Self-calibrating shape-measuring system based on fringe projection

The goal of optical SD-measurements is the determination of cartesian coordinates of surfaces. Using principles basing on fringe projection techniques coordinates are calculated of measured phases in fringes, image-coordinates of cameras and parameters of the system configuration. Mostly, three maesured values unambigous lead to one coordinate-tripel. A more comfortable way offer fotogrammetric measurements where more than three values are measured to calculate coordinates and additional to parameters describing the system configuration. Applying these experiences to fringe projection techniques it is possible to combine the advantages of both techniques. That guarantees high number of object points, quick data acquirement and a simultaneous determination of coordinates and system parameters with fotagrammetric bundle adjustment. Recent measurements showed the capabilities of that principle. The reliability of the coordinates is given by a standard deviation of less than 10 microns while the object diameter was up to 280 mm.