ENHANCEMENT OF WIRE DIAMETER MEASUREMENTS - COMPARISON BETWEEN FRAUNHOFER-DIFFRACTION AND LORENZ-MIE THEORY

Citation
D. Lebrun et al., ENHANCEMENT OF WIRE DIAMETER MEASUREMENTS - COMPARISON BETWEEN FRAUNHOFER-DIFFRACTION AND LORENZ-MIE THEORY, Optical engineering, 35(4), 1996, pp. 946-950
Citations number
21
Categorie Soggetti
Optics
Journal title
ISSN journal
00913286
Volume
35
Issue
4
Year of publication
1996
Pages
946 - 950
Database
ISI
SICI code
0091-3286(1996)35:4<946:EOWDM->2.0.ZU;2-W
Abstract
The Fraunhofer diffraction is compared with a numerical simulation bas ed on the Lorenz-Mie theory to improve the performance of a laser diff raction instrument. This instrument, based on the analysis of diffract ion fringes at the focal plane of a lens, is especially suitable for i ndividual wire diameter measurements. We show that the error due to Fr aunhofer approximation increases with an increase of the reflectivity and a decrease of the object diameter. Comparison with Lorenz-Mie theo ry enables us to correct these errors. For a given object, the laser d iffraction instrument reproduces diameter measurements with a very sma ll dispersion. (C) 1996 Society of Photo-Optical instrumentation Engin eers.