| Interaction, imagination and immersion some research needs | | BIBAK | Full-Text | 1-7 | |
| Thomas B. Sheridan | |||
| This paper discusses four ways that humans interact with their environments,
plus four variables that determine the experience of virtual reality, and also
which of the interactions support which of the VR-enhancing variables. Some
philosophical issues about immersion, the experience of presence, and the
meaning of reality are then considered. The engineering paradigm of estimation
is then reviewed as a way of bridging classical ontologica differences of
opinion about reality. Finally some VR research needs are discussed: haptics,
minimally invasive diagnosis and surgery, driving simulation, decision aids in
system operation, education, computer-aided synthesis, measures of presence and
whether presence enhances performance, social ills of VR, and the relation of
VR to spirituality. Keywords: Human, applications, definition, education, haptics, imagination, immersion,
interaction, ontology, presence, reality, spirituality, surgery, vehicles,
virtual | |||
| CAVERNsoft G2: a toolkit for high performance tele-immersive collaboration | | BIBAK | Full-Text | 8-15 | |
| Kyoung S. Park; Yong J. Cho; Naveen K. Krishnaprasad; Chris Scharver; Michael J. Lewis; Jason Leigh; Andrew E. Johnson | |||
| This paper describes the design and implementation of CAVERNsoft G2, a
toolkit for building collaborative virtual reality applications. G2's special
emphasis is on providing the tools to support high-performance computing and
data intensive systems that are coupled to collaborative, immersive
environments.
This paper describes G2's broad range of services, and demonstrates how they are currently being used in a collaborative volume visualization application. Keywords: CVE, Tele-immersion, VR, data-mining, high-performance computing, networking
library | |||
| Choosing and using a driving problem for CVE technology development | | BIBAK | Full-Text | 16-24 | |
| William L. Mitchell; Daphne Economou; Steve R. Pettifer; Adrian J. West | |||
| The need for a real-world driving problem to guide technology development
has long been recognised. However, this does not guarantee the identification
of requirements for technology development. This paper argues that a more
systematic approach is needed for choosing and making best use of a driving
problem for CVE technology. The method consists of identifying the stakeholders
in the technology development project. A series of issues must then be
addressed: choice of problem area, choice of application, choice of research
approach, design of the application, ensuring use by real users, choice of
method of study, and identification of technology requirements. The method is
illustrated by considering the development of the Deva CVE system with an
art-based application and with an educational application. Keywords: Design methodology, education, evaluation, human factors | |||
| Advanced real-time collaboration over the internet | | BIBAK | Full-Text | 25-32 | |
| Chris Joslin; Tom Molet; Nadia Magnenat-Thalmann | |||
| In this paper we present our Networked Virtual Environment (NVE) System,
called W-VLNET (Windows Virtual Life Network), which has been developed on the
Windows NT Operating System (OS). This paper emphasizes the Real-Time aspect of
this NVE system, the advanced interactivity that the system provides and its
ability to transfer data across the Internet so that geographically distant
users can collaborate with each other. Techniques for communication, scene
management, facial and body animation, and general user interaction modules are
detailed in this paper. The use of VRML97 and MPEG4 SHNC is overviewed to
stress the compatibility of the system with other similar Virtual Reality
systems. The software provides realistic virtual actors as well as sets of
applicable high-level actions in real-time. Related issues on obtaining actor
models and animating them in real-time are presented. We also introduce a case
study to show an example of how the system can be used. Keywords: Advanced Interaction, Distance Collaboration, Motion Tracking, Network
Virtual Environment, Networks, Real-Time Interactions | |||
| DEVA3: architecture for a large-scale distributed virtual reality system | | BIBAK | Full-Text | 33-40 | |
| Steve Pettifer; Jon Cook; James Marsh; Adrian West | |||
| In this paper we present work undertaken by the Advanced Interfaces Group at
the University of Manchester on the design and development of a system to
support large numbers of geographically distributed users in complex,
large-scale virtual environments (VEs).We shown how the problem of
synchronisation in the face of network limitations is being addressed by the
Deva system through the exploitation of subjectivity. Further, we present a
model for flexibly describing object behaviours in the VEs.
