Simon Voelker

FingerFlux: near-surface haptic feedback on tabletops

We introduce FingerFlux, an output technique to generate near-surface haptic feedback on interactive tabletops. Our system combines electromagnetic actuation with permanent magnets attached to the users hand. FingerFlux lets users feel the interface before touching, and can create both attracting and repelling forces. This enables applications such as reducing drifting, adding physical constraints to virtual controls, and guiding the user without visual output. We show that users can feel vibration patterns up to 35 mm above our table, and that FingerFlux can significantly reduce drifting when operating on-screen buttons without looking.

BendDesk: dragging across the curve

We present BendDesk, a hybrid interactive desk system that combines a horizontal and a vertical interactive surface via a curve. The system provides seamless touch input across its entire area. We explain scalable algorithms that provide graphical output and multi-touch input on a curved surface. In three tasks we investigate the performance of dragging gestures across the curve, as well as the virtual aiming at targets. Our main findings are: 1) Dragging across a curve is significantly slower than on flat surfaces. 2) The smaller the entrance angle when dragging across the curve, the longer the average trajectory and the higher the variance of trajectories across users. 3) The curved shape of the system impairs virtual aiming at targets.

Combining Direct and Indirect Touch Input for Interactive Workspaces using Gaze Input

Interactive workspaces combine horizontal and vertical touch surfaces into a single digital workspace. During an exploration of these systems, it was shown that direct interaction on the vertical surface is cumbersome and more inaccurate than on the horizontal one. To overcome these problems, indirect touch systems turn the horizontal touch surface into the input which allows manipulation of objects on the vertical display. If the horizontal touch surface also acts as a display, however, it becomes necessary to notify the system which screen is currently in use by providing a switching mode. We investigate the use of gaze tracking to perform these mode switches. In three user studies, we compare absolute and relative gaze augmented selection techniques with the traditional direct-touch approach. Our results show that our relative gaze augmented selection technique outperforms the other techniques for simple tapping tasks alternating between horizontal and vertical surfaces, and for dragging on the vertical surface. However, when tasks involve dragging across surfaces, the findings are more complex. We provide a detailed description of the proposed interaction techniques, a statistical analysis of these interaction techniques, and how they can be applied to systems that involve a combination of multiple horizontal and vertical touch surfaces.

Understanding flicking on curved surfaces

Flicking is a common interaction technique to move objects across large interactive surfaces, but little is known about its suitability for use on non-planar, curved surfaces. Flicking consists of two stages: First, visually determining the direction in which to flick the object, then planning and executing the corresponding gesture. Errors in both stages could influence flicking accuracy. We investigated flicking interactions on curved interactive surface to evaluate which type of error influences accuracy. Therefore, we carried out three user studies to analyze how each stage of flicking on a curved surface is influenced. Our main findings are: 1) Flicking gestures are more accurate if horizontal and vertical surface are joined by a continuous curve than if they are separated by an edge or gap. 2) Flicking gestures on curved surfaces are mostly influenced by the motor execution stage of the gesture rather than the visual perception stage. 3) Flicking accuracy decreases as the starting point of the gesture is moved closer to the curve. 4) We conclude with a first mathematical model to estimate the error users will make when flicking across a curve.

Simplifying Remote Collaboration through Spatial Mirroring

Even though remote collaboration through telepresence is supported by a variety of devices and display environments, it still has some inherent problems. One of these problems is the definition of a unified spatial reference system for the shared workspace in combination with an immersive representation of the collaborator. To mitigate this problem we propose a technique we call spatial mirroring. It is based on a virtual collaboration environment using two curved displays and aims to eliminate possible communication errors due to left/right misunderstandings. We explain the working principle and ideas behind spatial mirroring, and present two consecutive user studies in which we were able to verify its benefits.

Conceptual framework for surface manager on interactive tabletops

To date, most tabletop systems are designed with only a single application visible and accessible at any time, which is, in many cases, an underuse of the tabletop spacious surface, and counter-intuitive to the normal working environment of a table. Desktop window managers provide users facilities to launch and interact with concurrent applications, as well as manage their work items. However, these managers are designed for single-user systems and cannot be directly utilized in tabletops without sacrificing usability. In our research, we want to bring window manager facilities to tabletops. We approach this by first constructing a conceptual framework based on workplace theories and tabletop investigations to understand how users structure their work in these environments (see Figure 1). We will then use the resulting framework to guide our design of a sample surface manager.

Use the Force Picker, Luke: Space-Efficient Value Input on Force-Sensitive Mobile Touchscreens

Picking values from long ordered lists, such as when setting a date or time, is a common task on smartphones. However, the system pickers and tables used for this require significant screen space for spinning and dragging, covering other information or pushing it off-screen. The Force Picker reduces this footprint by letting users increase and decrease values over a wide range using force touch for rate-based control. However, changing input direction this way is difficult. We propose three techniques to address this. With our best candidate, Thumb-Roll, the Force Picker lets untrained users achieve similar accuracy as a standard picker, albeit less quickly. Shrinking it to a single table row, 20% of the iOS picker height, slightly affects completion time, but not accuracy. Intriguingly, after 70 minutes of training, users were significantly faster with this minimized Thumb-Roll Picker compared to the standard picker, at the same accuracy and only 6% of the gesture footprint. We close with application examples.

Sketch&Stitch: Interactive Embroidery for E-textiles

E-Textiles are fabrics that integrate electronic circuits and components. Makers use them to create interactive clothing, furniture, and toys. However, this requires significant manual labor and skills, and using technology-centric design tools. We introduce Sketch&Stitch, an interactive embroidery system to create e-textiles using a traditional crafting approach: Users draw their art and circuit directly on fabric using colored pens. The system takes a picture of the sketch, converts it to embroidery patterns, and sends them to an embroidery machine. Alternating between sketching and stitching, users build and test their design incrementally. Sketch&Stitch features Circuitry Stickers representing circuit boards, components, and custom stitch patterns for wire crossings to insulate, and various textile touch sensors such as pushbuttons, sliders, and 2D touchpads. Circuitry Stickers serve as placeholders during design. Using computer vision, they are recognized and replaced later in the appropriate embroidery phases. We close with technical considerations and application examples.

Release, Don't Wait!: Reliable Force Input Confirmation with Quick Release

Modern smartphones, like iPhone 7, feature touchscreens with co-located force sensing. This makes touch input more expressive, e.g., by enabling single-finger continuous zooming when coupling zoom levels to force intensity. Often, however, the user wants to select and confirm a particular force value, say, to lock a certain zoom level. The most common confirmation techniques are Dwell Time (DT) and Quick Release (QR). While DT has shown to be reliable, it slows the interaction, as the user must typically wait for 1 s before her selection is confirmed. Conversely, QR is fast but reported to be less reliable, although no reference reports how to actually detect and implement it. In this paper, we set out to challenge the low reliability of QR: We collected user data to (1) report how it can be implemented and (2) show that it is as reliable as DT (97.6% vs. 97.2% success). Since QR was also the faster technique and more preferred by users, we recommend it over DT for force confirmation on modern smartphones.

The BendDesk demo: multi-touch on a curved display

BendDesk is a curved interactive display that merges a vertical and a horizontal multi-touch surface with a curve. Users sitting at the table can perform multi-touch input on the entire surface. This demo shows the capabilities and potential applications of such a setup. We also present Bend Invaders, one of the first arcade games on a curved interactive surface. Our demo intends to encourage the discussion about the future of multi-touch in desk environments.