A replication attempts to confirm outcomes of earlier research, which is critical in validating and generalizing scientific findings. Yet, its prevalence and practices remain underexplored in Augmented and Virtual Reality (AR/VR) research. To address this, we present a scoping literature review of replication studies within IEEE ISMAR and IEEE VR, spanning 15 years from 2010 to 2024. Our analysis revealed that replication in AR/VR research is rare. Of 2167 total papers reviewed, less than 4 % were identified as replication studies. Of these, conceptual replications were the predominant type (57 %). Most of those were studies in VR (67 %) and within-subject designs (66 %). Complementing the literature survey results, we conducted an online survey with 61 participants about their experiences with replication studies and found that 39 % of them had conducted a replication study. However, limited resources and external motivation hamper the execution of replication studies among these AR/VR researchers. Combining the findings from our literature review and online survey, we discuss the current state of replication research and the factors contributing to its infrequency. We provide recommendations to improve AR/VR research replication practices, focusing on research culture and reporting, and discuss ongoing challenges.

Human-Robot-Collaboration can enhance workflows by leveraging the mutual strengths of human operators and robots. Planning and understanding robot movements remain major challenges in this domain. This problem is prevalent in dynamic environments that might need constant robot motion path adaptation. In this paper, we investigate whether a minimalistic encoding of the reachability of a point near an object of interest, which we call ReachVox, can aid the collaboration between a remote operator and a robotic arm in VR. Through a user study ($\mathrm{n}=20$), we indicate the strength of the visualization relative to a point-based reachability check-up.

The ‘keyword method’ is an effective technique for learning vocabulary of a foreign language. It involves creating a memorable visual link between what a word means and what its pronunciation in a foreign language sounds like in the learner’s native language. However, these memorable visual links remain implicit in the people’s mind and are not easy to remember for a large number of words. To enhance the memorisation and recall of the vocabulary, we developed an application that combines the keyword method with text-to-image generators to externalise the memorable visual links into visuals. These visuals represent additional stimuli during the memorisation process. To explore the effectiveness of this approach we first run a pilot study to investigate how difficult it is to externalise the descriptions of mental visualisations of memorable links, by asking participants to write them down. We used these descriptions as prompts for text-to-image generator (DALL-E 2) to convert them into images and asked participants to select their favourites. Next, we compared different text-to-image generators (DALL-E 2, Midjourney, Stable and Latent Diffusion) to evaluate the perceived quality of the generated images by each. Despite heterogeneous results, participants mostly preferred images generated by DALL-E 2, which was used also for the final study. In this study, we investigated whether providing such images enhances the retention of vocabulary being learned, compared to the keyword method alone. Our results indicate that people did not encounter difficulties describing their visualisations of memorable links and that providing corresponding images significantly increases memory retention.

As more applications of large language models (LLMs) for 3D content in immersive environments emerge, it is crucial to study user behavior to identify interaction patterns and potential barriers to guide the future design of immersive content creation and editing systems which involve LLMs. In an empirical user study with 12 participants, we combine quantitative usage data with post-experience questionnaire feedback to reveal common interaction patterns and key barriers in LLM-assisted 3D scene editing systems. We identify opportunities for improving natural language interfaces in 3D design tools and propose design recommendations. Through an empirical study, we demonstrate that LLM-assisted interactive systems can be used productively in immersive environments.

Virtual displays provided through head-worn displays (HWDs) offer users large screen space for productivity, but managing this space effectively presents challenges. Existing research shows that while increased screen space improves performance, it can also introduce significant window management overhead. This paper explores how to enhance window-switching strategies for virtual displays by leveraging eye tracking provided by HWDs and underutilized spaces around the main display area. We investigate the efficiency and usability of different cursor behaviors and selection modes in a Spatial Bar interface for window-switching tasks in augmented reality environments. Our study involved two primary selection modes: Gaze and Cursor, each tested with two cursor behaviors: Teleport and Stay. We measured objective performance metrics, including task completion time and error rates, and subjective evaluations using the NASA TLX and custom questionnaires. Results show that Cursor Stay, while familiar and comfortable for participants, was laborious and led to longer task completion times, particularly over large distances. Gaze Teleport led to the quickest window switching times, particularly in tasks where the original cursor position or the target window were far from the Spatial Bar.

We introduce the SpatialMouse, a hybrid pointing device that combines the capabilities of a desktop mouse with the spatial input of a virtual reality (VR) controller, enabling seamless transitions between 2D and 3D interaction spaces in immersive mixed reality environments. Holistic usage scenarios in mixed reality involve tasks suited alternately to 2D or 3D information spaces. Yet, existing input devices excel in either 2D or 3D, but not both, making it necessary to switch between multiple input devices (e.g., mouse and VR controller). Our SpatialMouse addresses this issue, offering the affordances of a desktop mouse for indirect 2D pointing and the spatial capabilities of VR controllers with six degrees of freedom. In a user study with 12 participants, our prototype significantly reduced perceived task load and improved user experience compared to switching between separate devices. We extract design recommendations to further support such hybrid input approaches.

This paper presents a mobile augmented reality (AR) system designed to enhance user experiences at cultural heritage (CH) sites by providing personalized content and points of interest (POI) recommendations. Applying semantic relatedness, we address the heterogeneity of CH POIs to improve personalization accuracy. Our system constructs a POI-based co-occurrence graph to model semantic relationships, enriching users’ visited AR content items for better recommendations. The proposed method integrates content-filtering-based recommendations with this graph and recommends personalized POIs and AR content items. A user study demonstrated that our system outperforms conventional methods by 9.4% in recommendation precision and recall, significantly enhancing user engagement and attention focus during CH tours.

When communicating with embodied conversational agents (ECAs) in virtual reality, there might be delays in the responses of the agents lasting several seconds, for example, due to more extensive computations of the answers when large language models are used. Such delays might lead to unnatural or frustrating interactions. In this paper, we investigate filler types to mitigate these effects and lead to a more positive experience and perception of the agent. In a within-subject study, we asked 24 participants to communicate with ECAs in virtual reality, comparing four strategies displayed during the delays: a multimodal behavioral filler consisting of conversational and gestural fillers, a base condition with only idle motions, and two symbolic indicators with progress bars, one embedded as a badge on the agent, the other one external and visualized as a thinking bubble. Our results indicate that the behavioral filler improved perceived response time, three subscales of presence, humanlikeness, and naturalness. Participants looked away from the face more often when symbolic indicators were displayed, but the visualizations did not lead to a more positive impression of the agent or to increased presence. The majority of participants preferred the behavioral fillers, only 12.5% and 4.2% favored the symbolic embedded and external conditions, respectively.

Although access to sufficient screen space is crucial to knowledge work, workers often find themselves with limited access to display infrastructure in remote or public settings. While virtual displays can be used to extend the available screen space through extended reality (XR) head-worn displays (HWD), we must better understand the implications of working with them in public settings from both users' and bystanders' viewpoints. To this end, we conducted two user studies. We first explored the usage of a hybrid AR display across real-world settings and tasks. We focused on how users take advantage of virtual displays and what social and environmental factors impact their usage of the system. A second study investigated the differences between working with a laptop, an AR system, or a VR system in public. We focused on a single location and participants performed a predefined task to enable direct comparisons between the conditions while also gathering data from bystanders. The combined results suggest a positive acceptance of XR technology in public settings and show that virtual displays can be used to accompany existing devices. We highlighted some environmental and social factors. We saw that previous XR experience and personality can influence how people perceive the use of XR in public. In addition, we confirmed that using XR in public still makes users stand out and that bystanders are curious about the devices, yet have no clear understanding of how they can be used.

Nowadays, Mixed Reality (MR) headsets are a game-changer for knowledge work. Unlike stationary monitors, MR headsets allow users to work with large virtual displays anywhere they wear the headset, whether in a professional office, a public setting like a cafe, or a quiet space like a library. This study compares four different layouts (eye level-close, eye level-far, below eye level-close, below eye level-far) of virtual displays regarding feelings of safety, perceived productivity, and social acceptability when working with MR in public. We test which layout is most preferred by users and seek to understand which factors affect users’ layout preferences. The aim is to derive useful insights for designing better MR layouts. A field study in a public library was conducted using a within-subject design. While the participants interact with a layout, they are asked to work on a planning task. The results from a repeated measure ANOVA show a statistically significant effect on productivity but not on safety and social acceptability. Additionally, we report preferences expressed by the users regarding the layouts and using MR in public.

Research on text entry in Virtual Reality (VR) has gained popularity but the efficient entry of accented characters, characters with diacritical marks, in VR remains underexplored. Entering accented characters is supported on most capacitive touch keyboards through a long press on a base character and a subsequent selection of the accented character. However, entering those characters on physical keyboards is still challenging, as they require a recall and an entry of respective numeric codes. To address this issue this paper investigates three techniques to support accented character entry on physical keyboards in VR. Specifically, we compare a contextaware numeric code technique that does not require users to recall a code, a key-press-only condition in which the accented characters are dynamically remapped to physical keys next to a base character, and a multimodal technique, in which eye gaze is used to select the accented version of a base character previously selected by keypress on the keyboard. The results from our user study $(n=18)$ reveal that both the key-press-only and the multimodal technique outperform the baseline technique in terms of text entry speed.

