Showing papers on "Mixed reality published in 2000"

Interactive Occlusion and Collision of Real and Virtual Objects in Augmented Reality

Abstract: We present several techniques for interactively performing occlusion and collision detection between static real objects and dynamic virtual objects in augmented reality. Computer vision algorithms are used to acquire data that model aspects of the real world. Either geometric models may be registered to real objects, or a depth map of the real scene may be extracted with computer vision algorithms. The computer vision-derived data are mapped into algorithms that exploit the power of graphics workstations, in order to interactively produce new effects in augmented reality. By combining live video from a calibrated camera with real-time renderings of the real-world data from graphics hardware, dynamic virtual objects occlude and are occluded by static real objects. As a virtual object is interactively manipulated collisions with real objects are detected, and the motion of the virtual object is constrained. Simulated gravity may then be produced by automatically moving the virtual object in the direction of a gravity vector until it encounters a collision with a real object.

Game apparatus for mixed reality space, image processing method thereof, and program storage medium

Abstract: A game apparatus allows a virtual object to act in a mixed reality space as if it had its own will. A player can play a game with the virtual object. Rules for controlling the action patterns of the virtual object on the basis of the objective of the game, and the relative positional relationship between the virtual object and the real object is pre-stored. The next action pattern of the virtual object is determined based on an operator command, the stored rule(s), a simulation progress status, and geometric information of a real object(s).

Interactive animation of cloth-like objects for virtual reality

Abstract: Modeling and animation of cloth has experienced important developments in recent years. As a consequence, complex textile models can be used to realistically drape objects or human characters in a fairly efficient way. However, real-time realistic simulation remains a major challenge, even if applications are numerous, from rapid prototyping to e-commerce. In this paper, we present a stable, real-time algorithm for animating cloth-like materials. Using a hybrid explicit/implicit algorithm, we perform fast and stable time integration of a physically-based model with rapid collision detection and response, as well as wind or liquid drag effects to enhance realism. We demonstrate our approach through a series of examples in VR environments, proving that real-time animation of cloth, even on low-end computers, is now achievable.

Mixed reality apparatus and mixed reality presentation method

Abstract: This invention provides a mixed reality apparatus and mixed reality presentation method, which can present reality even when a plurality of players share a common mixed reality space. Virtual objects (41–47) are superposed to hide devices such as an HMD and the like that another player wears.

Design of Virtual Reality Systems for Education: A Cognitive Approach

Abstract: One of the main problems with virtual reality as a learning tool is that there are hardly any theories or models upon which to found and justify the application development. This paper presents a model that defends the metaphorical design of educational virtual reality systems. The goal is to build virtual worlds capable of embodying the knowledge to be taught: the metaphorical structuring of abstract concepts looks for bodily forms of expression in order to make knowledge accessible to students. The description of a case study aimed at learning scientific categorization serves to explain and implement the process of metaphorical projection. Our proposals are based on Lakoff and Johnson's theory of cognition, which defends the conception of the embodied mind, according to which most of our knowledge relies on basic metaphors derived from our bodily experience.

Acting in virtual reality

Abstract: Three pairs of professional actors and a director each met in a shared non-immersive virtual reality system over a two-week period to rehearse a short play. The actors and director never met one another physically until a short time before a live rehearsal in front of an audience. The actors were represented by avatars which could be controlled to make a range of facial expressions, and some body movements, including navigation through the space. The study examined the extent to which virtual reality could be used by the actors and director to rehearse their later live performance. Four indicators captured by questionnaires show that over the period of the four days their sense of presence in the virtual rehearsal space, their co-presence with the other actor, and their degree of cooperation all increased. Moreover their evaluation of the extent to which the virtual rehearsal was similar to a real rehearsal also increased. Debriefing sessions with the actors and director are reported, which suggest that a performance level was reached in the virtual rehearsal which formed the basis of a successful live performance.

Revealing the realities of collaborative virtual reality

Abstract: We look at differences between the experience of virtual environments and physical reality, and consider making the technical limitations which cause these differences 'visible', aiming to provide resources to enhance communication between users. Three causes of such discrepancies are considered to illustrate this idea: field-of-view; haptic feedback; and network delays. For each, we examine ways of revealing the limitations of the virtual world as resources to better understand the intricacies of system and co-user behaviour. These examples introduce a broader discussion of design issues involved in producing interfaces for day-to-day collaboration through virtual environments. Issues include: the application and activity undertaken through the virtual world; the ability to focus on the business at hand rather than the system in use; and extent of users' familiarity with application and system.

Welbo: an embodied conversational agent living in mixed reality space

Abstract: This paper introduces a new type of anthropomorphic agent that lives in a 3D space where the real and virtual worlds are seamlessly merged. In this mixed reality (MR) space, people wearing a see-through head-mounted display can interact with both physical and virtual objects in real time. In this type of MR space, an embodied conversational agent, named "Welbo," is implemented to study how agent technology contributes. This agent has several unique features, compared with the conventional desktop agent.

