Locating A Projector Using The Strength of Beams Reflected on a Screen

In this paper, we propose a real-time calibration technique for a projector-camera system, which enables the system to locate the projector even while it is moving. Usually fiducial points are stuck on the screen and the camera tracks both the fiducial points and the quadrilateral illuminated by the projector. Then the projector is located by the tracking. Instead of the fiducial points, our real-time calibration technique uses the strength of the beams reflected on the screen. So, the projection area is not limited in size and position by fiducial points and also it can be extended over a wall as far as the reflected beams are observed. This advantage allows a user to turn the projector at any position on the screen to view the position-dependent image. We take the advantage to assemble a map viewer by connecting our projectorcamera system to Google Earth, which enables a user to view the map by moving the projector.