Relighting acquired models of outdoor scenes

Abstract

In this paper we introduce a relighting algorithm for diffuse outdoor scenes that enables us to create geometrically correct and illumination consistent models from a series of range scans and a set of overlapping photographs that have been taken under different illumination conditions. To perform the relighting we compute a set of mappings from the overlap region of two images. We call these mappings irradiance ratio maps (IRMs). Our algorithm handles cast shadows, being able to relight shadowed regions into non-shadowed regions and vice-versa. We solve these cases by computing four different IRMs, to handle all four combinations of shadowed vs. non-shadowed surfaces. To relight the non-overlapping region of an image, we look into the appropriate IRM which we index on surface normal, and apply its value to the corresponding pixels. The result is an illumination consistent set of images.