Abstract

A noncontact optical method to measure the surface roughness^1,2 of cold-rolled steel sheet in situ has been investigated. The method is based on measurement of the intensity of specularly reflected laser light from the steel sheet. A theoretical study and computer simulations show that the maximum range of surface roughness depends on the laser wavelength. The surface roughness values measured optically are proportional to the average surface roughness, Ra, measured by the conventional stylus method up to some limit. The conditions to maximize this limit have been found experimentally. The resultant limit agrees well with that of the computer simulations.

© 1993 Optical Society of America