Performance Relighting and Reflectance Transformation with <br>Time-Multiplexed Illumination
Performance Relighting and Reflectance Transformation with
Time-Multiplexed Illumination
SIGGRAPH 2005 Paper
Andreas Wenger     Andrew Gardner     Chris Tchou
Jonas Unger     Tim Hawkins     Paul Debevec
USC Institute for Creative Technologies

Actress Marissa Sellers performs in Light Stage 5 as a high speed camera films her lit by 152 lighting directions every 24th of a second. The images can be used to relight her in new lighting environments, or to estimate and transform the reflectance characteristics of her performance. Behind her is a gray board used for time-multiplexed matting.

Inset: Her performance virtually illuminated under two different real-world illumination environments.



We present a technique for capturing an actor's live-action performance in such a way that the lighting and reflectance of the actor can be designed and modified in postproduction. Our approach is to illuminate the subject with a sequence of time-multiplexed basis lighting conditions, and to record these conditions with a highspeed video camera so that many conditions are recorded in the span of the desired output frame interval. We investigate several lighting bases for representing the sphere of incident illumination using a set of discrete LED light sources, and we estimate and compensate for subject motion using optical flow and image warping based on a set of tracking frames inserted into the lighting basis. To composite the illuminated performance into a new background, we include a time-multiplexed matte within the basis. We also show that the acquired data enables time-varying surface normals, albedo, and ambient occlusion to be estimated, which can be used to transform the actor's reflectance to produce both subtle and stylistic effects.



SIGGRAPH 2005 Paper:

SIGGRAPH 2005 Video:

High Def Clip from SIGGRAPH 2005 ET:

SIGGRAPH 2004 Poster using nine spherical harmonics for relighting:

SIGGRAPH 2004 Poster Video using nine spherical harmonics for relighting:

2004 Technical Report:

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