VR devices have recently been actively promoted as tools for knowledge workers and prior work has demonstrated that VR can support some knowledge worker tasks. However, only a few studies have explored the effects of prolonged use of VR such as a study observing 16 participants working in VR and a physical environment for one work-week each and reporting mainly on subjective feedback. As a nuanced understanding of participants' behavior in VR and how it evolves over time is still missing, we report on the results from an analysis of 559 hours of video material obtained in this prior study. Among other findings, we report that (1) the frequency of actions related to adjusting the headset reduced by 46% and the frequency of actions related to supporting the headset reduced by 42% over the five days; (2) the HMD was removed 31% less frequently over the five days but for 41% longer periods; (3) wearing an HMD is disruptive to normal patterns of eating and drinking, but not to social interactions, such as talking. The combined findings in this work demonstrate the value of long-term studies of deployed VR systems and can be used to inform the design of better, more ergonomic VR systems as tools for knowledge workers.

Optical see-through head-mounted displays (OST HMDs) are a popular output medium for mobile Augmented Reality (AR) applications. To date, they lack efficient text entry techniques. Smartphones are a major text entry medium in mobile contexts but attentional demands can contribute to accidents while typing on the go. Mobile multi-display ecologies, such as combined OST HMD-smartphone systems, promise performance and situation awareness benefits over single-device use. We study the joint performance of text entry on mobile phones with text output on optical see-through head-mounted displays. A series of five experiments with a total of 86 participants indicate that, as of today, the challenges in such a joint interactive system outweigh the potential benefits.

Learning and practicing table tennis with traditional methods is a long, tedious process and may even lead to the internalization of incorrect techniques if not supervised by a coach. To overcome these issues, the presented study proposes an exergame with the aim of enhancing young female novice players’ performance by boosting muscle memory, making practice more interesting, and decreasing the probability of faulty training. Specifically, we propose an exergame based on skeleton tracking and a virtual avatar to support correct shadow practice to learn forehand drive technique without the presence of a coach. We recruited 44 schoolgirls aged between 8 and 12 years without a background in playing table tennis and divided them into control and experimental groups. We examined their stroke skills (via the Mott-Lockhart test) and the error coefficient of their forehand drives (using a ball machine) in the pre-test, post-test, and follow-up tests (10 days after the post-test). Our results showed that the experimental group had progress in the short and long term, while the control group had an improvement only in the short term. Further, the scale of improvement in the experimental group was significantly higher than in the control group. Given that the early stages of learning, particularly in girls children, are important in the internalization of individual skills in would-be athletes, this method could support promoting correct training for young females.

While the promise of autonomous vehicles has led to significant scientific and industrial progress, fully automated, SAE level 5 conform cars will likely not see mass adoption anytime soon. Instead, in many applications, human supervision, such as remote monitoring and teleoperation, will be required for the foreseeable future. While Virtual Reality (VR) has been proposed as one potential interface for teleoperation, its benefits and drawbacks over physical monitoring and teleoperation solutions have not been thoroughly investigated. To this end, we contribute three user studies, comparing and quantifying the performance of and subjective feedback for a VR-based system with an existing monitoring and teleoperation system, which is in industrial use today. Through these three user studies, we contribute to a better understanding of future virtual monitoring and teleoperation solutions for autonomous vehicles. The results of our first user study (n= 16) indicate that a VR interface replicating the physical interface does not outperform the physical interface. It also quantifies the negative effects that combined monitoring and teleoperating tasks have on users irrespective of the interface being used. The results of the second user study (n= 24) indicate that the perceptual and ergonomic issues caused by VR outweigh its benefits, like better concentration through isolation. The third follow-up user study (n= 24) specifically targeted the perceptual and ergonomic issues of VR; the subjective feedback of this study indicates that newer-generation VR headsets have the potential to catch up with the current physical displays.

