Identification of the dynamics of time-varying phase aberrations from time histories of the point-spread function

Identification of the dynamics of time-varying phase aberrations from time histories of the point-spread function

Doelman, R. (TU Delft Team Raf Van de Plas)
Klingspor, Måns (Linköping University)
Hansson, Anders (Linköping University)
Löfberg, Johan (Linköping University)
Verhaegen, M.H.G. (TU Delft Team Raf Van de Plas)

2019

To optimally compensate for time-varying phase aberrations with adaptive optics, a model of the dynamics of the aberrations is required to predict the phase aberration at the next time step. We model the time-varying behavior of a phase aberration, expressed in Zernike modes, by assuming that the temporal dynamics of the Zernike coefficients can be described by a vector-valued autoregressive (VAR) model. We propose an iterative method based on a convex heuristic for a rank-constrained optimization problem, to jointly estimate the parameters of the VAR model and the Zernike coefficients from a time series of measurements of the point-spread function (PSF) of the optical system. By assuming the phase aberration is small, the relation between aberration and PSF measurements can be approximated by a quadratic function. As such, our method is a blind identification method for linear dynamics in a stochastic Wiener system with a quadratic nonlinearity at the output and a phase retrieval method that uses a time-evolution-model constraint and a single image at every time step.

http://resolver.tudelft.nl/uuid:36614ab6-f219-45c2-a0ba-242160fcfe05

https://doi.org/10.1364/JOSAA.36.000809

1084-7529

Journal of the Optical Society of America A: Optics and Image Science, and Vision, 36 (5), 809-817

Institutional Repository

journal article

© 2019 R. Doelman, Måns Klingspor, Anders Hansson, Johan Löfberg, M.H.G. Verhaegen