Abstract: We describe a continuous adjoint formulation for radiance transport that allows a global illumination algorithm to focus on the directional interactions that contribute most to the visible scene. We show how the adjoint quantity for radiance can be described by an angular distribution that is only piecewise-continuous. This observation motivates the formulation of a related adjoint quantity, called exitant directional importance, whose angular distribution is continuous. We prove that exitant directional importance is equivalent to radiance in the sense that that the two quantities satisfy the same transport equation and can be propagated through the environment in the same fashion. An adjoint formulation can dramatically reduce the time to compute radiosities when much of the scene is invisible. We present some preliminary results that demonstrate how the adjoint formulation for radiance can provide significant speed-ups even when all surfaces are visible.

One-line summary: Exitant directional importance is continuous and transported like radiance.

Published in: Proceedings of the Fourth Eurographics Workshop on Rendering, pages 95-104. Eurographics, June 1993. (Paris, France, June 14-16.)

Download paper here: egwr93.pdf (abstract and color figures are missing).

Back to Per's publication page.