records on relays are retrieved in a
constant time, so that a ray traversal is implemented as a simple texture
lookup on GPU. Thus, the performance of our approach is only related to the
number of relays rather than scene size, while the number of relays is quite
small. In addition, because the traversal fields only depend on the internal
construction of each convex segment, they can be used to ray trace objects
undergoing rigid motions at a negligible extra cost. Experimental results show
that interactive rates could be achieved for dynamic scenes with the effects of
specular reflections and refractions on an ordinary desk PC with GPU. Keywords: dynamic scene, graphics processing units (GPU), pre-computation, ray tracing | |||
| Pyramidal displacement mapping: a GPU based artifacts-free ray tracing through an image pyramid | | BIBAK | Full-Text | 75-82 | |
| Kyoungsu Oh; Hyunwoo Ki; Cheol-Hi Lee | |||
| Displacement mapping enables us to details to polygonal meshes. We present a
real-time artifacts-free inverse displacement mapping method using per-pixel
ray tracing through an image pyramid on the GPU. In each pixel, we make a ray
and trace the ray through a displacement map to find an intersection. To skip
empty-regions safely, we use the quad-tree image pyramid of a displacement map
in top-down order. For magnification we estimate an intersection between a ray
and a bi-linearly interpolated displacement. For minification we perform a
mipmap-like prefiltering to improve quality of result images and rendering
performance. Results show that our method produces correct images even at steep
grazing angles. Rendering speed of test scenes were over hundreds of frames per
second and less influence to the resolution of the map. Our method is simple
enough to add to existing virtual reality systems easily. Keywords: GPU, displacement mapping, image-based rendering, quad-tree, real-time
rendering | |||
| Novel view generation for a real-time captured video object | | BIBAK | Full-Text | 83-86 | |
| Hua Chen; Peter F. Elzer | |||
| This paper describes a novel method of real-time novel view synthesis for an
object that is observed by two fixed video cameras in a natural environment.
Without reconstructing the 3D model of the object, the view of the object
corresponding to a virtual camera that moves between the two real cameras is
generated by applying a view morphing process to the object region in the image
pair captured in real-time. Using the captured live video frames, the proposed
method can not only generate realistic novel views in real-time, but also
ensure a natural and smooth image transition between the two cameras. It can be
used in a variety of Mixed Reality (MR) applications to integrate live video
objects into virtual environments. Experimental results verify the validity of
the proposed approach. Keywords: mixed reality, view synthesis | |||
| Hardware-accelerated jaggy-free visual hulls with silhouette maps | | BIBAK | Full-Text | 87-90 | |
| Chulhan Lee; Junho Cho; Kyoungsu Oh | |||
| Visual hull is intersection of cones made by back-projections of reference
images. We introduce a real-time rendering of jaggy-free visual hull rendering
method on programmable graphics hardware. By using texture mapping approach, we
render a visual hull quickly. At each silhouette pixel, we produce jaggy-free
images using silhouette information. Our implementation demonstrate
high-quality image in real-time. The complexity of our algorithm is O(N), where
N is the number of reference images. Thus the examples in this paper are
rendered over one hundred of frames per second without jaggies. Keywords: GPU, image-based rendering, silhouette map, visual hull | |||
| A fluid resistance map method for real-time haptic interaction with fluids | | BIBAK | Full-Text | 91-99 | |
| Yoshinori Dobashi; Makoto Sato; Shoichi Hasegawa; Tsuyoshi Yamamoto; Mitsuaki Kato; Tomoyuki Nishita | |||
| Haptic interfaces enable us to interact with a virtual world using our sense
of touch. This paper presents a method for realizing haptic interaction with
water. Our method displays forces acting on rigid objects due to water with a
high frame rate (500 Hz). To achieve this, we present a fast method for
simulating the dynamics of water. We decompose the dynamics into two parts. One
is a linear flow expressed by a wave equation used to compute water waves. The
other is a more complex and non-linear flow around the object. The fluid forces
due to the non-linear flow is precomputed by solving Navier-Stokes equations,
and stored in a database, named the Fluid Resistance Map. The precomputed
non-linear flow and the linear flow are combined to compute the forces due to
water. Keywords: computational fluid dynamics, fluid resistance, haptics, simulation, virtual
reality | |||
| Interaction techniques in large display environments using hand-held devices | | BIBAK | Full-Text | 100-103 | |
| Seokhee Jeon; Jane Hwang; Gerard J. Kim; Mark Billinghurst | |||
| Hand-held devices possess a large potential as an interaction device for
their today's ubiquity, and present us with an opportunity to devise new and
unique ways of interaction as a smart device with multi-modal sensing and
display capabilities. This paper introduces user interaction techniques (for
selection, translation, scaling and rotation of objects) using a
camera-equipped hand-held device such as a mobile phone or a PDA for large
shared environments. We propose three intuitive interaction techniques for 2D
and 3D objects in such an environment. The first approach uses the motion flow
information to estimate the relative motion of the hand-held device and
interact with the large display. The marker-object and marker-cursor approaches
both use software markers on the interaction object or on the cursor for the
various interactive tasks. The proposed interaction techniques can be further
combined with many auxiliary functions and wireless services (of the hand-held
devices) for seamless information sharing and exchange among multiple users. A
formal usability analysis is currently on-going. Keywords: hand-held device, interaction techniques, large shared display | |||
| Simple user-generated motion cueing can enhance self-motion perception (Vection) in virtual reality | | BIBAK | Full-Text | 104-107 | |
| Bernhard E. Riecke | |||
| Despite amazing advances in the visual quality of virtual environ-ments,
affordable-yet-effective self-motion simulation still poses a major challenge.
Using a standard psychophysical paradigm, the effectiveness of different
self-motion simulations was quantified in terms of the onset latency,
intensity, and convincingness of the per-ceived illusory self motion (vection).
Participants were asked to actively follow different pre-defined trajectories
through a naturalistic virtual scene presented on a panoramic projection screen
using three different input devices: a computer mouse, a joystick, or a
modified manual wheelchair. For the wheelchair, participants exerted their own
minimal motion cueing using a simple force-feedback and a velocity control
paradigm: small translational or rotational motions of the wheelchair (limited
to 8cm and 10ð, re-spectively) initiated a corresponding visual motion with
the visual velocity being proportional to the wheelchair deflection (similar to
a joystick). All dependent measures showed a clear enhancement of the perceived
self-motion when the wheelchair was used instead of the mouse or joystick.
