Fixed-Center Pan-Tilt Projector and Its Calibration Methods

We describe a new steerable projector, whose projection center precisely corresponds with its rotation center, which we call a “fixed-center pan-tilt (FC-PT) projector.” This mechanism allows it be set more easily to display graphics precisely on the planes in the environment than for other steerable projectors; wherever we would like to draw graphics, all we have to do are locate the FC-PT projector in the environment, and directing it to the corners of the planes whose 2D sizes have been measured. Moreover, by describing multiple planes in the environment by an integrated 2D coordinate system, it can display even a graphic that lies across a boundary line of two planes in a similar way to a paper poster folded along the planes.