We present Anu.js, a toolkit for web-based immersive analytics (IA). The IA design space is vast, multi-faceted, and everchanging, challenging development in the absence of robust authoring support. The web is a popular platform for visualization applications, research, and teaching, and by leveraging the benefits of web technologies and adopting imperative authoring paradigms we can achieve the necessary expressiveness, compatibility, and ergonomics to support IA research and development. Anu.js adapts D3’s data-binding model to 3D contexts, granting fine-grained control over the creation, representation, animation, performance, and interaction of 3D scene-graphs. Additionally, Anu.js offers declarative prefabs to support common visualization elements and interactions, and synergizes with popular visualization libraries which allows developers to leverage these proven utilities. We demonstrate Anu.js’s potential through our diverse example gallery, expert evaluation, and potential future applications. Through this, Anu.js empowers developers in accelerating the creation of novel and bespoke visualizations for immersive web-based applications.

Head-worn augmented reality (AR) allows audiences to be immersed and engaged in stories told by live presenters. While presenters may also be in AR to have the same level of immersion and awareness as their audience, this symmetric presentation style may diminish important social cues such as eye contact. In this work, we examine the effects this (a)symmetry has on engagement, group awareness, and social interaction in co-located one-on-one augmented presentations. We developed a presentation system incorporating 2D/3D content that audiences can view and interact with in AR, with presenters controlling and delivering the presentation in either a symmetric style in AR, or an asymmetric style with a handheld tablet. We conducted a within- and between-subjects evaluation with 12 participant pairs to examine the differences between these symmetric and asymmetric presentation modalities. From our findings, we extracted four themes and derived strategies and guidelines for designers interested in augmented presentations.

Mixed Reality (MR) has introduced innovative remote interaction opportunities in enterprise settings. Physical space sharing is a core aspect of MR, showing promise in remote training, meeting and guidance scenarios. However, this feature could pose security and privacy risks of exposing sensitive enterprise or employee data, as MR spatial sharing uses external cameras to capture physical space information. Despite these potential risks, little research has addressed the specific privacy and security challenges and their mitigations, motivating us to take an initial step in understanding this problem domain. In this poster, we aim to understand when employees share physical object and space during remote collaboration, the privacy and security concerns they have, and the use cases for physical space sharing they envision for their work. We conclude by outlining the next steps to address the challenges of designing privacy and security systems for employees and enterprise to minimize the risk associated with MR spatial sharing.

Social virtual worlds provide students in remote online courses with a unique approach to collaborative work and social interactions. However, the use of social virtual worlds in online learning raises concerns about what privacy and ethical issues students might encounter. To shed light on this topic, we examined college students' ( N = 68) ethical and privacy concerns about using social virtual worlds in multiple class sessions, courses, universities, virtual environments, and technologies. Students revealed (a) struggling to manage their identity between classmates and strangers, (b) discomfort over violations of their avatars' personal space, (c) problems of vulnerable populations experiencing harassment, nudity, and loneliness, and (d) concern over companies tracking and storing user data. In addition, the students described the technological advantages that mitigated their privacy and ethical concerns. We discuss the implications of our findings for the future of collaborative learning and the design of social virtual worlds.

Workplace mentorship is critical for career advancement, sense of belonging, and well-being. However, historically marginalized groups face barriers to effective mentorship including misaligned commitments, difficulty establishing comfort with mentors, and relationship persistence. We explore how 3D virtual environment (VE) counterspaces, or spaces that center the well-being of marginalized people, can circumnavigate these barriers and generate dedicated environments for workplace mentorship. We present Mentorship Garden: a digital counterspace designed to facilitate mentorship communication around commitments, goals, progress, and well-being. We deployed Mentorship Garden with 10 mentor-mentee pairs, recruited from DEI mentoring programs at a large global company, and interviewed them about their experiences. Overall, Mentorship Garden provided a relaxing space for participants to engage in rituals supporting historically marginalized individuals via mentorship, but revealed potential challenges in seamlessly integrating it in the workplace. We discuss design implications for creating virtual mentorship counterspaces in the workplace and opportunities for future research.

Hybrid options at conferences, which support in-person and remote attendance, have increasingly become the norm in order to broaden participation and promote sustainability. However, hybrid conferences are challenging, where in-person and remote attendees often have disjoint, parallel experiences with limited opportunity to interact with each other. To explore the potential for facilitating social interaction between in-person and remote conference attendees, we designed and built SocialMiXR, a research prototype that uses WebXR technologies to align the physical and virtual worlds into one hybrid space for socialization. We deployed SocialMiXR in a three-day field study with 14 in-person and remote attendees of an engineering conference. Our qualitative results demonstrate that participants felt they were together in the same conference experience, and formed meaningful connections with each other. At the same time, they faced difficulties balancing different realities and capabilities given their separate contexts. We discuss implications for the design of hybrid social experiences at conferences.