Compared to more traditional approaches of enhancing self-motion perception
(e.g., motion platforms, free walking areas, or treadmills) the current
approach of using a simple user-generated motion cueing has only minimal
requirements in terms of overall costs, required space, safety features, and
technical effort and expertise. Thus, the current approach might be promising
for a wide range of low-cost applications. Keywords: human factors, motion cueing, psychophysics, self-motion perception,
self-motion simulation, vection, virtual reality, wheelchair | |||
| Separating the effects of level of immersion and 3D interaction techniques | | BIBAK | Full-Text | 108-111 | |
| Ryan P. McMahan; Doug Gorton; Joe Gresock; Will McConnell; Doug A. Bowman | |||
| Empirical evidence of the benefits of immersion is an important goal for the
virtual environment (VE) community. Direct comparison of immersive systems and
non-immersive systems is insufficient because differences between such systems
may be due not only to the level of immersion, but also to other factors, such
as the input devices and interaction techniques used. In this paper, a study is
presented that separates the effects of level of immersion and 3D interaction
technique for a six-degree-of-freedom manipulation task. In the study, two
components of immersion -- stereoscopy and field of regard -- were varied and
three 3D interaction techniques -- HOMER, Go-Go, and DO-IT (a new keyboard- and
mouse-based technique) -- were tested. The results of the experiment show that
the interaction technique had a significant effect on object manipulation time,
while the two components of immersion did not. The implications of these
results are discussed for VE application developers. Keywords: 3D interaction, field of regard, immersive virtual environment | |||
| Limpid desk: see-through access to disorderly desktop in projection-based mixed reality | | BIBAK | Full-Text | 112-115 | |
| Daisuke Iwai; Kosuke Sato | |||
| We propose Limpid Desk which supports document search on a real desktop with
virtual transparentizing of the upper layer of a document stack in
projection-based mixed reality (MR)environments. In the system, users can
visually access a lower layer document without physically removing the upper
documents. This is accomplished by projecting a special pattern of light that
is calculated to compensate the appearances of the upper layer documents as if
they are transparent. In addition, we propose two types of visual effects for
users to cognize the progress of the transparentizing of real documents and to
recognize the layer number of the virtually exposing document, and execute
psychological tests to confirm the intuitiveness of these effects. This paper
also presents an intuitive document search interaction in the proposed system. Keywords: color reflectance compensation, projection-based mixed reality, smart desk,
transparentizing documents | |||
| Usability evaluation of the EPOCH multimodal user interface: designing 3D tangible interactions | | BIBAK | Full-Text | 116-122 | |
| Panagiotis Petridis; Katerina Mania; Daniel Pletinckx; Martin White | |||
| This paper expands on the presentation of a methodology that provides a
technology-enhanced exhibition of a cultural artefact through the use of a safe
hybrid 2D/3D multimodal interface. Such tangible interactions are based on the
integration of a 3DOF orientation tracker and information sensors with a
'Kromstaf' rapid prototype replica to provide tactile feedback. The multimodal
interface allows the user to manipulate the object via physical gestures which,
during evaluation, establish a profound level of virtual object presence and
user satisfaction. If a user cannot manipulate the virtual object effectively
many application specific tasks cannot be performed. This paper assesses the
usability of the multimodal interface by comparing it with two input devices --
the Magellan SpaceMouse, and a 'black box', which contains the same electronics
as the multimodal interface but without the tactile feedback offered by the
'Kromstaf' replica. A complete human-centred usability evaluation was conducted
utilizing task based measures in the form of memory recall investigations after
exposure to the interface in conjunction with perceived presence and user
satisfaction assessments. Fifty-four participants across three conditions
(Kromstaf, space mouse and black box) took part in the evaluation. Keywords: evaluation, multimodal user interfaces, perception, presence, virtual
environments | |||
| Entertainment virtual reality system for simulation of spaceflights over the surface of the planet Mars | | BIBAK | Full-Text | 123-132 | |
| Ricardo Olanda; Manolo Pérez; Pedr Morillo; Marcos Fernández; Sergio Casas | |||
| In recent years Virtual Reality technologies have enabled astronomers to
recreate and explore three dimensional structures of the Universe for
scientific purposes. Mars, due to its scientific interest,has been the focal
point of numerous research projects using these technologies, however, none of
these virtual reality tools have been developed specifically for entertainment
purposes.
The focus of this paper is to present MarsVR, as an entertainment research project that educates people on the topography and orography of the planet Mars from the perspective of popular science. Some projects have been designed MarsVR for entertainment purposes and include the latest advances in 3D real time applications. However, these applications have underestimated the relevant data necessary for simulating the planet Mars as an interactive virtual environment. Keywords: entertainment virtual reality, immersive visualization systems, terrain
representation | |||
| A versatile large-scale multimodal VR system for cultural heritage visualization | | BIBAK | Full-Text | 133-140 | |
| Chris Christou; Cameron Angus; Celine Loscos; Andrea Dettori; Maria Roussou | |||
| We describe the development and evaluation of a large-scale multimodal
virtual reality simulation suitable for the visualization of cultural heritage
sites and architectural planning. The system is demonstrated with a
reconstruction of an ancient Greek temple in Messene that was created as part
of a EU funded cultural heritage project (CREATE). The system utilizes a
CAVE-like theatre consisting of head-tracked user localization, a haptic
interface with two arms, and 3D sound. The haptic interface was coupled with a
realistic physics engine allowing users to experience and fully appreciate the
effort involved in the construction of architectural components and their
changes through the ages. Initial user-based studies were carried out, to
evaluate the usability and performance of the system. A simple task of stacking
blocks was used to compare errors and timing in a haptics-enabled system with a
haptics-disabled system. In addition, a qualitative study of the final system
took place while it was installed in a museum. Keywords: haptics, multimodal Interfaces, virtual heritage | |||
| System and infrastructure considerations for the successful introduction of augmented reality guides in cultural heritage sites | | BIBAK | Full-Text | 141-144 | |
| Athanasios M. Demiris; Vassilios Vlahakis; Nicolaos Ioannidis | |||
| Recent advances in augmented reality and portable systems bring us closer to
the introduction of such advanced technologies in everyday routine of cultural
heritage sites, providing an extremely helpful means of disseminating and
communicating information to the visitors of such sites. Portable multimedia
guides are already a reality, while fixed-position AR has also found its way to
various sites. So far the focus has always been on the terminal device
capabilities and functions, while the infrastructure necessary to support the
daily routine was somehow neglected. In this paper we will present a complete
systemic approach introducing a set of components we deem necessary for the
successful introduction of AR in such sites. Keywords: augmented reality in cultural heritage, content management, system
architecture | |||
| From motion capture to action capture: a review of imitation learning techniques and their application to VR-based character animation | | BIBAK | Full-Text | 145-154 | |
| Bernhard Jung; Heni Ben Amor; Guido Heumer; Matthias Weber | |||
| We present a novel method for virtual character animation that we call
action capture. In this approach, virtual characters learn to imitate the
actions of Virtual Reality (VR) users by tracking not only the users' movements
but also their interactions with scene objects.
