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We present results from the photometric and spectroscopic identification of 122 X-ray sources recently discovered by XMM-Newton in the 2-10 keV band (the HELLAS2XMM 1dF sample). Their flux cover the range 8E-15-4E-13 cgs and the total area…

We present the 2SXPS (Swift-XRT Point Source) catalog, containing 206,335 point sources detected by the Swift X-ray Telescope (XRT) in the 0.3--10 keV energy range. This catalog represents a significant improvement over 1SXPS, with double…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 P. A. Evans , K. L. Page , J. P. Osborne , A. P. Beardmore , R. Willingale , D. N. Burrows , J. A. Kennea , M. Perri , M. Capalbi , G. Tagliaferri , S. B. Cenko

Deconvolution is the most commonly used image processing method to remove the blur caused by the point-spread-function (PSF) in optical imaging systems. While this method has been successful in deblurring, it suffers from several…

Image and Video Processing · Electrical Eng. & Systems 2019-10-10 Huangxuan Zhao , Ziwen Ke , Ningbo Chen , Ke Li , Lidai Wang , Xiaojing Gong , Wei Zheng , Liang Song , Zhicheng Liu , Dong Liang , Chengbo Liu

Hadamard Transform Spectral Imaging (HTSI) is a multiplexing technique used to recover spectra via encoding with multi-slit masks, and is particularly useful in low photon flux applications where signal-independent noise is the dominant…

Instrumentation and Methods for Astrophysics · Physics 2025-10-24 John Nijim , Zoran Ninkov , Dmitry Vorobiev , Kevin Kearney

Optical microscopy is an essential tool in biology and medicine. Imaging thin, yet non-flat objects in a single shot (without relying on more sophisticated sectioning setups) remains challenging as the shallow depth of field that comes with…

Image and Video Processing · Electrical Eng. & Systems 2020-10-14 Adrian Shajkofci , Michael Liebling

Accurate multispectral image matching presents significant challenges due to non-linear intensity variations across spectral modalities, extreme viewpoint changes, and the scarcity of labeled datasets. Current state-of-the-art methods are…

Computer Vision and Pattern Recognition · Computer Science 2026-03-03 Ismail Can Yagmur , Hasan F. Ates , Bahadir K. Gunturk

This paper shows that compressed sensing realized by means of regularized deconvolution and the Finite Isotropic Wavelet Transform is effective and reliable in hard X-ray solar imaging. The method utilizes the Finite Isotropic Wavelet…

Solar and Stellar Astrophysics · Physics 2018-07-18 M. A. Duval-Poo , M. Piana , A. M. Massone

Hyperspectral images (HSIs) have been widely applied in many fields, such as military, agriculture, and environment monitoring. Nevertheless, HSIs commonly suffer from various types of noise during acquisition. Therefore, denoising is…

Image and Video Processing · Electrical Eng. & Systems 2021-04-07 Yan Gao , Feng Gao , Junyu Dong

We make the in-orbit calibration to the point-spread functions (PSFs) of the collimators of the Hard X-ray Modulation Telescope with the scanning observation of the Crab. We construct the empirical adjustments to the theoretically…

Instrumentation and Methods for Astrophysics · Physics 2020-02-05 Yi Nang , Jin-Yuan Liao , Na Sai , Chen Wang , Ju Guan , Cheng-Kui Li , Cheng-Cheng Guo , Yuan Liu , Jing Jin , Xiao-Bo Li , Shu Zhang , Shuang-Nan Zhang

Astronomical imaging based on photon count data is a non-trivial task. In this context we show how to denoise, deconvolve, and decompose multi-domain photon observations. The primary objective is to incorporate accurate and well motivated…

Instrumentation and Methods for Astrophysics · Physics 2018-11-21 Daniel Pumpe , Martin Reinecke , Torsten A. Enßlin

Real-world imaging systems acquire measurements that are degraded by noise, optical aberrations, and other imperfections that make image processing for human viewing and higher-level perception tasks challenging. Conventional cameras…

Computer Vision and Pattern Recognition · Computer Science 2021-05-11 Steven Diamond , Vincent Sitzmann , Frank Julca-Aguilar , Stephen Boyd , Gordon Wetzstein , Felix Heide

We present a blind multiframe image-deconvolution method based on robust statistics. The usual shortcomings of iterative optimization of the likelihood function are alleviated by minimizing the M-scale of the residuals, which achieves more…

Instrumentation and Methods for Astrophysics · Physics 2017-11-09 Matthias Lee , Tamas Budavari , Richard White , Charles Gulian

We develop and apply an enhanced regularization algorithm, used in RHESSI X-ray spectral analysis, to constrain the ill-posed inverse problem that is determining the DEM from solar observations. We demonstrate this computationally fast…

Solar and Stellar Astrophysics · Physics 2015-06-03 I. G. Hannah , E. P. Kontar

A non iterative direct blind deconvolution procedure, previously used successfully to sharpen Hubble Space Telescope imagery, is now found useful in sharpening nanoscale scanning electron microscope (SEM) and helium ion microscope (HIM)…

Instrumentation and Detectors · Physics 2025-02-28 Alfred S. Carasso , Andras E. Vladar

Previous studies determining which astronomical photometry software is best suited for a particular dataset are usually focused on speed, source classification, and/or meeting a sensitivity requirement. For faint objects in particular, the…

Instrumentation and Methods for Astrophysics · Physics 2013-05-27 Sarah Sonnett , Karen Meech , Robert Jedicke , Schelte Bus , John Tonry , Olivier Hainaut

Observations of the HI 21cm transition line promises to be an important probe into the cosmic dark ages and epoch of reionization. One of the challenges for the detection of this signal is the accuracy of the foreground source removal. This…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 A. Datta , S. Bhatnagar , C. L. Carilli

Due to the energy-dependent nature of the attenuation coefficient and the polychromaticity of the X-ray source, beam hardening effect occurs when X-ray photons penetrate through an object, causing a nonlinear projection data. When a linear…

Medical Physics · Physics 2018-12-07 Wei Zhao , Dengwang Li , Kai Niu , Wenjian Qin , Hao Peng , Tianye Niu

X-ray tomographic image reconstruction consists of determining an object function from its projections. In many applications such as non-destructive testing, we look for a fault region (air) in a homogeneous, known background (metal). The…

Data Analysis, Statistics and Probability · Physics 2007-05-23 A. Mohammad-Djafari , Ken Sauer

Distance metric learning (DML) is a critical factor for image analysis and pattern recognition. To learn a robust distance metric for a target task, we need abundant side information (i.e., the similarity/dissimilarity pairwise constraints…

Computer Vision and Pattern Recognition · Computer Science 2019-04-09 Yong Luo , Tongliang Liu , Dacheng Tao , Chao Xu

Hyperspectral (HS) images provide fine spectral resolution but have limited spatial resolution, whereas multispectral (MS) images capture finer spatial details but have fewer bands. HS-MS fusion aims to integrate HS and MS images to…

Image and Video Processing · Electrical Eng. & Systems 2025-11-12 Sagar Kumar , Unni V S , Kunal Narayan Chaudhury
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