3-D Imaging of surfaces for industrial applications: integration of structured light projection, Gray code projection and projector-camera calibration for improved performance

In this paper, two measurement procedures, aimed at the improvement of the performance of an optical whole field profilometer based on grating projection, are presented. The first procedure is based on the Gray code method. It performs a space encoding of the measurement area and yields 3-D range images in which even sharp discontinuities of the object shape can be measured. The second procedure performs the calibration of the optical components of the system, in order to describe the 3-D profile in a global coordinate system, and limiting the use of a reference surface only during the calibration of the profilometer. In the paper, the two procedures are detailed and some interesting experimental results are reported.