Applications of the system in use are described. Keywords: Distribution, Object behavior, Programming model, Subjectivity, System
architecture, Virtual Environments | |||
| Interactive reconstruction of virtual environments from photographs, with application to scene-of-crime analysis | | BIBAK | Full-Text | 41-48 | |
| Simon Gibson; Toby Howard | |||
| There are many real-world applications of Virtual Reality that require the
construction of complex and accurate three-dimensional models, suitably
structured for interactive manipulation. In this paper, we present
semi-automatic methods that allow such environments to be quickly and easily
built from photographs taken with uncalibrated cameras, and illustrate the
techniques by application to the real-world problem of scene-of-crime
reconstruction. Keywords: Computer Vision, Model Building, Photogrammetry, Scene of Crime
Reconstruction, Texture, Virtual Reality | |||
| Interactive 3D modeling using only one image | | BIBAK | Full-Text | 49-54 | |
| Sujin Liu; Zhiyong Huang | |||
| For virtual reality systems, modeling of 3D objects and scenes is important
and challenging. In this paper, we present an image-based interactive 3D
modeling framework consisting of three major modules: photogrammetric modeling,
human interaction, and texture mapping. These three modules are not
sequentially used and they are mixed in the whole modeling process. The major
idea is to explore the use of images in interactive modeling systems to achieve
the automation. In particular, the use of only one image is addressed. On one
side, unlike the common fully interactive modeling framework, the users are not
required to specify some low level details interactively which can be derived
automatically from the image. On the other side, it still requires human
interactions to do some high level tasks that the algorithms are difficult to
perform automatically. We have implemented the framework and experimental
results are good. Keywords: 2-D image, Modeling of 3-D shape, human computer interaction, texture
mapping | |||
| A hybrid method of image synthesis in IBR for novel viewpoints | | BIBAK | Full-Text | 55-60 | |
| Xuehui Liu; Hanqiu Sun; Enhua Wu | |||
| Due to visibility change and surface enlargement in producing a novel view
from a new viewpoint, 3D re-projection from one reference image in IBMR
inevitably produces holes in the destination image. Even worse, exposure errors
occur when a background region occluded is visible in a desired image because
of the absence of some background elements in the reference image. The general
solution to this kind of problems is to use multiple images from different
viewpoints as input source. By doing so however, the rendering cost would
increase with the number of reference images and the composition algorithm has
to rely on the z-buffer processing.
In fact, plenty of redundant information exists among different reference images. Seeking for a nice way to extract the information needed in the novel view from the reference images is the key issue in solving the problem. In this paper, we propose a new method of image synthesis from multiple reference images. The method combines forward warping and backward warping to fulfil the image composition task for a novel viewpoint. The primary inspiration behind the development of our image synthesis method comes from a fact that the polygon edge geometry may indicate where an exposure and, possible an exposure error occur in the destination image if object silhouettes are prior known. The feature that intersection between scanline and polygons must be in pairs is employed to distinguish holes caused by enlargement of surfaces from those by visibility change. Different heuristic methods are used to choose one image as a primary reference image which shares the most resemblance with the destination image, and other reference images for filling different kinds of holes. Depth continuity along scanline and the depth information already present in the destination image are employed to accelerate the searching process of the corresponding pixels for filling holes. Keywords: Image-Based modeling and rendering, backward warping, depth-image map,
epipolar geometry, forward warping | |||
| A framework for rapid evaluation of prototypes with augmented reality | | BIBAK | Full-Text | 61-66 | |
| Selim Balcisoy; Marcelo Kallmann; Pascal Fua; Daniel Thalmann | |||
| In this paper we present a new framework in Augmented Reality context for
rapid evaluation of prototypes before manufacture. The design of such
prototypes is a time consuming process, leading t o the need of previous
evaluation in realistic interactive environments. We have extended the
definition of modelling object geometry with modelling object behaviour being
able to evaluate them in a mixed environment. Such enhancements allow the
development of tools and methods to test object behaviour, and perform
interactions between real virtual humans and complex real and virtual objects.
