Contactless surface quality testing system for automatic production - using partly coherent light with superimposed incoherent component

摘要

The arrangement for contactless surface quality testing and surface roughness measurement enables simple, reliable, convenient, and non-destructive roughness measurement both for mass production applications and automated flexible production. The device is simply constructed and cheap to make. The object (8) is subjected to a selected cross-section of partly coherent light. The light reflected from the object is added to an additional incoherent component. The summed light is fed via a photodetector (15) measurement aperture (13) or via a line or matrix of detectors. The brightness pattern resulting from relative movement between the object or image and detector or matrix is scanned in the defocussed image. The measurement aperture can be larger than the average fleck dia. The brightness history at the aperture is evaluated statistically.