Gradient-Domain Bidirectional Path Tracing
Proc. Eurographics Symposium on Rendering, 2015
|Marco Manzi||Markus Kettunen||Miika Aittala
| University of Bern
||Aalto University, NVIDIA
||University of Bern
Gradient-domain path tracing has recently been introduced as an efficient realistic image synthesis algorithm. This paper introduces a bidirectional gradient-domain sampler that outperforms traditional bidirectional path tracing often by a factor of two to five in terms of squared error at equal render time. It also improves over unidirectional gradient-domain path tracing in challenging visibility conditions, similarly as conventional bidirectional path tracing improves over its unidirectional counterpart. Our algorithm leverages a novel multiple importance sampling technique and an efficient implementation of a high-quality shift mapping suitable for bidirectional path tracing. We demonstrate the versatility of our approach in several challenging light transport scenarios.
Avalilable on the gradient-domain path tracing project page.