Drawbacks of online education, especially at scale, include the isolation and loss of community that come with taking classes from one's home rather than in a typical coordinated classroom. In this series of studies, we explore the potential of an immersive virtual environment to recreate shared educational contexts in an online program, emphasizing those that focus on universal dynamics like discussions, Q&A, and lecture-watching. Using Mozilla Hubs-which offers virtual reality as well as a browser-based immersive environment for participants without VR headsets-we implement three common, student-driven on-campus environments: a lecture hall, a student lounge, and a poster session. We test these environments with students in an online graduate program through surveys and a controlled experiment. We find significant interest in the potential of these environments, but hurdles to their adoption as well.

As online education proliferates, one concern that has been raised is that it may fail to capture desirable emergent phe-nomena from on-campus programs. Student community is one example of such a phenomenon: on-campus student communities thrive based on synchronous collocation. An online program might be designed to capture all deliberate constructs in an on-campus program, but there may be beneficial side effects of synchronous collocation that are not apparent. In this work, we examine the issue of social isolation in an online graduate program. By happenstance, three studies were conducted in relative isolation looking at social isolation from different angles. The first study exam-ined trajectories in social presence as a semester proceeded. The second study developed an understanding of students' needs with regard to community in an online program. The third study tested out an immersive virtual environment to try to improve students' sense of connectedness. Combin-ing their findings, we find compelling evidence of the exist-ence of a Synchronicity Paradox in online education: stu-dents desire synchronicity to form strong social communi-ties, and yet part of the chief appeal of these online pro-grams is their asynchronicity. In light of this finding, we provide design guidelines for how synchronicity may be reintroduced into asynchronous programs without sacrific-ing the benefits of asynchronicity. More specifically, we propose that scale itself may be the key to building emer-gent synchronicity.

Augmented reality technology is a unique medium that can be helpful for young children's entertainment and education, but in order to achieve the benefits of this technology, augmented reality experiences need to be appropriately designed for young children's developing physical and cognitive skills. In the present study we investigated how 5-10 year-old children react to typical handheld augmented reality interaction techniques such as crosshair selection and finger selection, in AR environments that require them to change perspective or not. Our analysis shows significant impacts of age upon AR performance, with young children having slower selection times, more tracking losses, and taking longer to recover tracking. Significant differences were also found between AR interaction technique conditions, with finger selection being faster than crosshair selection, and interactions which required changes in perspective taking longer, generating more tracking losses, and more errors in selection. Furthermore, by analyzing children's performance in relation to metrics of physical and cognitive development, we identified correlations between AR interaction techniques performance and developmental tests of spatial relations, block construction and visuomotor precision. Gender differences were analyzed but no significant effects were detected.

We demonstrate a method for redirecting gaze of virtual avatars in distributed augmented reality (AR) meetings. As social cues are a necessity for effective communication, our method tries to preserve gaze awareness, one of the key elements of a face-to-face meeting. When using AR to bring multiple sites together in a distributed meeting, with different numbers of participants and physical arrangements across sites, gaze awareness is maintained regardless of the seating topology. By maintaining gaze, we hope to enhance the presence of remote attendees and improve communication among the users, making meetings in AR a practical option for teleconferencing.

The goal of this project is to use projection augmented reality to add design studio learning models to a classroom for an introductory Media Computation computer science class. Students do classwork using an enhanced version of Pythy, a web IDE for Python and Jython, that captures students' work and displays it around the room. We leverage the Microsoft RoomAlive Toolkit to construct a room-scale augmented reality using pairs of projectors and depth cameras. The system “pins” students' work to the walls, where teachers and students can see and discuss the work. We hope that by seeing each other's work, the system will foster collaboration and support the creation of STEM learning experiences that encourage creativity, innovation, and help build strong peer learning environments.

The Designer's Augmented Reality Toolkit (DART) was an augmented (AR) and mixed reality (MR) authoring tool targeted at new media designers. It was released in 2003 and was heavily used by a diverse population of creators for the next several years [28]. Ten years later, we approached a group of users to collect reflections on their use of DART, the artifacts they produced, their subsequent AR/MR authoring, their thoughts on the challenges of AR/MR authoring in general, and the state of modern tools. In this paper we present the findings from in-depth interviews with these DART developers and other AR experts. Their reflections provide insights on how to successfully engage non-technologists with new media and the challenges they face during authoring, the unique requirements of new media authoring, and how modern tools are still not meeting the needs of this type of author, highlighting where additional research is needed.