Action capture builds on conventional motion capture but differs from it in that higher-level action representations are transferred rather than low-level motion data. As an advantage, the learned actions can often be naturally applied to varying situations, thus avoiding retargetting problems of motion capture. The idea of action capture is inspired by human imitation learning; related methods have been investigated for a longer time in robotics. The paper reviews the relevant literature in these areas before framing the concept of action capture in the context of VR-based character animation. We also present an example in which the actions of a VR user are transferred to a virtual worked. Keywords: action capture, character animation, imitation learning, motion capture,
virtual reality | |||
| Real-time generation of populated virtual cities | | BIBAK | Full-Text | 155-164 | |
| Luiz Gonzaga da Silveira; Soraia Raupp Musse | |||
| This paper presents a new approach for real-time generation of 3D virtual
cities. The main goal is to provide of a generic framework which support
semi-automatic creation, manage-ment, and visualization of urban complex
environments for virtual human simulation, called virtual urban life (VUL). It
intends to minimize efforts of designers in the modeling of complex and huge
environments. A versatile multi-level data model has been developed to support
data management and visualization in an efficient way. Moreover, a polygon
partitioning algorithm addresses the city allotment problem in an automatic
way, according to input parameters and constraints. In addition, we discuss
some results of virtual populated city simulations developed with proposed
frame-work. Keywords: city modeling, crowd simulation, polygon partitioning and real-time
visualization, terrain modeling, virtual life simulation | |||
| From motion capture data to character animation | | BIBAK | Full-Text | 165-168 | |
| Gaojin Wen; Zhaoqi Wang; Shihong Xia; Dengming Zhu | |||
| In this paper, we propose a practical and systematical solution to the
mapping problem that is from 3D marker position data recorded by optical motion
capture systems to joint trajectories together with a matching skeleton based
on least-squares fitting techniques. First, we preprocess the raw data and
estimate the joint centers based on related efficient techniques. Second, a
skeleton of fixed length which precisely matching the joint centers are
generated by an articulated skeleton fitting method. Finally, we calculate and
rectify joint angles with a minimum angle modification technique. We present
the results for our approach as applied to several motion-capture behaviors,
which demonstrates the positional accuracy and usefulness of our method. Keywords: articulated skeleton fitting, motion capture | |||
| Learning system for human motion characters of traditional arts | | BIBAK | Full-Text | 169-172 | |
| Yoshinori Maekawa; Takuya Oda; Taku Komura; Yoshihisa Shinagawa | |||
| A useful learning system for human motion characters of traditional arts,
such as Mai (Japanese classic dance), Kabuki (one of Japan's traditional stage
arts), etc., is being developed. In such arts an effective system to pass the
tradition down from a top artist to next generations is required. Video
contents are generally used to pass the human motions in traditional arts down
for non-experts. However, the video contents normally show the human motions as
the views from a single direction. If the human motions are presented from
orthogonal three-directions at the same time, it comes more useful. So, our
learning system produces the three-dimensional human motion by the sequences of
views from a single direction in the video contents, then, the motions from any
directions can be presented simultaneously with the video contents.
In addition, a learner can check the difference in motion between a top artist and him/herself by the producing his/her three-dimensional skeleton motion with our system and the overlapping it with one of the top artist. Here, in the comparison between two different physiques (a top artist and a learner) a simple adjustment method is suggested. In our study standard motion capture processes are employed, but our goal is to develop an original practical training system of performers' motion for beginners in traditional arts. In this paper the developing system is demonstrated for Kyo-mai (Mai originated in Kyoto) as example. The developing system can be useful not only in performing arts but also in industry or in sports. Keywords: computer graphics, human motion analysis, motion capture, traditional arts,
training tools | |||
| Utilizing jump flooding in image-based soft shadows | | BIBAK | Full-Text | 173-180 | |
| Guodong Rong; Tiow-Seng Tan | |||
| This paper studies the usage of the GPU as a collection of groups of related
processing units, where each group communicates in some way to complete a
computation efficiently and effectively. In particular, we use the GPU to
perform jump flooding to pass information among groups of processing units in
the design of two simple real-time soft shadow algorithms. These two algorithms
are purely image-based in generating plausible soft shadows. Their
computational costs depend mainly on the resolution of the shadow map or the
screen. They run on an order of magnitude faster than existing comparable
methods. Keywords: game programming, hard shadow, interactive application, parallel prefix,
penumbra map, programmable graphics hardware | |||
| Layered probability maps: basic framework and prototype system | | BIBAK | Full-Text | 181-188 | |
| Yutaka Kunita; Masahiro Ueno; Keiji Tanaka | |||
| We propose an image-based rendering method called"layered prob-ability
mapping." The algorithm requires modest computer power, but produces
high-quality output images even from textureless or noisy input images. Thus,
real-time applications such as immersive teleconferencing and live broadcasting
are promising areas of use. The key idea is layered probability map (LPM)
representation using a set of two-dimensional probabilistic functions. This
accommodates ambiguities regarding object depth. To test the feasibility of
this method, we developed a prototype system with nine synchronized cameras and
a thirteen-PC cluster. By calculating the algorithm in parallel, stable 5-15fps
image generation has been achieved without any off-line procedures between the
image capture and display. Keywords: image-based rendering, real-time graphics, three-dimensional video | |||
| Dynamic load-balanced rendering for a CAVE system | | BIBAK | Full-Text | 189-192 | |
| Tetsuro Ogi; Takaya Uchino | |||
| Recently, PC clusters have been used to construct CAVE-like immersive
projection displays. However, in order to improve the rendering performance of
PC cluster-based CAVE systems, the number of node PCs should be increased in
