Shield Fields: Modeling and Capturing 3D Occluders

The authors describe a unified representation of occluders in light transport and photography using shield fields: the 4D attenuation function which acts on any light field incident on an occluder. The authors' key theoretical result is that shield field can be used to decouple the effects of occluders and incident illumination. They first describe the properties of shield fields in the frequency-domain and briefly analyze the forward problem of efficiently computing cast shadows.