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Proceedings Paper

Measurement of atmospheric MTF in a littoral environment
Author(s): Derek J. Griffith; Francois P. J. le Roux; Piet B. W. Schwering; Mark Holloway
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Paper Abstract

Measurement of atmospheric modulation transfer function (MTF) derived from the point spread function is an alternative to the use of scintillometry in characterizing the effects of turbulence as well as optical scattering. This experiment involved measurement of the system point spread function at 630 nm wavelength, over a 1.8 km path between the shoreline and Roman Rock lighthouse, which is offshore in False Bay near Simonstown, South Africa. Four telescopes at heights between 4 m and 14 m above the sea surface were mounted at the shoreline looking at two point sources mounted at heights of 6 m and 13 m above the sea surface on the lighthouse. The telescopes were equipped with digital charge-coupled device (CCD) cameras and the system MTF of the combination was measured. While the point spread function is also sensitive to atmospheric scattering, scintillation is driven largely by turbulence. Measurements were made under a wide variety of environmental conditions and the differences between image quality metrics and scintillation metrics were examined. Local weather parameters, visibility and sea temperature were also monitored during the campaign and the impact of these parameters on image quality was assessed. Divergent trends in scintillation and image quality were encountered.

Paper Details

Date Published: 2 October 2008
PDF: 8 pages
Proc. SPIE 7113, Electro-Optical and Infrared Systems: Technology and Applications V, 711308 (2 October 2008); doi: 10.1117/12.799797
Show Author Affiliations
Derek J. Griffith, Council for Scientific and Industrial Research (South Africa)
Francois P. J. le Roux, Council for Scientific and Industrial Research (South Africa)
Piet B. W. Schwering, TNO Defence, Security and Safety (Netherlands)
Mark Holloway, Council for Scientific and Industrial Research (South Africa)


Published in SPIE Proceedings Vol. 7113:
Electro-Optical and Infrared Systems: Technology and Applications V
David A. Huckridge; Reinhard R. Ebert, Editor(s)

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