We propose a framework for testing the design of objects i an augmented reality context, where a virtual human is able to perform evaluation tests with an object composed of real and virtual components. In this paper our framework is described and a case study is presented. Keywords: Augmented Reality, Human Factors, Object Behaviour, Prototyping, Virtual
Humans | |||
| An immersive modeling system for 3D free-form design using implicit surfaces | | BIBAK | Full-Text | 67-74 | |
| Masatoshi Matsumiya; Haruo Takemura; Naokazu Yokoya | |||
| We present a new free-form interactive modeling technique based on the
metaphor of clay work. This paper discusses design issues and an immersive
modeling system which enables a user to design intuitively and interactively 3D
solid objects with curved surfaces by using one's finger. Shape deformation is
expressed by simple formulas without complex calculation because of skeletal
implicit surfaces employed to represent smooth free-form surfaces. A
polygonization algorithm that generates polygonal representation from implicit
surfaces is developed to reduce the time required for rendering curved
surfaces, since conventional graphics hardware is optimized for displaying
polygons. The prototype system has shown that a user can design 3D solid
objects composed of curved surfaces in a short time by deforming objects
intuitively using one's finger in real time. Keywords: CAD, Head Mounted Displays, Implicit Surfaces, Solid Modeling, Virtual
Reality | |||
| A framework for the structured design of VR/AR content | | BIBAK | Full-Text | 75-82 | |
| C. Geiger; V. Paelke; C. Reimann; W. Rosenbach | |||
| We describe a framework that allows to easily design and implement virtual
and augmented reality worlds. Based on a structured design approach for
interactive animated 3D content we want to supply designers and content experts
of complex virtual environments with a component based toolset for the
structured design of the visual and abstract components of 3D applications. Keywords: Design Framework, Interactive 3D Animation, Virtual and Augmented Reality | |||
| Conceptual free-form styling on the responsive workbench | | BIBA | Full-Text | 83-91 | |
| Gerold Wesche; Marc Droske | |||
| A two-handed 3D styling system for free-form surfaces in a table-like Virtual Environment, the Responsive Workbench (RWB), is described. Intuitive curve and surface deformation tools based on variational modeling and interaction techniques adapted to 3D VR modeling applications are proposed. The user draws curves (cubic B-splines) directly in the Virtual Environment using a stylus as an input device. The curves are connected automatically, such that a curve network develops. A combination of automatic and user-controlled topology extraction modules creates the connectivity information. The underlying surface model is based on B-spline surfaces, or, alternatively, uses multisided patches [20] bounded by closed loops of curve pieces. | |||
| Multi-resolution spatial model for large-scale virtual environment | | BIBAK | Full-Text | 92-96 | |
| ChangHun Park; Heedong Ko; TaiYun Kim | |||
| The goal of this paper is to optimize interest management for the
scalability of networked virtual environments. To remove the needless load of
co-presence, the interest manager restricts the consistency of shared virtual
space by means of relevance. We propose multi-resolution spatial model (MRSM)
for the optimization of an interest manager, which pays attention to all
participants in order to determine the limitation of consistency. They enable
an interest manager to control the granularity of relevance filtering without
disturbing co-presence. When an interest manager realize relevance against the
movements of players, MRSM supports the detection of avatar's location and the
estimation of relevance at different cost according to level-of-detail. And,
this paper presents an algorithm that applies the size of neighbor to the
modification of level-of-detail while the efficiency is guaranteed. Keywords: Interest management, Networked virtual space, Scalability, filter update,
level-of-detail (LOD), multi-resolution spatial model (MRSM), relevance
realization, state update | |||
| Message caching for local and global resource optimization in shared virtual environments | | BIBAK | Full-Text | 97-102 | |
| Helmuth Trefftz; Ivan Marsic | |||
| The use of Shared Virtual Environments is growing in areas such as
multi-player video games, military and industrial training, and collaborative
design and engineering. As a result, different mixes of computing power and
graphics capabilities of the participating computers arise naturally as the
variety of people/organizations sharing a virtual environment grows. This paper
presents an adaptive mechanism to reduce bandwidth usage and to optimize the
use of computing resources of heterogeneous computers mixes utilized in a
shared virtual environment. The mechanism is based on caching of both outgoing-
and incoming-messages. We also report the results of implementing the proposed
scheme in a simple shared virtual environment. Keywords: Message Caching, Networking, Shared Virtual Environments, Virtual Reality | |||
| Scalable interest management using interest group based filtering for large networked virtual environments | | BIBAK | Full-Text | 103-108 | |
| Seunghyun Han; Mingyu Lim; Dongman Lee | |||
| As distributed virtual environment (DVE) scales in terms of users and
network latency, a key aspect to consider is scalability for interactive
performance because a large number of objects likely impose heavy burden
especially on the network and computational resources. To improve the
scalability, various relevance-filtering mechanisms and aggregation mechanisms
have been proposed. However the existing filtering mechanisms do not scale well
in terms of interactive performance as the number of users increases and crowds
in a specific place.
