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Optical Engineering

Processing of glass cylinder diffraction patterns scanned with a photodiode array: influence of the optical transfer function of diodes on dimensional measurements
Author(s): Cafer Ozkul; Denis Lebrun; Daniel Allano; Anne Leduc; Ahmed M. Abdelghani-Idrissi
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Paper Abstract

Far-field diffraction patterns of a glass cylinder are spatially sampled with a photodiode array. Three photometric signal processing methods are discussed. The first one is based on the analysis of fringes in the central lobe. It can be used for diameter monitoring, but not for a wide range of diameter measurements. The second method consists of best-fitting between the theoretical model of the irradiance distribution in the central fringe and the corresponding experimental data. The accuracy of this method (±1 μm, in the range 10 to 50 μm) is improved by introducing the optical transfer function (OTF) of the photosensitive area into the calculation. The third method uses a reliable estimation of the intensity at the center and the half-width of the central fringe in order to resolve the inverse problem by Newton's method. This method can be used for realtime measurements but must be improved by statistical approaches.

Paper Details

Date Published: 1 December 1991
PDF: 7 pages
Opt. Eng. 30(12) doi: 10.1117/12.56014
Published in: Optical Engineering Volume 30, Issue 12
Show Author Affiliations
Cafer Ozkul
Denis Lebrun, Univ. of Rouen (France)
Daniel Allano, Univ. of Rouen (France)
Anne Leduc, Univ. of Rouen (France)
Ahmed M. Abdelghani-Idrissi, Univ. of Rouen (France)

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