Optical profilometer in white light

Abstract
Recently optical methods for roughness measurement have been developed. However, most of them only enable the usual criteria Ra and Rt to be determined. A method is presented based upon the defocusing of a white light beam. This method enables one to determine any statistical parameters, profiles or 3D images of the surface being measured. Results obtained are compared with those determined with a technical stylus for samples of various roughness.
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