Auto-fit multiple movable projections into one display screen

摘要

This paper presents an analysis of auto fitting multiple projections to a single screen using a camera as feedback. The projector camera system is consisting of two (or more) mobile projectors, a stationary camera, and a planar screen. The method assumes the camera to be calibrated with the condition to capture the full planar screen site. For ideal system, the geometrically compensating images projected on the screen from both projectors need to coincide so that the displayed images will always be aligned and centered on the screen with a correct aspect ratio. The system automatically performs correction calculation on-line on the captured camera frames and recovers all transformations to recommend for movable/robot projector and/or to apply on each projector's frame. To realize these properties, we adopt software approach while presuming that hardware one is available on-demand. In the proposed software, the auto-correction is obtained by measuring the actual coordinates of the projectors and achieved by either finding the maximum intersection rectangle of both (or multiple) projections and auto-adjusting of each video frames in graphic card buffers, or by calculating the transformation matrix to mechanically correct positions of mobile/robot projectors. We adopt a fast method to find the maximum intersection rectangle and extend it to be able to deal with temporal changes of the system. We show experimental results obtained by a simulated testing system where the overall execution time is less than the frame's displaying frequency.