In this paper, we propose a new scalable filtering scheme that reduces the number of messages by dynamically grouping users based on their interests and distance. Within a group, members communicate with each other with high fidelity. However, a representative sends up-to-dated group information of members with low transmission frequency when they are not of immediate interest but are still within the interest area. The representative is elected from members of the group in distributed manner. The proposed scheme enhances the interactive performance scalability of large-scale DVE systems as much as 18% compared with the existing approach. Keywords: Interest management, Networked virtual environments, Representative user,
User interest-based group | |||
| Scalable predictive concurrency control for large distributed virtual environments with densely populated objects | | BIBAK | Full-Text | 109-114 | |
| Dongman Lee; Jeonghwa Yang; Soon J. Hyun | |||
| We propose an enhanced prediction-based concurrency control scheme that
supports the scalability of concurrency control for large distributed virtual
environments especially where entities are highly populated and tend to gather
closely. The prediction scheme is based on an entity-centric multicast group.
Only the users surrounding a target entity multicast the ownership requests via
an entity multicast group and become owner candidates. The current owner
predicts the next owner among the owner candidates and sends an ownership to
the next owner in advance. However, if entities are assigned their own
multicast address when they are close to each other, users have to continuously
issue join messages as moving by the entities. To reduce the network and
message exchange overhead, we use the location proximity of entities in virtual
environments. By grouping closely gathered entities into one entity group and
sharing a multicast address among group member entities, we reduce the number
of frequent join and leave operations and join messages, therefore maintain
enough interactive performance. The experiment results show that the proposed
mechanism improves scalability especially when entities are closely gathered. Keywords: Large scale distributed virtual environments, concurrency control, entity
group, entity-centric multicast group, prediction scheme, scalability | |||
| Conservative visibility preprocessing for walkthroughs of complex urban scenes | | BIBAK | Full-Text | 115-128 | |
| JunHyeok Heo; Jaeho Kim; KwangYun Wohn | |||
| Visibility preprocessing is a useful method to reduce the complexity of
scenes to be processed in real-time, and so enhances the overall rendering
performance for interactive visualization of virtual environments. In this
paper, we propose an efficient visibility preprocessing method. The proposed
method is able to handle more general environments, like urban environments,
and remove invisible polygons jointly blocked by multiple occluders. The
proposed method requires O(nm) time and O(n+m) space. By selecting a suitable
value for m, user can select a suitable level of trade-off between the
preprocessing time and the quality of the computational result. In the proposed
method, we assume that navigatable areas in virtual environments are
partitioned into rectangular parallelepiped cells or sub-worlds. To preprocess
the visibility of each polygon for a given partitioned cell, we should
determine at least the area-to-area visibility. That is inherently a
four-dimensional problem. In the proposed method, we efficiently express
four-dimensional visibility information on two-dimensional spaces and keep it
within a ternary tree. which is conceptually similar to a BSP (Binary Space
Partitioning) tree, by exploiting the characteristics of conservative
visibility. Keywords: Conservative Visibility, Occlusion Culling, Visibility Determination,
Visibility Preprocessing | |||
| Fast perception-based depth of field rendering | | BIBAK | Full-Text | 129-133 | |
| Jurriaan D. Mulder; Robert van Liere | |||
| Current algorithms to create depth of field (DOF) effects are either too
costly to be applied in VR systems, or they produce inaccurate results. In this
paper, we present a new algorithm to create DOF effects. The algorithm is based
on two techniques: one of high accuracy and one of high speed but less
accurate. The latter is used to create DOF effects in the peripheral viewing
area where accurate results are not necessary. The first is applied to the
viewing volume focussed at by the viewer. Both techniques make extensive use of
rendering hardware, for texturing as well as image processing. The algorithm
presented in this paper is an improvement over other (fast) DOF algorithms in
that it is faster and provides better quality DOF effects where it matters
most. Keywords: depth of field rendering, virtual reality | |||
| A new BSP tree framework incorporating dynamic LoD models | | BIBAK | Full-Text | 134-141 | |
| Zhigeng Pan; Zhiliang Tao; Chiyi Cheng; Jiaoying Shi | |||
| In this paper we present a new BSP (Binary Space Partitioning (BSP) tree.
