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Proceedings Paper

Processing Of Diffraction Patterns Scanned With A Photodiode Array Influence Of The Optical Transfer Function Of Diodes On Linewidth Measurements
Author(s): C. Ozkul; A. Leduc; D. Allano; 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 (± 1μm, in the range 10-50μm) is improved by introducing the OTF of the photosensitive area in 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 real-time measurements but must be improved by statistical approaches.

Paper Details

Date Published: 11 October 1989
PDF: 10 pages
Proc. SPIE 1135, Image Processing III, (11 October 1989); doi: 10.1117/12.961655
Show Author Affiliations
C. Ozkul, University of Rouen (France)
A. Leduc, University of Rouen (France)
D. Allano, University of Rouen (France)
M. Abdelghani-Idrissi, University of Rouen (France)

Published in SPIE Proceedings Vol. 1135:
Image Processing III
Jacques Frank Duvernoy, Editor(s)

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