Three-dimensional vision using structured light applied to quality control in production line

摘要

Traditional backlighting vision systems are unable to measure the height dimensions of an object. It can then be more convenient to use a 3D scanner, based for example on the projection of structured light. Despite the high potential of this technique and the growing demand of the industry for performing quality vision control, 3D measurement systems are still often considered as unusual solutions. This proceeding presents our 3D measurement laboratory setup based on the projection of structured light by means of a LCD beamer. This system is intended to be used in automated assembly line. The height information comes from a phase map obtained through temporal phase unwrapping. This phase always contain noise. Part of this noise brings a random phase error. A simple estimator of the random phase error is presented. It gives two parameters to which it is necessary to pay attention in order to predict measurement repeatability and thus to improve it. The estimator is experimentally validated on our setup.