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Proceedings Paper

A novel dynamic optical low-pass filter
Author(s): Branko Petljanski
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Paper Abstract

Most contemporary still and video cameras employ various optically birefringent materials as optical low-pass filters (OLPF) in order to minimize alias artifacts in the image. Due to the slope characteristics of these filters, camera designers are faced with the choice of either under correcting to maintain image resolution, allowing some aliasing, or eliminating aliases with a more aggressive design that will also compromise the image modulation transfer function (MTF). Furthermore, most OLPFs are designed as optical elements with a frequency response that does not change even if the frequency responses of other elements of the capturing systems are altered. In this paper, we demonstrate the use of a parallel optical window or, alternatively, a rigid mirror positioned between a lens and an imager as an OLPF. Controlled x- and y-axis rotations of the window and the mirror result in a manipulation of the point spread function (PSF) of the system and frequency content of imaged continuous scenes. We evaluate the system MTF when various window functions are used to shape PSF, such as rectangle, triangle, Blackman-Harris etc. We also present results of our experiments when the dynamic OLPF's support and shape are altered to accommodate the optical performance of lenses and imager characteristics.

Paper Details

Date Published: 18 January 2010
PDF: 12 pages
Proc. SPIE 7537, Digital Photography VI, 75370W (18 January 2010); doi: 10.1117/12.838921
Show Author Affiliations
Branko Petljanski, Florida Atlantic Univ. (United States)
Panavision Inc. (United States)

Published in SPIE Proceedings Vol. 7537:
Digital Photography VI
Francisco Imai; Nitin Sampat; Feng Xiao, Editor(s)

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