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The convergence of the generalized alternating projection (GAP) algorithm is studied in this paper to solve the compressive sensing problem $\yv = \Amat \xv + \epsilonv$. By assuming that $\Amat\Amat\ts$ is invertible, we prove that GAP…

Information Theory · Computer Science 2015-09-22 Xin Yuan , Hong Jiang , Paul Wilford

Purpose: Parallel imaging and compressed sensing reconstructions of large MRI datasets often have a prohibitive computational cost that bottlenecks clinical deployment, especially for 3D non-Cartesian acquisitions. One common approach is to…

Image and Video Processing · Electrical Eng. & Systems 2023-10-13 Julio A. Oscanoa , Frank Ong , Siddharth S. Iyer , Zhitao Li , Christopher M. Sandino , Batu Ozturkler , Daniel B. Ennis , Mert Pilanci , Shreyas S. Vasanawala

In this paper, we analyze the convergence %semi-convergence properties of projected non-stationary block iterative methods (P-BIM) aiming to find a constrained solution to large linear, usually both noisy and ill-conditioned, systems of…

Numerical Analysis · Mathematics 2022-02-11 Mahdi Mirzapour , Andrzej Cegielski , Tommy Elfving

We propose Diverse Restormer (DART), a novel image restoration method that effectively integrates information from various sources (long sequences, local and global regions, feature dimensions, and positional dimensions) to address…

Computer Vision and Pattern Recognition · Computer Science 2024-04-10 Juan Wen , Yawei Li , Chao Zhang , Weiyan Hou , Radu Timofte , Luc Van Gool

The decision tree is a flexible machine learning model that finds its success in numerous applications. It is usually fitted in a recursively greedy manner using CART. In this paper, we investigate the convergence rate of CART under a…

Machine Learning · Statistics 2023-10-27 Rahul Mazumder , Haoyue Wang

Kaczmarz's alternating projection method has been widely used for solving a consistent (mostly over-determined) linear system of equations Ax=b. Because of its simple iterative nature with light computation, this method was successfully…

Numerical Analysis · Computer Science 2014-07-22 Tim Wallace , Ali Sekmen

We propose a new modeling approach for scatter estimation and descattering in polyenergetic X-ray computed tomography (CT) based on fitting models to local neighborhoods of a training set. X-ray CT is widely used in medical and industrial…

Image and Video Processing · Electrical Eng. & Systems 2021-09-30 Michael T. McCann , Marc L. Klasky , Jennifer L. Schei , Saiprasad Ravishankar

Under conditions that prevent tangential intersection, we prove quadratic convergence of a projection algorithm for the feasibility problem of finding a point in the intersection of a smooth curve and line in $\mathbb{R}^2$. This nonconvex…

Optimization and Control · Mathematics 2025-10-22 Jordan Collard , Scott B. Lindstrom

Dual-energy computed tomography (CT) is to reconstruct images of an object from two projection datasets generated from two distinct x-ray source energy spectra. It can provide more accurate attenuation quantification than conventional CT…

Medical Physics · Physics 2018-05-15 Wenxiang Cong , Daniel Harrison , Yan Xi , Ge Wang

Two characteristics that make convex decomposition algorithms attractive are simplicity of operations and generation of parallelizable structures. In principle, these schemes require that all coordinates update at the same time, i.e., they…

Optimization and Control · Mathematics 2018-03-07 Giorgos Stathopoulos , Colin N. Jones

It is well known in the literature that the problem of learning the structure of Bayesian networks is very hard to tackle: its computational complexity is super-exponential in the number of nodes in the worst case and polynomial in most…

Computation · Statistics 2017-04-14 Marco Scutari

Many imaging technologies rely on tomographic reconstruction, which requires solving a multidimensional inverse problem given a finite number of projections. Backprojection is a popular class of algorithm for tomographic reconstruction,…

Image and Video Processing · Electrical Eng. & Systems 2020-06-03 Xueqing Liu , Paul Sajda

The network alignment problem asks for the best correspondence between two given graphs, so that the largest possible number of edges are matched. This problem appears in many scientific problems (like the study of protein-protein…

Computation · Statistics 2017-07-18 Efe Onaran , Soledad Villar

In this paper we revisit the well-known constrained projection approximation subspace tracking algorithm (CPAST) and derive, for the first time, non-asymptotic error bounds. Furthermore, we introduce a novel sparse modification of CPAST…

Methodology · Statistics 2018-11-27 Denis Belomestny , Ekaterina Krymova

A Jacobian-free inversion method is presented to accelerate Electrical Resistivity Tomography (ERT) for shallow aquifer characterization. The ERT problem typically implements the adjoint state method to efficiently compute Jacobian during…

Geophysics · Physics 2022-02-02 Jonghyun Lee

SPECT (Single-photon Emission Computerized Tomography) and PET (Positron Emission Tomography) are essential medical imaging tools, for which the sampling angle number, scan time should be chosen carefully to compromise between image quality…

Medical Physics · Physics 2015-06-16 Xiaolin Zhou , Minkai Yun , Xuexiang Cao , Shuangquan Liu , Lu Wang , Xianchao Huang , Long Wei

In ultrasound nondestructive testing, a widespread approach is to take synthetic aperture measurements from the surface of a specimen to detect and locate defects within it. Based on these measurements, imaging is usually performed using…

Signal Processing · Electrical Eng. & Systems 2020-12-09 Jan Kirchhof , Sebastian Semper , Christoph W. Wagner , Eduardo Pérez , Florian Römer , Giovanni Del Galdo

We study the convergence of stochastic fixed point iterations in the consistent case (in the sense of Butnariu and Fl{\aa}m (1995)) in several different settings, under decreasingly restrictive regularity assumptions of the fixed point…

Optimization and Control · Mathematics 2020-03-26 Neal Hermer , D. Russell Luke , Anja Sturm

Quantifying material mass and electron density from computed tomography (CT) reconstructions can be highly valuable in certain medical practices, such as radiation therapy planning. However, uniquely parameterising the X-ray attenuation in…

Medical Physics · Physics 2019-04-30 Jonathan H. Mason , Alessandro Perelli , William H. Nailon , Mike E. Davies

Many applications require recovering a matrix of minimal rank within an affine constraint set, with matrix completion a notable special case. Because the problem is NP-hard in general, it is common to replace the matrix rank with the…

Machine Learning · Computer Science 2015-07-08 Bo Xin , David Wipf