Something from nothing: augmenting a paper-based work practice via multimodal interaction

Abstract: In this paper, we describe Rasa: an environment designed to augment, rather than replace, the work habits of its users. These work habits include drawing on Post-it™ notes using a symbolic language. Rasa observes and understands this language, assigning meaning simultaneously to objects in both the physical and virtual worlds. With Rasa, users rollout a paper map, register it, and move the augmented objects from one place to another on it. Once an object is augmented, users can modify the meaning represented by it, ask questions about that representation, view it in virtual reality, or give directions to it, all with speech and gestures. We examine the way Rasa uses language to augment objects, and compare it with prior methods, arguing that language is a more visible, flexible, and comprehensible method for creating augmentations than other approaches.

SeamlessDesign for 3D object creation

Abstract: The paper discusses SeamlessDesign, a novel collaborative workspace for rapid creation of 3D objects with constraints. Its seamless design supports both shape and behavioral designs of 3D objects in a unified and intuitive manner. Virtual and augmented setups support both multiple perspectives for parallel activity and face-to-face interaction for rich awareness.

An optical see-through display for mutual occlusion of real and virtual environments

Abstract: In a mixed reality system, mutual occlusion of real and virtual environments enhances the user's feeling that virtual objects truly exist in the real world. However, conventional optical see-through displays cannot present mutual occlusion correctly since the synthetic objects always appear as semi-transparent ghosts floating in front of the real scene. In this paper, we propose a novel display design that attacks this well-known unsettled problem. Our optical see-through display with mutual occlusion capability has the following advantages: (1) since the light-blocking mechanism is embedded in the display and no additional setting is needed, it can be used anywhere, e.g. outdoors; (2) since incoming light can easily be cut off in any situation, virtual images keep their original intended colors, e.g. black; (3) since the light-blocking mechanism is separated from the display for color graphics, most existing see-through displays can be employed. We also describe our prototype display, which has confirmed the effectiveness of the approach.

Virtualized architectural heritage: new tools and techniques

Abstract: Technology has come a long way in solving many of the early limitations of virtual reality (VR) and virtual worlds have quietly found growing acceptance in selected areas. However, issues of graphic quality and speed has dogged virtual world heritage developers, forcing simplistic representations and triggering criticism from the heritage community. In addition, until recently there was also a lack of inexpensive software and data standards (such as QuickTimeVR and Virtual Reality Modeling Language, or VRML) for creating visually realistic interactive environments. Although significant advances have been made, the accurate virtual representation of historic and cultural landmarks has been limited by a lack of tools to quickly, inexpensively, and accurately model reality. The representation of built heritage requires two distinct forms of 3D data, current, real-world conditions and virtual or theorized historical interpretations. We call the combination of the two forms virtualized as opposed to virtual. Despite the use of numerous measurement technologies in traditional heritage work, existing tools lacked the optimal mix of features required for virtualized architectural environments. Dissatisfied with available choices. We began an extensive analysis of available technologies. In this article, we review results in heritage projects with two emerging systems.

Traversable interfaces between real and virtual worlds

Abstract: Traversable interfaces establish the illusion that virtual and physical worlds are joined together and that users can physically cross from one to the other. Our design for a traversable interface combines work on tele-embodiment, mixed reality boundaries and virtual environments. It also exploits non-solid projection surfaces, of which we describe four examples. Our design accommodates the perspectives of users who traverse the interface and also observers who are present in the connected physical and virtual worlds, an important consideration for performance and entertainment applications. A demonstrator supports encounters between members of our laboratory and remote visitors.

Toward spontaneous interaction with the Perceptive Workbench

Abstract: Until now, we have interacted with computers mostly by using wire-based devices. Typically, the wires limit the distance of movement and inhibit freedom of orientation. In addition, most interactions are indirect. The user moves a device as an analog for the action created in the display space. We envision an untethered interface that accepts gestures directly and can accept any objects we choose as interactors. We discuss methods for producing more seamless interaction between the physical and virtual environments through the Perceptive Workbench. We applied the system to an augmented reality game and a terrain navigating system. The Perceptive Workbench can reconstruct 3D virtual representations of previously unseen real-world objects placed on its surface. In addition, the Perceptive Workbench identifies and tracks such objects as they are manipulated on the desk's surface and allows the user to interact with the augmented environment through 2D and 3D gestures.

Virtual heritage: what next?

