A short guide to modulated light

ABSTRACT

Many types of tangible interaction systems, such as interactive surfaces and gesture-based interfaces, are based on various kinds of optical tracking, using infrared illuminators and cameras. One drawback of these setups is that they suffer from problems common to optical trackers, such as sensitivity to stray environment light from artificial and natural sources. In this paper, we present a method to significantly enhance tracking robustness for those systems which employ active illumination. Through addition of a small electronic circuit which modulates the LEDs used to illuminate the scene, contrast can be significantly increased.

REFERENCES

• 1: Advanced Realtime Tracking. ARTrack. http://www.ar-tracking.de/.
• 2: Florian Echtler , Manuel Huber , Gudrun Klinker, Shadow tracking on multi-touch tables, Proceedings of the working conference on Advanced visual interfaces, May 28-30, 2008, Napoli, Italy [doi>10.1145/1385569.1385640]
• 3: F. Echtler and G. Klinker. Tracking mobile phones on interactive tabletops. In MEIS '08: Proceedings of the Workshop on Mobile and Embedded Interactive Systems, 2008.
• 4: Jefferson Y. Han, Low-cost multi-touch sensing through frustrated total internal reflection, Proceedings of the 18th annual ACM symposium on User interface software and technology, October 23-26, 2005, Seattle, WA, USA [doi>10.1145/1095034.1095054]
• 5: Hiroshi Ishii , Brygg Ullmer, Tangible bits: towards seamless interfaces between people, bits and atoms, Proceedings of the SIGCHI conference on Human factors in computing systems, p.234-241, March 22-27, 1997, Atlanta, Georgia, United States [doi>10.1145/258549.258715]
• 6: Martin Kaltenbrunner , Ross Bencina, reacTIVision: a computer-vision framework for table-based tangible interaction, Proceedings of the 1st international conference on Tangible and embedded interaction, February 15-17, 2007, Baton Rouge, Louisiana [doi>10.1145/1226969.1226983]
• 7: Microsoft. Surface. http://www.microsoft.com/surface/.
• 8: NaturalPoint. OptiTrack. http://www.naturalpoint.com/optitrack/.
• 9: OSRAM Opto Semiconductors. SFH 4250 Datasheet. http://www.osram-os.com/.
• 10: T. van Roon. 555 timer tutorial. http://www.uoguelph.ca/~antoon/gadgets/555/555.html.
• 11: Andrew D. Wilson, PlayAnywhere: a compact interactive tabletop projection-vision system, Proceedings of the 18th annual ACM symposium on User interface software and technology, October 23-26, 2005, Seattle, WA, USA [doi>10.1145/1095034.1095047]

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.2 User Interfaces (D.2.2, H.1.2, I.3.6)
          Subjects: Input devices and strategies (e.g., mouse, touchscreen)

Keywords:
hardware, infrared, input device, optical tracking