RoomAlive is a proof-of-concept prototype that transforms any room into an immersive, augmented entertainment experience. Our system enables new interactive projection mapping experiences that dynamically adapts content to any room. Users can touch, shoot, stomp, dodge and steer projected content that seamlessly co-exists with their existing physical environment. The basic building blocks of RoomAlive are projector-depth camera units, which can be combined through a scalable, distributed framework. The projector-depth camera units are individually auto-calibrating, self-localizing, and create a unified model of the room with no user intervention. We investigate the design space of gaming experiences that are possible with RoomAlive and explore methods for dynamically mapping content based on room layout and user position. Finally we showcase four experience prototypes that demonstrate the novel interactive experiences that are possible with RoomAlive and discuss the design challenges of adapting any game to any room.

In this paper we present our experience of eliciting metaphors through the process of game design with children. For the purpose of determining a set of user interactions desired in children's augmented-reality experiences, we have conducted a study in which children used craft materials to design augmented-reality games. Game interactions and mappings between physical and virtual worlds were then analyzed to reveal metaphors in children's thinking. We describe the wide range of elicited metaphors, and argue for the use of game design as a process for metaphor elicitation.

Physical interfaces have been widely adopted in digital games. In our project, we research one such type of physical interface---handheld augmented reality interfaces, and aim to create an engaging and novel play experience. Designing such games requires us to combine knowledge from both Human-computer interaction and game design domains. In this paper, we present a few research questions that we raised or encountered during the process of designing and developing the handheld AR game NerdHerder. We also present our current solutions and answers to these questions. We are going to conduct user studies to understand how handheld AR games are played in the wild. We will release the game and let mobile device users play it in their natural environments. Through the process of designing and iterating NerdHerder, we call for more research that explores how to adopt HCI principles into game design.

The motivation of this workshop is to discuss future direction of content authoring in the field of Augmented Reality, as well as to discuss the current state of art on content creation and content authoring for augmented reality. The workshop will comprise of a paper session where authoring papers, late-breaking results and overviews over state-of-the-art are presented. In the afternoon, we will follow up with discussion sessions on different topics ranging from content creation and authoring to content distribution for AR and a short closing session.

Many augmented reality (AR) applications require a seamless blending of real and virtual content as key to increased immersion and improved user experiences. Photorealistic and non-photorealistic rendering (NPR) are two ways to achieve this goal. Compared with photorealistic rendering, NPR stylizes both the real and virtual content and makes them indistinguishable. Maintaining temporal coherence is a key challenge in NPR. We propose a NPR framework with support for temporal coherence by leveraging model-space information. Our systems targets painterly rendering styles of NPR. There are three major steps in this rendering framework for creating coherent results: tensor field creation, brush anchor placement, and brush stroke reshaping. To achieve temporal coherence for the final rendered results, we propose a new projection-based surface sampling algorithm which generates anchor points on model surfaces. The 2D projections of these samples are uniformly distributed in image space for optimal brush stroke placement. We also propose a general method for averaging various properties of brush stroke textures, such as their skeletons and colors, to further improve the temporal coherence. We apply these methods to both static and animated models to create a painterly rendering style for AR. Compared with existing image space algorithms our method renders AR with NPR effects with a high degree of coherence.

Augmented reality (AR) designers have great potential to enrich children's lives through AR experiences in education and entertainment. A significant difficulty in designing for children is that tremendous physical and cognitive development occurs across the first 10 years of life, and the changes in children's capabilities and limitations impact how these users respond to AR designs. Currently, little is known about how developmental changes relate to AR designs, or what AR designs are effective for young children. In this work, we focus on children 6–9 years old, presenting several concepts from developmental psychology and discussing how these relate to AR designs. Specifically, we investigate children's skills in the categories of motor abilities, spatial cognition, attention, logic and memory, and we discuss the relationship of these skills to current and hypothetical AR designs. Through this work, we intend to strengthen the field's understanding of AR usability and design, resulting in the generation of effective AR experiences for young users.

Mixed reality (MR), from location- and context-aware systems through immersive augmented reality applications, has been studied in research labs for more than two decades. With the advent of the modern smartphone, and the rapid adoption of wireless broadband technologies, this research is moving out of the lab and into the real world. Beyond just providing a platform for MR to reach a broad range of users, the capabilities and limitations of the smartphone provide a set of constraints on what kinds of applications can and cannot be delivered to consumers that have fundamentally changed how researchers think about MR. We examine previous definitions of MR, and reimagine the term as a class of experiences occurring in an ecosystem consisting of the smartphone, the cloud, and the user. Using a selection of current MR applications as a lens, we identify three key areas of continuing evolution and suggest how the development of a next-generation MR environment can help us channel the future growth of MR in research, industrial, and consumer communities.