Virtual Reality (VR) has the potential to support mobile knowledge workers by complementing traditional input devices with a large three-dimensional output space and spatial input. Previous research on supporting VR knowledge work explored domains such as text entry using physical keyboards and spreadsheet interaction using combined pen and touch input. Inspired by such work, this paper probes the VR design space for authoring presentations in mobile settings. We propose PoVRPoint-a set of tools coupling pen- and touch-based editing of presentations on mobile devices, such as tablets, with the interaction capabilities afforded by VR. We study the utility of extended display space to, for example, assist users in identifying target slides, supporting spatial manipulation of objects on a slide, creating animations, and facilitating arrangements of multiple, possibly occluded shapes or objects. Among other things, our results indicate that 1) the wide field of view afforded by VR results in significantly faster target slide identification times compared to a tablet-only interface for visually salient targets; and 2) the three-dimensional view in VR enables significantly faster object reordering in the presence of occlusion compared to two baseline interfaces. A user study further confirmed that the interaction techniques were found to be usable and enjoyable.

Virtual Reality (VR) provides new possibilities for modern knowledge work. However, the potential advantages of virtual work environments can only be used if it is feasible to work in them for an extended period of time. Until now, there are limited studies of long-term effects when working in VR. This paper addresses the need for understanding such long-term effects. Specifically, we report on a comparative study $i$, in which participants were working in VR for an entire week-for five days, eight hours each day-as well as in a baseline physical desktop environment. This study aims to quantify the effects of exchanging a desktop-based work environment with a VR-based environment. Hence, during this study, we do not present the participants with the best possible VR system but rather a setup delivering a comparable experience to working in the physical desktop environment. The study reveals that, as expected, VR results in significantly worse ratings across most measures. Among other results, we found concerning levels of simulator sickness, below average usability ratings and two participants dropped out on the first day using VR, due to migraine, nausea and anxiety. Nevertheless, there is some indication that participants gradually overcame negative first impressions and initial discomfort. Overall, this study helps lay the groundwork for subsequent research, by clearly highlighting current shortcomings and identifying opportunities for improving the experience of working in VR.

Learning vocabulary in a primary or secondary language is enhanced when we encounter words in context. This context can be afforded by the place or activity we are engaged with. Existing learning environments include formal learning, mnemonics, flashcards, use of a dictionary or thesaurus, all leading to practice with new words in context. In this work, we propose an enhancement to the language learning process by providing the user with words and learning tools in context, with VocabulARy. VocabulARy visually annotates objects in AR, in the user's surroundings, with the corresponding English (first language) and Japanese (second language) words to enhance the language learning process. In addition to the written and audio description of each word, we also present the user with a keyword and its visualisation to enhance memory retention. We evaluate our prototype by comparing it to an alternate AR system that does not show an additional visualisation of the keyword, and, also, we compare it to two non-AR systems on a tablet, one with and one without visualising the keyword. Our results indicate that AR outperforms the tablet system regarding immediate recall, mental effort and task-completion time. Additionally, the visualisation approach scored significantly higher than showing only the written keyword with respect to immediate and delayed recall and learning efficiency, mental effort and task-completion time.

Immersive Analytics is a quickly evolving field that unites several areas such as visualisation, immersive environments, and human-computer interaction to support human data analysis with emerging technologies. This research has thrived over the past years with multiple workshops, seminars, and a growing body of publications, spanning several conferences. Given the rapid advancement of interaction technologies and novel application domains, this paper aims toward a broader research agenda to enable widespread adoption. We present 17 key research challenges developed over multiple sessions by a diverse group of 24 international experts, initiated from a virtual scientific workshop at ACM CHI 2020. These challenges aim to coordinate future work by providing a systematic roadmap of current directions and impending hurdles to facilitate productive and effective applications for Immersive Analytics.

Virtual Reality (VR) can enhance the display and interaction of mobile knowledge work and in particular, spreadsheet applications. While spreadsheets are widely used yet are challenging to interact with, especially on mobile devices, using them in VR has not been explored in depth. A special uniqueness of the domain is the contrast between the immersive and large display space afforded by VR, contrasted by the very limited interaction space that may be afforded for the information worker on the go, such as an airplane seat or a small work-space. To close this gap, we present a tool-set for enhancing spreadsheet interaction on tablets using immersive VR headsets and pen-based input. This combination opens up many possibilities for enhancing the productivity for spreadsheet interaction. We propose to use the space around and in front of the tablet for enhanced visualization of spreadsheet data and meta-data. For example, extending sheet display beyond the bounds of the physical screen, or easier debugging by uncovering hidden dependencies between sheet's cells. Combining the precise on-screen input of a pen with spatial sensing around the tablet, we propose tools for the efficient creation and editing of spreadsheets functions such as off-the-screen layered menus, visualization of sheets dependencies, and gaze-and-touch-based switching between spreadsheet tabs. We study the feasibility of the proposed tool-set using a video-based online survey and an expert-based assessment of indicative human performance potential.

