Automatic Keystone Correction for Camera-assisted Presentation Interfaces

Rahul Sukthankar, Robert Stockton, and Matthew Mullin
Proceedings of International Conference on Multimedia Interfaces, October, 2000.


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Abstract
Projection systems have become the ubiquitous infrastructure for presentation technology. However, unless the projector is precisely aligned to the presentation screen, the resulting image suffers from perspective (keystone) distortions requiring manual optical or digital correction. This tedious process must be repeated whenever the projector or screen is moved and is increasingly relevant given the emerging trend towards highly-portable LCD projection systems. This paper presents a presentation interface that pre-warps the image to be projected in such a way that the distortions induced by the projector-screen geometry precisely negate the warping. An uncalibrated, low-resolution digital camera is used to infer the projector-screen geometry and to automatically determine the pre-warping parameters. This vision-based system is augmented with a natural interface that enables the user to interactively refine the suggested rectification. Arbitrary distortions due to projector placement are negated, allowing the projector (and camera) to be placed \emph{anywhere} in the presentation room --- for instance, at the side rather than the center of the room. Our solution works with existing projector hardware, and could easily be incorporated into the next generation of LCD projector systems.

Keywords
computer vision, human-computer interaction

Notes
Associated Center(s) / Consortia: Vision and Autonomous Systems Center

Text Reference
Rahul Sukthankar, Robert Stockton, and Matthew Mullin, "Automatic Keystone Correction for Camera-assisted Presentation Interfaces," Proceedings of International Conference on Multimedia Interfaces, October, 2000.

BibTeX Reference
@inproceedings{Sukthankar_2000_3396,
   author = "Rahul Sukthankar and Robert Stockton and Matthew Mullin",
   title = "Automatic Keystone Correction for Camera-assisted Presentation Interfaces",
   booktitle = "Proceedings of International Conference on Multimedia Interfaces",
   month = "October",
   year = "2000",
}