Augmented Reality (AR) is becoming more interesting to a variety of research communities beyond the small group of researchers that have traditionally studied AR technology. From its earliest years, AR has been presented as a subset of Mixed Reality (MR), and both have been conceived of in terms of the technologies they use. However, while the definition of AR has been fixed for a number of years, MR is much more ambiguous. Through a re-examination of the accepted definition of AR, we derive a new definition of MR that centers on human experience rather than technology. Then, through discussion of a number of paradigmatic examples that fit this new definition, we generate a classification system for MR experiences based on the concept of spatial scale and its associated cognitive processes. Finally, we discuss how this new "scale model" of MR helps to identify key concepts that can be used in the design process of future MR experiences.

The motivation of this workshop is to discuss future directions of content authoring in the field of Augmented Reality, as well as to discuss the current state of art on content creation and asset assembly. The workshop will comprise of a paper session where papers, late-breaking results and overviews over state-of-the-art in content authoring for AR are presented. In the afternoon, we will follow up with a discussion on different topics ranging from AR asset creation to content distribution and a closing session. Our goal is to collect ideas and thoughts of research about desired approaches for authoring content for AR, as well as review current and future needs to achieve a high quality content and at the same time scalable approaches for AR.

In this poster, we present the idea of “virtual transparency” for video see-through AR. In fully synthetic 3D graphics, head-tracked motion parallax has been shown to be a powerful depth cue for understanding the structure of the virtual world. To leverage head-tracked motion parallax in video see-through AR, the view of the virtual and physical world must change together in response to head motion. We present a system for accomplishing this, and discuss the benefits and limitations of our approach.

A common vision of Augmented Reality (AR) is that of a person immersed in a diverse collection of virtual information, superimposed on their view of the world around them. If such a vision is to become reality, an ecosystem for AR must be created that satisfies at least these properties: multiple sources (or channels of interactive information) must be able to be simultaneously displayed and interacted with, channels must be isolated from each other (for security and stability), channel authors must have the flexibility to design the content and interactivity of their channel, and the application must fluidly integrate with the ever-growing cloud of systems and services that define our digital lives. In this paper, we present the design and implementation of the Argon AR Web Browser and describe our vision of an AR application environment that leverages the WWW ecosystem. We also describe KARML, our extension to KML (the spatial markup language for Google Earth and Maps), that supports the functionality required for mobile AR. We combine KARML with the full range of standard web technologies to create a standards-based web browser for mobile AR. KARML lets users develop 2D and 3D content using existing web technologies and facilitates easy deployment from standard web servers. We highlight a number of projects that have used Argon and point out the ways in which our web-based architecture has made previously impractical AR concepts possible.

Academic/Research Overview of Mobile Augmented Reality Introduction to the Qualcomm AR Platform — Features and Usage Scenarios Developing Mobile AR Applications using Qualcomm's Unity Extension Introduction to Qualcomm's QCAR SDK Native API Cross Platform Development with the Native QCAR SDK

What authoring possibilities arise by blending machine and human control of live embodied character experiences? This paper explores two different "behind-the-scenes" roles for human operators during a three-month gallery installation of an embodied character experience. In the Transcription role, human operators type players' spoken utterances; then, algorithms interpret the player's intention, choose from pre-authored dialogue based on local and global narrative contexts, and procedurally animate two embodied characters. In the Discourse role, human operators select from semantic categories to interpret player intention; algorithms use this "discourse act" to automate character dialogue and animation. We compare these two methods of blending control using game logs and interviews, and document how the amateur operators initially resisted having to learn the Discourse version, but eventually preferred having the authorial control it afforded. This paper also outlines a design space for blending machine and human control in live character experiences.

A seamless blending of the real and virtual worlds is key to increased immersion and improved user experiences for augmented reality (AR). Photorealistic and non-photorealistic rendering (NPR) are two ways to achieve this goal. Non-photorealistic rendering creates an abstract version of both the real and virtual world by stylization to make them indistinguishable. We presented a painterly rendering algorithm for AR applications. This algorithm paints composed AR video frames with bump-mapping curly brushstrokes. Tensor fields are created for each frame to define direction for brushstrokes. The anchor point of a brushstroke is tracked or warped from frame to frame. Brushstrokes are also reshaped to provide better temporal coherence. The major difference between our algorithm and existing NPR work in general graphics and AR/VR areas is we use feature points across composed AR video frames to maintain coherence in the rendering.