The Ebbinghaus illusion, also known as Titchner Circles, is a well- known perceptual illusion affecting the perceived size of a disc enclosed by an annulus of either larger or smaller discs. Though many have found highly consistent results with regard to the effect of the illusion on size perception, there have been mixed results when studying its effect on action-based tasks. In this paper, we present a study utilizing a head-worn virtual environment to examine the effect of the Ebbinghaus illusion on depth judgments as measured using a blind-reaching task. We found that participants’ size judgments were symmetrically affected by the classic "large annulus" and "small annulus" configurations, but their distance judgments were asymmetrically affected. Large annulus configurations had no significant effect on distance judgments while small annulus configurations resulted in significant underestimation of target distances. Despite this asymmetry, both configurations resulted in response times of similar magnitude that were significantly longer than those of the non-illusory control condition.

Virtual Reality (VR) has the potential to transform knowledge work. One advantage of VR knowledge work is that it allows extending 2D displays into the third dimension, enabling new operations, such as selecting overlapping objects or displaying additional layers of information. On the other hand, mobile knowledge workers often work on established mobile devices, such as tablets, limiting interaction with those devices to a small input space. This challenge of a constrained input space is intensified in situations when VR knowledge work is situated in cramped environments, such as airplanes and touchdown spaces. In this paper, we investigate the feasibility of interacting jointly between an immersive VR head-mounted display and a tablet within the context of knowledge work. Specifically, we 1) design, implement and study how to interact with information that reaches beyond a single physical touchscreen in VR; 2) design and evaluate a set of interaction concepts; and 3) build example applications and gather user feedback on those applications.

Digital-augmentation of print-media can provide contextually relevant audio, visual, or haptic content to supplement the static text and images. The design of such augmentation--its medium, quantity, frequency, content, and access technique--can have a significant impact on the reading experience. In the worst case, such as where children are learning to read, the print medium can become a proxy for accessing digital content only, and the textual content is avoided. In this work, we examine how augmented content can change the reader's behaviour with a comic book. We first report on the usage of a commercially available augmented comic for children, providing evidence that a third of all readers converted to simply viewing the digital media when printed content is duplicated. Second, we explore the design space for digital content augmentation in print media. Third, we report a user study with 136 children that examined the impact of both content length and presentation in a digitally-augmented comic book. From this, we report a series of design guidelines to assist designers and editors in the development of digitally-augmented print media.

In the context of immersive VR Head-Mounted Displays, physical keyboards have been proven to be an efficient typing interface. However, text entry using physical keyboards typically requires external camera-based tracking systems. Touch-sensitive physical keyboards allow for on-surface interaction, with sensing integrated into the keyboard itself, but have not been utilized for VR. We propose to utilize touch-sensitive physical keyboards for text entry as an alternative sensing mechanism for tracking user's fingertips and present a first prototype for VR.

Text entry is a challenge for Virtual Reality (VR) applications. In the context of immersive VR Head-Mounted Displays, text entry has been investigated for standard physical keyboards as well as for various hand representations. Specifically, prior work has indicated that minimalistic fingertip visualizations are an efficient hand representation. However, they typically require external tracking systems. Touch-sensitive physical keyboards allow for on-surface interaction, with sensing integrated into the keyboard itself. However, they have not been thoroughly investigated within VR. Our work brings together the domains of VR text entry and touch-sensitive physical keyboards. Specifically, we propose to utilize touch-sensitive physical keyboards for text entry as an alternative sensing mechanism for tracking user's fingertips and study its performance in a preliminary user study.

Physical keyboards are common peripherals for personal computers and are efficient standard text entry devices. Recent research has investigated how physical keyboards can be used in immersive head-mounted display-based Virtual Reality (VR). So far, the physical layout of keyboards has typically been transplanted into VR for replicating typing experiences in a standard desktop environment. In this paper, we explore how to fully leverage the immersiveness of VR to change the input and output characteristics of physical keyboard interaction within a VR environment. This allows individual physical keys to be reconfigured to the same or different actions and visual output to be distributed in various ways across the VR representation of the keyboard. We explore a set of input and output mappings for reconfiguring the virtual presentation of physical keyboards and probe the resulting design space by specifically designing, implementing and evaluating nine VR-relevant applications: emojis, languages and special characters, application shortcuts, virtual text processing macros, a window manager, a photo browser, a whack-a-mole game, secure password entry and a virtual touch bar. We investigate the feasibility of the applications in a user study with 20 participants and find that, among other things, they are usable in VR. We discuss the limitations and possibilities of remapping the input and output characteristics of physical keyboards in VR based on empirical findings and analysis and suggest future research directions in this area.

