A Median Cut Algorithm for Light Probe Sampling
SIGGRAPH 2005 Poster
Paul Debevec   
USC Institute for Creative Technologies

Published in: Reinhard, Ward, Pattanaik, and Debevec, High Dynamic Range Imaging: Acquistion, Display, and Image-Based Lighting, Ch. 9, "Image-Based Lighting", Morgan-Kaufmann, 2005, pp. 430-433.

We present a technique for approximating a light probe image as a constellation of light sources based on a median cut algorithm. The algorithm is simple to implement, runs efficiently, and can realistically represent a complex lighting environment with as few as 64 point light sources.


SIGGRAPH 2005 Poster Abstract
MedianCutSampling.pdf, (3MB)

Supplemental Images Poster Abstract
MedianCutSampling_plate.pdf, (5.4MB)

There is an implementation of the Median Cut sampling algorithm as an HDR Shop 1.0 plugin in Francesco Banterle's Banty's Toolkit beta 1.1 , which produces a simple text file with the light parameters.

The algorithm is also implemented in Jeremy Pronk's Image-Based Lighting Tools package, with support for Maya and Mental Ray.