This paper discusses an experiment carried out in an AR test bed called “the pit”. Inspired by the well-known VR acrophobia study of Meehan et al. [18], the experimental goals were to explore whether VR presence instruments were useful in AR (and to modify them where appropriate), to compare additional measures to these well-researched techniques, and to determine if findings from VR evaluations can be transferred to AR. An experimental protocol appropriate for AR was developed. The initial experimental findings concern varying immersion factors (frame rate) and their effect on feelings of presence, user performance and behavior. Unlike the VR study, which found differing frame rates to affect presence measures, there were few differences in the five frame rate modes in our study as measured by the qualitative and quantitative instruments, which included physiological responses, a custom presence questionnaire, task performance, and user behavior. The AR presence questionnaire indicated users experienced a high feeling of presence in all frame rate modes. Behavior, performance, and interview results indicated the participants felt anxiety in the pit environment. However, the physiological data did not reflect this anxiety due to factors of user experience and experiment design. Efforts to develop a useful AR test bed and to identify results from a large data set has produced a body of knowledge related to AR evaluation that can inform others seeking to create AR experiments.

Widespread future adoption of augmented reality technology will rely on a broadly accessible standard for authoring and distributing content with, at a minimum, the flexibility and interactivity provided by current web authoring technologies. We introduce KHARMA, an open architecture based on KML for geospatial and relative referencing combined with HTML, JavaScript and CSS technologies for content development and delivery. This architecture uses lightweight representations that decouple infrastructure and tracking sources from authoring and content delivery. Our main contribution is a re-conceptualization of KML that turns HTML content formerly confined to balloons into first-class elements in the scene. We introduce the KARML extension that gives authors increase control over the presentation of HTML content and its spatial relationship to other content.

In this paper we introduce AR Scratch, the first augmented-reality (AR) authoring environment designed for children. By adding augmented-reality functionality to the Scratch programming platform, this environment allows pre-teens to create programs that mix real and virtual spaces. Children can display virtual objects on a real-world space seen through a camera, and they can control the virtual world through interactions between physical objects. This paper describes the system design process, which focused on appropriately presenting the AR technology to the typical Scratch population (children aged 8-12), as influenced by knowledge of child spatial cognition, programming expertise, and interaction metaphors. Evaluation of this environment is proposed, accompanied by results from an initial pilot study, as well as discussion of foreseeable impacts on the Scratch user community.

This paper describes an interactive Augmented Reality (AR) art installation based on, and in, an ISO (International Organization for Standardization) shipping container. The work was inspired by the book, "The Box" [1] written by Marc Levinson, and the theatrical work of Petr Sourek [2] which explores the persona of Malcom McLean, inventor of the shipping container as we know it today.

This paper describes the structure, format, and outcome of an experimental class in Handheld Augmented Reality Game Design conducted as an inter-institutional collaboration between the Georgia Institute of Technology and Savannah College of Art and Design. It analyzes several unique elements of the class, especially the need for rapid prototyping of multiple games when exploring game design using novel game technology, and highlights important issues regarding interdisciplinary collaboration and mobile augmented reality gaming. The paper also discusses several approaches taken by students in completing class assignments, which suggest viable design strategies for the creation of future handheld augmented reality experiences.

An ongoing research problem in Augmented Reality (AR) is to improve tracking and display technology in order to minimize registration errors. However, perfect registration is not always necessary for users to understand the intent of an augmentation. This paper describes the results of an experiment to evaluate the effects of registration error in a Lego block placement task and the effectiveness of graphical context at ameliorating these effects. Three types of registration error were compared: no error, fixed error and random error. These three errors were evaluated with no context present and some graphical context present. The results of this experiment indicated that adding graphical context to a scene in which some registration error is present can allow a person to effectively operate in such an environment, in this case completing the Lego block placement task with a reduced number of errors made and in a shorter amount of time.

An ongoing research problem in Augmented Reality (AR) is to improve tracking and display technology in order to minimize registration errors. However, perfect registration is not always necessary for users to understand the intent of an augmentation. This paper describes the results of an experiment to evaluate the effects of graphical context in a Lego block placement task when the graphics are located outside of the task area. Four conditions were compared: fully registered AR; non-registered AR; a heads-up display (HUD) with the graphics always visible in the field of view; and a HUD with the graphics not always visible in the field of view. The results of this experiment indicated that registered AR outperforms both non-registered AR and graphics displayed on a HUD. The results also indicated that non-registered AR does not offer any significant performance advantages over a HUD, but is rated as less intrusive and can keep non-registered graphics from cluttering the task space.

Registration errors between the physical world and computer- generated objects are a central problem in Augmented Reality (AR) systems. Some existing AR systems have demonstrated how to dynamically estimate registration errors based on estimates of spatial errors in the system. Using these error estimates, these systems also demonstrated a number of ways of ameliorating the effects of registration error. One central part of this previous work was the creation and use of error regions around objects; unfortunately, the analytic methods used only created accurate regions for simple convex objects. In this paper, we present a simple and stable algorithm for generating the uncertainty regions for complex objects, including non-convex objects and objects with interior holes. We demonstrate how our approach can be used to create a set of more accurate error-based highlights in the presence of registration error, and also be used as a general highlighting mechanism.

