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Data assisted reconstruction algorithms, incorporating trained neural networks, are a novel paradigm for solving inverse problems. One approach is to first apply a classical reconstruction method and then apply a neural network to improve…

Numerical Analysis · Mathematics 2020-03-26 Yoeri E. Boink , Markus Haltmeier , Sean Holman , Johannes Schwab

An efficient nonlinear contrast source inversion scheme for electromagnetic imaging of sparse two-dimensional investigation domains is proposed. To avoid generating a sequence of linear sparse optimization problems, the non-linearity is…

Signal Processing · Electrical Eng. & Systems 2021-04-13 Ali I. Sandhu , Abdulla Desmal , Hakan Bagci

Observers experience a series of limitations when measuring galaxy kinematics, such as variable seeing conditions and aperture size. These effects can be reduced using empirical corrections, but these equations are usually applicable within…

Astrophysics of Galaxies · Physics 2020-07-08 K. E. Harborne , J. van de Sande , L. Cortese , C. Power , A. S. G. Robotham , C. D. P. Lagos , S. Croom

Inverse Problem techniques offer powerful tools which deal naturally with marginal data and asymmetric or strongly smoothing kernels, in cases where parameter-fitting methods may be used only with some caution. Although they are typically…

Astrophysics · Physics 2007-05-23 Norman Gray , Iain J. Coleman

The COSMOS field has been the subject of a wide range of observations, with a number of studies focusing on reconstructing the 3D dark matter density field. Typically, these studies have focused on one given method or tracer. In this paper,…

Many inverse problems involve two or more sets of variables that represent different physical quantities but are tightly coupled with each other. For example, image super-resolution requires joint estimation of the image and motion…

Numerical Analysis · Mathematics 2019-06-26 James Herring , James Nagy , Lars Ruthotto

In this work, we consider nonconvex composite problems that involve inf-convolution with a Legendre function, which gives rise to an anisotropic generalization of the proximal mapping and Moreau-envelope. In a convex setting such problems…

Optimization and Control · Mathematics 2019-03-29 Emanuel Laude , Tao Wu , Daniel Cremers

Determining the mass of stars is crucial both to improving stellar evolution theory and to characterising exoplanetary systems. Asteroseismology offers a promising way to estimate stellar mean density. When combined with accurate radii…

Solar and Stellar Astrophysics · Physics 2015-06-03 D. R. Reese , J. P. Marques , M. J. Goupil , M. J. Thompson , S. Deheuvels

In this paper we present a general forward fitting method for multichannel image restoration based on regularized chi2. We introduce separable regularizations that account for the dynamic of the model and take advantage of the continuities…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 S. Bongard , F. Soulez , E. Thiebaut , E. Pécontal

This paper presents an uncalibrated deep neural network framework for the photometric stereo problem. For training models to solve the problem, existing neural network-based methods either require exact light directions or ground-truth…

Computer Vision and Pattern Recognition · Computer Science 2021-04-20 Berk Kaya , Suryansh Kumar , Carlos Oliveira , Vittorio Ferrari , Luc Van Gool

A wide range of applications arising in machine learning and signal processing can be cast as convex optimization problems. These problems are often ill-posed, i.e., the optimal solution lacks a desired property such as uniqueness or…

Optimization and Control · Mathematics 2019-07-18 Mostafa Amini , Farzad Yousefian

This paper presents a convex optimization-based method for finding the globally optimal solutions of a class of mixed-integer non-convex optimal control problems. We consider problems that are non-convex in the input norm, which is a…

Optimization and Control · Mathematics 2019-11-20 Danylo Malyuta , Michael Szmuk , Behcet Acikmese

Interferometric Synthetic Aperture Radar (InSAR) Imaging methods are usually based on algorithms of match-filtering type, without considering the scene's characteristic, which causes limited imaging quality. Besides, post-processing steps…

Signal Processing · Electrical Eng. & Systems 2022-10-07 Xu Zhan , Xiaoling Zhang , Shunjun Wei , Jun Shi

In this paper we extend a recent idea of formulating and regularizing inverse problems as minimization problems, so without using a forward operator, thus avoiding explicit evaluation of a parameter-to-state map. We do so by rephrasing…

Numerical Analysis · Mathematics 2020-04-28 Kha Van Huynh , Barbara Kaltenbacher

We consider the high-resolution imaging problem of 3D point source image recovery from 2D data using a method based on point spread function (PSF) engineering. The method involves a new technique, recently proposed by S.~Prasad, based on…

Signal Processing · Electrical Eng. & Systems 2019-06-13 Chao Wang , Raymond Chan , Mila Nikolova , Robert Plemmons , Sudhakar Prasad

We consider the nonconvex regularized method for low-rank matrix recovery. Under the assumption on the singular values of the parameter matrix, we provide the recovery bound for any stationary point of the nonconvex method by virtue of…

Optimization and Control · Mathematics 2024-12-24 Xin Li , Dongya Wu

Over the next few years new spectroscopic surveys (from the optical surveys of the Sloan Digital Sky Survey and the 2 degree Field survey through to space-based ultraviolet satellites such as GALEX) will provide the opportunity and…

Astrophysics · Physics 2009-10-31 A. J. Connolly , A. S. Szalay

Stochastic composition optimization draws much attention recently and has been successful in many emerging applications of machine learning, statistical analysis, and reinforcement learning. In this paper, we focus on the composition…

Machine Learning · Computer Science 2018-01-01 Zhouyuan Huo , Bin Gu , Ji Liu , Heng Huang

Sparse inversion of gravity data based on $L_1$-norm regularization is discussed. An iteratively reweighted least squares algorithm is used to solve the problem. At each iteration the solution of a linear system of equations and the…

Geophysics · Physics 2022-08-16 Saeed Vatankhah , Rosemary A. Renaut , Vahid. E. Ardestani

We seek to find a shapelet-based scheme for deconvolving galaxy images from the PSF which leads to unbiased shear measurements. Based on the analytic formulation of convolution in shapelet space, we construct a procedure to recover the…

Astrophysics · Physics 2015-03-03 Peter Melchior , Rene Andrae , Matteo Maturi , Matthias Bartelmann
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