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Proceedings Paper

Wavefront integration from difference data
Author(s): Klaus R. Freischlad
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Paper Abstract

Recently, measurements with slope sensitive optical tests, such as shearing interferometry, Shack-Hartmann test, or Ronchi test, have become of great interest. The primary outcome of these measurements are the slope or difference data of the wavefront under test. Therefore, a numerical reconstruction procedure is necessary to integrate these difference data in order to obtain the desired wavefront map. This paper describes a numerically efficient reconstruction technique for orthogonal difference data as they are obtained, e.g., in lateral shearing interferometers. The reconstruction process consists of two steps. The integration is carried out as a filtering operation in the spatial frequency domain. Since it requires two full rectangular arrays of valid x- and y-difference data, an additional step is necessary to accommodate for general pupil shapes, e.g., circular pupil with central obscuration. This additional step consists of synthetically generating difference data at the previously invalid data points. The reconstruction is unbiased and has a very slow error propagation, i.e., the variance of the noise on the reconstructed wavefronts is approximately equal to the variance of the difference noise.

Paper Details

Date Published: 5 February 1993
PDF: 7 pages
Proc. SPIE 1755, Interferometry: Techniques and Analysis, (5 February 1993); doi: 10.1117/12.140771
Show Author Affiliations
Klaus R. Freischlad, Carl Zeiss (Germany)

Published in SPIE Proceedings Vol. 1755:
Interferometry: Techniques and Analysis
Gordon M. Brown; Osuk Y. Kwon; Malgorzata Kujawinska; Graeme T. Reid, Editor(s)

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