Automatic fault detection on smooth curved surfaces - using laser scanning technique and suited to coachwork testing

摘要

A device for testing smooth, curved surfaces, such as the coachwork of vehicles, and which depends on a laser beam scanning of the surface to detect faults in it, is presented. The apparatus consists basically of a laser source and scanning arrangement which directs a beam in a number of parallel lines over the surface to be tested. The reflections of this from the surface are monitored by a television camera and analysing unit. The criterion by which the analysing unit tests the surface concerns the separation of the canned lines from the surface, and any deformation results in a reduction of this separation at some point.