Abstraction and Depiction of Sparsely Scanned Outdoor Environments

Abstract

This paper describes various techniques and applications of rendering three-dimensionally digitized outdoor en- vironments in non-photorealistic rendering styles. The difficulty in rendering outdoor environments is accommodating their inaccuracy, incompleteness, and large size to deliver a smooth animation without suggesting the underlying data deficiency. Standard rendering approaches often expose and inadvertently emphasize missing and noisy data, producing unpleasant images. Our use of non-photorealistic rendering allows us to de-emphasize these problems and produce aesthetically pleasing images. The key approach discussed in this paper employs artistic drawing techniques to illustrate features of varying importance and accuracy. We use point-based representations of the scanned environments and operate directly on the point-based models for abstraction and rendering. We de- velop a unified framework for producing sketchy, profile, painterly, cartoon, and intermingled styles. We describe a level-of-detail data structure, the continuous resolution queue, to promise coherent and consistent animation. We also leverage modern graphics hardware to achieve interactive rendering of large scenes.