MF+C: Linking suboptimal projections to detail on handheld devices

Abstract

Mobile Focus + Context (mF+C) involves using a handheld device as a focus screen for content on an immersive display or mobile projector. In this work we examine how using a focus device can mitigate poor context image quality due to environmental factors. In an exploratory study we compare three techniques for linking focus and context: lens-focus (Lens), where the device works as a mobile lens held parallel to and in front of the context, center-focus (Centered), where the user holds the device in the center of the projection and pans both context and focus by swiping, and marker-focus (Marker), where the focus region is highlighted on the context, and the user pans the focus by swiping. Participants performed searching, tracing, and detail acquisition tasks with maps and electronics diagrams under a range of simulated projection conditions. All techniques were able to mitigate poor projection quality and performed comparably in time and precision, but the effectiveness of each technique was impacted by task type. There was lower variation in time between participants using Lens for tracing tasks versus the other techniques, but wider variation for searching tasks. Tasks completed using sub-optimal projections involved more time spent looking at the context image than tasks with clear projections, however this difference is less pronounced for the Lens technique. We propose a hybrid Lens-Marker approach for mobile Focus+Context applications in dynamic environments.