We first summarize the path integral formulation by Veach [Veach 1998]. Using the path integral formulation, light transport simulation can be expressed as: Ij = Ω fj (¯ x)dµ(¯ x), (1) where j is an index to the pixel (or measurement), fj is the measurement contribution function, µ is a measure of paths, and Ω is the set of transport paths of all lengths… (More)