BSP trees are one of the most successful space partitioning techniques, since
they allow both object modeling and classification in one single structure. In
this paper, we present a new framework designed for a multi-resolution modeling
system that incorporates the BSP tree structure and dynamic levels of detail
models. It has the advantages of both BSP and multi-resolution representations.
The tree construction and traversal routines for the multi-resolution BSP tree
are discussed in detail. Images and timing for our implementation are provided. Keywords: BSP trees, Multi-resolution modeling, mesh simplification, real-time
rendering | |||
| Developing an efficient technique of selection and manipulation in immersive V.E. | | BIBAK | Full-Text | 142-146 | |
| Chang Geun Song; No Jun Kwak; Dong Hyun Jeong | |||
| An Interaction Task in Virtual Reality is such that a user can modify a
computer generated virtual world using various techniques. But current
interaction techniques cannot be applicable for most virtual environments due
to their inefficiency and inconvenience. In this paper, we propose a selection
and manipulation technique called the Finger-gesture. We evaluate its
usefulness by conducting quantitative and qualitative experiments within a
specific environment. Results indicate our new technique is more efficient in
selection and modification tasks than other existing techniques including Go-Go
and Ray-casting in terms of the task completion time and accuracy. Keywords: 3D interaction technique, Finger-Gesture, Go-Go, Ray-casting, Virtual
Reality | |||
| Immersive graph navigation using direct manipulation and gestures | | BIBAK | Full-Text | 147-152 | |
| Noritaka Osawa; Kikuo Asai; Yuji Y. Sugimoto | |||
| An immersive graph visualization and navigation system is proposed. Its
visualization is based on a multiple-focus layout technique using heat models.
Virtual temperatures influence the graph layout. The navigation uses a
combination of the layout technique and hand gestures. The system allows one to
have multiple-focus nodes and to move a focus by direct manipulation and hand
gestures dynamically. Direct manipulation by hand can arrange nodes and choose
focus nodes. Hand gestures can control a focus area using a spotlight-like heat
radiation, A forefinger points the direction of the spotlight and an angle
between the forefinger and the thumb controls a spread angle of the spotlight.
This technique enables one to navigate a graph in an immersive virtual space. Keywords: direct manipulation, graph navigation, graph visualization, hand gestures,
heat models | |||
| VR user interface: closed world interaction | | BIBAK | Full-Text | 153-159 | |
| Ching-Rong Lin; R. Bowen Loftin | |||
| In this paper, we describe a user interface technique that uses a bounding
box as a metaphor to facilitate interaction in a Virtual Reality (VR)
environment. Because this technique is based on the observation that some of
the VR application fields are contained in a closed world, we call it Closed
World Interaction (CWI). After the user defines a closed world, the necessary
virtual buttons are shown around the closed world which is presented by a
frame. These virtual buttons are then used to interact with models. We also
integrate some of the 2D Windows, Icons, Mouse and Pointer (WIMP) metaphors
into CWI technique, reflecting our belief that users will be able to adapt to
this environment quickly, A series of user studies were conducted to
investigate the effectiveness of this technique. The results indicate that
users can define a closed world quickly. Experience appears to be an important
factor, and users can be trained to become familiar with CWI in the VR
environment. The constrained interactions can also enhance the accuracy of
selection. Two-handed manipulation somewhat improves the speed. Keywords: 3D interaction, Virtual Reality and visualization | |||
| Virtual reality for education? | | BIBAK | Full-Text | 160-165 | |
| Don Allison; Larry F. Hodges | |||
| It is still unclear what, if any, impact virtual reality will have on public
education. The virtual reality gorilla system is being used as a testbed to
study if and how virtual reality might be useful as an aid in educating middle
school children, and to investigate the issues that arise when building virtual
reality systems for knowledge acquisition and concept formation. Keywords: Virtual reality, education, middle school | |||
| Animated deformations with radial basis functions | | BIBAK | Full-Text | 166-174 | |
| Jun-yong Noh; Douglas Fidaleo; Ulrich Neumann | |||
| We present a novel approach to creating deformations of polygonal models
using Radial Basis Functions (RBFs) to produce localized real-time
deformations. Radial Basis Functions assume surface smoothness as a minimal
constraint and animations produce smooth displacements of affected vertices in
a model. Animations are produced by controlling an arbitrary sparse set of
control points defined on or near the surface of the model. The ability to
directly manipulate a facial surface with a small number of point motions
facilitates an intuitive method for creating facial expressions for virtual
environment applications such as an immersive teleconferencing system or
