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The nonlinear curvature wavefront sensor (nlCWFS) uses multiple (typically four) out-of-focus images to reconstruct the phase and amplitude of a propagating light beam. Because these images are located between the pupil and focal planes,…

Instrumentation and Methods for Astrophysics · Physics 2024-07-23 Caleb A. Abbott , Justin R. Crepp , Stanimir O. Letchev , Connor M. Smith

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

Prevalent Computational Aberration Correction (CAC) methods are typically tailored to specific optical systems, leading to poor generalization and labor-intensive re-training for new lenses. Developing CAC paradigms capable of generalizing…

Computer Vision and Pattern Recognition · Computer Science 2026-03-13 Xiaolong Qian , Qi Jiang , Yao Gao , Lei Sun , Zhonghua Yi , Kailun Yang , Luc Van Gool , Kaiwei Wang

Microlocal analysis provides deep insight into singularity structures and is often crucial for solving inverse problems, predominately, in imaging sciences. Of particular importance is the analysis of wavefront sets and the correct…

Image and Video Processing · Electrical Eng. & Systems 2019-07-11 Héctor Andrade-Loarca , Gitta Kutyniok , Ozan Öktem , Philipp Petersen

Detection of a gravitational-wave stochastic background via ground or space-based gravitational-wave detectors requires the cross-correlation of the response of two or more independent detectors. The cross-correlation involves a…

General Relativity and Quantum Cosmology · Physics 2009-11-06 Lee Samuel Finn , Shane L. Larson , Joseph D. Romano

This work focuses on a parameter-free joint piecewise smooth image denoising and contour detection. Formulated as the minimization of a discrete Mumford-Shah functional and estimated via a theoretically grounded alternating minimization…

Image and Video Processing · Electrical Eng. & Systems 2023-02-01 Charles-Gérard Lucas , Barbara Pascal , Nelly Pustelnik , Patrice Abry

A fraction of the XMM-Newton/EPIC FOV is obscured by the dysfunctional (i.e. bad) pixels. The fraction varies between different EPIC instruments in a given observation. These complications affect the analysis of extended X-ray sources…

Instrumentation and Methods for Astrophysics · Physics 2021-03-03 J. Nevalainen , I. Valtchahov , R. D. Saxton , S. Molendi

Accurate human localization is crucial for various applications, especially in the Metaverse era. Existing high precision solutions rely on expensive, tag-dependent hardware, while vision-based methods offer a cheaper, tag-free alternative.…

Computer Vision and Pattern Recognition · Computer Science 2025-01-28 Tianyi Zhang , Wengyu Zhang , Xulu Zhang , Jiaxin Wu , Xiao-Yong Wei , Jiannong Cao , Qing Li

This contribution deals with image restoration in optical systems with coherent illumination, which is an important topic in astronomy, coherent microscopy and radar imaging. Such optical systems suffer from wavefront distortions, which are…

Instrumentation and Methods for Astrophysics · Physics 2017-04-04 Claudius Zelenka , Reinhard Koch

Community and core-periphery are two widely studied graph structures, with their coexistence observed in real-world graphs (Rombach, Porter, Fowler \& Mucha [SIAM J. App. Math. 2014, SIAM Review 2017]). However, the nature of this…

Machine Learning · Computer Science 2024-06-10 Chandra Sekhar Mukherjee , Jiapeng Zhang

Continuous wavefront sensing benefits space observatories in on-orbit optical performance maintenance. To measure the phase of a wavefront, phase retrieval is an attractive technique as it uses multiple point spread function (PSF) images…

Instrumentation and Methods for Astrophysics · Physics 2024-09-17 Hyukmo Kang , Kyle Van Gorkom , Meghdoot Biswas , Daewook Kim , Ewan S. Douglas

We present two complementary algorithms suitable for using focal-plane measurements to control a wavefront corrector with an extremely high spatial resolution. The algorithms use linear approximations to iteratively minimize the aberrations…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Visa Korkiakoski , Christoph U. Keller , Niek Doelman , Matthew Kenworthy , Gilles Otten , Michel Verhaegen

We consider the problem of direction finding using partly calibrated arrays, a distributed subarray with position errors between subarrays. The key challenge is to enhance angular resolution in the presence of position errors. To achieve…

Signal Processing · Electrical Eng. & Systems 2022-12-12 Guangbin Zhang , Tianyao Huang , Yimin Liu , Xiqin Wang , Yonina C. Eldar

Real-time seeing and outer scale estimation at the location of the focus of a telescope is fundamental for the adaptive optics systems dimensioning and performance prediction, as well as for the operational aspects of instruments. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Patrice Martinez

We present a concept to improve the spatial resolution of silicon pixel-detectors via the implementation of a sub-pixel cross-coupling, which introduces directional charge sharing between pixels. The charge-collection electrode is segmented…

Instrumentation and Detectors · Physics 2020-07-24 Sinuo Zhang , David-Leon Pohl , Tomasz Hemperek , Jochen Dingfelder

Spectral clustering has found extensive use in many areas. Most traditional spectral clustering algorithms work in three separate steps: similarity graph construction; continuous labels learning; discretizing the learned labels by k-means…

Machine Learning · Computer Science 2017-11-15 Zhao Kang , Chong Peng , Qiang Cheng , Zenglin Xu

This paper considers the problem of compact source detection on a Gaussian background in 1D. Two aspects of this problem are considered: the design of the detector and the filtering of the data. Our detection scheme is based on local maxima…

Astrophysics · Physics 2009-11-10 M. Lopez-Caniego , D. Herranz , R. B. Barreiro , J. L. Sanz

Direct imaging of Earth-like planets from space requires dedicated observatories, combining large segmented apertures with instruments and techniques such as coronagraphs, wavefront sensors, and wavefront control in order to reach the high…

In this paper we use the Cramer-Rao lower uncertainty bound to estimate the maximum precision that could be achieved on the joint simultaneous (or 2D) estimation of photometry and astrometry of a point source measured by a linear CCD…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Rene A. Mendez , Jorge F. Silva , Rodrigo Orsotica , Rodrigo Lobos

A fundamental limitation of object detectors is that they suffer from "spatial bias", and in particular perform less satisfactorily when detecting objects near image borders. For a long time, there has been a lack of effective ways to…

Computer Vision and Pattern Recognition · Computer Science 2024-06-04 Zhaohui Zheng , Yuming Chen , Qibin Hou , Xiang Li , Ping Wang , Ming-Ming Cheng