ON THE CALIBRATION OF MAPVISION 4D SYSTEM

Mapvision 4D measurement machine uses video cameras and a light projector to quickly make a precise 3-D point cloud from a given small-scale 3-D object. The use of more than just two cameras makes it possible to control the quality of the measured data, which makes Mapvision 4D more flexible than conventional 3-D measurement machines. The calibration of this kind of photogrammetric machine requires that all possible effects due to the optical, electronic, and mathematical transformations from the 3-D space to the video images have to be taken into account. The calibration is made using a free-network bundle adjustment, which is constrained using known distances and points on precise planes. With the first prototype, an operational measurement accuracy of ±5 μm is achieved.