Many Augmented Reality (AR) systems use a 2d barcode or some other marker from which to locate virtual items. In a museum or other public place with a mixed audience with AR and non-AR users it may not be practical, or even possible to use visible markers.

An Infrared light filtered to project (or scan) the marker onto the surface would not be visible with human eyes but easily seen by most any electronic camera ( try pointing your remote control at your webcam etc ).

I'm hoping this is an obvious idea... but willing to bet someone's already patented it... grrr...?
-- justinj, Feb 04 2010

Fujitsu yellow lines thing http://www.research...s/uclip/index_e.htm
[kodabar, Feb 05 2010]

EURion constellation http://en.wikipedia...URion_constellation
Printed on many banknotes the EURion constellation is a way of hiding extra information in plain sight. [kodabar, Feb 05 2010]

I like this idea, but you might have a hard time patenting it.

Kodak invented a barcode that is printed in near-infrared flurorophores which fluoresce infrared when illuminated with a laser. That's about 15 years old.

A more interesting approach has been taken by Fujitsu where they print a series of very fine yellow lines over a colour image. These are pretty much invisible to the naked eye, but show up quite well to a digital camera.
-- kodabar, Feb 05 2010



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