Massively Multiplayer Online Worlds (MMOs) are persistent virtual environments where people play, experiment and socially interact. In this paper, we demonstrate that MMOs also provide a powerful platform for Augmented Reality (AR) applications, where we blend together locations in physical space with corresponding places in the virtual world. We introduce the notion of AR stages, which are persistent, evolving spaces that encapsulate AR experiences in online three-dimensional virtual worlds. We discuss the concepts and technology necessary to use an MMO for AR, including a novel set of design concepts aimed at keeping such a system easy to learn and use. By leveraging the features of the commercial MMO Second Life, we have created a powerful AR authoring environment accessible to a large, diverse set of users.

Non-photorealistic rendering (NPR) is an attractive approach for seamlessly blending virtual and physical content in Augmented Reality (AR) applications. Simple NRP techniques, that use information from a single rendered image, have been demonstrated in real-time AR systems. More complex NRP techniques require visual coherence across multiple frames of video, and typical offline algorithms are expensive and/or require global knowledge of the video sequence. To use such techniques in real-time AR, fast algorithms must be developed that do not require information past the currently rendered frame. This paper presents a watercolor-like NPR style for AR applications with some degree of visual coherence.

In this paper we present the results of a qualitative, empirical study exploring the impact of immersive technologies on presence and engagement, using the interactive drama Façade as the object of study. In this drama, players are situated in a married couple's apartment, and interact primarily through conversation with the characters and manipulation of objects in the space. We present participants' experiences across three different versions of Façade -- augmented reality (AR) and two desktop computing based implementations, one where players communicate using speech and the other using typed keyboard input. Through interviews and observations of players, we find that immersive AR can create an increased sense of presence, confirming generally held expectations. However, we demonstrate that increased presence does not necessarily lead to more engagement. Rather, mediation may be necessary for some players to fully engage with certain interactive media experiences.

An ongoing research problem in Augmented Reality (AR) is to improve tracking and display technology in order to minimize registration errors. However, perfect registration is not always necessary for users to understand the intent of an augmentation. This paper describes the results of an experiment to evaluate the effects of registration error in a Lego block placement task and the effectiveness of graphical context at ameliorating these effects. Three types of registration error were compared: no error, fixed error and random error. These three errors were evaluated with no context present and some graphical context present. The results of this experiment indicated that adding graphical context to a scene in which some registration error is present can allow a person to effectively operate in such an environment, in this case completing the Lego block placement task with a reduced number of errors made and in a shorter amount of time.

Our demonstration presents AR Façade, a phyiscally embodied version of the interactive drama Façade, at the Beall Center in Irvine, CA. In this drama, players are situated in a married couple's apartment, and interact primarily through conversation with the characters and manipulation of objects in the space. Our demonstration will include two versions of the experience - an immersive augmented reality (AR) version and a desktop computing based implementation, where players communicate using typed keyboard input. Our recent study cross media study revealled emperical differences between the versions [Dow et al. 2007]. Through interviews and observations of players, we found that immersive AR can create an increased sense of presence, confirming generally held expectations. However, we learned that increased presence does not necessarily lead to more engagement. Rather, mediation may be necessary for some players to fully engage with certain immersive media experiences.

We present a concept for augmented reality entertainment, called AR Karaoke, where users perform their favorite dramatic scenes with virtual actors. AR Karaoke is the acting equivalent of traditional Karaoke, where the goal is to facilitate an acting experience for the user that is entertaining for both the user and audience. Prototype implementations were created to evaluate various user interfaces and design approach reveal guidelines that are relevant to the design of mixed reality applications in the domains of gaming, performance, and entertainment.

Butterfly effect is a 3D puzzle game using augmented reality. The key motivation was to create a game that leverages the structure of the physical world during gameplay without requiring the computer to have a detailed model of the space. The butterflies are virtual, but the space the player navigates is physical. The player travels her environment, collecting the butterflies. For butterflies that are out of reach, the player can rotate the virtual world in 90 degree chunks about an arbitrary axis to bring them to an accessible location.

A significant problem encountered when building Augmented Reality (AR) systems is that all spatial knowledge about the world has uncertainty associated with it. This uncertainty manifests itself as registration errors between the graphics and the physical world, and ambiguity in user interaction. In this paper, we show how estimates of the registration error can be leveraged to support predictable selection in the presence of uncertain 3D knowledge. These ideas are demonstrated in osgAR, an extension to OpenSceneGraph with explicit support for uncertainty in the 3D transformations. The osgAR runtime propagates this uncertainty throughout the scene graph to compute robust estimates of the probable location of all entities in the system from the user's viewpoint, in real-time. We discuss the implementation of selection in osgAR, and the issues that must be addressed when creating interaction techniques in such a system.

