Snap Target: Investigating an Assistance Technique for Mobile Magic Lens Interaction With Large Displays

Abstract

Modern handheld devices can act as "magic lenses" for public displays and enable camera-based real-time interaction with their contents, thus allowing for manifold interactive applications in public space. To learn more about the characteristics of common techniques and to provide guidelines for new ones, a comparative user study was conducted. With regard to two basic task types (selection and translation) and two typical devices (smartphone and tablet), three interaction techniques in-depth were evaluated: direct touch-based input (Touch), cross-hair targeting (Target), and a new technique based on a dynamic cross-hair on the screen that snaps to visible nearby screen objects (Snap Target). The study results indicate that successful interaction with the Touch technique strongly depends on the usage context: Although Touch enables fast selection, it incurs many errors when small targets have to be selected on a smartphone. Target supports such difficult selections better, but Snap Target proved to be most robust in both investigated task types. Also, users stated that they felt best supported by the latter technique. Cross-hair-based techniques, especially Snap Target, were found to be well suitable for scenarios where several device types need to be supported under similar conditions. Implications and further work are discussed.

Comparing Four Touch-Based Interaction Techniques for an Image-Based Audience Response System

“…There are many more interesting and possibly accurate interaction techniques (e.g., back-ofdevice interaction (Baudisch & Chu, 2009;Wobbrock, Myers, & Aung, 2008), dual finger selection (Benko, Wilson, & Baudisch, 2006) and "gravity" selection (where the cursor is "pulled" towards the target) (Baldauf & Fröhlich, 2014;Grossman & Balakrishnan, 2005;Sears & Shneiderman, 1991)), but the four techniques discussed above are the most plausible for an image-based ARS. Other techniques are (currently) not suitable for such a system for various reasons (e.g., back-of-device interaction is not supported by most devices, dual finger selection is awkward on small screens, and gravity selection only works when the system knows the user's intended target, which is impossible in an image-based ARS).…”

Interactive lens through smartphones for supporting level-of-detailed views in a public display

“…Personal mobile devices have been identified as promising remote controllers for enabling the interaction with digital contents for public displays, and several respective mobile techniques have been introduced so far by academia and industry [1].…”

“…Despite many advances in smart devices and interaction techniques, most of the devices are inherently limited in terms of their screen size and amount of information they can display and share. Thus, mobile collaboration and interaction is still not supported sufficiently to allow people to have ad-hoc meetings where they cooperatively execute tasks and manipulate shared information through their smartphones [1][2][3][4][5].…”

Perspective Correct Hand-held Augmented Reality for Improved Graphics and Interaction

“…A basic implementation of a center-based selection technique would pick a virtual object when it is at the center of the screen. The snap-target modification [4] increases the reach and reduces the necessary precision by allowing the selection of objects near the center of the screen. Our modification, allows the selection of the virtual object closest to the screen center anywhere on the screen, see Figure 3.…”

“…There are a number of non-touch, device pose-based selection techniques: Baldauf and Fröhlich presented two techniques they call "Target" and "Snap Target" [4]. Their Target selection uses a centered cross-hair while the Snap Target applies a dynamic cross-hair that snaps to a selectable object when it is near to the center of the screen.…”