Photon Differentials in Space and Time

Abstract

Abstract. We present a novel photon mapping algorithm for animations. We extend our previous work on photon differentials [12] with time differentials. The result is a first order model of photon cones in space an time that effectively reduces the number of required photons per frame as well as efficiently reduces temporal aliasing without any need for in-between-frame photon maps.

Photon Differential Splatting for Rendering Caustics

“…Finally, our splatting approach can be extended to include motion blur and other temporal aspects by using full spatio‐temporal photon differentials [SFES11]. This means that we need third positional and directional differential vectors, where the partial derivatives are taken with respect to time.…”

Antialiasing complex global illumination effects in path-space

“…Cone tracing [Heckbert and Hanrahan 1984;Shinya et al 1987] can prefilter geometry and 3D color data [Neyret 1998;Crassin et al 2009], approximating soft shadows and smooth indirect illumination. Ray differentials [Igehy 1999;Chen and Arvo 2000;Schjøth et al 2007;Elek et al 2014] propagate local differentials from sensors (or lights) through only specular reflection and refraction events, but they cannot correctly handle non-specular interactions. Suykens and Willems' path differentials [2001] most closely resemble our work, albeit with several important differences: while they also identify the importance of devising prefiltering footprints at path vertices, path differentials only account for transport and filtering from eye subpaths and neglect the effects of the light source (and transport from light subpaths), resulting in over-blurring.…”

Antialiasing Complex Global Illumination Effects in Path-Space

“…Cone tracing [Heckbert and Hanrahan 1984;Shinya et al 1987] can prefilter geometry and 3D color data [Neyret 1998;Crassin et al 2009], approximating soft shadows and smooth indirect illumination. Ray differentials [Igehy 1999;Chen and Arvo 2000;Schjøth et al 2007;Elek et al 2014] propagate local differentials from sensors (or lights) through only specular reflection and refraction events, but they cannot correctly handle non-specular interactions.…”