Optical three-dimensional measurements by radially symmetric structured light projection.

This structured light projection technique has been developed for the inspection of holes and tubes. In contrast to others, the triangulation base is parallel to the line of sight. The features of systems using this measurement method are the following: high accuracy in the wide-angle region, minimal diameter, symmetry of the measurements to the line of sight, and simplified coordinate calculation. The prototype application is the optics of the sewer pipe inspection robot KARO. Application fields are medical or technical wide-angle inspection systems (e.g., endoscopes).