A SharpView Font with Enhanced Out-of-Focus Text Legibility for Augmented Reality Systems

In an optical see-through augmented reality system, virtual and real information can be viewed at different distances. This requires users to frequently change their eye focus from one distance to another, and only one piece of information is in sharp focus while the other is out of focus. Previous studies have found that due to out-of-focus virtual information, when integrating information between the distances, users suffer fatigue and miss important information. Therefore, this paper introduces a novel font, termed a SharpView font, which looks sharper and more legible than standard fonts when seen out of focus. Our method models out-of-focus blur with Zernike polynomials and coefficients, develops a focus correction algorithm based on constrained total variation optimization, and proposes a novel gradient-based algorithm to quantify the sharpness of textual information. We have evaluated the SharpView font through simulation and optically viewed camera-based measurement. When seen out of focus, our proposed font are significantly sharper than standard fonts, as assessed both visually and quantitatively through simulation (40%-44%), as well as the optics of an augmented reality display (24%-32%).