J. Draréni, S. Roy and P. Sturm.

In this paper we address the problem of geometric video projector calibration using a markerless planar surface (wall) and a partially calibrated camera. Instead of using control points to infer the camera-wall orientation, we find such relation  by efficiently sampling the hemisphere of  possible orientations. This process is so fast that even the focal of the camera can be estimated during  the sampling process. Hence, physical grids and full knowledge of camera parameters are no longer necessary to calibrate a video projector.

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