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Recent measurements of vertical extents and positions of the chromospheric hard X-ray (HXR) flare sources based on Ramaty High-Energy Spectroscopic Imager (RHESSI) observations show a significant inconsistency with the theoretical…

Solar and Stellar Astrophysics · Physics 2016-12-07 Z. Moravec , M. Varady , J. Kasparova , D. Kramolis

8000 images of the Solar corona were captured during the June 2001 total Solar eclipse. New software for the alignment of the images and an automated technique for detecting intensity oscillations using multi scale wavelet analysis were…

Astrophysics · Physics 2009-11-10 A. C. Katsiyannis , F. Murtagh

X-ray polarization is a powerful tool for unveiling the anisotropic characteristics of high-energy celestial objects. We present a novel imaging reconstruction method designed for hard X-ray polarimeters employing a Si CMOS sensor and coded…

Instrumentation and Methods for Astrophysics · Physics 2024-07-09 Tsubasa Tamba , Hirokazu Odaka , Taihei Watanabe , Toshiya Iwata , Tomoaki Kasuga , Atsushi Tanimoto , Satoshi Takashima , Masahiro Ichihashi , Hiromasa Suzuki , Aya Bamba

This work is concerned with applying iterative image reconstruction, based on constrained total-variation minimization, to low-intensity X-ray CT systems that have a high sampling rate. Such systems pose a challenge for iterative image…

Medical Physics · Physics 2016-11-17 Emil Y. Sidky , Rick Chartrand , Yuval Duchin , Christer Ullberg , Xiaochuan Pan

Texture is one of the most obvious characteristics in solar images and it is normally described by texture features. Because textures from solar images of the same wavelength are similar, we assume texture features of solar images are…

Instrumentation and Methods for Astrophysics · Physics 2019-09-04 Peng Jia , Yi Huang , Bojun Cai , Dongmei Cai

At hard X-ray energies, the bright footpoint emission from solar flare loops often prevents a detailed analysis of the weaker loop-top source morphology due to the limited dynamic range available for X-ray imaging. Here, we study the X1.3…

Solar and Stellar Astrophysics · Physics 2016-12-21 Frederic Effenberger , Fatima Rubio da Costa , Vahe Petrosian

Sparse-view computed tomography (CT) is an effective method to reduce the radiation exposure in medical imaging. To reduce the severe streaking artifacts that occur in reconstructed images due to violation of the Nyquist/Shannon sampling…

Medical Physics · Physics 2026-03-17 Huiying Li , Yizhuang Song

Hyperspectral super-resolution refers to the problem of fusing a hyperspectral image (HSI) and a multispectral image (MSI) to produce a super-resolution image (SRI) that has fine spatial and spectral resolution. State-of-the-art methods…

Signal Processing · Electrical Eng. & Systems 2018-12-05 Charilaos I. Kanatsoulis , Xiao Fu , Nicholas D. Sidiropoulos , Wing-Kin Ma

The field of medical image reconstruction has seen roughly four types of methods. The first type tended to be analytical methods, such as filtered back-projection (FBP) for X-ray computed tomography (CT) and the inverse Fourier transform…

Image and Video Processing · Electrical Eng. & Systems 2019-08-19 Saiprasad Ravishankar , Jong Chul Ye , Jeffrey A. Fessler

Imaging X-rays by direct focusing offers greater sensitivity and a higher dynamic range compared to techniques based on indirect imaging. The Focusing Optics X-ray Solar Imager (FOXSI) is a sounding rocket payload that uses seven sets of…

The refractive index (RI) of cells and tissues is crucial in pathophysiology as a noninvasive and quantitative imaging contrast. Although its measurements have been demonstrated using three-dimensional quantitative phase imaging methods,…

Classical methods for X-ray computed tomography are based on the assumption that the X-ray source intensity is known, but in practice, the intensity is measured and hence uncertain. Under normal operating conditions, when the exposure time…

Numerical Analysis · Mathematics 2017-07-17 Hari Om Aggrawal , Martin Skovgaard Andersen , Sean Rose , Emil Y. Sidky

Inverse rendering methods aim to estimate geometry, materials and illumination from multi-view RGB images. In order to achieve better decomposition, recent approaches attempt to model indirect illuminations reflected from different…

Computer Vision and Pattern Recognition · Computer Science 2023-09-15 Haoqian Wu , Zhipeng Hu , Lincheng Li , Yongqiang Zhang , Changjie Fan , Xin Yu

The Helioseismic Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) records line-of-sight Dopplergram images of convective flows on the surface. These images are used to obtain the multi-scale convective spectrum. We design…

Solar and Stellar Astrophysics · Physics 2021-08-09 Samarth G Kashyap , Shravan M Hanasoge

CLEAN is a well-established deconvolution approach to Fourier imaging at both radio wavelwengths and hard X-ray energies. However, specifically for hard X-ray imaging, CLEAN suffers two significant drawbacks: a rather limited degree of…

Solar and Stellar Astrophysics · Physics 2025-09-10 Miriana Catalano , Anna Volpara , Paolo Massa , Michele Piana , Anna Maria Massone

High-energy (>20keV) X-ray photon detection at high quantum yield, high spatial resolution and short response time has long been an important area of study in physics. Scintillation is a prevalent method but limited in various ways.…

Instrumentation and Detectors · Physics 2020-09-02 Eldred Lee , Michael R. James , Kaitlin M. Anagnost , Zhehui Wang , Eric R. Fossum , Jifeng Liu

High-contrast imaging for the detection and characterization of exoplanets relies on the instrument's capability to block out the light of the host star. Some current post-processing methods for calibrating out the residual speckles use…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Marie Ygouf , Laurent M. Mugnier , David Mouillet , Thierry Fusco , Jean-Luc Beuzit

The evolution from 3rd to 4th generation synchrotron radiation (SR) sources significantly enhanced their coherence, making coherent scattering techniques such as coherent X-ray diffraction imaging (CXDI) and X-ray photon correlation…

Accelerator Physics · Physics 2021-10-20 Han Xu , Zhongzhu Zhu , Peng Liu , Yuhui Dong , Liang Zhou

Magnetic Resonance Imaging (MRI) is an inherently multi-contrast modality, where cross-contrast priors can be exploited to improve image reconstruction from undersampled data. Recently, diffusion models have shown remarkable performance in…

Image and Video Processing · Electrical Eng. & Systems 2025-10-27 Yue Wang , Yuanbiao Yang , Zhuo-xu Cui , Tian Zhou , Bingsheng Huang , Hairong Zheng , Dong Liang , Yanjie Zhu

Computed tomography is widely used to examine internal structures in a non-destructive manner. To obtain high-quality reconstructions, one typically has to acquire a densely sampled trajectory to avoid angular undersampling. However, many…

Image and Video Processing · Electrical Eng. & Systems 2020-12-10 Haoyu Wei , Florian Schiffers , Tobias Würfl , Daming Shen , Daniel Kim , Aggelos K. Katsaggelos , Oliver Cossairt
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