Optical high-precision three-dimensional vision-based quality control of manufactured parts by use of synthetic images and knowledge for image-data evaluation and interpretation

Vision-based evaluation of industrial workpieces can make efficient use of knowledge-based approaches, in particular for quality control, inspection, and accurate-measurement tasks. A possible approach is to compare real images with conceptual (synthetic) images generated by use of standard computer-aided design models, which include tolerances and take the application-specific conditions into account (e.g., the measured-calibration data). Integrated in (industrial) real-life environments, our evaluation methods have been successfully applied to on-line inspection of manufactured parts including sculptured surfaces, using structured light techniques for the reconstruction of three-dimensional shapes. Accuracies in the range 15-50 microm are routinely achieved by use of either isolated images or spatially registered image sequences.