Surface Roughness Studies of Finger Prints Using Speckle Interferometry

Measurement and control of surface roughness are important in many fields, such as magnetic media, semiconductor processing and optics. Typical roughness measurements are performed using stylus profilers, non-contact optical profilers, or scanning probe microscopes (SPM).An experimental approach for surface roughness evaluation based on the speckle pattern imaging has been attempted in this work by a simple configuration of setup consisting of laser, laboratory spectrometer, Beam Expander and CCD camera. The speckle image is processed by imageJ software and the surface parameters like skewness, kurtosis, histogram and correlation has been determined. The technique reported here has a great potential for precise and non-contact optical measurement of rough surfaces. (Akinoro Mouri et al., 2002). The present study focuses on diffuse scattering and the corresponding speckle patterns obtained at different angles in the range 82 to 87 with an increment of one degree. Standard glass slides used as surfaces were imprinted with and without fingerprints in an attempt to study the influence of patterns. A correlation function (R) is defined for values of skewness, Kurtois and standard Deviations with and without finger prints for the same angles.