Metrological evaluation of Structured Light 3D scanning system with an optical feature-based gauge

This work evaluates the dimensional accuracy that is able to reach a commercial Structured White-Light scanning (SWL) equipment. This technology is widely used in many Reverse Engineering applications. It allows to quickly capture and create pointclouds from photographs (taken from different orientations) of a fringe projection pattern. For the survey, a novel optical feature-based gauge has been used. The gauge is endowed with basic geometrical features made of matt white ceramic material, and located on a Carbon Fiber Reinforce Polymer (CFRP) structure. The reference measurements of the gauge are obtained using CMM by contact, which makes possible to compare the measurements obtained by the SWL sensor with those obtained by the CMM. In the experimentation, two different tests were carried out: long-distance test, searching for the global capture of the gauge (at the maximum range of the SWL) and short-distance test, looking for the maximum attainable precision. The survey offers some practical values of the accuracy affordable in each case.