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Proceedings Paper

Some Experience With The Use Of A Moire Test Pattern In The Measurement Of The Optical Transfer Function
Author(s): L. Dabergerova; J. Daberger
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Paper Abstract

Incoherently illuminated sinewave objects are generally employed as tar-gets in transfer function studies. Since it is not easy to obtain good targets of this type, other targets have been proposed which, by the aid of appropriate filtering, can be transformed into effectively sinusoidal gratings. The rectangular-and triangu-larwave objects are mostly used in this connection (Ref.l) . The latter is especially advantageous since the higher harmonics of its Fourier-series representation converge-more rapidly than those in a rectangular wave. A practical method of generating test objects of triangular waveform is based on the utilization of moire fringes produced by two crossed gratings (Ron-chi rulings) -(]Ref.2 and 3). By ro-tating the two gratings in opposite directions the spatial frequency of the moire fringes can be varied continuously and linearly with time,observing simultaneously the condition that the scanning time-frequency remains the same for all spatial frequencies. In order to achieve the desired accuracy in OTF measurements with an equipment using the mentioned test ob-ject it is necessary to satisfy certain conditions. One of these is good quality of the basic gratings, another is correct positioning in the driving mechanism.

Paper Details

Date Published: 1 June 1974
PDF: 8 pages
Proc. SPIE 0046, Image Assessment and Specification, (1 June 1974); doi: 10.1117/12.953998
Show Author Affiliations
L. Dabergerova, MEOPTA (Czechoslovakia)
J. Daberger, MEOPTA (Czechoslovakia)

Published in SPIE Proceedings Vol. 0046:
Image Assessment and Specification
David T. Dutton, Editor(s)

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