Physorg.com
http://www.physorg.com/news116850872.html
This project is a work in progress. Initial findings and a paper on the subject may be found at: Respectful Cameras: Detecting Visual Markers in Real-Time to Address Privacy Concerns. Jeremy Schiff, Marci Meingast, Deirdre K. Mulligan, Shankar Sastry, and Ken Goldberg. International Conference on Intelligent Robots and Systems (IROS) . [Submitted] San Diego, California. October 2007.