Chair: Per Ola Kristensson, University of St Andrews, UK
LightGuide: Projected Visualizations for Hand Movement Guidance
Contribution & Benefit: Describes a new approach to movement guidance, where visual hints are digitally projected on a user's hand. Can help users perform complex movements such as in exercise or playing an instrument.
Abstract » LightGuide is a system that explores a new approach to gesture guidance where we project guidance hints directly on a user�s body. These projected hints guide the user in completing the desired motion with their body part which is particularly useful for performing movements that require accuracy and proper technique, such as during exercise or physical therapy. Our proof-of-concept implementation consists of a single low-cost depth camera and projector and we present four novel interaction techniques that are focused on guiding a user�s hand in mid-air. Our visualizations are designed to incorporate both feedback and feedforward cues to help guide users through a range of movements. We quantify the performance of LightGuide in a user study comparing each of our on-body visualizations to hand animation videos on a computer display in both time and accuracy. Exceeding our expectations, participants performed movements with an average error of 21.6mm, nearly 85% more accurately than when guided by video.ACM
Understanding Flicking on Curved Surfaces
Contribution & Benefit: This paper investigates flicking gestures on curved interactive surfaces. It provides a mathematical model to estimate the error users will make when flicking across a curve.
Abstract » 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.ACM
MirageTable: Freehand Interaction on a Projected Augmented Reality Tabletop
Contribution & Benefit: MirageTable is a novel augmented reality system which enables instant digitization of physical objects, correct 3D perspective views, and interaction using bare hands without gloves or trackers.
Abstract » Instrumented with a single depth camera, a stereoscopic projector, and a curved screen, MirageTable is an interactive system designed to merge real and virtual worlds into a single spatially registered experience on top of a table. Our depth camera tracks the user�s eyes and performs a real-time capture of both the shape and the appearance of any object placed in front of the camera (including user�s body and hands). This real-time capture enables perspective stereoscopic 3D visualizations to a single user that account for deformations caused by physical objects on the table. In addition, the user can interact with virtual objects through physically-realistic freehand actions without any gloves, trackers, or instruments. We illustrate these unique capabilities through three application examples: virtual 3D model creation, interactive gaming with real and virtual objects, and a 3D teleconferencing experience that not only presents a 3D view of a remote person, but also a seamless 3D shared task space. We also evaluated the user�s perception of projected 3D objects in our system, which confirmed that the users can correctly perceive such objects even when they are projected over different background colors and geometries (e.g., gaps, drops).ACM
How Screen Transitions Influence Touch and Pointer Interaction Across Angled Display Arrangements
Contribution & Benefit: User study investigating the effects of screen transitions on touch and pointer interaction across angled display arrangements. Can assist developers in understanding how to design novel interactive display arrangements.
Abstract » Digital office environments often integrate multiple displays in a variety of arrangements. We investigated the combination of a horizontal and a directly connected vertical display, which together form a digital workspace. In particular, we were interested in the effect of the physical transition (bezel, edge or curve) on dragging. In a study participants performed dragging tasks across both display planes with direct touch as well as a pointing device. Contrary to our expectations, we found no significant effect on task completion time. Only regarding accuracy the curved transition performed better than edge and bezel. Interestingly, the subjective judgment did generally not match the objective results. These findings suggest that we need to rethink our understanding of display continuities in terms of usability as well as user satisfaction.ACM
How Small Can You Go? Analyzing the Effect of Visual Angle in Pointing Tasks
Contribution & Benefit: Presents results of a study on pointing performance for targets occupying small visual angles. Suggests a steep performance degradation for targets occupying a visual angle below 3 minutes of arc.
Abstract » People are increasingly using wireless mice from across rooms as they use computers as entertainment centers. As a consequence, they often have to point at targets occupying small visual angles. In this note we present the results of a study on pointing performance for targets occupying small visual angles. Our results suggest there is a steep degradation of pointing performance in both accuracy and speed for targets occupying a visual angle below 3 minutes of arc.ACM