2022, Fink, Daniel, Zagermann, Johannes, Reiterer, Harald, Jetter, Hans-Christian

Augmented reality (AR) can create the illusion of being virtually co-located during remote collaboration, e.g., by visualizing remote co-workers as avatars. However, spatial awareness of each other’s activities is limited as physical spaces, including the position of physical devices, are often incongruent. Therefore, alignment methods are needed to support activities on physical devices. In this paper, we present the concept of Re-locations, a method for enabling remote collaboration with augmented reality in incongruent spaces. The idea of the concept is to enrich remote collaboration activities on multiple physical devices with attributes of co-located collaboration such as spatial awareness and spatial referencing by locally relocating remote user representations to user-defined workspaces. We evaluated the Re-locations concept in an explorative user study with dyads using an authentic, collaborative task. Our findings indicate that Re-locations introduce attributes of co-located collaboration like spatial awareness and social presence. Based on our findings, we provide implications for future research and design of remote collaboration systems using AR.

2017, Plank, Thomas, Jetter, Hans-Christian, Rädle, Roman, Klokmose, Clemens N., Luger, Thomas, Reiterer, Harald

A sizable part of HCI research on cross-device interaction is driven by the vision of users conducting complex knowledge work seamlessly across multiple mobile devices. This is based on the Weiserian assumption that people will be inclined to distribute their work across multiple ``pads' if such are available. We observed that this is not the reality today, even when devices were in abundance. We present a study with 24 participants in 12 dyads completing a collaborative visualization task with up to six tablets. They could choose between three different visualization types to answer questions about economic data. Tasks were designed to afford simultaneous use of tablets, either with linked or independent views. We found that users typically utilized only one tablet per user. A quantitative and qualitative analysis revealed a ``legacy bias' that introduced barriers for using more tablets and reduced the overall benefit of multi-device visualization.

2015, Rädle, Roman, Jetter, Hans-Christian, Schreiner, Mario, Lu, Zhihao, Reiterer, Harald, Rogers, Yvonne

Cross-device interaction between multiple mobile devices is a popular field of research in HCI. However, the appropriate design of this interaction is still an open question, with competing approaches such as spatially-aware vs. spatially-agnostic techniques. In this paper, we present the results of a two-phase user study that explores this design space: In phase 1, we elicited gestures for typical mobile cross-device tasks from 4 focus groups (N=17). The results show that 71% of the elicited gestures were spatially-aware and that participants strongly associated cross-device tasks with interacting and thinking in space. In phase 2, we implemented one spatially-agnostic and two spatially-aware techniques from phase 1 and compared them in a controlled experiment (N=12). The results indicate that spatially-aware techniques are preferred by users and can decrease mental demand, effort, and frustration, but only when they are designed with great care. We conclude with a summary of findings to inform the design of future cross-device interactions.

2014, Rädle, Roman, Jetter, Hans-Christian, Marquardt, Nicolai, Reiterer, Harald, Rogers, Yvonne

We present HuddleLamp, a desk lamp with an integrated RGB-D camera that precisely tracks the movements and positions of mobile displays and hands on a table. This enables a new breed of spatially-aware multi-user and multi-device applications for around-the-table collaboration without an interactive tabletop. At any time users can add or remove displays and reconfigure them in space in an ad-hoc manner without the need of installing any software or attaching markers. Additionally, hands are tracked to detect interactions above and between displays, enabling fluent cross-device interactions. The demo consists of the technical implementation of HuddleLamp's hybrid sensing and a Web-based architecture for installation-free ad-hoc collaboration. We demonstrate our implementation by showing a variety of possible interaction techniques.

2021, Auer, Stefan, Gerken, Jens, Reiterer, Harald, Jetter, Hans-Christian

Airlines and flying schools use high-end physical flight simulators (PFS) to reduce costs and risks of pilot training. However, such PFS with full-scale cockpits have very high acquisition and operation costs. In contrast, recent consumer-grade and off-the-shelf soft- and hardware can be used to create increasingly realistic virtual reality flight simulators (VRFS) that could potentially serve as cost-efficient and flexible alternatives. We present a user study with 11 participants to determine whether consumer-grade VRFS can supplement or even replace a PFS during cockpit familiarization training (CFT). We compared a full-scale Boeing 737-800NG PFS with a VRFS based on off-the-shelf flight simulator software combined with a consumer-grade head-mounted display and either finger tracking or a handheld controller as input device. Participants performed instrument reading tasks and check procedures from the aircraft’s operating manual. We did not observe statistically significant differences in successful instrument reading tasks, error rates and task completion between PFS and VRFS during CFT. However, we found that VRFS’ Mental Demand, Physical Demand, Effort, task completion times, and levels of simulator sickness were significantly higher and exceeded acceptable levels. We conclude that future consumer-grade VRFS will need to improve soft- and hard- ware for interacting with simulated switches and reduce simulator sickness before they can serve as PFS alternatives for CFT.