Abstract: Virtual heritage is the use of computer-based interactive technologies to record, preserve or recreate artifacts, sites and actors of historic, artistic, religious and cultural significance and to deliver the results openly to a global audience in such a way as to provide formative educational experiences through electronic manipulations of time and space. Where do we go from here, and what can we expect in the next decade? Already we're witnessing the evolution of systems making virtual reality (VR) accessible to social and working groups for applications hitherto considered out of the question. For those with just a basic PC and access to the Web, VR is now a technology that promotes active participation, through contributions to virtual libraries or repositories, or becoming involved as avatars (virtual humans) in shared electronic communities. We can now harness the power of video games engines, backed up with tutorials, patches and 3D model libraries from the Web. VR is no longer a limited sensory experience, accessible to a few fortunate individuals. Neither is it a technology destined to replace the real experience of traveling to a historical site or museum and experiencing the true ambience and splendor of the past first-hand. It's a means by which we can increase our understanding of (and respect for) our sociological, cultural and natural past, with the ultimate aim of making our future a more rewarding experience for those yet to come.

The virtual round table - a collaborative augmented multi-user environment

Abstract: Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. CVE 2000 San Francisco CA USA Copyright ACM 2000 1-58113-303-0/00/09...$5.00 ABSTRACT Existing immersed virtual reality and particularly augmented reality systems are usually based on dedicated and expensive hardware and I/O devices. Nevertheless they often provide limited support for the collaboration between multiple users and can hardly be used for arbitrary location independent application environments. Additionally, navigation and interaction within such virtual environments are not very natural or intuitive, making them difficult to use. This paper will introduce a new collaborative augmented reality environment the Virtual Round Table. This environment is designed to support location-independent mixed reality applications, overcoming the limitations for collaboration and interaction of existing approaches. Moreover it extends the physical workplace of the users into the virtual environment, while preserving traditional verbal and non-verbal communication and cooperation mechanisms.

Telepointer: Hands-free completely self-contained wearable visual augmented reality without headwear and without any infrastructural reliance

Abstract: Telepointer is a wearable hands-free, headwear-free device that allows the wearer to experience a visual collaborative telepresence, with text, graphics, and a shared cursor, displayed directly on real world objects. It is completely portable and can be used almost anywhere since it does not rely on infrastructure. It is operated through a Reality User Interfaces (RUI) that allows direct interaction with the real world, establishing a kind of computing that is completely free of metaphors.

Augmented Reality Using Uncalibrated Video Sequences

Abstract: Augmented Reality (AR) aims at merging the real and the virtual in order to enrich a real environment with virtual information. Augmentations range from simple text annotations accompanying real objects to virtual mimics of real-life objects inserted into a real environment. In the latter case the ultimate goal is to make it impossible to differentiate between real and virtual objects. Several problems need to be overcome before realizing this goal. Amongst them are the rigid registration of virtual objects into the real environment, the problem of mutual occlusion of real and virtual objects and the extraction of the illumination distribution of the real environment in order to render the virtual objects with this illumination model. This paper will unfold how we proceeded to implement an Augmented Reality System that registers virtual objects into a totally uncalibrated video sequence of a real environment that may contain some moving parts. The other problems of occlusion and illumination will not be discussed in this paper but are left as future research topics.

System lag tests for augmented and virtual environments

Abstract: We describe a simple technique for accurately calibrating the temporal lag in augmented and virtual environments within the Enhanced Virtual Hand Lab (EVHL), a collection of hardware and software to support research on goal-directed human hand motion. Lag is the sum of various delays in the data pipeline associated with sensing, processing, and displaying information from the physical world to produce an augmented or virtual world. Our main calibration technique uses a modified phonograph turntable to provide easily tracked periodic motion, reminiscent of the pendulum-based calibration technique of Liang, Shaw and Green. Measurements show a three-frame (50 ms) lag for the EVHL. A second technique, which uses a specialized analog sensor that is part of the EVHL, provides a “closed loop” calibration capable of sub-frame accuracy. Knowing the lag to sub-frame accuracy enables a predictive tracking scheme to compensate for the end-toend lag in the data pipeline. We describe both techniques and the EVHL environment in which they are used.

A framework for the structured design of VR/AR content

Abstract: 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 conten we want to supply designers and content experts of complex virtual environments with a component based to olset for the structured design of the visual and abstract components of 3D applications.

Augmented Reality: An Application for Architecture

Abstract: Virtual reality (VR) can be used as a powerful, three dimensional method to interface with computers. By wearing a head mounted audio-visual display, position and orientation sensors, and tactile interface devices, one can actively inhabit an inclusive computer generated environment. Another area of computing that has seen substantial progress is mobile computing. With computing devices diminishing in size and with options like wireless networking, a user is no longer limited to his physical desktop. Augmented reality (AR) works on similar principles as virtual reality. Yet, unlike VR where the user is immersed in a completely virtual environment, augmented reality overlays virtual objects and data on the real world. This is usually achieved using see-through head mounted displays and tracking devices. The critical problem with present augment reality systems is the lack of real-time speed and accurate tracking. Because we are overlaying information over the real world, small errors in tracking information are easily detected by the human eye. Considerable experimentation and research is currently underway surrounding the use of VR in the architectural design process. Architecture will also be affected as AR based systems become more powerful. Augmented reality based systems combined with wearable computers will become powerful new tools with a wide range of applications for architecture. This paper describes an augmented reality system as a facility management tool.

