Performance comparison of white Light - Optical profilometers

White light interferometry is routinely used for the reconstruction of the micro geometry of mechanical parts when high precision is needed. By this technique, the surface height of each point of the test piece is measured by estimating the abscissa of maximum interference. Several approaches have been proposed so far to perform the measurement, from the simple identification of the baricentrum of the intensity, to the FFT analysis or the use of geometric phase shifters. These approaches correspond to different setups and analysis algorithms, so that one would like to know which solution is best. In this paper, some of the most known design solutions have been analyzed in terms of measurement bias and uncertainty. In the first phase of the study some of the most critical components of the setups have been experimentally characterized, then the various configurations have been analyzed by designed computer experiments coupled with Monte Carlo simulations. The most attractive numerical results have been confirmed by a few physical trials.