accordance with the number of screens that are included. In this research, a
mechanism for dynamic load-balanced rendering in a PC cluster system
incorporating an arbitrary number of nodes was developed. This system
constructs the cluster system by using a chain connection-type compositor
board, whereby load-balancing can be controlled dynamically in response to the
movement of the virtual objects or of the user's viewpoint. This paper
describes the implementation of this dynamic load-balanced rendering method and
presents the results of an evaluation experiment. Keywords: PC cluster, immersive projection display, load-balancing | |||
| Dynamic aspects of real-time face-rendering | | BIBAK | Full-Text | 193-196 | |
| Yvonne Jung; Christian Knöpfle | |||
| Simulating the visual appearance and lighting of human skin is a difficult
task, which is addressed by researchers for several years. Because of the
availability of high performance, programmable graphics boards, now it is
possible to use techniques formerly only available to offline rendering. In
this paper we present solutions to improve the visual quality of skin by
enhancing such techniques to real-time application. Furthermore dynamic
properties like aging and emotional changes in the appearance of a face like
blushing and weeping are introduced to obtain convincing results at interactive
frame rates for immersive virtual worlds. Keywords: emotions, shader, skin rendering, virtual reality | |||
| Interactive editing of segmented volumetric datasets in a hybrid 2D/3D virtual environment | | BIBAK | Full-Text | 197-206 | |
| Alexander Bornik; Reinhard Beichel; Dieter Schmalstieg | |||
| In this paper we present a novel system for segmentation refinement, which
allows for interactive correction of surface models generated from imperfect
automatic segmentations of arbitrary volumetric data. The proposed approach is
based on a deformable surface model allowing interactive manipulation with a
hybrid user interface consisting of an immersive stereoscopic display and a
Tablet PC. The user interface features visualization methods and manipulation
tools specifically designed for quick inspection and correction of typical
defects resulting from automated segmentation of medical datasets. A number of
experiments show that typical segmentation problems can be fixed within a few
minutes using the system, while maintaining real-time responsiveness of the
system. Keywords: 3D user interfaces, hybrid user interfaces, interactive segmentation,
segmentation refinement, virtual reality | |||
| Robust line tracking using a particle filter for camera pose estimation | | BIBAK | Full-Text | 207-211 | |
| Fakhreddine Ababsa; Malik Mallem | |||
| This paper presents a robust line tracking approach for camera pose
estimation which is based on particle filtering framework. Particle filters are
sequential Monte Carlo methods based on point mass (or "particle")
representations of probability densities, which can be applied to any
state-space model. Their ability to deal with non-linearities and non-Gaussian
statistics allows to improve robustness comparing to existing approaches, such
as those based on the Kalman filter. We propose to use the particle filter to
compute the posterior density for the camera 3D motion parameters. The
experimental results indicate the effectiveness of our approach and demonstrate
its robustness even when dealing with severe occlusion. Keywords: 3D pose estimation, augmented reality, line tracking, particle filter | |||
| A reprocessing tool for quantitative data analysis in a virtual environment | | BIBAK | Full-Text | 212-215 | |
| E. J. Griffith; M. Koutek; F. H. Post; T. Heus; H. J. J. Jonker | |||
| This paper presents an approach to help speed up and unify the exploration
and analysis of time-dependent, volumetric data sets by easily incorporating
new qualitative and quantitative information into an exploratory virtual
environment (VE). The new information is incorporated through one or more
expedited offline "reprocessing" steps, which compute properties of objects
extracted from the data. These objects and their properties are displayed in
the exploratory VE. A case study involving atmospheric data is presented to
demonstrate the utility of the method. Keywords: data visualization, virtual reality | |||
| The development of glove-based interfaces with the TRES-D methodology | | BIBAK | Full-Text | 216-219 | |
| José P. Molina; Arturo S. García; Diego Martinez; Francisco J. Manjavacas; Victor Blasco; Victor López; Pascual González | |||
| The development of 3D user interfaces is mostly focused on technology and
the ways of using it, and so the main concerns are the selection of hardware,
software and interaction techniques. The process of development itself is as
important as these issues, but it is usually ignored or poorly documented. This
paper introduces the TRES-D methodology, and illustrates its application in the
development of three different glove-based interfaces, not only to show the
benefits of using these devices, but also the benefits of using such a
methodological framework. Keywords: 3d user interfaces, data gloves | |||
| Supporting guided navigation in mobile virtual environments | | BIBAK | Full-Text | 220-226 | |
| Rafael Garcia Barbosa; Maria Andréia Formico Rodrigues | |||
| Developing interactive 3D graphics for mobile Java applications is a
reality. Recently, the Mobile 3D Graphics (M3G) API was proposed to provide an
efficient 3D graphics environment suitable for the J2ME platform. However, new
services and applications using interactive 3D graphics, which have already
achieved reasonable standards on the desktop, do not yet exist for
resource-constrained handheld devices. In this work, we developed a framework
for supporting guided navigation in mobile virtual environments. To illustrate
its main functionalities, a virtual rescue training was designed, implemented
and tested on mobile phones. Users can load virtual environments from a remote
PC server, navigate through them, find an optimal and collision-free path from
one place to another, and obtain additional information on the objects. Keywords: guided navigation, mobile device, virtual environment | |||
| Navigation aids for multi-floor virtual buildings: a comparative evaluation of two approaches | | BIBAK | Full-Text | 227-235 | |
| Luca Chittaro; Subramanian Venkataraman | |||
| Virtual environments (VEs) very often contain buildings that have to be
navigated by users. In the literature, several navigation aids based on maps
have been proposed for VEs, but in virtual buildings they have been typically
used for single-floor scenarios. In this paper, we propose and experimentally
evaluate two different navigation aids for multi-floor virtual buildings, one
based on 3D maps and the other based on 2D maps. We compared subjects'
performance with two different types of tasks: search and direction estimation.