2016, Zagermann, Johannes, Pfeil, Ulrike, Rädle, Roman, Jetter, Hans-Christian, Klokmose, Clemens, Reiterer, Harald

Cross-device collaboration with tablets is an increasingly popular topic in HCI. Previous work has shown that tablet-only collaboration can be improved by an additional shared workspace on an interactive tabletop. However, large tabletops are costly and need space, raising the question to what extent the physical size of shared horizontal surfaces really pays off. In order to analyse the suitability of smaller-than-tabletop devices (e.g. tablets) as a low-cost alternative, we studied the effect of the size of a shared horizontal interactive workspace on users' attention, awareness, and efficiency during cross-device collaboration. In our study, 15 groups of two users executed a sensemaking task with two personal tablets (9.7") and a horizontal shared display of varying sizes (10.6", 27", and 55"). Our findings show that different sizes lead to differences in participants' interaction with the tabletop and in the groups' communication styles. To our own surprise we found that larger tabletops do not necessarily improve collaboration or sensemaking results, because they can divert users' attention away from their collaborators and towards the shared display.

2015, Müller, Jens, Rädle, Roman, Jetter, Hans-Christian, Reiterer, Harald

Dynamic peephole navigation represents a technique for navigating large information spaces in an egocentric way. Studies have shown cognitive benefits for a vertical peephole orientation, when compared to non-egocentric interaction styles. To see how the aspect of canvas orientation effects user performance, we conducted a study (N=16) which revealed that canvas orientation has no significant effect on either navigation performance or spatial memory. We also found a significantly lower physical demand and a higher mental demand in the horizontal orientation. For short-term activities we therefore propose a vertical orientation, while for long-term activities horizontal dynamic peephole navigation is more suitable.

2018, Rädle, Roman, Jetter, Hans-Christian, Fischer, Jonathan, Gabriel, Inti, Klokmose, Clemens N., Reiterer, Harald, Holz, Christian

PolarTrack is a novel camera-based approach to detecting and tracking mobile devices inside the capture volume. In PolarTrack, a polarization filter continuously rotates in front of an off-the-shelf color camera, which causes the displays of observed devices to periodically blink in the camera feed. The periodic blinking results from the physical characteristics of current displays, which shine polarized light either through an LC overlay to produce images or through a polarizer to reduce light reflections on OLED displays. PolarTrack runs a simple detection algorithm on the camera feed to segment displays and track their locations and orientations, which makes PolarTrack particularly suitable as a tracking system for cross-device interaction with mobile devices. Our evaluation of PolarTrack's tracking quality and comparison with state-of-the-art camera-based multi-device tracking showed a better tracking accuracy and precision with similar tracking reliability. PolarTrack works as standalone multi-device tracking but is also compatible with existing camera-based tracking systems and can complement them to compensate for their limitations.

2015, Zagermann, Johannes, Pfeil, Ulrike, Schreiner, Mario, Rädle, Roman, Jetter, Hans-Christian, Reiterer, Harald

Even though mobile devices are ubiquitous and users often own several of them, using them in concert to achieve a common goal is not well supported and remains a challenge for HCI. In this paper, we report on our observations of cross-device usage within groups when they engaged in a dyadic collaborative sensemaking task. Based on our findings, we discuss limitations of a state-of-the-art cross-device setting and present a set of design recommendations. We then propose an alternative design that aims for greater flexibility when using mobile devices to enable a free configuration of workspaces depending on users’ current activity.

2015, Schreiner, Mario, Rädle, Roman, Jetter, Hans-Christian, Reiterer, Harald

While Mark Weiser's vision of ubiquitous computing is getting closer to reality, a fundamental part of it - the interconnection of devices into a "ubiquitous network" - is not achieved yet. Differences in hardware, architecture, and missing standardizations are just some reasons for this. We think that existing research is not versatile enough and too tailored to either single applications, hardware, or location. We contribute Connichiwa -- a versatile framework for creating web applications across multiple devices. We base Connichiwa on four key goals: integration of existing devices, independence of network infrastructure, versatility of application scenario, and usability of its API. Connichiwa runs web applications on off-the-shelf consumer devices. With no external dependencies, such as a server, it enables a great variety of possible scenarios. We tested the technical feasibility of Connichiwa in seven example applications and plan to evaluate the framework and the usability of its API in a one-week Hackathon.