Prakash: Lighting-Aware Motion Capture Using
Photosensing Markers and Multiplexed Illumination

R Raskar, H Nii, B de Decker, Y Hashimoto, J Summet, D Moore, Y Zhao, J Westhues, P Dietz, M Inami, S Nayar, J Barnwell, M Noland, P Bekaert, V Branzoi, E Bruns

ACM  SIGGRAPH 2007  Paper

Movie (100MB)      Movie (50MB)      Paper      Etech Demo (also at Siggrapgh 2007)

Imperceptible Photosensing Marker Tags for
Location + Orientation + Incident Illumination + Reflectance + Unique Id Capture in Ambient Light
at 500Hz, for inexpensive(<$1K) on-set motion capture.

For Business or Licensing Contact Information, please see below.


MERL: Ramesh Raskar, Jonathan Westhues, Paul Dietz, John Barnwell,
U of Tokyo: Hideaki Nii,
Universiteit Hasselt, Belgium: Bert de Decker, Philippe Bekaert,
University of Electro-Communications, Tokyo: Yuki Hashimoto, Masahiko Inami
Georgia Institute of Technology: Jay Summet,
Syracuse U.: Dylan Moore,
Brown U.: Yong Zhao
Columnia University: Shree K. Nayar,  Vlad Branzoi
University of North Carolina at Chapel Hill: Michael Noland
Bauhaus University,  Weimar, Germany: Erich Bruns

EETimes  [Local],  CGWorldVFXWorld , DigitalArts

IEEE Signal Processing Magazine on latest Mo-cap Methods

Wikipedia on Motion Capture

Second Skin: Augmenting Human Performance and Improving Motor Learning

Dennis Miaw and Ramesh Raskar, MIT Media Lab
  • Improving and training for performance, sports, dance, tai chi, etc
  • Physical therapy for mentally and physically challenged individuals
  • Assisting elderly people who might have difficulty with daily activities
Project website: Second Skin, Camera Culture Group
Media: Technology Review, BitStream, DVICE, Slashdot, Fast Company

Photosensing Tag for Location+Orientation+Incident Illumination Capture

Comparison of Our system with other Optical Mocap systems

Figure Above: Motion and illumination capture in a natural setting with imperceptible tags. (Top row: Left) A video frame from a recording session. (Right) A virtual sword inserted with correct location, orientation, lighting and motion blur. (Bottom Right) Traces of hidden tags superimposed on an actor running in sunlight. Comparison of Prakash system with other Camera-based Optical Motion Capture systems.


In this paper, we present a high speed optical motion capture method which can measure three dimensional motion, orientation, and incident illumination at tagged points in a scene. We use tracking tags that can be imperceptibly embedded in attire or other objects and can work in natural lighting conditions. Our system can support an unlimited number of tags in a scene, and each tag has a unique id thus eliminating marker reacquisition issues. Our tags also provide incident illumination data which can be used when inserting synthetic elements in order to match the lighting of the scene at the time of capturing. This makes the technique ideal for on-set motion capture or the 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 their location and orientation but also their incident illumination and the reflectance of the surfaces to which they are attached. We use our untethered tag system to demonstrate methods of adding special effects to captured videos that cannot be accomplished using pure vision techniques that rely on camera images.

Siggraph ETech 2006: Instant Replay:
LumiNetra: 500 Hz Tracking with Inexpensive IR Photosensors

This page shows results using our high-speed space labeling projectors and links to additional information about the project.

Powerpoint Slides [PPT File 4MB]

Movie [AVI File 15MB]

Report by SportsVideo, New instant replay technology looks to end controversies


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Camera Culture Group MIT Media Lab, Cambridge, MA, USA