Imperceptible Simplification on Mobile Displays

Abstract

Graphics on mobile devices is becoming popular because untethered computing is convenient and makes workers more productive. Mobile displays have a wide range of resolutions that affect the scene Level-of-Detail (LoD) that users can perceive: smaller displays show less detail, therefore lower resolution meshes and textures are acceptable. Mobile devices frequently have limited battery energy, low memory and disk space. To minimize wasting limited system resources, the authors render mobile graphics scenes at the lowest LoD at which users do not perceive distortion due to simplification. This is called LoD the Point of Imperceptibility (PoI). Increasing the mesh or texture resolution beyond the PoI wastes valuable system resources without increasing perceivable visual realism. The authors propose a perceptual metric that can easily be evaluated to identify the LoD corresponding to a target mobile display’s PoI and accounts for object geometry, lighting and shading. Previous work did not directly compute changes in the PoI due to target screen resolution. The perceptual metric generates a screen-dependent Pareto distribution with a knee point that corresponds to the PoI. We employ wavelets for simplification, which gives direct access to the mesh undulation frequency that we then use to parameterize the CSF curve.