Analysis of Surface Roughness using Laser Speckle Interferometry

When a surface is illuminated with a coherent light such as a laser beam, speckle pattern consisting of bright and dark regions is observed. It depends on the surface parameters and carries important information about the roughness of the surface. Various methods and techniques are employed for the determination of surface roughness parameters using other experimental techniques. In this paper, an experimental approach for surface roughness evaluation based on the speckle pattern imaging has been attempted by a simple configuration of setup consisting laser and CCD camera. The speckle image is processed by ImageJ software and the surface parameters like skewness, kurtosis and histogram have been studied.. The technique reported here has a great potential for precise and non-contact optical measurements of rough surfaces.