The Siggraph 2003 presentation on the ESC Lighting Reconstruction Toolkit, an Image-Based Lighting approach used on The Matrix Reloaded and The Matrix Revolutions are online here.

Authors:

Abstract:
The demands of photo-realism required of the effects for The Matrix Reloaded and The Matrix Revolutions led us to create a system for directly and accurately reconstructing real world lighting environments. The Lighting Reconstruction Toolkit builds on research in the area of Image-based Lighting and extends current techniques to enable the reconstruction of lighting that more closely matches the real world.

The full writeup and slides are available below

Full writeup:
Light Reconstruction Siggraph 2003

Slides: