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Proceedings Paper

The Use Of Azimuth Scan MTF Techniques For The Evaluation Of Optical Components And Systems
Author(s): N. P. Barton
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Paper Abstract

In an azimuth scan MTF test the test pattern is rotated so that a continuous scan through all orientations is obtained. Generally the system operates at a single spatial frequency but it need not necessarily be thus limited. Several methods are possible for generating the test target; that found most effective at MVEE is to use a radial grating rotating with a planetary motion in conjunction with a pinhole and detector arrangement as analyser. Initially such a system was used to test sights which had given variations between radial and tangential MTF responses in on-axis tests. For this use the method provided an effective test, and azimuth scan MTF equipment arrangements have subsequently been incorporated in production test equipment. This paper is mainly concerned with additional uses of azimuth scan equipment in more complex evaluation tasks on afocal instruments in which, while measuring the MTF at a single spatial frequency, data are obtained on dioptre setting, curvature of field, astigmatism and graticule focus for axial and extra axial field points. Nominally plane surfaced components can be tested by azimuth scan techniques and the reduced MTF caused by non-flat head mirrors and prisms is illustrated. Methods of presentation of derived data are described and it is shown that some particular defects can be more effectively indicated by the shape of azimuth scan records than by other tests.

Paper Details

Date Published: 12 October 1977
PDF: 7 pages
Proc. SPIE 0098, Assessment of Imaging Systems I, (12 October 1977); doi: 10.1117/12.955289
Show Author Affiliations
N. P. Barton, Procurement Executive, Ministry of Defence Military Vehicles and Engineering Establishment (England)

Published in SPIE Proceedings Vol. 0098:
Assessment of Imaging Systems I
Thomas L. Williams, Editor(s)

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