Temporal Radiance Caching


(a) Current Frame	(b) Record Positions	(c) Record Lifespan	(d) Next Frame

Our temporal caching method reuses irradiance and radiance records in multiple frames. When computing the global illumination solution for the current frame (a), our method estimates where the lighting changes using simple observations. For each record generated in current frame (b), our temporal weighting function estimates the future change of lighting and defines the lifespan and temporal gradients of each record (c), green and red colors respectively representing long and short lifespan. Since a record is reused in several frames, the computation cost of the global illumination solution for next frames is drastically reduced.

Abstract:
We present a novel method for fast, high quality computation of glossy global illumination in animated environments. Building on the irradiance caching and radiance caching algorithms, our method leverages temporal coherence by sparse temporal sampling and interpolation of the indirect lighting. In our approach, part of the global illumination solution computed in previous frames is reused in the current frame. Our reusing scheme adapts to the change of incoming radiance by updating the indirect lighting only where there is a significant change. By reusing data in several frames, our method removes the flickering artifacts and yields a significant speedup compared to classical computation in which a new cache is computed for every frame. We also define temporal gradients for smooth temporal interpolation. A key aspect of our method is the absence of any additional complex data structure, making the implementation into any existing renderer based on irradiance and radiance caching straightforward. We describe the implementation of our method using graphics hardware for improved performance.

Publications:
P. Gautron, K. Bouatouch, S. Pattanaik
Temporal Radiance Caching
SIGGRAPH 2006 Sketches
Links: PDF PPT PPT+Videos Bundle(EXE+PPZ)

P. Gautron, K. Bouatouch, S. Pattanaik
Temporal Radiance Caching
Technical Report no. 1796, IRISA, Rennes, France
Links: PDF BibTex References

Videos:

Full Video (95MB)	Cube in a Box (2MB)	Moving Light (2MB)
Flying Kite (22MB)	Japanese Interior (26MB)	Spheres (20MB)

Link:
Temporal Radiance Caching is part of the Radiance Caching Project