Abstract

The measurement of surface roughness is typically an important parameter for describing the quality of fine finished parts. Examples include measurements of finely polished flat and curved optics, computer hard disks, semiconductor wafers and optical disks. Most often an RMS or RA roughness value is reported for the part, typically by the high spatial information. Other surface information can also be of interest, including mid-spatial roughness and figure information. Three basic surface profiles are generally used to define the surface, including total profile, waviness and roughness. A different approach is to examine the spatial information on the surface by using the power spectrum or the autocovariance function. Both of these functions can be calculated over any user selected spatial frequency region.

© 1992 Optical Society of America