In this special issue ofIEEE Transactions on Visualization and Computer Graphics (TVCG), we are pleased to present theTVCGpapers from the 18th IEEE International Symposium on Mixed and Augmented Reality (ISMAR 2019), held October 14–18 in Beijing, China. ISMAR continues the over 20-year long tradition of IWAR, ISMR, and ISAR, and is undoubtedly the premier conference for mixed and augmented reality in the world.

Alphanumeric text entry is a challenge for Virtual Reality (VR) applications. VR enables new capabilities, impossible in the real world, such as an unobstructed view of the keyboard, without occlusion by the user's physical hands. Several hand representations have been proposed for typing in VR on standard physical keyboards. However, to date, these hand representations have not been compared regarding their performance and effects on presence for VR text entry. Our work addresses this gap by comparing existing hand representations with minimalistic fingertip visualization. We study the effects of four hand representations (no hand representation, inverse kinematic model, fingertip visualization using spheres and video inlay) on typing in VR using a standard physical keyboard with 24 participants. We found that the fingertip visualization and video inlay both resulted in statistically significant lower text entry error rates compared to no hand or inverse kinematic model representations. We found no statistical differences in text entry speed.

We study the performance and user experience of two popular mainstream text entry devices, desktop keyboards and touchscreen keyboards, for use in Virtual Reality (VR) applications. We discuss the limitations arising from limited visual feedback, and examine the efficiency of different strategies of use. We analyze a total of 24 hours of typing data in VR from 24 participants and find that novice users are able to retain about 60% of their typing speed on a desktop keyboard and about 40-45% of their typing speed on a touchscreen keyboard. We also find no significant learning effects, indicating that users can transfer their typing skills fast into VR. Besides investigating baseline performances, we study the position in which keyboards and hands are rendered in space. We find that this does not adversely affect performance for desktop keyboard typing and results in a performance trade-off for touchscreen keyboard typing.

In this special issue ofIEEE Transactions on Visualization and Computer Graphics (TVCG), we are pleased to present theTVCGpapers from the 17th IEEE International Symposium on Mixed and Augmented Reality (ISMAR 2018), held October 16–20 in Munich, Germany. ISMAR continues the 20-year long tradition of IWAR, ISMR, and ISAR, and is undoubtedly the premier conference for mixed and augmented reality in the world.

Optical see-through head-mounted displays (OST HMDs) are a major output medium for Augmented Reality, which have seen significant growth in popularity and usage among the general public due to the growing release of consumer-oriented models, such as the Microsoft Hololens. Unlike Virtual Reality headsets, OST HMDs inherently support the addition of computer-generated graphics directly into the light path between a user's eyes and their view of the physical world. As with most Augmented and Virtual Reality systems, the physical position of an OST HMD is typically determined by an external or embedded 6-Degree-of-Freedom tracking system. However, in order to properly render virtual objects, which are perceived as spatially aligned with the physical environment, it is also necessary to accurately measure the position of the user's eyes within the tracking system's coordinate frame. For over 20 years, researchers have proposed various calibration methods to determine this needed eye position. However, to date, there has not been a comprehensive overview of these procedures and their requirements. Hence, this paper surveys the field of calibration methods for OST HMDs. Specifically, it provides insights into the fundamentals of calibration techniques, and presents an overview of both manual and automatic approaches, as well as evaluation methods and metrics. Finally, it also identifies opportunities for future research.

We present HeadPhones (Headtracking + smartPhones), a novel approach for the spatial registration of multiple mobile devices into an ad hoc multi-display environment. We propose to employ the user's head as external reference frame for the registration of multiple mobile devices into a common coordinate system. Our approach allows for dynamic repositioning of devices during runtime without the need for external infrastructure such as separate cameras or fiducials. Specifically, our only requirements are local network connections and mobile devices with built-in front facing cameras. This way, HeadPhones enables spatially-aware multi-display applications in mobile contexts. A user study and accuracy evaluation indicate the feasibility of our approach.

Around-device interaction techniques aim at extending the input space using various sensing modalities on mobile and wearable devices. In this paper, we present our work towards extending the input area of mobile devices using front-facing device-centered cameras that capture reflections in the human eye. As current generation mobile devices lack high resolution front-facing cameras we study the feasibility of around-device interaction using corneal reflective imaging based on a high resolution camera. We present a workflow, a technical prototype and an evaluation, including a migration path from high resolution to low resolution imagers. Our study indicates, that under optimal conditions a spatial sensing resolution of 5 cm in the vicinity of a mobile phone is possible.

