Prakash: Lighting aware motion capture using photosensing markers and multiplexed illuminators

Ramesh Raskar, Hideaki Nii, Bert Dedecker, Yuki Hashimoto, Jay Summet, Dylan Moore, Yong Zhao, Jonathan Westhues, Paul Dietz, John Barnwell, Shree Nayar, Masahiko Inami, Philippe Bekaert, Michael Noland, Vlad Branzoi, Erich Bruns

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


In this paper, we present a high speed optical motion capture method that can measure three dimensional motion, orientation, and incident illumination at tagged points in a scene. We use tracking tags that work in natural lighting conditions and can be imperceptibly embedded in attire or other objects. Our system supports an unlimited number of tags in a scene, with each tag uniquely identified to eliminate marker reacquisition issues. Our tags also provide incident illumination data which can be used to match scene lighting when inserting synthetic elements. The technique is therefore ideal for on-set motion capture or real-time broadcasting of virtual sets. Unlike previous methods that employ high speed cameras or scanning lasers, we capture the scene appearance using the simplest possible optical devices - a light-emitting diode (LED) with a passive binary mask used as the transmitter and a photosensor used as the receiver. We strategically place a set of optical transmitters to spatio-temporally encode the volume of interest. Photosensors attached to scene points demultiplex the coded optical signals from multiple transmitters, allowing us to compute not only receiver location and orientation but also their incident illumination and the reflectance of the surfaces to which the photosensors are attached. We use our untethered tag system, called Prakash, to demonstrate methods of adding special effects to captured videos that cannot be accomplished using pure vision techniques that rely on camera images.

Original languageEnglish
Article number1276422
JournalACM Transactions on Graphics
Issue number3
Publication statusPublished - 2007 Jul 29
Externally publishedYes

ASJC Scopus subject areas

  • Computer Graphics and Computer-Aided Design


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