The effect of interior bezel presence and width on magnitude judgement

© The Authors, 2014. This is the author's version of the work. It is posted here by permission for your personal use. Not for redistribution. First published in print by Canadian Human-Computer Communications Society, and also in electronic form by ACM, Wallace, J. R., Vogel, D., & Lank, E. (2014). The effect of interior bezel presence and width on magnitude judgement. In Proceedings of Graphics Interface 2014 (pp. 175–182). Montreal, Quebec, Canada: Canadian Information Processing Society.Large displays are often constructed by tiling multiple small displays, creating visual discontinuities from inner bezels that may affect human perception of data. Our work investigates how bezels impact magnitude judgement, a fundamental aspect of perception. Two studies are described which control for bezel presence, bezel width, and user-to-display distance. Our findings form three implications for the design of tiled displays. Bezels wider than 0.5cm introduce a 4-7% increase in judgement error from a distance, which we simplify to a 5% rule of thumb when assessing display hardware. Length judgements made at arm's length are most affected by wider bezels, and are an important use case to consider. At arm's length, bezel compensation techniques provide a limited benefit in terms of judgement accuracy. Copyright held by authors

Evaluating and Improving Image Quality of Tiled Displays

Tiled displays are created by grouping multiple displays together to form one very large display. These tiled displays are often the only suitable option for displaying very large images but suffer from a grid distortion caused by gaps between each sub-display’s active region. This grid distortion is fundamentally different from other, well-studied, image distortions (e.g., blur, noise, compression) and the impact of these grid distortions has thus far not been studied. This research addresses this lack of attention by investigating the grid distortion’s quality impact and creating perceptual algorithms to reduce this impact. We measure the quality impact of the grid distortion by creating two new image quality assessment (IQA) databases for tiled images. These databases provide significant insight into the unique characteristics of the grid distortion and provide a baseline against which to measure the performance of current IQA metrics. We use these databases to show that current metrics do not adequately reflect the quality impact of the grid distortions, and we create a new metric specifically for tiled images that statistically (with 95% confidence) outperforms current metrics. We improve perceived tiled display image quality by creating new image-correction algorithms based on elements of the human visual system (HVS). These correction techniques modify the perceived quality of the displayed images without directly modifying the static grid distortion. These algorithms are shown, through the use of a third subjective user study, to clearly and consistently improve the perceived quality of tiled images.1 yea