While we witness significant changes in display technologies, to date, the majority of display form factors remain flat. The research community has investigated other geometric display configuration given the rise to cubic displays that create the illusion of a 3D virtual scene within the cube. We present a self-contained mobile perspective cubic display (mpCubee) assembled from multiple smartphones. We achieve perspective correct projection of 3D content through head-tracking using built-in cameras in smartphones. Furthermore, our prototype allows to spatially manipulate 3D objects on individual axes due to the orthogonal configuration of touch displays.

We present a demonstration of HeadPhones (Headtracking + smart-Phones), a novel approach for the spatial registration of multiple mobile devices into an ad hoc multi-display environment. We propose to employ the user's head as external reference frame for the registration of multiple mobile devices into a common coordinate system. Our approach allows for dynamic repositioning of devices during runtime without the need for external infrastructure such as separate cameras or fiducials. Specifically, our only requirements are local network connections and mobile devices with built-in front facing cameras. This way, HeadPhones enables spatially-aware multi-display applications in mobile contexts.

Augmented Reality is a technique that enables users to interact with their physical environment through the overlay of digital information. While being researched for decades, more recently, Augmented Reality moved out of the research labs and into the field. While most of the applications are used sporadically and for one particular task only, current and future scenarios will provide a continuous and multi-purpose user experience. Therefore, in this paper, we present the concept of Pervasive Augmented Reality, aiming to provide such an experience by sensing the user's current context and adapting the AR system based on the changing requirements and constraints. We present a taxonomy for Pervasive Augmented Reality and context-aware Augmented Reality, which classifies context sources and context targets relevant for implementing such a context-aware, continuous Augmented Reality experience. We further summarize existing approaches that contribute towards Pervasive Augmented Reality. Based our taxonomy and survey, we identify challenges for future research directions in Pervasive Augmented Reality.

We present a novel approach for extending the input space around unmodified mobile devices. Using built-in front-facing cameras of unmodified handheld devices, GlassHands estimates hand poses and gestures through reflections in sunglasses, ski goggles or visors. Thereby, GlassHands creates an enlarged input space, rivaling input reach on large touch displays. We introduce the idea along with its technical concept and implementation. We demonstrate the feasibility and potential of our proposed approach in several application scenarios, such as map browsing or drawing using a set of interaction techniques previously possible only with modified mobile devices or on large touch displays. Our research is backed up with a user study.

Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, optically variable devices such as holograms are important, but difficult to inspect. Augmented Reality can provide all relevant information on standard mobile devices. However, hologram verification on mobiles still takes long and provides lower accuracy than inspection by human individuals using appropriate reference information. We aim to address these drawbacks by automatic matching combined with a special parametrization of an efficient goal-oriented user interface which supports constrained navigation. We first evaluate a series of similarity measures for matching hologram patches to provide a sound basis for automatic decisions. Then a re-parametrized user interface is proposed based on observations of typical user behavior during document capture. These measures help to reduce capture time to approximately 15 s with better decisions regarding the evaluated samples than what can be achieved by untrained users.

Display devices on and around the body such as smartwatches, head-mounted displays or tablets enable users to interact on the go. However, diverging input and output fidelities of these devices can lead to interaction seams that can inhibit efficient mobile interaction, when users employ multiple devices at once. We present MultiFi, an interactive system that combines the strengths of multiple displays and overcomes the seams of mobile interaction with widgets distributed over multiple devices. A comparative user study indicates that combined head-mounted display and smartwatch interfaces can outperform interaction with single wearable devices.

Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, view-dependent elements such as holograms are interesting, but the expertise of individuals performing the task varies greatly. Augmented Reality systems can provide all relevant information on standard mobile devices. Hologram verification still takes long and causes considerable load for the user. We aim to address this drawback by first presenting a work flow for recording and automatic matching of hologram patches. Several user interfaces for hologram verification are presented, aiming to noticeably reduce verification time. We evaluate the most promising interfaces in a user study with prototype applications running on off-the-shelf hardware. Our results indicate that there is a significant difference in capture time between interfaces but that users do not prefer the fastest interface.

