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In this paper we present new optimization strategies for the reconstruction of X-ray images of solar flares by means of the data collected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The imaging concept of the…

Instrumentation and Methods for Astrophysics · Physics 2014-06-26 S. Bonettini , M. Prato

Solar nanoflares are small eruptive events releasing magnetic energy in the quiet corona. If nanoflares follow the same physics as their larger counterparts, they should emit hard X-rays (HXRs) but with a rather faint intensity. A copious…

One of the most important parameters determining the sensitivity of X-ray telescopes is their effective area as a function of the X-ray energy. The computation of the effective area of a Wolter-I mirror, with either a single layer or…

Instrumentation and Methods for Astrophysics · Physics 2015-09-15 D. Spiga , V. Cotroneo

Regularized imaging spectroscopy was introduced for the construction of electron flux images at different energies from count visibilities recorded by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). In this work we seek…

Solar and Stellar Astrophysics · Physics 2023-11-14 Anna Volpara , Paolo Massa , Sam Krucker , A Gordon Emslie , Michele Piana , Anna Maria Massone

We present a new analytical technique, combining Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) high-resolution imaging and spectroscopic observations, to visualize solar flare emission as a function of spectral component…

Instrumentation and Methods for Astrophysics · Physics 2015-09-15 Amir Caspi , Albert Y. Shih , James M. McTiernan , Säm Krucker

We investigate strong gravitational lensing in the concordance $\Lambda$CDM cosmology by carrying out ray-tracing along past light cones through the Millennium Simulation, the largest simulation of cosmic structure formation ever carried…

Astrophysics · Physics 2007-12-03 Stefan Hilbert , Simon D. M. White , Jan Hartlap , Peter Schneider

Grazing-incidence X-ray optics have revolutionized X-ray astrophysics. The ability to concentrate flux to a tiny detection region provides a dramatic reduction in background and a consequent very large improvement in sensitivity. The X-ray…

Instrumentation and Methods for Astrophysics · Physics 2023-04-05 Finn E. Christensen , Brian D. Ramsey

Impact flashes on the moon are caused by high-speed collisions of celestial bodies with the lunar surface. The study of the impacts is critical for exploring the evolutionary history and formation of the Moon, and for quantifying the risk…

Instrumentation and Methods for Astrophysics · Physics 2024-12-05 Da Song , Hong-bo Cai , Shen Wang , Jing Wang

We present a concept for a machine-learning classification of hard X-ray (HXR) emissions from solar flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), identifying flares that are either occulted by the…

Solar and Stellar Astrophysics · Physics 2021-02-24 Shin-nosuke Ishikawa , Hideaki Matsumura , Yasunobu Uchiyama , Lindsay Glesener

Traditional ultrasound simulation methods solve wave equations numerically, achieving high accuracy but at substantial computational cost. Faster alternatives based on convolution with precomputed impulse responses remain relatively slow,…

Medical Physics · Physics 2025-10-14 Felix Duelmer , Mohammad Farid Azampour , Nassir Navab

Implicit representations like Neural Radiance Fields (NeRF) showed impressive results for photorealistic rendering of complex scenes with fine details. However, ideal or near-perfectly specular reflecting objects such as mirrors, which are…

Computer Vision and Pattern Recognition · Computer Science 2023-10-17 Leif Van Holland , Ruben Bliersbach , Jan U. Müller , Patrick Stotko , Reinhard Klein

X-ray imaging is a prevalent technique for non-invasively visualizing the interior of the human body and opaque instruments. In most commercial x-ray modalities, an image is formed by measuring the x-rays that pass through the object of…

Medical Physics · Physics 2023-05-23 A. Ben Yehuda , O. Sefi , Y. Klein , R. H Shukrun , H. Schwartz , E. Cohen , S. Shwartz

Astronomical X-ray observatories with grazing incidence optics face the problem of pseudo-focusing of low energy protons from the mirrors towards the focal plane. Those protons constitute a variable, unpredictable component of the non X-ray…

Instrumentation and Methods for Astrophysics · Physics 2020-04-15 R. Amato , T. Mineo , A. D'Aì , S. Diebold , V. Fioretti , A. Guzman , S. Lotti , C. Macculi , S. Molendi , E. Perinati , C. Tenzer , A. Santangelo

X-ray is widely applied for transmission imaging due to its stronger penetration than natural light. When rendering novel view X-ray projections, existing methods mainly based on NeRF suffer from long training time and slow inference speed.…

Image and Video Processing · Electrical Eng. & Systems 2024-10-29 Yuanhao Cai , Yixun Liang , Jiahao Wang , Angtian Wang , Yulun Zhang , Xiaokang Yang , Zongwei Zhou , Alan Yuille

We investigate the scientific impact of the Wide Field X-ray Telescope mission. We present simulated images and spectra of X-ray sources as observed from the three surveys planned for the nominal 5-year WFXT lifetime. The goal of these…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-01 P. Tozzi , J. Santos , H. Yu , A. Bignamini , P. Rosati , S. Borgani , S. Campana , P. Conconi , R. Gilli , M. Paolillo , A. Ptak , the WFXT Team

Eye tracking is an important tool with a wide range of applications in Virtual, Augmented, and Mixed Reality (VR/AR/MR) technologies. State-of-the-art eye tracking methods are either reflection-based and track reflections of sparse point…

Computer Vision and Pattern Recognition · Computer Science 2023-03-10 Tianfu Wang , Jiazhang Wang , Oliver Cossairt , Florian Willomitzer

Full ray-tracing maps of gravitational lensing, constructed from N-Body simulations, represent a fundamental tool to interpret present and future weak lensing data. However the limitation of computational resources and storage capabilities…

This chapter describes the history, principles, and recent developments of large field of view X-ray optics based on lobster eye designs. Most of grazing incidence (reflective) X-ray imaging systems used in astronomy and other applications,…

Instrumentation and Methods for Astrophysics · Physics 2023-04-05 Rene Hudec , Charly Feldman

This work aims at the precise and efficient computation of the x-ray projection of an image represented by a linear combination of general shifted basis functions that typically overlap. We achieve this with a suitable adaptation of ray…

Image and Video Processing · Electrical Eng. & Systems 2025-09-15 Youssef Haouchat , Sepand Kashani , Philippe Thévenaz , Michael Unser

The penetrating power of X rays underpins important applications such as medical radiography. However, this same attribute makes it challenging to achieve flexible on-demand patterning of X-ray beams. One possible path to this goal is…

Image and Video Processing · Electrical Eng. & Systems 2023-08-07 David Ceddia , Alaleh Aminzadeh , Philip K. Cook , Daniele Pelliccia , Andrew M. Kingston , David M. Paganin