While the 2D navigation aid outperformed the 3D one for the search task, there
were no significant differences between the two aids for the direction
estimation task. Keywords: evaluation, multi-floor virtual buildings, navigation aids | |||
| Z-Goto for efficient navigation in 3D environments from discrete inputs | | BIBAK | Full-Text | 236-239 | |
| Martin Hachet; Fabrice Decle; Pascal Guitton | |||
| 3D interactive applications are now appearing on mobile devices such as
phones and PDAs. Compared to classical desktop or immersive configurations,
mobile devices induce several constraints that intrinsically limit the user
performance in interactive tasks. Consequently, a special effort has to be made
in order to adapt the classical 3D user interfaces to mobile settings. In this
paper, we propose a new key-based technique that favors navigation in 3D
environments. Compared to a classical "go to" approach, our technique called
Z-Goto directly operates in the 3D space. This accelerates the user's
displacements by reducing the number of required keystrokes. Moreover, the
construction of the cognitive maps is improved, as Z-Goto favors depth
perception. An experiment shows that Z-Goto obtains better completion times
compared to a standard "go to" technique for a primed search task on mobile
device. It also shows that the user satisfaction for this new technique is
good. Keywords: interaction technique, mobile devices, navigation tasks, travel and
wayfinding | |||
| 3D visualization technologies for teleguided robots | | BIBAK | Full-Text | 240-243 | |
| Salvatore Livatino; Filippo Privitera | |||
| The use of 3D stereoscopic visualization may provide a user with higher
comprehension of remote environments in teleoperation when compared to 2D
viewing. Works in the literature have demonstrated how stereo vision
contributes to improve perception of some depth cues often for abstract tasks,
while little can be found about the advantages of stereoscopic visualization in
mobile robot teleguide applications. This work investigates stereoscopic robot
teleguide under different conditions, including typical navigation scenarios
and the use of synthetic and real images. This work also investigates how user
performance may vary when employing different display technologies. Results
from a set of test trials ran on five virtual reality systems emphasized few
aspects which represent a base for further investigation as well as a guide
when designing specific systems for telepresence. Keywords: 3D visualization, stereo vision, teleoperation, telerobotics, virtual
reality | |||
| The illusionhole with polarization filters | | BIBAK | Full-Text | 244-251 | |
| Yoshifumi Kitamura; Tomokazu Nakayama; Takashi Nakashima; Sumihiko Yamamoto | |||
| We have proposed the IllusionHole system, which allows three or more people
to simultaneously observe stereoscopic images from dynamically changing
individual viewpoints. With a simple configuration, this system provides
intelligible 3D stereoscopic images free of flicker and distortion. Based on
the IllusionHole concept, we have built a prototype system using two liquid
crystal projectors and polarizing filters. This paper describes the details of
this prototype. We investigate how the image formation position of the
stereographic image is affected by sources of errors such as measurements of
the user's interpupillary distance and observing position. We also measure and
discuss the variation of brightness and hue with viewing direction. Keywords: CSCW, collaborative work, education, illusionhole, interactive, multiple
users, science museum, stereoscopic display | |||
| Extending the scene graph with a dataflow visualization system | | BIBAK | Full-Text | 252-260 | |
| Michael Kalkusch; Dieter Schmalstieg | |||
| Data ow graphs are a very successful paradigm in scientific visualization,
while scene graphs are a leading approach in interactive graphics and virtual
reality. Both approaches have their distinct advantages, and both build on a
common set of basic techniques based on graph data structures. However, despite
these similarities, no unified implementation of the two paradigms exists. This
paper presents an in-depth analysis of the architectural components of dataflow
visualization and scene graphs, and derives a design that integrates both these
approaches.
The implementation of this design builds on a common software infrastructure based on a scene graph, and extends it with virtualized dataflow, which allows the use of the scene graph structure and traversal mechanism for dynamically building and evaluating dataflow. Keywords: dataflow visualization system, object hierarchies, scene graph,
visualization | |||
| Media productions for a dome display system | | BIBAK | Full-Text | 261-264 | |
| Athanasios Gaitatzes; Georgios Papaioannou; Dimitrios Christopoulos; Gjergji Zyba | |||
| As the interest of the public for new forms of media grows, museums and
theme parks select real time Virtual Reality productions as their presentation
medium. Based on three-dimensional graphics, interaction, sound, music and
intense story telling they mesmerize their audiences. The Foundation of the
Hellenic World (FHW) having opened so far to the public three different Virtual
Reality theaters, is in the process of building a new Dome-shaped Virtual
Reality theatre with a capacity of 130 people. This fully interactive theatre
will present new experiences in immersion to the visitors. In this paper we
present the challenges encountered in developing productions for such a large
spherical display system as well as building the underlying real-time display
and support systems. Keywords: computer clusters, spherical display systems, stereoscopic display | |||
| Analytical compensation of inter-reflection for pattern projection | | BIBAK | Full-Text | 265-268 | |
| Yasuhiro Mukaigawa; Takayuki Kakinuma; Yuichi Ohta | |||
| If a pattern is projected onto a concave screen,the desired view cannot be
correctly observed due to the influence of inter-reflections. This paper
proposes a simple but effective technique for photometric compensation in
consideration of inter-reflections. The compensation is accomplished by
canceling inter-reflections estimated by the radiosity method. The significant
advantage of our method is that iterative calculations are not necessary
because it analytically solves the inverse problem of inter-reflections. Keywords: inter-reflection, projector | |||
| P2P Network for very large virtual environment | | BIBAK | Full-Text | 269-276 | |
| Romain Cavagna; Christian Bouville; Jerome Royan | |||
| The ever increasing speed of Internet connections has led to a point where
it is actually possible for every end user to seamlessly share data on
Internet. Peer-To-Peer (P2P) networks are typical of this evolution. The goal
of our paper is to show that server-less P2P networks with self-adaptive
assignment techniques can efficiently deal with very large environments such as
met in the geovisualization domain. Our method allows adaptative view-dependent
visualization thanks to a hierarchical and progressive data structure that
describes the environment. In order to assess the global efficiency of this P2P
technique, we have implemented a dedicated real time simulator. Experimentation
results are presented using a hierarchical LOD model of a very large urban
environment. Keywords: peer-to-peer, self-adaptation, self-organization, self-scalability,
simulation, virtual environment | |||
| Dynamic interactive VR network services for education | | BIBAK | Full-Text | 277-286 | |
| Krzysztof Walczak; Rafal Wojciechowski; Wojciech Cellary | |||
| Global information society and knowledge-based economy will generate a need
for life-long learning on a mass scale. To deal with this challenge,
traditional education should be extended with new forms of learning and
teaching by employing advanced technologies such as virtual and mixed reality.
In order to provide learners with these forms of education, a wide range of
VR-based interactive educational network services should be developed.
Technologies for delivering such network services are already available.
Currently, a challenge is to develop methods and tools for efficient creation
of vast amounts of VR-based learning material.