Head Mounted Displays such as Google Glass and the META have the potential to spur consumer-oriented Optical See-Through Augmented Reality applications. A correct spatial registration of those displays relative to a user's eye(s) is an essential problem for any HMD-based AR application. We provide an overview of established and novel approaches for the calibration of those displays including hands on experience in which participants will calibrate such head mounted displays. The following list provides a tentative list of topics covered during the tutorial. • Part 1: Introduction to OST calibration • Why OST Calibration is important? • Differences to Camera Calibration • Introduce camera calibration • Why is OST calibration hard? • The user in the loop — pointing accuracy • Slipping, the need for recalibration • Principal aspects of OST-HMD calibration • overview of data collection • confirmation methods • optimization • mono vs stereo • Details of OST calibration • Data collection methods: • SPAAM, Multi Point collection, stereo methods • Confirmation methods • Optimization approaches • Evaluation: perceptual measures vs. analytic measures • State of the art: Semi-, fully automatic calibration methodses • Part 2: Hands-on calibration • SPAAM-based calibration of Epson Moverio/ Google Glass with inside-out marker tracker.

We work towards ad-hoc augmentation of public displays on handheld devices, supporting user perspective rendering of display content. Our prototype system only requires access to a screencast of the public display, which can be easily provided through common streaming platforms and is otherwise self-contained. Hence, it easily scales to multiple users.

We demonstrate ad-hoc augmentation of public displays on handheld devices, supporting user perspective rendering of display content. Our prototype system only requires access to a screencast of the public display, which can be easily provided through common streaming platforms and is otherwise self-contained. Hence, it easily scales to multiple users.

Verification of paper documents is an important part of checking a person's identity, authorization for access or simply establishing a trusted currency. Many documents such as passports or paper bills include holograms or other view-dependent elements that are difficult to forge and therefore are used to verify the genuineness of that document. View-dependent elements change their appearance based both on viewing direction and dominant light sources, thus it requires special knowledge and training to accurately distinguish original elements from forgeries. We present an interactive application for mobile devices that integrates the recognition of the documents with the interactive verification of view-dependent elements. The system recognizes and tracks the paper document, provides user guidance for view alignment and presents a stored image of the element's appearance depending on the current view of the document also recording user decisions. We describe how to model and capture the underlying spatially varying BRDF representation of view-dependent elements. Furthermore, we evaluate this approach within a user study and demonstrate that such a setup captures images that are recognizable and that can be correctly verified.

We repeated a study on the usage of a magic lens and a static peephole interface for playing a find-and-select game in a public space. While we reproduced the study setup and procedure the task was conducted in a public transportation stop with different characteristics. The results on usage duration and user preference were significantly different from those reported for previous conditions. We investigate possible causes, specifically the differences in the spatial characteristics and the social contexts in which the study took place.

The development of mobile Augmented Reality application became increasingly popular over the last few years. However, many of the existing solutions build on the reuse of available standard metaphors for visualization and interaction without considering the manifold contextual factors of their use. Within this workshop we want to discuss theoretical design approaches and practical tools which should help developers to make more informed choices when exploring the design space of Augmented Reality interfaces in mobile contexts.

Magic lens and static peephole interfaces are used in numerous consumer mobile phone applications such as Augmented Reality browsers, games or digital map applications in a variety of contexts including public spaces. Interface performance has been evaluated for various interaction tasks involving spatial relationships in a scene. However, interface usage outside laboratory conditions has not been considered in depth in the evaluation of these interfaces.

We present an efficient natural feature tracking pipeline solely implemented in JavaScript. It is embedded in a web technology-based Augmented Reality system running plugin-free in web browsers. The evaluation shows that real-time framerates on desktop computers and while on smartphones interactive framerates are achieved.

The potential of Augmented Reality (AR) to support industrial processes has been demonstrated in several studies. While there have been first investigations on user related issues in the long-duration use of mobile AR systems, to date the impact of theses systems on physiological and psychological aspects is not explored extensively. We conducted an extended study in which 19 participants worked 4 hours continuously in an order picking process with and without AR support. Results of the study comparing strain and work efficiency are presented and open issues are discussed.

Abstract In this paper we present several techniques to interactively explore representations of 2D vector fields. Through a set of simple hand postures used on large, touch‐sensitive displays, our approach allows individuals to custom‐design glyphs (arrows, lines, etc.) that best reveal patterns of the underlying dataset. Interactive exploration of vector fields is facilitated through freedom of glyph placement, glyph density control, and animation. The custom glyphs can be applied individually to probe specific areas of the data but can also be applied in groups to explore larger regions of a vector field. Re‐positionable sources from which glyphs—animated according to the local vector field—continue to emerge are used to examine the vector field dynamically. The combination of these techniques results in an engaging visualization with which the user can rapidly explore and analyze varying types of 2D vector fields, using a virtually infinite number of custom‐designed glyphs.