A Theory of Multiplexed Illumination

• Authors: Yoav Y. Schechner;Shree K. Nayar;Peter N. Belhumeur
• Venue: ICCV '03 Proceedings of the Ninth IEEE International Conference on Computer Vision - Volume 2
• Year: 2003

Imaging of objects under variable lighting directions is animportant and frequent practice in computer vision andimage-based rendering. We introduce an approach that significantlyimproves the quality of such images. Traditionalmethods for acquiring images under variable illuminationdirections use only a single light source per acquired image.In contrast, our approach is based on a multiplexing principle,in which multiple light sources illuminate the objectsimultaneously from different directions. Thus, the objectirradiance is much higher. The acquired images are thencomputationally demultiplexed. The number of image acquisitionsis the same as in the single-source method. Theapproach is useful for imaging dim object areas. We givethe optimal code by which the illumination should be multiplexedto obtain the highest quality output. For n imagescorresponding to n light sources, the noise is reduced by\sqrt n/2 relative to the signal. This noise reduction translatesto a faster acquisition time or an increase in density of illuminationdirection samples. It also enables one to use lightingwith high directional resolution using practical setups,as we demonstrate in our experiments.