In this paper, a method of dynamic content creation is described, which enables flexible authoring and manipulation of VR-based educational contents in interactive network environments. Application of this method to several architectural variants of educational systems is discussed. Keywords: X-VR, distance learning and teaching, interactive 3D, mixed reality, virtual
reality | |||
| Are two heads better than one?: object-focused work in physical and in virtual environments | | BIBAK | Full-Text | 287-296 | |
| Ilona Heldal; Maria Spante; Mike Connell | |||
| Under which conditions has collaboration added value over individual work?
How does performance change when using different technologies? These are
important questions for industry and for research. This paper addresses them
for pairs versus individuals using physical objects and virtual representations
for object-focused task-solving. Based upon previous research on pair's
performance and experiences for collaboration in a real setting and four
different distributed virtual environments (VEs), single-user experimental
studies were carried out. The results show that in relation to performance,
pairs working in networked CAVE; technologies are superior compared to
individuals, or pairs working in other distributed settings. In general, social
interaction works as a facilitator for this type of task solving in networked
VEs. Though, best performance was found in the real setting, with no major
difference when comparing individuals versus pairs, working in VEs often were
appreciated higher than working with physical objects. Keywords: collaboration, immersive, performance, presence, social interaction,
usability, virtual environments | |||
| A differential method for the haptic rendering of deformable objects | | BIBAK | Full-Text | 297-304 | |
| Remis Balaniuk | |||
| This paper introduces a new method for the computation of contact forces
during the haptic interaction between a rigid probe and a soft virtual object.
Traditional methods used to estimate forces inside a haptic loop are based on a
penetration distance of the haptic probe inside the virtual objects. This
unnatural approach creates some visual incoherences when simulating the contact
with rigid objects, but works fine on the force estimation side. For soft
objects however, the use of a penetration distance makes less sense and creates
many problems both visually and haptically. We propose a method that considers
the penetration of the probe inside the virtual object as being an
approximation error, and performs an iterative model adjustment estimating a
local elasticity for the deformable object. Forces are computed incrementally.
The proposed approach is independent from any particular implementation used
for simulating the deformable object. The force estimation is based on the
actual shape of the object, considering its deformations, allowing multiple
users to interact with a same object while feeling the influence of each other.
Experimental results are presented. Keywords: haptic interfaces, soft-tissue modeling, virtual reality | |||
| A framework for bounded-time collision detection in haptic interactions | | BIBAK | Full-Text | 305-311 | |
| Maurizio de Pascale; Domenico Prattichizzo | |||
| In this paper we present the V-GRAPH, a framework for bounded-time collision
detection for point-like haptic interactions. This frame-work employs
strategies similar to those used by the Lin-Canny and Dobkin-Kirkpatrick
algorithms but, differently from these ones, it uses a partition of the space
focused on vertices only, which al-lows both for an easier implementation and
for usage with non-convex objects without the need for splitting the original
mesh. In a preprocessing phase the mesh is analyzed to extract neighboring
information based on Voronoi theory, then this data is used at run-time in a
greedy visit exploiting motion coherence to achieve fast proximity queries.
Finally standard segment-triangle intersection tests are eventually carried out
to identify the exact point of collision. Moreover the framework can be easily
extended to multiple levels of detail. Computational analysis and experimental
results show that execution times are independent from mesh complexity,
achieving same running times even on models composed by mil-lions of polygons.
These features make it particularly suited for virtual museum and digital
sculpting applications. Implementation is straightforward and freely available
tools can be used for pre-processing. Keywords: V-GRAPH, Voronoi, bounded time, collision detection, haptic | |||
| Tactylus, a pen-input device exploring audiotactile sensory binding | | BIBAK | Full-Text | 312-315 | |
| Ernst Kruijff; Gerold Wesche; Kai Riege; Gernot Goebbels; Martijn Kunstman; Dieter Schmalstieg | |||
| Recent studies have shown that through a careful combination of multiple
sensory channels, so called multisensory binding effects can be achieved that
can be beneficial for collision detection and texture recognition feedback.
During the design of a new pen-input device called Tactylus, specific focus was
put on exploring multisensory effects of audiotactile cues to create a new, but
effective way to interact in virtual environments with the purpose to overcome
several of the problems noticed in current devices. Keywords: 3D user interfaces, audiotactile feedback, sensory, substitution | |||
| Using neuromuscular electrical stimulation for pseudo-haptic feedback | | BIBAK | Full-Text | 316-319 | |
| Ernst Kruijff; Dieter Schmalstieg; Steffi Beckhaus | |||
| This paper focuses at the usage of neuromuscular electrical stimulation
(NMES) for achieving pseudo-haptic feedback. By stimulating the motor nerves,
muscular contractions can be triggered that can be matched to a haptic event.
Reflecting an initial user test, we will explain how this process can be
realized, by investigating the physiological processes involved. Relating the
triggered feedback to general haptics, its potential in future interfaces will
be identified and laid out in a development roadmap. Keywords: 3D user interfaces, biofeedback, haptic feedback, neuroelectrical
stimulation | |||
| A haptic toolkit for the development of immersive and web-enabled games | | BIBAK | Full-Text | 320-323 | |
| E. Ruffaldi; A. Frisoli; M. Bergamasco; C. Gottlieb; F. Tecchia | |||
| The creation of applications of Virtual Reality enabled with Haptic
interaction and dynamic simulation requires usually to cover many
implementation details that increase the development time and the effectiveness
of the application itself. This work presents one game application that has
been developed using a Haptic toolkit for the rapid application development,
that integrates 3D graphics,haptic feedback and dynamic simulation.
The resulting application can be easily deployed on the Web directly to the final user. Keywords: game, haptics, virtual environments, web | |||
| PNORMS: platonic derived normals for error bound compression | | BIBAK | Full-Text | 324-333 | |
| João Fradinho Oliveira; Bernard Francis Buxton | |||
| 3D models of millions of triangles invariably repeatedly use the same
12-byte unit normals. Several bit-wise compression algorithms exist for
efficient storage and progressive transmission and visualization of normal
vectors. However such methods often incur a reconstruction time penalty which,
in the absence of dedicated hardware acceleration, make real-time rendering
with such compression/reconstruction methods prohibitive. In particular,
several methods use a subdivided octahedron to create look-up normals, where
the bit length of normal indices varies according to the number of subdivisions
used. Not much attention has been given to the error in the normals using such
schemes. We show that different Platonic solids create different amounts of
normals for each subdivision or bit length in bit-wise compression terms, with
different distributions and associated errors. In particular we show that
subdividing the icosahedron gives a smaller maximum and mean error than its
counterparts Platonic solids. This result has led us to create an alternative
to bit-wise compression of normal ids for real-time rendering, where we use a
x5 subdivided icosahedron to create 2.5 times more normals than a x5 subdivided
octahedron, with less error, and exploit the advantages of absolute normal
indices that do not require reconstruction at run-time, whilst still having
memory savings of over 83% when using 2-byte indices.