DDDOOLZ. A Virtual Reality Sketch Tool for Early Design

Abstract: This paper presents DDDoolz, a desktop-VR three-dimensional voxel sketchtool. DDDoolz is developed in the Design Systems Group to explore the use of Virtual Reality technology in the early design stage. The aim is to offer a sketch-like environment in VR with an unobtrusive interface. The paper presents DDDoolz, how it is used in education and with partners in architectural practice, and some future developments.

Collaborative augmented reality environments: integrating VR, working materials, and distributed work spaces

Abstract: In this work, we present a new method for displaying stereo scenes, which speeds up the rendering time of complex geometry. We first discuss a scene splitting strategy, allowing us to partition objects to the distant background or the near foreground. Furthermore, wededuce a computation rule for positioning a cutting plane in the scene.

Out and About — Real World Teleconferencing

Abstract: Videoconferencing has traditionally been confined to desktop or office environments. However, a large percentage of the workforce is engaged in mobile occupations away from the desktop. In this paper we describe how augmented reality can be used to develop new forms of teleconferencing to support these workers. To provide an example of one approach, we have developed an augmented reality system that allows virtual avatars and live video of remote collaborators to be superimposed over any real location. Viewed in a lightweight headmounted display, the remote collaborators appear as part of the user's real environment. We present results comparing conferencing in this setting with traditional desktop audio and video conferencing.

Virtually nothing: re-evaluating the significance of cyberspace

Abstract: This paper provides a critical analysis of virtual environments made in recent leisure and cultural studies discussions, which claim virtual reality to be the technotopia of post-modern society. Such positions describe virtual realities as worlds of infinite freedom, which transcend human subjectivity and where identity becomes no longer burdened by the prejudices of persons. Arguing that cyberspace offers little more than a token gesture towards such liberation, the paper suggests a shift in focus from the power relations that might change or remain because of virtual environments, to an awareness of their implications for human beings. Such technologies as chat rooms, the Internet and cyber-sex, are used to illustrate the fundamental challenge of virtual leisure to the human condition. This human condition is often presumed to represent ‘reality/actuality’ and, as such, is said to be in contrast to virtual environments. However, this paper extends its critique of virtual reality, by questioning such a d...

Augmented Reality with Back-Projection Systems using Transflective Surfaces

Abstract: In this paper, we describe the use of a hand-held semi-transparent mirror to support augmented reality tasks with back-projection systems. This setup overcomes the problem of occlusion of virtual objects by real ones linked with such display systems. The presented approach allows an intuitive and effective application of immersive or semi-immersiv e virtual reality tasks and interaction techniques to an augmented surrounding space. Thereby, we use the tracked mirror as an interactive image-plane that merges the reflected graphics, which are displayed on the projection plane, with the transmitted image of the real environment. In our implementation, we also address traditional augmented reality problems, such as real-object registration and virtual-object occlusion. The presentation is complemented by a hypothesis of conceivable further setups that apply transflective surfaces to support a mixed reality (i.e., combined AR and VR) environment.

Augmented reality for real and virtual humans

Abstract: Current virtual reality technologies provide many ways to interact with virtual humans. Most of those techniques, however, are limited to synthetic elements and require cumbersome sensors. We have combined a real-time simulation and rendering platform with a real-time, non-invasive vision-based recognition system to investigate interactions in a mixed environment with real and synthetic elements. In this paper, we present the resulting system, the example of a checkers game between a real person and an autonomous virtual human to demonstrate its performance.

Construction of an immersive mixed environment using an omnidirectional stereo image sensor

Abstract: Recently virtual reality (VR) systems have been incorporating rich information available in the real world into VR environments in order to improve their reality. This stream has created the field of mixed reality which seamlessly integrates real and virtual worlds. This paper describes a novel approach to the construction of a mixed environment. The approach is based on capturing the dynamic real world by using a video-rate omnidirectional stereo image sensor. The mixed environment is constructed of two different types of models: (1) texture-mapped cylindrical 3-D model of dynamic real scenes and (2) 3-D computer graphics (CG) model. The cylindrical 3-D model is generated from full panoramic stereo images obtained by the omnidirectional sensor that uses a pair of hexagonal pyramidal mirrors and twelve CCD cameras. A prototype system has been developed to confirm the feasibility of the proposed method, in which panoramic binocular stereo images of the mixed environment are projected on a cylindrical immersive display depending on user's viewpoint in real time.