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X-ray energy spectrum plays an essential role in imaging and related tasks. Due to the high photon flux of clinical CT scanners, most of the spectrum estimation methods are indirect and are usually suffered from various limitations. The…

Medical Physics · Physics 2016-04-19 Wei Zhao , Qiude Zhang , Tianye Niu

Detector lag and gantry motion during x-ray exposure and integration both result in azimuthal blurring in CT reconstructions. These effects can degrade image quality both for high-resolution features as well as low-contrast details. In this…

Medical Physics · Physics 2018-05-31 Steven Tilley , Alejandro Sisniega , Jeffrey H. Siewerdsen , J. Webster Stayman

A Generative Adversarial Network (GAN) with generator $G$ trained to model the prior of images has been shown to perform better than sparsity-based regularizers in ill-posed inverse problems. Here, we propose a new method of deploying a…

Machine Learning · Computer Science 2019-10-25 Ankit Raj , Yuqi Li , Yoram Bresler

In computed tomography (CT), the forward model consists of a linear Radon transform followed by an exponential nonlinearity based on the attenuation of light according to the Beer-Lambert Law. Conventional reconstruction often involves…

Computer Vision and Pattern Recognition · Computer Science 2026-03-25 Sara Fridovich-Keil , Fabrizio Valdivia , Gordon Wetzstein , Benjamin Recht , Mahdi Soltanolkotabi

Large-scale Fourier modes of the cosmic density field are of great value for learning about cosmology because of their well-understood relationship to fluctuations in the early universe. However, cosmic variance generally limits the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Omar Darwish , Simon Foreman , Muntazir M. Abidi , Tobias Baldauf , Blake D. Sherwin , P. Daniel Meerburg

Using recent advances in generative artificial intelligence (AI) brought by diffusion models, this paper introduces a new synergistic method for spectral computed tomography (CT) reconstruction. Diffusion models define a neural network to…

Image restoration aims to recover high-quality images from degraded observations. When the degradation process is known, the recovery problem can be formulated as an inverse problem, and in a Bayesian context, the goal is to sample a clean…

Image and Video Processing · Electrical Eng. & Systems 2025-10-13 Darshan Thaker , Abhishek Goyal , René Vidal

Binary tomography is concerned with reconstructing a binary image from a very small number or other limited CT projection data. This problem itself not only possesses several medical imaging applications but also can be considered a model…

Image and Video Processing · Electrical Eng. & Systems 2022-08-24 Haytham A. Ali , Katsuya Fujii , Hiroyuki Kudo

Multiple scattering of an electromagnetic wave as it passes through an object is a fundamental problem that limits the performance of current imaging systems. In this paper, we describe a new technique-called Series Expansion with…

Computer Vision and Pattern Recognition · Computer Science 2017-05-12 Hsiou-Yuan Liu , Dehong Liu , Hassan Mansour , Petros T. Boufounos , Laura Waller , Ulugbek S. Kamilov

Several recent methods for tomographic reconstruction of stress and strain fields from Bragg-edge neutron strain images have been proposed in the literature. This paper presents an extension of a previously demonstrated approach based on…

Instrumentation and Detectors · Physics 2019-09-26 J. N. Hendriks , A. W. T. Gregg , C. M. Wensrich , W. Wills

Hybrid X-ray and magnetic resonance (MR) imaging promises large potential in interventional medical imaging applications due to the broad variety of contrast of MRI combined with fast imaging of X-ray-based modalities. To fully utilize the…

Image and Video Processing · Electrical Eng. & Systems 2019-11-20 Bernhard Stimpel , Christopher Syben , Tobias Würfl , Katharina Breininger , Philipp Hoelter , Arnd Dörfler , Andreas Maier

Diffusion models have been demonstrated as powerful deep learning tools for image generation in CT reconstruction and restoration. Recently, diffusion posterior sampling, where a score-based diffusion prior is combined with a likelihood…

Medical Physics · Physics 2024-09-02 Shudong Li , Xiao Jiang , Matthew Tivnan , Grace J. Gang , Yuan Shen , J. Webster Stayman

X-ray ptychography is a cutting edge imaging technique providing ultra-high spatial resolutions. In ptychography, phase retrieval, i.e., the recovery of a complex valued signal from intensity-only measurements, is enabled by exploiting a…

Image and Video Processing · Electrical Eng. & Systems 2022-09-14 Felix Wittwer , Peter Modregger

Standard diffusion models (DMs) rely on the total destruction of data into non-informative white noise, forcing the backward process to denoise from a fully unstructured noise state. While ensuring diversity, this results in a cumbersome…

Computer Vision and Pattern Recognition · Computer Science 2026-02-09 Baohua Yan , Jennifer Kava , Qingyuan Liu , Xuan Di

We introduce a novel reflection-mode diffraction tomography technique that enables simultaneous recovery of forward and backward scattering information for high-resolution 3D refractive index reconstruction. Our technique works by imaging a…

Optics · Physics 2025-02-12 Tongyu Li , Jiabei Zhu , Yi Shen , Lei Tian

Density reconstruction from X-ray projections is an important problem in radiography with key applications in scientific and industrial X-ray computed tomography (CT). Often, such projections are corrupted by unknown sources of noise and…

Image and Video Processing · Electrical Eng. & Systems 2026-02-26 Siddhant Gautam , Marc L. Klasky , Balasubramanya T. Nadiga , Trevor Wilcox , Gary Salazar , Saiprasad Ravishankar

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

Reconstructing the 3D shape of an object from a single RGB image is a long-standing and highly challenging problem in computer vision. In this paper, we propose a novel method for single-image 3D reconstruction which generates a sparse…

Computer Vision and Pattern Recognition · Computer Science 2023-02-24 Luke Melas-Kyriazi , Christian Rupprecht , Andrea Vedaldi

Recently, diffusion models have been used to solve various inverse problems in an unsupervised manner with appropriate modifications to the sampling process. However, the current solvers, which recursively apply a reverse diffusion step…

Machine Learning · Computer Science 2024-05-21 Hyungjin Chung , Byeongsu Sim , Dohoon Ryu , Jong Chul Ye

X-ray diffusive dark-field imaging, which allows spatially unresolved microstructure to be mapped across a sample, is an increasingly popular tool in an array of settings. Here, we present a new algorithm for phase and dark-field computed…

Medical Physics · Physics 2023-12-07 T. A. Leatham , D. M. Paganin , K. S. Morgan