In this paper [MacIntyre et al 2004]. we describe The Designer's Augmented Reality Toolkit (DART). DART is built on top of Macromedia Director, a widely used multimedia development environment. We summarize the most significant problems faced by designers working with AR in the real world, and discuss how DART addresses them. Most of DART is implemented in an interpreted scripting language, and can be modified by designers to suit their needs. Our work focuses on supporting early design activities, especially a rapid transition from storyboards to working experience, so that the experiential part of a design can be tested early and often. DART allows designers to specify complex relationships between the physical and virtual worlds, and supports 3D animatic actors (informal, sketch-based content) in addition to more polished content. Designers can capture and replay synchronized video and sensor data, allowing them to work off-site and to test specific parts of their experience more effectively.

An important problem for augmented reality is registration error. No system can be perfectly tracked, calibrated or modeled. As a result, the overlaid graphics are not aligned perfectly with objects in the physical world. This can be distracting, annoying or confusing. In this paper, we propose a method for mitigating the effects of registration errors that enables application developers to build dynamically adaptive AR displays. Our solution is implemented in a programming toolkit called OSGAR. Built upon OpenSceneGraph (OSG), OSGAR statistically characterizes registration errors, monitors those errors and, when a set of criteria are met, dynamically adapts the display to mitigate the effects of the errors. Because the architecture is based on a scene graph, it provides a simple, familiar and intuitive environment for application developers. We describe the components of OSGAR, discuss how several proposed methods for error registration can be implemented, and illustrate its use through a set of examples.

In this paper we present an approach for exposing tracking technology in an accessible and flexible way to users of a rapid prototyping system for mixed (MR) and augmented reality (AR). Our system provides a tracking framework that alleviates the need for a high level of expertise while also presenting a model of the technology that allows for flexible modification of tracking configurations, the ability to quickly change an application from one type of tracking technology to another, and the creation of synthetic trackers for playback of prerecorded data, data fusion from multiple trackers, and wizard-of-oz applications.

In this paper, we describe The Designer's Augmented Reality Toolkit (DART). DART is built on top of Macromedia Director, a widely used multimedia development environment. We summarize the most significant problems faced by designers working with AR in the real world, and discuss how DART addresses them. Most of DART is implemented in an interpreted scripting language, and can be modified by designers to suit their needs. Our work focuses on supporting early design activities, especially a rapid transition from story-boards to working experience, so that the experiential part of a design can be tested early and often. DART allows designers to specify complex relationships between the physical and virtual worlds, and supports 3D animatic actors (informal, sketch-based content) in addition to more polished content. Designers can capture and replay synchronized video and sensor data, allowing them to work off-site and to test specific parts of their experience more effectively.

This demonstration highlights the Designer's Augmented Reality Toolkit (DART), a system that allows users to easily create augmented reality (AR) experiences. Over the past year our research has focused on the creation of this toolkit that can be used by technologists, designers, and students alike to rapidly prototype AR applications. Current approaches to AR development involve extensive programming and content creation as well as knowledge of technical topics involving cameras, trackers, and 3D geometry. The result is that it is very difficult even for technologists to create AR experiences. Our goal was to eliminate these obstacles that prevent such users from being able to experiment with AR. The DART system is based on the Macromedia Director multimedia-programming environment, the de facto standard for multimedia content creation. DART uses the familiar Director paradigms of a score, sprites and behaviors to allow a user to visually create complex AR applications. DART also provides low-level support for the management of trackers, sensors, and camera via a Director plug-in Xtra. This demonstration will show the wide range of AR and other types of multimedia applications that can be created with DART, and visitors will have the opportunity to use DART to create their own experiences.

Virtual Reality (VR), Augmented Reality (AR) and other realities along the Mixed Reality(MR) continuum use multi-sensory displays and spatial interaction to enable a number of usefuland novel applications. These virtual worlds are able to train, explore and entertain in addition toaugment the real world with information for our everyday lives. To perform tasks such as traveland other interaction, researchers in these worlds have focused heavily on issues of three-dimensionalinteraction, including interaction techniques, user interface metaphors and inputdevices but always with an outlook centric to their particular position along the MR continuum.This has resulted in interfaces tuned to certain MR instances that are not possible in them allbecause of factors such as the display types, tracking issues or interference and limits from thereal world.This panel brings together diverse researchers across the MR continuum to discuss theirresearch and dissect the similarities and differences of each other's fields. The result is anunderstanding of interfaces across these realities and a merger of developing terminology,techniques and tools for future collaborations.Panel members will give a description of their research followed by a short vision of futureinterface research. Audience questions submitted via index cards are heavily encouraged andexpected to shape the panel discussion and direction.

