Abstract: To meet the requirement of accurate and convenient 3D measurement for some large parts in reverse engineering, a full field of view scanning system that is mainly composed of a CCD camera, a galvanometer and a laser projector is proposed. The mirror that is rotated by a galvanometer reflects the laser plane, and sweeps the view field of the camera. The camera is calibrated by using a planar target according to the radial alignment constraint(RAC) approach and the principle of cross-ratio invariance. For obtaining the 3D coordinate of a point in a laser plane, the orientation and position of the laser plane are computed according to the angle of the galvanometer and the intersected lines on the target. Hence the three coordinates of a point on the laser plane can be directly obtained from the camera model and the stripe on CCD image. Experiment studies show that the developed system possesses good accuracy. It can identify the fine structure on a large part, also it is portable and convenient for field measurement.

Key words: Full field of view scanning, Calibration, Optical-triangulation, Reverse engineering