Slide projector calibration based on calibration of digital camera

Abstract

With the development of non-contact measurement in the close-range photogrammetry, the use of the projector becomes frequent and familiar. In order to take full advantages of the slide projector, the slide projector is steered on the basis of the traditional method of the digital camera taking images. The paper proposes a flexible and effective technique for the slide projector calibration based on the calibration of digital camera. The technique only requires a planar grid, a rotating platform and a computer. The planar grid is put on the center of the rotating platform functioned as a control ground. The computer can control the rotating platform to rotate regularly and dominate the slide projector and the digital camera to project slides and take images automatically and synchronously. The algorithm with 2D direct linear transformation (2D-DLT) and collinear equations is used to calibrate the digital camera first. By the similar algorithm above, the interior parameters of the slide projector can be determined too. Then the calibration of the slide projector is achieved finally. The operation method in detail and the algorithm are addressed systematically and entirely. The feasibility and the exactness of the technique for the calibration of the slide projector based on the digital camera calibration put forward in this paper are verified by the results of real experimental data.