ABSTRACT
The size and resolution of computer displays has increaseddramatically, allowing more information than ever to berendered on-screen. However, items can now be so small orscreens so cluttered that users need to lean forward toproperly examine them. This behavior may be detrimentalto a user’s posture and eyesight. Our Lean and Zoomsystem detects a user’s proximity to the display using acamera and magnifies the on-screen content proportionally.This alleviates dramatic leaning and makes items morereadable. Results from a user study indicate people find thetechnique natural and intuitive. Most participants found onscreencontent easier to read, and believed the techniquewould improve both their performance and comfort.Author KeywordsLean, magnification, semantic zooming, user interfaces,assistive technology, proximity aware, posture, sensors.
ACM Classification Keywords H5.2. [User Interfaces]: Interaction Styles, Graphical UserInterfaces.I
NTRODUCTION
People naturally lean towards items in order to betterinspect them. The magnification provided by beingphysically closer can expose otherwise unseen details.However, the cumulative effects of repeated leaning can bedetrimental to users’ posture [2]. Also, the need to focus oncloser-than-usual surfaces can cause eyestrain, doublevision, headaches and other vision-related problems [2].This lean behavior is prevalent in computer use; displaytechnology has advanced considerably, both in size andresolution, allowing more information to be rendered onscreen than ever before. The magnitude of this problem isgrowing as people spend an ever-increasing amount of timein front of computers, both at work and home.The most obvious way to counteract this problem would beto design user interfaces such that items are easily viewableand leaning is rendered unnecessary. However, this isimpractical on several levels. Foremost, it is simply notpossible to upgrade all software to have this desiredbehavior. Secondly, people have different thresholds forwhen leaning becomes necessary. An attempt to design auser interface that works for the lowest commondenominator would likely result in a less productiveinterface for a majority of users. Lastly, the need formagnification is highly content- and user-specific. There isno reliable way to establish what content users would preferto see with extra or less detail. For example, a photographof a class reunion encountered online might warrant a closeexamination by some people, but not others


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