Non-contact optical measurement of material surfaces with a laser based sensor

Abstract

The precise measurement of surface roughness is an important ability in surface engineering applications. Non-destructive techniques like laser speckle characterization is one of the key analysis for the surface of the material. The speckles coming from different atomic and subatomic regions are recorded for different surfaces like rough, smooth and non smooth surfaces, using a laboratory designed laser sensor. The sensitivity of speckle signals measured at different distances from the surfaces are recorded. The strength of the signal and its variation with distances of the source from the surfaces provides significant information about surface conditions embedded in the present work. Furthermore, the speckle contrast changes significantly with the change of the beam strength of incidence laser signal with distance which provides clear illuminance of the texture of the material.