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Limited angle problem is a challenging issue in x-ray computed tomography (CT) field. Iterative reconstruction methods that utilize the additional prior can suppress artifacts and improve image quality, but unfortunately require increased…

Medical Physics · Physics 2016-10-04 Hanming Zhang , Liang Li , Kai Qiao , Linyuan Wang , Bin Yan , Lei Li , Guoen Hu

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

A solution to the inversion problem of scattering would offer aberration-free diffraction-limited 3D images without the resolution and depth-of-field limitations of lens-based tomographic systems. Powerful algorithms are increasingly being…

The concept of coded mask imaging in theory and in practice is reviewed, with particular emphasis on image reconstruction techniques. The techniques are simple in principle but become more complicated when one takes into account real,…

Astrophysics · Physics 2007-05-23 G. K. Skinner

Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution…

X-ray crystallography (XC) is an experimental technique used to determine three-dimensional crystalline structures. The acquired data in XC, called diffraction patterns, is the Fourier magnitudes of the unknown crystalline structure. To…

Image and Video Processing · Electrical Eng. & Systems 2019-07-09 Samuel Pinilla , Jorge Bacca , Cesar Vargas , Juan Carlos Poveda-Jaramillo , Henry Arguello

We introduce a new CT image reconstruction algorithm that is less affected by various artifacts. The new reconstruction algorithm is a method of minimizing the difference between synchrotron X-ray tomography data and sinograms generated…

Medical Physics · Physics 2021-11-22 Byung Chun Kim , Hyunju Lee , Kyungtaek Jun

Large medical imaging data sets are becoming increasingly available, but ensuring sample quality without significant artefacts is challenging. Existing methods for identifying imperfections in medical imaging rely on data-intensive…

Image and Video Processing · Electrical Eng. & Systems 2023-11-15 Daniele Ravi , Frederik Barkhof , Daniel C. Alexander , Lemuel Puglisi , Geoffrey JM Parker , Arman Eshaghi

Increasing spatial image resolution is an often required, yet challenging task in image acquisition. Recently, it has been shown that it is possible to obtain a high resolution image by covering a low resolution sensor with a non-regular…

Image and Video Processing · Electrical Eng. & Systems 2022-04-11 Markus Jonscher , Jürgen Seiler , Thomas Richter , André Kaup

Purpose: Handheld gamma cameras with coded aperture collimators are under investigation for intraoperative imaging in nuclear medicine. Coded apertures are a promising collimation technique for applications such as lymph node localization…

Medical Physics · Physics 2024-01-22 Tobias Meißner , Laura Antonia Cerbone , Paolo Russo , Werner Nahm , Jürgen Hesser

Resolution enhancements are often desired in imaging applications where high-resolution sensor arrays are difficult to obtain. Many computational imaging methods have been proposed to encode high-resolution scene information on…

Image and Video Processing · Electrical Eng. & Systems 2018-10-29 Kevin Beale , Jianbo Chen , Kevin F. Kelly , Justin Romberg

Wide-field (> 100 deg$^2$) hard X-ray coded-aperture telescopes with high angular resolution (< 2') will enable a wide range of time domain astrophysics. For instance, transient sources such as gamma-ray bursts can be precisely localized…

Instrumentation and Methods for Astrophysics · Physics 2016-12-28 Jaesub Hong , Branden Allen , Jonathan Grindlay , Scott Barthelmy

We propose a novel method for large-scale image stitching that is robust against repetitive patterns and featureless regions in the imagery. In such cases, state-of-the-art image stitching methods easily produce image alignment artifacts,…

Computer Vision and Pattern Recognition · Computer Science 2021-07-29 Matti Pellikka , Valtteri Lahtinen

Artifacts on magnetic resonance scans are a serious challenge for both radiologists and computer-aided diagnosis systems. Most commonly, artifacts are caused by motion of the patients, but can also arise from device-specific abnormalities…

Image and Video Processing · Electrical Eng. & Systems 2022-10-18 Lennart Alexander Van der Goten , Kevin Smith

X-ray computed tomography (CT) reconstructs the internal morphology of a three dimensional object from a collection of projection images, most commonly using a single rotation axis. However, for objects containing dense materials like…

Image and Video Processing · Electrical Eng. & Systems 2024-06-27 Diyu Yang , Craig A. J. Kemp , Soumendu Majee , Gregery T. Buzzard , Charles A. Bouman

Uniqueness of solution is proved for any ptychographic scheme with a random masks under a minimum overlap condition and local geometric convergence analysis is given for the alternating projection (AP) and Douglas-Rachford (DR) algorithms.…

Numerical Analysis · Mathematics 2018-02-14 Pengwen Chen , Albert Fannjiang

Motion artifacts present in magnetic resonance imaging (MRI) can seriously interfere with clinical diagnosis. Removing motion artifacts is a straightforward solution and has been extensively studied. However, paired data are still heavily…

Image and Video Processing · Electrical Eng. & Systems 2024-12-12 Jiahua Xu , Dawei Zhou , Lei Hu , Jianfeng Guo , Feng Yang , Zaiyi Liu , Nannan Wang , Xinbo Gao

We implement an algorithm for detecting and removing artifacts from astronomical images by means of outlier rejection during stacking. Our method is capable of addressing both small, highly significant artifacts such as cosmic rays and, by…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 D. Gruen , S. Seitz , G. M. Bernstein

Medical images may contain various types of artifacts with different patterns and mixtures, which depend on many factors such as scan setting, machine condition, patients' characteristics, surrounding environment, etc. However, existing…

Image and Video Processing · Electrical Eng. & Systems 2021-10-26 Yu-Jen Chen , Yen-Jung Chang , Shao-Cheng Wen , Yiyu Shi , Xiaowei Xu , Tsung-Yi Ho , Meiping Huang , Haiyun Yuan , Jian Zhuang

In this article, we consider the limited angle problem in computed X-ray tomography. A common practice is to use the filtered back projection with the limited data. However, this practice has been shown to introduce the artifacts along some…

Classical Analysis and ODEs · Mathematics 2015-06-22 Linh V. Nguyen