Whats a fiducial?
A fiducial or fiduciary marker is often a graphical symbol that is identified by a computer vision system. The marker is known beforehand to the computer vision algorithm and therefore the only task for the computer vision system is to identify and locate the fiducial symbol in the image. Practically speaking, a fiducial symbol is a sticker that needs to be attached to a physical object in order to make it visible to the computer vision algorithm. For an example of such a maker, see: http://reactivision.sourceforge.net/images/reactivision02.
