Into the Blue: Better Caustics through Photon Relaxation
Article first published online: 27 MAR 2009
© 2008 The Author(s) Journal compilation © 2008 The Eurographics Association and Blackwell Publishing Ltd.
Computer Graphics Forum
Volume 28, Issue 2, pages 319–328, April 2009
How to Cite
Spencer, B. and Jones, M.W. (2009), Into the Blue: Better Caustics through Photon Relaxation. Computer Graphics Forum, 28: 319–328. doi: 10.1111/j.1467-8659.2009.01371.x
- Issue published online: 27 MAR 2009
- Article first published online: 27 MAR 2009
- Computer Graphics [I.3.7]: Three-Dimensional Graphics and Realism - Global Illumination
The photon mapping method is one of the most popular algorithms employed in computer graphics today. However, obtaining good results is dependent on several variables including kernel shape and bandwidth, as well as the properties of the initial photon distribution. While the photon density estimation problem has been the target of extensive research, most algorithms focus on new methods of optimising the kernel to minimise noise and bias. In this paper we break from convention and propose a new approach that directly redistributes the underlying photons. We show that by relaxing the initial distribution into one with a blue noise spectral signature we can dramatically reduce background noise, particularly in areas of uniform illumination. In addition, we propose an efficient heuristic to detect and preserve features and discontinuities. We then go on to demonstrate how reconfiguration also permits the use of very low bandwidth kernels, greatly improving render times whilst reducing bias.