Whole field surface roughness measurement by laser speckle correlation technique

This paper describes a speckle correlation technique for the determination of surface roughness, ranging from 1.6 to 50 mum. Instead of moving the las er beam, the specimen is rotated to achieve angular speckle correlation (AS C) in the far-field plane. The technique is simple and requires minimum opt ical alignment. The experimental results show a good agreement with the sta ndard specimen of known roughness. An error analysis on the experiment has been carried out. Together with the theoretical curves, the roughness value s can be easily related to the change of incidence angle at a particular vi sibility of the correlation fringes between two speckle patterns. (C) 2001 Elsevier Science Ltd. All rights reserved.