51 citations · 259 across the 38 of their papers we have counts for
10 papers · 1 filter
Estimating solution smoothness and data noise with Tikhonov regularization
Daniel Gerth, Ronny Ramlau
A main drawback of classical Tikhonov regularization is that often the parameters required to apply theoretical results, e.g., the smoothness of the sought-after solution and the n…
MICADO PSF-Reconstruction work package description
Matteo Simioni, Carmelo Arcidiacono, Andrea Grazian +25
The point spread function reconstruction (PSF-R) capability is a deliverable of the MICADO@ESO-ELT project. The PSF-R team works on the implementation of the instrument software de…
Direction dependent Point spread function reconstruction for Multi-Conjugate Adaptive Optics on Giant Segmented Mirror Telescopes
Roland Wagner, Daniela Saxenhuber, Ronny Ramlau +1
Modern Giant Segmented Mirror Telescopes (GSMT) like the Extremely Large Telescope (ELT), currently under construction depend heavily on Adaptive Optics (AO) systems to correct for…
An augmented wavelet reconstructor for atmospheric tomography
Ronny Ramlau, Bernadett Stadler
Atmospheric tomography, i.e. the reconstruction of the turbulence profile in the atmosphere, is a challenging task for adaptive optics (AO) systems of the next generation of extrem…
Subspace Recycling-based Regularization Methods
Ronny Ramlau, Kirk M. Soodhalter, Victoria Hutterer
Subspace recycling techniques have been used quite successfully for the acceleration of iterative methods for solving large-scale linear systems. These methods often work by augmen…
A mathematical approach towards THz tomography for non-destructive imaging
Simon Hubmer, Alexander Ploier, Ronny Ramlau +2
In this paper, we consider the imaging problem of terahertz (THz) tomography, in particular as it appears in non-destructive testing. We derive a nonlinear mathematical model descr…
Frame Decompositions of Bounded Linear Operators in Hilbert Spaces with Applications in Tomography
Simon Hubmer, Ronny Ramlau
We consider the decomposition of bounded linear operators on Hilbert spaces in terms of functions forming frames. Similar to the singular-value decomposition, the resulting frame d…
Real-time implementation of an iterative solver for atmospheric tomography
Bernadett Stadler, Roberto Biasi, Mauro Manetti +1
The image quality of the new generation of earthbound Extremely Large Telescopes (ELTs) is heavily influenced by atmospheric turbulences. To compensate these optical distortions a…
A Frame Decomposition of the Atmospheric Tomography Operator
Simon Hubmer, Ronny Ramlau
We consider the problem of atmospheric tomography, as it appears for example in adaptive optics systems for extremely large telescopes. We derive a frame decomposition, i.e., a dec…
A note on the minimization of a Tikhonov functional with -penalty
Fabian Hinterer, Simon Hubmer, Ronny Ramlau
In this paper, we consider the minimization of a Tikhonov functional with an penalty for solving linear inverse problems with sparsity constraints. One of the many approac…