The authors describe a prototype augmented reality (AR) system that allowed them to experiment with interfaces to a 3-dimensional spatialized information space based on the World Wide Web (WWW). The authors call such an information space the Real-World Wide Web (RWWW), because it merges the WWW with the physical world. They present the assumptions they make about the characteristics of such a system, discuss the implications of those assumptions for AR interfaces, and describe their initial experiences creating a prototype RWWW browser.

All augmented reality (AR) systems must deal with registration errors. While most AR systems attempt to minimize registration errors through careful calibration, registration errors can never be completely eliminated in any realistic system. In this paper, we describe a robust and efficient statistical method for estimating registration errors. Our method generates probabilistic error estimates for points in the world, in either 3D world coordinates or 2D screen coordinates. We present a number of examples illustrating how registration error estimates can be used in AR interfaces, and describe a method for estimating registration errors of objects based on the expansion and contraction of their 2D convex hulls.

In this paper, we describe Kimura, an augmented office environment to support common multitasking practices. Previous systems, such as Rooms, limit users by constraining the interaction to the desktop monitor. In Kimura, we leverage interactive projected peripheral displays to support the perusal, manipulation and awareness of background activities. Furthermore, each activity is represented by a montage comprised of images from current and past interaction on the desktop. These montages help remind the user of past actions, and serve as a springboard for ambient context-aware reminders and notifications.

We present Repo-3D, a general-purpose, object-oriented library for developing distributed, interactive 3D graphics applications across a range of heterogeneous workstations.Repo-3D is designed to make it easy for programmers to rapidly build prototypes using a familiar multi-threaded, object-oriented programming paradigm.All data sharing of both graphical and non-graphical data is done via general-purpose remote and replicated objects, presenting the illusion of a single distributed shared memory.Graphical objects are directly distributed, circumventing the "duplicate database" problem and allowing programmers to focus on the application details.Repo-3D is embedded in Repo, an interpreted, lexically-scoped, distributed programming language, allowing entire applications to be rapidly prototyped.We discuss Repo-3D's design, and introduce the notion of local variations to the graphical objects, which allow local changes to be applied to shared graphical structures.Local variations are needed to support transient local changes, such as highlighting, and responsive local editing operations.Finally, we discuss how our approach could be applied using other programming languages, such as Java.

We describe COTERIE, a toolkit that provides languagelevel support for building distributed virtual environments. COTERIE is based on the distributed data-object paradigm for distributed shared memory. Any data object in COTE-RIE can be declared to be a Shared Object that is replicated fully in any process that is interested in it. These Shared Objects support asynchronous data propagation with atomic serializable updates, and asynchronous notification of updates. COTERIE is built in Modula-3 and uses existing Modula-3 packages that support an integrated interpreted language, multithreading, and 3D animation. Unlike other VE toolkits, COTERIE is based on a set of general-purpose parallel and distributed language concepts designed with the needs of virtual environments in mind. We summarize the

We describe the design and implementation of a prototype heads-up window system intended for use in a 3D environment.Our system includes a see-through head-mounted display that runs a full X server whose image is overlaid on the user's view of the physical world.The user's head is tracked so that the display indexes into a large X bitmap, effectively placing the user inside a display space that is mapped onto part of a surrounding virtual sphere.By tracking the user's body, and interpreting head motion relative to it, we create a portable information surround that envelopes the user as they move about.We support three kinds of windows implemented on top of the X server: windows fixed to the head-mounted display, windows fixed to the information surround, and windows fixed to locations and objects in the 3D world.Objects can also be tracked, allowing windows to move with them.To demonstrate the utility of this model, we describe a small hypermedia system that allows links to be made between windows and windows to be attached to objects.Thus, our hypermedia system can forge links between any combination of physical objects and virtual windows.

Luminance contrast is the basis of text legibility, and maintaining luminance contrast is essential for any color selection algorithm. In principle, it can be calculated precisely on a sufficiently well-calibrated display surface, but calibration is very expensive. Consequently, most current systems deal with contrast using heuristics. However, the usual CRT setup puts the display surface into a state that is relatively predictable. Luminance values can be estimated based on this state, and these luminance values have been used to calculate contrast using the Michelson definition. This paper proposes a method for determining the contrast of colored areas displayed on a CRT. It uses a contrast metric that is in wide use in visual psychophysics and shows that the metric can be approximated reasonably without display measurement, as long as it is possible to assume that the CRT has been adjusted according to usual CRT setup standards.