entertainment. Smooth deformations of the human face or other models are
possible and illustrated with examples of a variety of expressions and mouth
shapes. Keywords: Facial Animation, Geometry Deformation, MPEG-4, Radial Basis Functions | |||
| A simplified deformation for real-time 3D character animation | | BIBAK | Full-Text | 175-182 | |
| Sang-Won Ghyme; Ki-Hong Kim; Hyun-Bin Kim | |||
| The basic ideas for realistic and real-time animation of 3D character are
described through three steps. First, we just choose two deformations among all
kinds of deformations that happen in the human body, because these deformations
are globally noticed and can be performed in real-time. Second, we decide what
body parts of a character are deformed from the anthropometrics data. Last, we
propose simple and fast implementations for two deformations. Using proposed
ideas, the authoring tool that make a deformable character from a rigid polygon
model and test deformation of it, is introduced. And the animation player to
animate a deformable character generated from the authoring tool is also
introduced. Keywords: Computer Animation, Computer Graphics, Deformation, Modeling, Modeling Tool,
Motion Player, Real-Time, Skeleton, Virtual Character, Virtual Human, Virtual
Reality | |||
| Web-based 3D media information system | | BIBAK | Full-Text | 183-187 | |
| Yong-Moo Kwon; Ig-Jae Kim; Sang Chul Ahn; Hyoung-Gon Kim | |||
| This paper introduces web-based 3D media information system. We first
address two promising 3D modeling techniques, i.e., image-based 3D modeling and
laser scanning based 3D modeling. Especially, we present two approaches of the
image-based 3D modeling. One is an off-line approach using multiview images
which is captured with single camera and a robot arm. The another one is an
on-line approach that extends a commercial triclops camera system. We also
utilize a 3D modeling scheme based on a laser scanner and a 3D reverse modeler.
Using our 3D modeling environments, we construct several kinds of 3D models. We
also implement web-based 3D media information management and retrieval system
using XML data server, which provides services of 3D models. Our web-based 3D
media information system has a goal of services of various types of 3D models
and contents through WWW, which is currently focused on the development and
management of 3D models of Korea cultural heritage. Keywords: 3D media information system, Image-based 3D modeling, laser scanning based
3D modeling | |||
| Direct haptic rendering of isosurface by intermediate representation | | BIBAK | Full-Text | 188-194 | |
| Kwong-Wai Chen; Pheng-Ann Heng; Hanqiu Sun | |||
| With the development of volume visualization methods, we can easily extract
meaningful information from volumetric data using interactive graphics and
imaging. Haptic interaction of volumetric data adds a new modality to volume
visualization that has an advantage in presenting complex attributes of local
region. However, the benefits of haptic rendering of volumetric data have only
been recognized recently. Most traditional haptic rendering methods are
developed to compute realistic interaction force with geometric primitives.
Direct volume haptic rendering allows haptic palpation of volumetric data, but
lacks of the ability of simulating the contact sensation of stiff embedded
implicit surface.
In this paper, we propose a direct haptic rendering method for isosurface in volumetric data using a point-based haptic feedback device, without the extraction of the isosurface to geometric representations such as polygons. Our algorithm extends the intermediate representation approach that had been introduced for dealing with complex virtual environment, to haptically render volumetric data. The algorithm uses a virtual plane as an intermediate representation of the implicit isosurface, and computes the point interaction force applied to the haptic interface based on this virtual plane. Using this approach, we are able to gain higher haptic servo rate for volumetric data. It makes maintenance of the stability of the simulation easier, and applicable to noisy data without preprocessing. We have developed our algorithm and tested with synthetic data and medical data, using the PHANToM haptic interface. Keywords: Force Feedback, Haptic Rendering, Virtual Reality, Volume Visualization | |||
| Dual projection-based VR system for the light weight motion-based driving simulator | | BIBAK | Full-Text | 195-198 | |
| Sang-Hun Nam; Dong-Hoon Lee; Jang-Hwan Im; Young-Ho Chai | |||
| This paper proposes a projection-based VR system using the window and camera
projection paradigms simultaneously. This technique can be applied to the
Driving Simulator, which consists of 6 D.O.F. motion platform and projection
screens separated from the motion platform. Keywords: Driving Simulator, Motion Platform, Projection System, Quaternions, Virtual
Reality | |||
| Development of tension based haptic interface and possibility of its application to virtual reality | | BIBAK | Full-Text | 199-205 | |
| Seahak Kim; Masahiro Ishii; Yasuharu Koike; Makoto Sato | |||
| Continuous advances in computer technology are making it possible to
construct virtual environments with an ever-increasing sense of visual realism.
