Sonja Rümelin

NaviRadar: a novel tactile information display for pedestrian navigation

We introduce NaviRadar: an interaction technique for mobile phones that uses a radar metaphor in order to communicate the users correct direction for crossings along a desired route. A radar sweep rotates clockwise and tactile feedback is provided where each sweep distinctly conveys the users current direction and the direction in which the user must travel. In a first study, we evaluated the overall concept and tested five different tactile patterns to communicate the two different directions via a single tactor. The results show that people are able to easily understand the NaviRadar concept and can identify the correct direction with a mean deviation of 37° out of the full 360° provided. A second study shows that NaviRadar achieves similar results in terms of perceived usability and navigation performance when compared with spoken instructions. By using only tactile feedback, NaviRadar provides distinct advantages over current systems. In particular, no visual attention is required to navigate; thus, it can be spent on providing greater awareness of ones surroundings. Moreover, the lack of audio attention enables it to be used in noisy environments or this attention can be better spent on talking with others during navigation.

Free-hand pointing for identification and interaction with distant objects

In this paper, we investigate pointing as a lightweight form of gestural interaction in cars. In a pre-study, we show the technical feasibility of reliable pointing detection with a depth camera by achieving a recognition rate of 96% in the lab. In a subsequent in-situ study, we let drivers point to objects inside and outside of the car while driving through a city. In three usage scenarios, we studied how this influenced their driving objectively, as well as subjectively. Distraction from the driving task was compensated by a regulation of driving speed and did not have a negative influence on driving behaviour. Our participants considered pointing a desirable interaction technique in comparison to current controller-based interaction and identified a number of additional promising use cases for pointing in the car.

How to make large touch screens usable while driving

Large touch screens are recently appearing in the automotive market, yet their usability while driving is still controversial. Flat screens do not provide haptic guidance and thus require visual attention to locate interactive elements that are displayed. Thus, we need to think about new concepts to minimize the visual attention needed for interaction, to keep the drivers focus on the road and ensure safety. In this paper, we explore three different approaches. The first one is designed to make use of proprioception. The second approach incorporates physical handles to ease orientation on a large flat surface. In the third approach, directional touch gestures are applied. We describe the results of a comparative study that investigates the required visual attention as well as task performance and perceived usability, in comparison to a state-of-the-art multifunctional controller. We found that direct touch buttons provide the best results regarding task completion time, but with a size of about 6x8 cm, they were not yet large enough for blind interaction. Physical elements in and around the screen space were regarded useful to ease orientation. With touch gestures, participants were able to reduce visual attention to a lower level than with the remote controller. Considering our findings, we argue that there are ways to make large screens more appropriate for in-car usage and thus harness the advantages they provide in other aspects.

I feel it in my fingers: haptic guidance on touch surfaces

Touch screens are on the rise and replace traditional knobs and buttons at a fast pace. However, their lack of tangible guidance and feedback can become a problem in scenarios where visual attention is scarce. Besides dynamic tactile feedback by vibrations, the usability of touch screens can be improved by static haptic structures such as shaped or structured surfaces. In this paper we describe the prototype of an in-vehicle application using unimanual four-finger interaction and haptic guidance in order to avoid visual distraction from the primary task of driving. We built a low fidelity prototype with static haptics using an Android tablet and silicone foil. A user study showed that flexible positioning of touch buttons mapped to the users fingers was more convenient and produced fewer errors than fixed positioning. A curved haptic border provided the user with orientation and allowed a new selection mode: dragging buttons over the edge resulted in a reduced interaction time when compared to double tapping. We present several different variants for unimanual multifinger interaction on planar and non-planar surfaces. Our results can support the development of future concepts for blind interaction.

Out of Shape, Out of Style, Out of Focus

ZusammenfassungWenn sich Computertechnik nahtlos in unseren Alltag integrieren soll, dann erfordert dies neue Bauformen und Interaktionsstile, die auf die menschlichen Fähigkeiten abgestimmt sind. Dieser Artikel zeigt drei Gestaltungsaspekte auf, mittels derer wir eine solche Integration erreichen können. Er beschreibt in aller Kürze eine Reihe von Prototypen der Arbeitsgruppen Medieninformatik und Mensch-Maschine-Interaktion an der LMU München und reflektiert kurz den verwendeten methodischen Ansatz.