We present a low cost method to measure and characterize the end-to-end latency when using a touch system (tap latency) or an input device equipped with a physical button. Our method relies on a vibration sensor attached to a finger and a photo-diode to detect the screen response. Both are connected to a micro-controller connected to a host computer using a low-latency USB communication protocol in order to combine software and hardware probes to help determine where the latency comes from. We present the operating principle of our method before investigating the main sources of latency in several systems. We show that most of the latency originates from the display side. Our method can help application designers characterize and troubleshoot latency on a wide range of interactive systems.

Hotkeys are an efficient method of selecting commands on a keyboard. However, these shortcuts are often underused by users. We present Métamorphe, a novel keyboard with keys that can be individually raised and lowered to promote hotkeys usage. Métamorphe augments the output of traditional keyboards with haptic and visual feedback, and offers a novel design space for user input on raised keys (e.g., gestures such as squeezing or pushing the sides of a key). We detail the implementation of Métamorphe and discuss design factors. We also report two user studies. The first is a user-defined interface study that shows that the new input vocabulary is usable and useful, and provides insights into the mental models that users associate with raised keys. The second user study shows improved eyesfree selection performance for raised keys as well as the surrounding unraised keys.

Figure 1: Illustration of manual RayCursor: a) the user controls a cursor along the ray using relative displacements of their thumb on the controller's touchpad; b) the target closest to the cursor is highlighted. Illustration of semi-auto RayCursor: c) by default, it works like Raycasting. The cursor (in black) is positioned at the intersection with a target; d) the target remains selected if the cursor moves out of the target, until it is closer to another target; e) the user can manually move the cursor using the controller's touchpad, to select another target (the cursor turns red to indicate manual mode); f) if the user does not touch the touchpad for 1s, the cursor returns to its behaviour described in c). ABSTRACTRaycasting is the most common target pointing technique in virtual reality environments. However, performance on small and distant targets is impacted by the accuracy of the pointing device and the user's motor skills. Current pointing facilitation techniques are currently only applied in the context of the virtual hand, i.e. for targets within reach. We propose enhancements to Raycasting: filtering the ray, and adding a controllable cursor on the ray to select the nearest target. We describe a series of studies for the design of the visual feedforward, filtering technique, as well as a comparative study between different 3D pointing techniques.Our results show that highlighting the nearest target is one of the most efficient visual feedforward technique. We also show that filtering the ray reduces error rate in a drastic way. Finally we show the benefits of RayCursor compared to Raycasting and another technique from the literature.

Abstract-Spatial information can be difficult to present to a visually impaired computer user. In this paper we examine a new kind of tactile cueing for non-visual interaction as a potential solution, building on earlier work on vibrotactile Tactons. However, unlike vibrotactile Tactons, we use a pin array to stimulate the finger tip. Here, we describe how to design static and dynamic Tactons by defining their basic components. We then present user tests examining how easy it is to distinguish between different forms of pin array Tactons demonstrating accurate Tacton sets to represent directions. These experiments demonstrate usable patterns for static, wave and blinking pin array Tacton sets for guiding a user in one of eight directions. A study is then described that shows the benefits of structuring Tactons to convey information through multiple parameters of the signal. By using multiple independent parameters for a Tacton, this study demonstrates participants perceive more information through a single Tacton. Two applications using these Tactons are then presented: a maze exploration application and an electric circuit exploration application designed for use by and tested with visually impaired users.

The role of haptic feedback on virtual embodiment is investigated in this paper in a context of active and fine manipulation. In particular, we explore which haptic cue, with varying ecological validity, has more influence on virtual embodiment. We conducted a within-subject experiment with 24 participants and compared self-reported embodiment over a humanoid avatar during a coloring task under three conditions: force feedback, vibrotactile feedback, and no haptic feedback. In the experiment, force feedback was more ecological as it matched reality more closely, while vibrotactile feedback was more symbolic. Taken together, our results show significant superiority of force feedback over no haptic feedback regarding embodiment, and significant superiority of force feedback over the other two conditions regarding subjective performance. Those results suggest that a more ecological feedback is better suited to elicit embodiment during fine manipulation tasks.

Smartwatches and activity trackers are becoming prevalent, providing information about health and fitness, and offering personalized progress monitoring. These wearable devices often offer multimodal feedback with embedded visual, audio, and vibrotactile displays. Vibrations are particularly useful when providing discreet feedback, without users having to look at a display or anyone else noticing, thus preserving the flow of the primary activity. Yet, current use of vibrations is limited to basic patterns, since representing more complex information with a single actuator is challenging. Moreover, it is unclear how much the user's current physical activity may interfere with their understanding of the vibrations. We address both issues through the design and evaluation of ActiVibe, a set of vibrotactile icons designed to represent progress through the values 1 to 10. We demonstrate a recognition rate of over 96% in a laboratory setting using a commercial smartwatch. ActiVibe was also evaluated in situ with 22 participants for a 28-day period. We show that the recognition rate is 88.7% in the wild and give a list of factors that affect the recognition, as well as provide design guidelines for communicating progress via vibrations.

Figure 1: Our three-application demo: (a) SMS application: the thumb can be used to feed-forward the current mapping between indivdual fingers and commands; here, the index triggers the copy command. (b) PDF annotation application: (b1) thumb showing the different subsets of commands available for selection; after sliding the thumb in the corresponding direction, (b2) updated feed-forward corresponding to the top-right set. (c) Vectorial drawing application demo: non-dominant thumb and index select a command mapping enabling the dominant ring finger to draw an ellipse. ABSTRACTIdentifying which fingers are in contact with a multi-touch surface provides a very large input space that can be leveraged for command selection. However, the numerous possibilities enabled by such vast space come at the cost of discoverability. To alleviate this problem, we introduce a three-step interaction pattern inspired by hotkeys that also supports feedforward. We illustrate this interaction with three applications allowing us to explore and adapt it in different contexts.

International audienceIdentifying which fingers are touching a multi-touch surface provides a very large input space. We describe FingerCuts, an interaction technique inspired by desktop keyboard shortcuts to exploit this potential. FingerCuts enables integrated command selection and parameter manipulation, it uses feed-forward and feedback to increase discoverability, it is backward compatible with current touch input techniques, and it is adaptable for different touch device form factors. We implemented three variations of FingerCuts, each tailored to a different device form factor: tabletop, tablet, and smartphone. Qualitative and quantitative studies conducted on the tabletop suggests that with some practice, FingerCuts is expressive, easy-to-use, and increases a sense of continuous interaction flow and that interaction with FingerCuts is as fast, or faster than using a graphical user interface. A theoretical analysis of FingerCuts using the Fingerstroke-Level Model (FLM) matches our quantitative study results, justifying our use of FLM to analyse and validate the performance for the other device form factors