నైరూప్య

Study of Surface Roughness by Stylus Profilometer and Binary Laser Speckle B/D Counting Techniques

R.Balamurugan, S.Muruganand

In this paper, surface roughness measurements by non contact method of Binary Speckle Pattern (BSP) and contact method of stylus profilometer have been presented. When an optically rough surface is illuminated with a highly coherent source of Laser, the granular bright and dark pattern known as speckle is observed. Intensity of the Speckle image depends on the surface roughness and carries information about it. The speckle images obtained by He- Ne laser with CCD camera were binarized and examined. To evaluate the surface roughness, pixel ratios of bright and dark regions (B/D counting) of various speckle images of different surface roughness are used. The results are compared with the surface roughness parameter Ra obtained from stylus profilometer.