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Automatic discovery and curve fitting of absorption bands in hyperspectral data can enable the analyst to identify materials present in a scene by comparison with library spectra. This procedure is common in laboratory spectra, but is…

Instrumentation and Methods for Astrophysics · Physics 2014-01-23 Adrian J. Brown

Optimal extraction is a key step in processing the raw images of spectra as registered by two-dimensional detector arrays to a one-dimensional format. Previously reported algorithms reconstruct models for a mean one-dimensional spatial…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 M. Zechmeister , G. Anglada-Escudé , A. Reiners

X-ray ionized reflection occurs when a surface is irradiated with X-rays so intense that its ionization state is determined by the ionization parameter xi propto F/n, where F is the incident flux and n the gas density. It occurs in…

Astrophysics · Physics 2010-04-06 R. R. Ross , A. C. Fabian

Multidimensional unfolding methods are widely used for visualizing item response data. Such methods project respondents and items simultaneously onto a low-dimensional Euclidian space, in which respondents and items are represented by ideal…

Methodology · Statistics 2020-09-04 Yunxiao Chen , Zhiliang Ying , Haoran Zhang

We introduce Spectral Guidance, a framework for controlling diffusion models by leveraging the intrinsic geometry of the generative process. As data is progressively corrupted by noise, only a small number of features remain informative for…

Machine Learning · Computer Science 2026-05-29 Gabriel Moreira , Manuel Marques , João Paulo Costeira , Chenyan Xiong

Environmental $\gamma$-rays constitute a crucial source of background in various nuclear, particle and quantum physics experiments. To evaluate the flux rate and the spectrum of $\gamma$ background, we have developed a novel and…

Instrumentation and Detectors · Physics 2024-04-08 Taiyuan Liu , Mingxuan Xue , Haiping Peng , Kangkang Zhao , Deyong Duan , Yichao Wang , Changqing Feng , Yifeng Wei , Qing Lin , Zizong Xu , Xiaolian Wang

Near total reflection regime has been widely used in X-ray science, specifically in grazing incidence small angle X-ray scattering and in hard X-ray photoelectron spectroscopy. In this work, we introduce some practical aspects of using near…

We develop a novel method to separate the components of a diffuse emission process based on an association with the energy spectra. Most of the existing methods use some information about the spatial distribution of components, e.g.,…

Instrumentation and Methods for Astrophysics · Physics 2012-02-07 Dmitry Malyshev

Current X-ray observatories make it possible to follow the evolution of transient and variable X-ray binaries across a broad range in luminosity and source behavior. In such studies, it can be unclear whether evolution in the low energy…

High Energy Astrophysical Phenomena · Physics 2014-11-20 J. M. Miller , E. M. Cackett , R. C. Reis

Established x-ray diffraction methods allow for high-resolution structure determination of crystals, crystallized protein structures or even single molecules. While these techniques rely on coherent scattering, incoherent processes like…

Near-infrared (NIR) detectors -- which use non-destructive readouts to measure time-series counts-per-pixel -- play a crucial role in modern astrophysics. Standard NIR flux extraction techniques were developed for space-based observations…

Ultrafast scattering using X-rays or electrons is an emerging method to obtain structure dynamics at the atomic length and time scales. However, directly resolving in real-space atomic motions is inherently limited by the finite detector…

Atomic Physics · Physics 2023-02-09 Adi Natan

The methods and techniques for the slitless spectroscopy software aXe, which was designed to reduce data from the various slitless spectroscopy modes of Hubble Space Telescope instruments, are described. aXe can treat slitless spectra from…

Astrophysics · Physics 2015-05-13 Martin Kümmel , Jeremy Walsh , Norbert Pirzkal , Harald Kuntschner , Anna Pasquali

As photon counting detectors are being explored for medical and industrial imaging applications, there is a critical need to understand spectral characteristics of scattered x-ray photons. Scattered radiation is detrimental to x-ray imaging…

Medical Physics · Physics 2022-12-14 Cale E. Lewis , Mini Das

In recent years, x-ray speckle tracking techniques have emerged as viable tools for wavefront metrology and sample imaging applications. These methods are based on the measurement of near-field images. Thanks to the simple experimental…

Image and Video Processing · Electrical Eng. & Systems 2020-03-31 Andrew J. Morgan , Kevin T. Murray , Harry M. Quiney , Saša Bajt , Henry N. Chapman

A lighting-based multispectral imaging system using an RGB camera and a projector is one of the most practical and low-cost systems to acquire multispectral observations for estimating the scene's spectral reflectance information. However,…

Image and Video Processing · Electrical Eng. & Systems 2020-12-21 Hironori Hidaka , Yusuke Monno , Masatoshi Okutomi

Since its launch on October 2002 the INTEGRAL satellite is performing an deep survey of the hard X-ray sky with unprecedented sensitivity and positional accuracy. This allowed pinpointing, through positional cross-correlation with catalogs…

Astrophysics · Physics 2009-11-11 Nicola Masetti

Prospects of parametric x-rays (PXR) application for the development of a tuneable quasi-monochromatic x-ray source for medical imaging are discussed. Analysis of basic requirements for electron accelerator shows that it must be relatively…

General Physics · Physics 2007-05-23 Alexander Lobko , Olga Lugovskaya

Bi-temporal change detection is highly sensitive to acquisition discrepancies, including illumination, season, and atmosphere, which often cause false alarms. We observe that genuine changes exhibit higher patch-wise singular-value entropy…

Computer Vision and Pattern Recognition · Computer Science 2026-03-25 Zelin Lei , Yaoxing Ren , Jiaming Chang

X-ray speckles have been used for a wide variety of experiments, ranging from imaging (and tomography), wavefront sensing, spatial coherence measurements all the way to x-ray photon correlation spectroscopy (XPCS) and ptychography. In the…

Medical Physics · Physics 2024-04-19 Rafael Celestre , Laurene Quenot , Christopher Ninham , Emmanuel Brun , Luca Fardin