Inspection of Screw Holes on Machine Parts Using Robot Vision

Machine parts have numerous screw holes on them to enable them to be assembled with other parts. If those holes are not placed precisely at the correct locations, the assembly process cannot be accomplished. Quality control departments spend considerable time and effort trying to inspect machine parts manually. This article describes a robot vision based inspection system that constructs a 3-D model of the machine part, including the screw holes and then compares it to a perfect model. A camera connected to a robot arm takes pictures of the machine part from different angles allowing the computer to extract straight lines to be used as features for 3-D reconstruction.