51 citations · 259 across the 38 of their papers we have counts for
41 papers
Heat Conduction with Phase Change in Permafrost Modules of Vegetation Models
David Hötten, Jenny Niebsch, Ronny Ramlau +1
We consider the problem of heat conduction with phase change, that is essential for permafrost modeling in Land Surface Models and Dynamic Global Vegetation Models. These models re…
On some analytic properties of the atmospheric tomography operator: Non-Uniqueness and reconstructability issues
Ronny Ramlau, Bernadett Stadler
In this paper, we consider the atmospheric tomography operator, which describes the effect of turbulent atmospheric layers on incoming planar wavefronts. Given wavefronts from diff…
High fidelity adaptive mirror simulations with reduced order models
Bernadett Stadler, Roberto Biasi, Mauro Manetti +3
In the design process of large adaptive mirrors numerical simulations represent the first step to evaluate the system design compliance in terms of performance, stability and robus…
An Inverse Problems Approach to Pulse Wave Analysis in the Human Brain
Lukas Weissinger, Simon Hubmer, Ronny Ramlau +1
Cardiac pulsations in the human brain have received recent interest due to their possible role in the pathogenesis of neurodegenerative diseases. Further interest stems from their…
Regularization of linear inverse problems with irregular noise using embedding operators
Xinyan Li, Simon Hubmer, Shuai Lu +1
In this paper, we investigate regularization of linear inverse problems with irregular noise. In particular, we consider the case that the noise can be preprocessed by certain adjo…
VISIONS: The VISTA Star Formation Atlas -- I. Survey overview
Stefan Meingast, João Alves, Hervé Bouy +37
VISIONS is an ESO public survey of five nearby (d < 500 pc) star-forming molecular cloud complexes that are canonically associated with the constellations of Chamaeleon, Corona Aus…
Off-axis Point Spread Function Reconstruction for Single Conjugate Adaptive Optics
Roland Wagner, Jenny Niebsch, Ronny Ramlau
Modern Giant Segmented Mirror Telescopes (GSMTs) like the Extremely Large Telescope, which is currently under construction, depend heavily on Adaptive Optics (AO) systems to correc…
Subaperture-based Digital Aberration Correction for OCT: A Novel Mathematical Approach
Simon Hubmer, Ekaterina Sherina, Ronny Ramlau +2
In this paper, we consider subaperture-based approaches for the digital aberration correction (DAC) of optical coherence tomography (OCT) images. In particular, we introduce a math…
Localization of fixed dipoles at high precision by accounting for sample drift during illumination
Fabian Hinterer, Magdalena C. Schneider, Simon Hubmer +3
Single molecule localization microscopy relies on the precise quantification of the position of single dye emitters in a sample. This precision is improved by the number of photons…
LBT SOUL data as a science test bench for MICADO PSF-R tool
Matteo Simioni, Carmelo Arcidiacono, Roland Wagner +14
Current state-of-the-art adaptive optics (AO) provides ground-based, diffraction-limited observations with high Strehl ratios (SR). However, a detailed knowledge of the point sprea…
Point spread function reconstruction for SOUL+LUCI LBT data
Matteo Simioni, Carmelo Arcidiacono, Roland Wagner +14
This paper presents the status of an ongoing project aimed at developing a PSF reconstruction software for adaptive optics (AO) observations. In particular, we test for the first t…
A projected Nesterov-Kaczmarz approach to stellar population-kinematic distribution reconstruction in Extragalactic Archaeology
Fabian Hinterer, Simon Hubmer, Prashin Jethwa +3
In this paper, we consider the problem of reconstructing a galaxy's stellar population-kinematic distribution function from optical integral field unit measurements. These quantiti…
Performance of an iterative wavelet reconstructor for the Multi-conjugate Adaptive Optics RelaY of ESO's ELT
Bernadett Stadler, Ronny Ramlau
The Multi-conjugate Adaptive Optics RelaY (MAORY) is one of the key Adaptive Optics (AO) systems on the European Southern Observatory's Extremely Large Telescope. MAORY aims to ach…
Characterizations of Adjoint Sobolev Embedding Operators with Applications in Inverse Problems
Simon Hubmer, Ekaterina Sherina, Ronny Ramlau
We consider the Sobolev embedding operator and its role in the solution of inverse problems. In particular, we collect various properties and investigate…
On Regularization via Frame Decompositions with Applications in Tomography
Simon Hubmer, Ronny Ramlau, Lukas Weissinger
In this paper, we consider linear ill-posed problems in Hilbert spaces and their regularization via frame decompositions, which are generalizations of the singular-value decomposit…
Adaptive optics imaging with a pyramid wavefront sensor for visual science
Elisabeth Brunner, Julia Shatokhina, Muhammad Faizan Shirazi +6
The pyramid wavefront sensor (P-WFS) has replaced the Shack-Hartmann (SH-) WFS as sensor of choice for high performance adaptive optics (AO) systems in astronomy because of its fle…
Robust and bias-free localization of individual fixed dipole emitters achieving the Cramér Rao bound
Fabian Hinterer, Magdalena C. Schneider, Simon Hubmer +5
Single molecule localization microscopy has the potential to resolve structural details of biological samples at the nanometer length scale. However, to fully exploit the resolutio…
Phase-contrast THz-CT for non-destructive testing
Peter Fosodeder, Simon Hubmer, Alexander Ploier +3
A new approach for image reconstruction in THz computed tomography (THz-CT) is presented. Based on a geometrical optics model containing the THz signal amplitude and phase, a novel…
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…