We are pleased to announce our award of Best Paper at Eurographics 2013 for our paper Photon Parameterisation for Robust Relaxation Constraints, Ben Spencer and Mark W. Jones. [Link to paper]
The paper introduces a technique that augments each photon with information about its origin trajectory. Using this, lighting is separable during density estimation queries. Additionally, we spot fine edge detail using PCA allowing us to employ photon relaxation without detrimental effects. This results in high qualify photon maps that reduce variance and can be rendered with very low bandwidth kernels reducing bias. [Link to news on EG.org]
This paper presents a novel approach to detecting and preserving fine illumination structure within photon maps. Data derived from each photon’s primal trajectory is encoded and used to build a high-dimensional kd-tree. Incorporation of these new parameters allows for precise differentiation between intersecting ray envelopes, thus minimizing detail degradation when combined with photon relaxation. We demonstrate how parameter-aware querying is beneficial in both detecting and removing noise. We also propose a more robust structure descriptor based on principal components analysis that better identifies anisotropic detail at the sub-kernel level.We illustrate the effectiveness of our approach in several example scenes and show significant improvements when rendering complex caustics compared to previous methods.
Ben Spencer and Mark W. Jones
Computer Graphics Forum, Volume 32, Issue 2pt1, pages 83–92, May 2013. [doi]
Best paper, Eurographics 2013.