Share Email Print
cover

Proceedings Paper

Using multispectral information to decrease the spectral artifacts in sparse-aperture imagery
Author(s): Noah R. Block; Robert E. Introne; John R. Schott
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Optical sparse-aperture telescopes represent a promising new technology to increase the effective diameter of an optical system while reducing its weight and stowable size. The sub-apertures of a sparse-aperture system are phased to synthesize a telescope system that has a larger effective aperture than any of the independent sub-apertures. Sparse-apertures have mostly been modeled to date using a "gray-world" approximation where the input is a grayscale image. The gray-world model makes use of a "polychromatic" optical transfer function (OTF) where the spectral OTFs are averaged to form a single OTF. This OTF is then convolved with the grayscale image to create the resultant sparse-aperture image. The model proposed here uses a spectral image-cube as the input to create a panchromatic or multispectral result. These outputs better approximate an actual system because there is a higher spectral fidelity present than a gray-world model. Unlike its Cassegrain counterpart that has a well behaved OTF, the majority of sparse-aperture OTFs have very oscillatory and attenuated natures. When a spectral sparse-aperture model is used, spectral artifacts become apparent when the phasing errors increase beyond a certain threshold. This threshold can be based in part on the type of phasing error (i.e. piston, tip/tilt, and the amount present in each sub-aperture), as well as the collection conditions, including configuration, signal-to-noise ratio (SNR), and fill factor. This research addresses whether integrating a restored multispectral sparse-aperture image into a panchromatic image will decrease the amount of spectral artifacts present. The restored panchromatic image created from integrating multispectral images is compared to a conventional panchromatic sparse-aperture image. Conclusions are drawn through image quality analysis and the change in spectral artifacts.

Paper Details

Date Published: 19 May 2005
PDF: 12 pages
Proc. SPIE 5798, Spaceborne Sensors II, (19 May 2005); doi: 10.1117/12.604002
Show Author Affiliations
Noah R. Block, Rochester Institute of Technology (United States)
Robert E. Introne, Rochester Institute of Technology (United States)
John R. Schott, Rochester Institute of Technology (United States)


Published in SPIE Proceedings Vol. 5798:
Spaceborne Sensors II
Peter Tchoryk; Brian Holz, Editor(s)

© SPIE. Terms of Use
Back to Top