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Tomographic image reconstruction is relevant for many medical imaging modalities including X-ray, ultrasound (US) computed tomography (CT) and photoacoustics, for which the access to full angular range tomographic projections might be not…

Image and Video Processing · Electrical Eng. & Systems 2019-06-14 Valery Vishnevskiy , Richard Rau , Orcun Goksel

With the Extremely Large Telescope-generation telescopes come new challenges. The complexity of these telescopes' pupil creates new problems for Adaptive Optics. In particular, the large spiders necessary to support the massive optics of…

Adaptive optics systems correct atmospheric turbulence in real time. Most adaptive optics systems used routinely correct in the near infrared, at wavelengths greater than 1 micron. MagAO- X is a new extreme adaptive optics (ExAO) instrument…

During its move from the mountaintop of Cerro Pachon in Chile to the peak of Mauna Kea in Hawaii, the Gemini Planet Imager will make a pit stop to receive various upgrades, including a pyramid wavefront sensor. As a highly non-linear…

Iterative algorithms are widely used in digital signal processing applications. With the case study of radio astronomy calibration processing, this work contributes towards revealing and exploiting the intrinsic error resilience of…

Signal Processing · Electrical Eng. & Systems 2025-02-21 G. A. Gillani , A. Krapukhin , A. B. J. Kokkeler

Over the past fifty years, wavefront sensing technology has continuously evolved from basic techniques to high-precision systems, serving as a core methodology in adaptive optics (AO). Beyond traditional wavefront retrieval methods based on…

Optics · Physics 2025-05-13 Rundong Fan , Zichao Wang , Pei Li , Lei Huang

The WMMSE beamforming algorithm is a popular approach to address the NP-hard weighted sum rate (WSR) maximization beamforming problem. Although it efficiently finds a local optimum, it requires matrix inverses, eigendecompositions, and…

Signal Processing · Electrical Eng. & Systems 2023-02-15 Lissy Pellaco , Joakim Jaldén

As we look to the next generation of adaptive optics systems, now is the time to develop and explore the technologies that will allow us to image rocky Earth-like planets; wavefront control algorithms are not only a crucial component of…

Earth and Planetary Astrophysics · Physics 2023-09-06 J. Fowler , Rico Landman

We consider the geometric optics problem of finding a system of two reflectors that transform a spherical wavefront into a beam of parallel rays with prescribed intensity distribution. Using techniques from optimal transportation theory, it…

Numerical Analysis · Mathematics 2011-11-08 Tilmann Glimm , Nick Henscheid

In this manuscript we demonstrate a method to reconstruct the wavefront of focused beams from a measured diffraction pattern behind a diffracting mask in real-time. The phase problem is solved by means of a neural network, which is trained…

Image and Video Processing · Electrical Eng. & Systems 2021-04-07 Jonathon White , Sici Wang , Wilhelm Eschen , Jan Rothhardt

Microwave imaging is commonly based on the solution of linearized inverse scattering problems by matched filtering algorithms, i.e., by applying the adjoint of the forward scattering operator to the observation data. A more rigorous…

Image and Video Processing · Electrical Eng. & Systems 2024-12-23 Matthias M. Saurer , Han Na , Marius Brinkmann , Thomas F. Eibert

We present the results obtained with an end-to-end simulator of an Extreme Adaptive Optics (XAO) system control loop. It is used to predict its on-sky performances and to optimise the AO loop algorithms. It was first used to validate a…

Instrumentation and Methods for Astrophysics · Physics 2023-01-10 Anthony Berdeu , Michel Tallon , Éric Thiébaut , Mary Angelie Alagao , Sitthichat Sukpholtham , Maud Langlois , Adithep Kawinkij , Puttiwat Kongkaew

Plane Wave imaging enables many applications that require high frame rates, including localisation microscopy, shear wave elastography, and ultra-sensitive Doppler. To alleviate the degradation of image quality with respect to conventional…

Signal Processing · Electrical Eng. & Systems 2021-12-24 Nishith Chennakeshava , Ben Luijten , Massimo Mischi , Yonina C. Eldar , Ruud J. G. van Sloun

The inversion of linear systems is a fundamental step in many inverse problems. Computational challenges exist when trying to invert large linear systems, where limited computing resources mean that only part of the system can be kept in…

Distributed, Parallel, and Cluster Computing · Computer Science 2017-09-05 Yushan Gao , Thomas Blumensath

Optical diffraction tomography relies on solving an inverse scattering problem governed by the wave equation. Classical reconstruction algorithms are based on linear approximations of the forward model (Born or Rytov), which limits their…

Computational Engineering, Finance, and Science · Computer Science 2017-09-01 Emmanuel Soubies , Thanh-An Pham , Michael Unser

(abridged) Extreme adaptive optics (XAO) encounters severe difficulties to cope with the high speed (>1kHz), high accuracy and high order requirements for future extremely large telescopes. An innovative high order adaptive optics system…

Instrumentation and Methods for Astrophysics · Physics 2015-09-29 Christian Delacroix , Maud Langlois , Magali Loupias , Eric Thiébaut , Louisa Adjali , Jonathan Leger , Michel Tallon

Incorporating a deep generative model as the prior distribution in inverse problems has established substantial success in reconstructing images from corrupted observations. Notwithstanding, the existing optimization approaches use gradient…

Machine Learning · Computer Science 2023-01-31 Tianci Liu , Tong Yang , Quan Zhang , Qi Lei

In this article, we revisit iterative methods for solving the inverse problem of photoacoustic tomography in free space. Recently, there have been interesting developments on explicit formulations of the adjoint operator, demonstrating that…

Analysis of PDEs · Mathematics 2017-05-16 Markus Haltmeier , Linh V. Nguyen

In the context of large-angle cone-beam tomography (CBCT), we present a practical iterative reconstruction (IR) scheme designed for rapid convergence as required for large datasets. The robustness of the reconstruction is provided by the…

Imaging through complex scattering media is severely limited by aberrations and scattering which obscure images and reduce resolution. Confocal and temporal gatings partly filter out multiple scattering but are severely degraded by…

Optics · Physics 2026-05-18 Yiwen Zhang , Minh Dinh , Zeyu Wang , Tianhao Zhang , Tianhang Chen , Chia Wei Hsu
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