We present results using 2-byte indices for a target max error of 1.3ð degrees and 4-byte for a max error of <0.1ð. We present two hierarchical encoding methods, a fast method which allows one to dynamically encode large sets of modified triangles, useful for task, and a slower but more accurate method that caters for symmetry present in the subdivision solid being used. Different levels of a database allow for different cartoon like shading effects. The advantages of these databases are that they can be re-used for any object, and have studied bounds on the maximum errors of normals for yet to be known geometry such as new objects to be added to a scene. This error bound is also independent of the size and normal distribution of the object that we wish to add. In order to visualize the colour coding distribution of the errors in the normals of large models a simple 1-byte color encoding algorithm was developed. Keywords: colour compression, error bound, normal compression, run-time encoding | |||
| Intuitively specifying object dynamics in virtual environments using VR-WISE | | BIBAK | Full-Text | 334-337 | |
| Bram Pellens; Frederic Kleinermann; Olga De Troyer | |||
| Designing and building Virtual Environments is not an easy task, especially
when it comes to specifying object behavior where either knowledge about
animation techniques or programming skills are required. With our approach,
VR-WISE, we try to facilitate the design of VEs and make this more accessible
to novice users. In this paper, we present how behavior is specified in
VR-WISE, as well as the prototype developed for the approach. Keywords: behavior, conceptual modeling, design phase, virtual reality | |||
| A robust method for analyzing the physical correctness of motion capture data | | BIBAK | Full-Text | 338-341 | |
| Yi Wei; Shihong Xia; Dengming Zhu | |||
| The physical correctness of motion capture data is important for human
motion analysis and athlete training. However, until now there is little work
that wholly explores this problem of analyzing the physical correctness of
motion capture data. In this paper, we carefully discuss this problem and solve
two major issues in it. Firstly, a new form of Newton-Euler equations encoded
by quaternions and Euler angles which are very fit for analyzing the motion
capture data are proposed. Secondly, a robust optimization method is proposed
to correct the motion capture data to satisfy the physical constraints. We
demonstrate the advantage of our method with several experiments. Keywords: equations of multi-rigid- body's motion, motion capture data, physical
correctness | |||
| Developing a 3D simulated bio-terror crises communication training module | | BIBAK | Full-Text | 342-345 | |
| Edward Carpenter; Induk Kim; Laura Arns; Mohan J. Dutta-Berman; Krishna Madhavan | |||
| The anthrax attacks of 2001 brought professional and public attention to the
significance of successful crisis communication in the context of bioterrorism.
The project discussed in this paper is an initiative taken to respond to the
calls for more effective bio-terror crises communication training. The goal of
this project is to address various challenges in bio-terror crises
communication by developing an innovative crisis communication training module
for public relations students. This goal is achieved by attending to two main
factors: (a) keen awareness of important theories in crises communication
response, and (b) "hands-on" training in real-time bio-terror communication
handling techniques. This paper introduces the process taken to develop 3D
simulated crisis communication training material and presents future plans to
assess its effectiveness. Keywords: bioterrorism, communications, crisis control, virtual reality | |||
| Simplified animation circuit for metadata-based behavior model query and retrieval | | BIBAK | Full-Text | 346-349 | |
| Tien-Lung Sun; Yu-Lun Chang | |||
| This paper describes an approach to simplify the animation circuit so that
useful metadata could be extracted to facilitate behavior model storage and
retrieval. In the VR model of a product, the tasks performed by the behavior
nodes could be classified into three categories, i.e., changing the attributes
of a part, animating the behavior of a part, and detecting user's interaction
with a part. Based on this property, 2-tuple metadata (P, T) is designed to
represent the behavior node, where P is the part operated by behavior node and
T is tasks performed by the behavior node. The parts and tasks contained in the
metadata are hierarchical classified. The process to simplify the animation
circuit consists of two major steps. First, the behavior nodes in the animation
circuit are converted to their metadata. The resulted graph is called a
metadata graph. Secondly, the metadata graph is simplified by merging nodes
that have the same classifications. The structured metadata extracted from the
metadata graphs allows behavior model query and retrieval to be performed at
different levels of abstractions. Keywords: VR model, VRML, behavior, query and retrieval | |||
| Control of eye-movement to decrease VE-sickness | | BIBAK | Full-Text | 350-355 | |
| Michiteru Kitazaki; Tomoaki Nakano; Naoyuki Matsuzaki; Hiroaki Shigemasu | |||
| One of well-known theories for motion sickness and VE (Virtual Environment)
sickness is 'sensory conflict' theory. In this paper, we investigated whether
the conflict between actual (extra-retinal) eye-movement and visually-simulated
(retinal) eye-movement affects the VE-sickness. In results, we found that
VE-sickness was significantly decreased by the control of observer's
eye-movement with a stationary/moving fixation point. When the extra-retinal
and retinal eye-movements were incongruent while the observer's head was
actively moving, the VE-sickness was increased for sickness-sensitive
observers. These results suggest that we can decrease VE-sickness by
controlling eye-movements with a stationary/moving fixation point to remove
conflict of extra-retinal and visual eye-movements. This is a new proposal of
the way to decrease VE-sickness. Keywords: VE sickness, extra-retinal information, eye-movement, motion sickness,
visual information | |||
| Hand-held virtual reality: a feasibility study | | BIBAK | Full-Text | 356-363 | |
| Jane Hwang; Jaehoon Jung; Gerard Jounghyun Kim | |||
| Hand-held computing devices are ubiquitous and have become part of our lives
these days. Moreover, hand-held devices are also increasingly being equipped
with special sensors and non-traditional displays. As such, it raises the
question of whether such a "small" and "reduced" device could serve as an
effective virtual reality (VR) platform and provide sufficient immersion and
presence, e.g. through multimodal interaction. In this paper, we address this
question by comparing the perceived field of view (FOV) and level of immersion
and presence among the users' of VR platforms, varied in the sizes of
physical/software FOV and in styles of interaction. In particular, we consider
a motion based interaction, a style of interaction uniquely suitable for the
"hand-held" devices. Our experimental study has revealed that when a motion
based interaction was used, the FOV perceived by the user for the small hand
held device was significantly greater than (around 50%) the actual. Other
displays using the button or mouse/keyboard interface did not exhibit such a
phenomenon. In addition, the level of user felt presence was higher than even
