Speckle correlation technique to determine roughness in the dermatologic interval

Abstract

A non-invasive method is proposed to determine human skin roughness. The technique is based on measurement of the correlation between two field distributions scattered by a metallised triafol (cellulose acetate foil) replica of the epidermal area to be analysed. The two speckle patterns are produced from the same rough surface illuminated by two coherent plane waves (He-Ne laser) under two slightly different angles. The accuracy of the method is highlighted by measurements made on a set of standard samples with roughnesses previously determined by mechanical profilometry. Analysis of the results indicates a precision of around 10%, and an applicability within the interest range of very rough surfaces in excess of 4-5 microns.

On Roughness Measurement by Angular Speckle Correlation

“…The different procedures based on the speckle phenomenon for roughness measurement and their applications are well known [6][7][8][9][10][11][12][13][14]. This article deals with the classical angular speckle correlation technique (ASC), which requires an accurate alignment of the optical system and which is very sensitive to environment vibrations.…”