60 likes | 303 Views
Paraxial Curvature WFS algorithms. Assuming a paraxial beam propagating along the z-axis, we have the transport of intensity equation (TIE) :. Iterative FFT: C . Roddier and F. Roddier , J Opt Soc Am A 10, 2277-87 (1993) Series expansion:
E N D
Paraxial Curvature WFS algorithms Assuming a paraxial beam propagating along the z-axis, we have the transport of intensity equation (TIE): • Iterative FFT: • C. Roddier and F. Roddier, J Opt Soc Am A10, 2277-87 (1993) • Series expansion: • T. E. Gureyev and K. A. Nugent, J. Opt. Soc. Am. A 13, 1670-1682 (1996) • Wavefront compensation: • Both the Iterative FFT and the Series Expansion algorithms are first order approximations valid only highly defocused images. • The accuracy of the WCS algorithm can be improved by iteratively compensating the effect of the estimated aberrations on the defocused images. (C. Roddier and F. Roddier, J Opt Soc Am A10, 2277-87 (1993) ) AOS Review • Tucson, Arizona • Sep 10, 2013
Algorithmic Challenges for LSST • LSST WFS challenges & algorithmic modifications • Large Central Obscuration (61%) • Fast f/number (f/1.23) • Off-axis Distortion and Vignetting (~1.7o) • Split Sensor Design (covering 1.51° to 1.84°) AOS Review • Tucson, Arizona • Sep 10, 2013
Tests using PhoSim Images Field=(1.185,1.185) Field=(1.237,1.237) telescope perturbations and atmospheric turbulence turned off Phosim V3.2.6 April 2013 AOS Review • Tucson, Arizona • Sep 10, 2013
Tests of WFS with Perturbed LSST Model AOS Review • Tucson, Arizona • Sep 10, 2013
Algorithmic Linearity Z7 on M1M3 (in wave) Z7 on M1M3 (in wave) AOS Review • Tucson, Arizona • Sep 10, 2013
Algorithmic Noise (Algorithmic + atmospheric) Correlation coefficients (Algorithmic + atmospheric) Covariance matrix Variance Singular values AOS Review • Tucson, Arizona • Sep 10, 2013