Surface Roughness Effect On Laser Speckle Spectral Density

This work presents an attempt to develop a new procedure to evaluate surface roughness through the utilization of the spectral densities of laser speckles by image processing techniques. Preliminary results indicated a trend in which the peak of the spectral density would shift towards a lower frequency for higher surface roughness. This trend has not, however, been conclusive in another experimental setting which attempted to magnify that trend. This inconsistency may have been attributed to the possibility that the results were defining a finer pitch roughness rather than coarser pitch roughness which the specimens were considered at. Further studies are then required on the specific state of the specimens by using other conventional techniques. The work, however, indicates a possible potential for this spectral density technique by laser speckle image processing to evaluate surface roughness conditions. © 1986 SPIE