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This paper concerns the problem of recovering an unknown but structured signal $x \in R^n$ from $m$ quadratic measurements of the form $y_r=|<a_r,x>|^2$ for $r=1,2,...,m$. We focus on the under-determined setting where the number of…

Machine Learning · Computer Science 2017-02-22 Mahdi Soltanolkotabi

In this work, we focus on separable convex optimization problems with linear and box constraints and compute the solution in closed-form as a function of some Lagrange multipliers that can be easily computed in a finite number of…

Information Theory · Computer Science 2014-03-25 Antonio A. D'Amico , Luca Sanguinetti , Daniel P. Palomar

This paper studies the problem of reconstructing binary matrices that are only accessible through few evaluations of their discrete X-rays. Such question is prominently motivated by the demand in material science for developing a tool for…

Combinatorics · Mathematics 2007-05-23 Alberto Del Lungo , Andrea Frosini , Maurice Nivat , Laurent Vuillon

We develop mask iterative hard thresholding algorithms (mask IHT and mask DORE) for sparse image reconstruction of objects with known contour. The measurements follow a noisy underdetermined linear model common in the compressive sampling…

Machine Learning · Statistics 2011-12-05 Aleksandar Dogandzic , Renliang Gu , Kun Qiu

In this paper we derive a moment relaxation for large-scale nonsmooth optimization problems with graphical structure and spherical constraints. In contrast to classical moment relaxations for global polynomial optimization that suffer from…

Optimization and Control · Mathematics 2023-09-27 Robin Kenis , Emanuel Laude , Panagiotis Patrinos

We study convex relaxation algorithms for phase retrieval on imaging problems. We show that structural assumptions on the signal and the observations, such as sparsity, smoothness or positivity, can be exploited to both speed-up convergence…

Optimization and Control · Mathematics 2014-04-09 Fajwel Fogel , Irène Waldspurger , Alexandre d'Aspremont

A simple, yet general, formalism for the optimized linear combination of astrophysical images is constructed and demonstrated. The formalism allows the user to combine multiple undersampled images to provide oversampled output at high…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Barnaby Rowe , Christopher Hirata , Jason Rhodes

In imaging modalities recording diffraction data, the original image can be reconstructed assuming known phases. When phases are unknown, oversampling and a constraint on the support region in the original object can be used to solve a…

Signal Processing · Electrical Eng. & Systems 2018-10-17 Alberto Pietrini , Carl Nettelblad

This paper studies a recovery task of finding a low multilinear-rank tensor that fulfills some linear constraints in the general settings, which has many applications in computer vision and graphics. This problem is named as the low…

Optimization and Control · Mathematics 2013-10-08 Lei Yang , Zheng-Hai Huang , Yufan Li

Learning sparse models from data is an important task in all those frameworks where relevant information should be identified within a large dataset. This can be achieved by formulating and solving suitable sparsity promoting optimization…

Optimization and Control · Mathematics 2025-02-18 V. Cerone , S. M. Fosson , D. Regruto , A. Salam

We consider the constrained Linear Inverse Problem (LIP), where a certain atomic norm (like the $\ell_1 $ norm) is minimized subject to a quadratic constraint. Typically, such cost functions are non-differentiable, which makes them not…

Optimization and Control · Mathematics 2025-07-08 Mohammed Rayyan Sheriff , Floor Fenne Redel , Peyman Mohajerin Esfahani

In this paper, we consider the problem of minimizing the sum of two convex functions subject to linear linking constraints. The classical alternating direction type methods usually assume that the two convex functions have relatively easy…

Optimization and Control · Mathematics 2015-07-10 Tianyi Lin , Shiqian Ma , Shuzhong Zhang

l1 reweighting algorithms are very popular in sparse signal recovery and compressed sensing, since in the practice they have been observed to outperform classical l1 methods. Nevertheless, the theoretical analysis of their convergence is a…

Machine Learning · Computer Science 2018-12-10 Sophie M. Fosson

We study the nonparametric least squares estimator (LSE) of a multivariate convex regression function. The LSE, given as the solution to a quadratic program with $O(n^2)$ linear constraints ($n$ being the sample size), is difficult to…

Computation · Statistics 2015-09-29 Rahul Mazumder , Arkopal Choudhury , Garud Iyengar , Bodhisattva Sen

We propose an approach based on convex relaxations for certifiably optimal robust multiview triangulation. To this end, we extend existing relaxation approaches to non-robust multiview triangulation by incorporating a truncated least…

Computer Vision and Pattern Recognition · Computer Science 2023-04-06 Linus Härenstam-Nielsen , Niclas Zeller , Daniel Cremers

Demixing refers to the challenge of identifying two structured signals given only the sum of the two signals and prior information about their structures. Examples include the problem of separating a signal that is sparse with respect to…

Information Theory · Computer Science 2015-03-20 Michael B. McCoy , Joel A. Tropp

We describe and examine an algorithm for tomographic image reconstruction where prior knowledge about the solution is available in the form of training images. We first construct a nonnegative dictionary based on prototype elements from the…

Computer Vision and Pattern Recognition · Computer Science 2015-08-18 Sara Soltani , Martin S. Andersen , Per Christian Hansen

We present a novel complex number formulation along with tight convex relaxations for the aircraft conflict resolution problem. Our approach combines both speed and heading control and provides global optimality guarantees despite…

Computational Engineering, Finance, and Science · Computer Science 2017-09-20 David Rey , Hassan Hijazi

We propose a new fast algorithm for solving one of the standard formulations of image restoration and reconstruction which consists of an unconstrained optimization problem where the objective includes an $\ell_2$ data-fidelity term and a…

Optimization and Control · Mathematics 2015-05-14 Manya V. Afonso , José M. Bioucas-Dias , Mário A. T. Figueiredo

We propose a novel method to accurately reconstruct a set of images representing a single scene from few linear multi-view measurements. Each observed image is modeled as the sum of a background image and a foreground one. The background…

Computer Vision and Pattern Recognition · Computer Science 2013-09-19 Gilles Puy , Pierre Vandergheynst