ADAPTIVE WHOLE-FIELD OPTICAL PROFILOMETRY - A STUDY OF THE SYSTEMATIC-ERRORS

An analysis of the sources of systematic errors in an optical whole-fi eld profilometer based on the projection of fringes is presented here. In the system, the determination of the object profile is performed b y triangulation. Both the period of the fringes and the geometrical sy stem parameters on which triangulation operates (i.e. the distance bet ween the object and the acquistion/projection units, and the distance between the acquisition unit and the projection unit) represent the in put parameters of the profile evaluation algorithm. The influence on t he height error introduced by an inaccuracy in the determination of th e projected fringe period, as well as of the geometrical parameters of the system, is investigated here. The distortion in reconstructing th e object shape due to the finite distance illumination scheme used in the system is also studied. The results obtained from the analysis are used to increase the accuracy of the optical profilometer by means of a suitably developed correction algorithm.