New approaches for phase determination

Fringe projection and passive photogrammetry for measuring range to remote points are both based on triangulation. Applying the phase-shift technique to fringe projection, point clouds with high spatial resolution and limited accuracy can be generated. Because of the one-dimensional phase information, the geometric sensor calibration is needed for object point determination. In photogrammetry, highly accurate image operators are applied in order to solve the problem of image correspondence for structures like circles, crosses ore natural patterns with a limited spatial resolution. Based on the image point coordinates, object point determination can be performed as well as sensor calibrations. In this paper two approaches are presented to combine the advantages of both strategies. The image correspondence problem is solved by using projected fringes with different orientations. High spatial resolution is obtained by the phase - shifting technique. Systematical error sources like phase-shifting errors or nonsinusodial waveforms will be eliminated by applying special algorithms in addition to a passive setup. Redundancy will be improved by increasing the number of sample points.