that from a large projection based VR platform. The paper demonstrates the
distinct possibility of realizing reasonable virtual reality even with devices
with a small visual field of view and limited processing power. Keywords: field of view, hand-held devices, immersion, motion based interface,
presence, task performance, virtual reality | |||
| Presence in response to dynamic visual realism: a preliminary report of an experiment study | | BIBAK | Full-Text | 364-367 | |
| Pankaj Khanna; Insu Yu; Jesper Mortensen; Mel Slater | |||
| This paper describes an experiment that examines the influence of visual
realism on reported presence. 33 participants experienced two different
renderings of a virtual environment that depicts a pit in the centre of a room,
in a head-tracked head-mounted display. The environment was rendered using
parallel ray tracing at 15fps, but in one condition ray casting (RC) was used
achieving a result equivalent to OpenGL based per-pixel local illumination, and
in the second full recursive ray tracing (RT). The participants were randomly
allocated to two groups -- one that experienced RC first followed by RT, and
the second group in the opposite order. Reported presence was obtained by
questionnaires following each session. The results indicate that reported
presence, in terms of the 'sense of being there' was significantly higher for
the RT than for the RC condition. Keywords: presence, virtual environments | |||
| The impact of immersive virtual reality displays on the understanding of data visualization | | BIBAK | Full-Text | 368-371 | |
| Ahmed Bayyari; M. Eduard Tudoreanu | |||
| This paper presents evidence that situational awareness in a visualization
of data benefits from immersive, virtual reality display technology because
such displays appear to support better understanding of the visual information.
Our study was designed to de-emphasize perceptual and interaction
characteristics of the dis-plays and found that the task of counting targets is
strongly influenced by the type of system used to render the visualization.
Immersive-type displays outperformed traditional monitors. The target objects
in the study have distinguishing features that cannotmbe identified from a
distance to alleviate the effect of perceptual differences among displays.
Counting was chosen because it entails basic understanding of the relationship
among the data values in order to recognize previously counted items. The
display choices consisted of a traditional monitor and three configurations of
an immersive, projection environment, obtained by selectively turning off one
or two projectors of a three-wall CAVE. Keywords: evaluation, immersion, information visualization, virtual reality | |||
| Effects of physical display size and amplitude of oscillation on visually induced motion sickness | | BIBAK | Full-Text | 372-375 | |
| Hiroaki Shigemasu; Toshiya Morita; Naoyuki Matsuzaki; Takao Sato; Masamitsu Harasawa; Kiyoharu Aizawa | |||
| Viewing environment is an important factor to understand the mechanism of
visually induced motion sickness (VIMS). In Experiment 1, we investigated
whether the symptom of VIMS changed depending on viewing angle and physical
display size. Our results showed that larger viewing angle made the symptom of
sickness severer and nausea symptom changed depending on physical display size
with identical viewing angles. In Experiment 2, we investigated effects of
viewing angle and amplitude of oscillation. The results showed that the effects
of viewing angle were not only related to amplitude of oscillation but also to
the other factors of viewing angle. Keywords: SSQ, amplitude of oscillation, visual angle, visually induced motion
sickness | |||
| Variations in physiological responses of participants during different stages of an immersive virtual environment experiment | | BIBAK | Full-Text | 376-382 | |
| Andrea Brogni; Vinoba Vinayagamoorthy; Anthony Steed; Mel Slater | |||
| This paper presents a study of the fine grain physiological responses of
participants to an immersive virtual simulation of an urban environment. The
analysis of differences in participant responses at various stages of the
experiment (baseline recordings, training, first half and second half of the
urban simulation) are examined in detail. It was found that participants
typically show a stress response during the training phase and a stress
response towards the end of the simulation of the urban experience.
There is also some evidence that variations in the level of visual realism based the texture strategy used was associated with changes in mental stress. Keywords: evaluation, human response, immersive virtual environments, physiology | |||
| Building a complete virtual reality application | | BIBA | Full-Text | 383 | |
| Franco Tecchia | |||
| The development of a complete Virtual Reality application is a complex
activity that requires good knowledge of several time-critical tasks: Computer
Graphics, real-time Physics, Haptics and network programming are examples of
the components needing to coexist in a modern Virtual Reality system.
Each of these building blocks constitutes a research field on its own and a vast literature exists on techniques and algorithms useful to address specific problems; still, from a more high level perspective, only through tight integration and balanced design can a complex framework achieve optimal performances. Having to address such a range of integration issues, the development of a Virtual Reality application can in practice turn out to be a very lengthy and difficult process, where fundamental design choices and their implications should be carefully considered. The choice of the right tools is also very important, as common everyday practice shows how difficult is still to put together a successful and robust system. This tutorial aims at giving an overview of what are the main components involved in the task, how they should interact, and what are the inherent difficulties to place everything together. The tutorial is divided in two parts: The second part will introduce a real-life and recent example of integrated framework, to be used as a reference and base of discussion for the design of the next generation of integrated development environment and their applications. | |||
| Virtual reality systems and applications | | BIBA | Full-Text | 384 | |
| A. Gaitatzes; G. Papaioannou; D. Christopoulos | |||
| In this tutorial we will present the infrastructure required, both software
and hardware, to create the Virtual Reality (VR) illusion. The history and the
application areas of VR will be presented. From the software required to the
image generator to the different display systems -- both head based and
projection based -- all components of a VR system as well as practical
deployment issues will be investigated. The stereo depth principle will be
explained along with the different stereo methodologies available today.
Aspects of a VR experience like immersion and collaboration will be explored.
Other topics include the physical interface and interaction devices and the
methods of manipulating a Virtual Environment by tracking users and devices.
An attempt will be made to differentiate VR from pre-rendered Computer Graphics by presenting the issues concerning Real Time graphics. Finally possible future developments in the areas of Virtual Reality technology and Virtual Environments will be presented. | |||