NDTnet 1998 Aug, Vol.3 No.8

Abstract

In several applications, it is necessary to measure the surface characteristics of a wire, so, it is important to measure them along the manufacturing process. Coherent light scattered from rough surfaces carries on information about them. Several works showed the relation between the statistical properties of the surface and the statistical properties of the light diffused from it (1,2), always dealing with plane surfaces and we have also carried out two techniques to obtain the roughness and the correlation length of such surfaces: the angular speckle correlation (3) and the evolution of the angular distribution of the mean intensity (4).

In this work we study the scattering of light from cylindrical surfaces. The geometry is shown in figure 1. The reflected light from this surface generates a cone. The intersection of this cone and the observation plane is a circumference. When the surface is rough, the circumference becomes diffuse. Figure 2 shows a typical intensity pattern on the observation plane registered on a CCD camera.We show that this pattern is related with the statistical parameters which characterize the surface. We obtain these parameters by extending the above mentioned techniques to this kind of surfaces.These methods may be applied to on line wire surface testing where conventional procedures are inadequate.

Figure 1. ; Figure 2

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References
1. Goodman, Tech. Report A°2303-1, Stanford Electronics Lahoratories (1963).
2. Enloe, Bell Syst. Tech. J., vol. 46, p. 1479(1967).
3. M. A. Rehollo, Ph.D. Thesis, University of La Plata, Argentina (1995).
4.Rehollo, F. Perez Quinfian and N. G. Gaggioli, Journal of Modern Optics, Vol. 44, n°3, p. 447-460, (1997).

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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