What is lacking are interfaces that allow users to manipulate virtual objects
in an intuitive manner. In this paper, we present a 7 DOF tension-based haptic
interface that allows users to not only grip an object but also to sense an
object's width. We have developed a system to utilize the physical action of
gripping to display grasp manipulation in virtual environments. We also present
a method to calculate the position and display force associated with this
gripping mechanism. Finally, we show the validity of our proposed haptic
interface through examples. Keywords: 7DOF, SPIDAR-G, Tension based haptic interface | |||
| Incorporating co-presence in distributed virtual music environment | | BIBAK | Full-Text | 206-211 | |
| Byungdae Jung; Jaein Hwang; Sangyoon Lee; Gerard Jounghyun Kim; Hyunbin Kim | |||
| In this paper, we present "PODIUM (POstech Distributed virtual Music
environment)", a distributed virtual environment that allows users to
participate in a shared space and play music with other participants in a
collaborative manner. In addition to playing virtual instruments, users can
communicate and interact in various ways to enhance the collaboration and,
thus, the quality of the music played together. Musical messages are generated
note by note through interaction with the keyboard, mouse, and other devices,
and transmitted through an IP-multicasting network among participants. In
addition to such note-level information, additional messages for visualization,
and interaction are supported. Real world based visualization has been chosen,
against, for instance, abstract music world based visualization, to promote
"co-presence" (e.g. recognize and interact with other players), which is deemed
important for collaborative music production. In addition to the entertainment
purpose, we hope that DVME will find great use in casual practice sessions for
even professional performers/orchestras/bands.
Since even a slight interruption in the flow of the music or out-of-synch graphics and sound would dramatically decrease utility of the system, we employ various techniques to minimize the network delay. An adapted server-client architecture and UDP's are used to ensure fast packet deliveries and reduce the data bottleneck problem. Time-critical messages such as MIDI messages are multicasted among clients, and the less time-critical and infrequently updated messages are sent through the server. Predefined animations of avatars are invoked by interpreting the musical messages. Using the latest graphics and sound processing hardware, and by maintaining an appropriate scene complexity, and a frame rate sufficiently higher than the fastest note duration, the time constraint for graphics and sound synchronization can be met. However, we expect the network delay could cause considerable problems when the system is scaled up for many users and processing simultaneous notes (for harmony). To assess the scalability, we carried out a performance analysis of our system model to derive the maximum number of simultaneous participants. For example, according to our data, about 50 participants should be able to play together without significant disruption, each using one track with five simultaneous notes and for playing a musical piece at a speed of 16 ticks per second in a typical PC/LAN environment. In hopes of enhancing the feeling of "co-presence" among participants, a simple sound localization technique is used to compute panning and relative volumes from positions and orientations of participants. This reduced sound localization model is used also in order to minimize the computational cost and the network traffic. Participants can send predefined messages by interacting with the keyboard, mouse, and other input devices. All of the predefined messages are mapped into simple avatar motions, such as playing various types of instruments (players), making applause (audience), and conducting gestures (conductors). We believe that for coordinated music performance, indirect interaction will be the main interaction method, for example, exchanging particular gestures, signals, and voice commands to synchronize music, confirming and reminding expression of the upcoming portion of the music, and just exchanging glances to enjoy each others' emotion. In this view, there would be mainly three groups of participants: conductor, players, and the audience, playing different roles, but creating co-presence together through mutual recognition. We ran a simple experiment comparing the music performance of two groups of participants, one provided with co-presence cues and the other without, and found no performance edge by the group with the co-presence cues. Such a result can serve as one guideline for building music-related VR applications. Keywords: Co-presence, Distributed Virtual Reality, Interaction, Networked Virtual
Reality, Virtual Music | |||