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We propose a new reconstruction operator that aims to recover the missing parts of a function given the observed parts. This new operator belongs to a new, very large class of functional operators which includes the classical regression…

Statistics Theory · Mathematics 2019-05-14 Alois Kneip , Dominik Liebl

Sparse estimation methods are aimed at using or obtaining parsimonious representations of data or models. While naturally cast as a combinatorial optimization problem, variable or feature selection admits a convex relaxation through the…

Machine Learning · Computer Science 2012-04-23 Francis Bach , Rodolphe Jenatton , Julien Mairal , Guillaume Obozinski

A different compressive sensing framework, convolution with white noise waveform followed by subsampling at fixed (not randomly selected) locations, is studied in this paper. We show that its recoverability for sparse signals depends on the…

Optimization and Control · Mathematics 2009-09-30 Yin Xiang , Lianlin Li , Fang Li

In this paper we approximate high-dimensional functions $f\colon\mathbb T^d\to\mathbb C$ by sparse trigonometric polynomials based on function evaluations. Recently it was shown that a dimension-incremental sparse Fourier transform (SFT)…

Numerical Analysis · Mathematics 2023-06-07 Felix Bartel , Fabian Taubert

Sparse-view computed tomography (CT) enables fast and low-dose CT imaging, an essential feature for patient-save medical imaging and rapid non-destructive testing. In sparse-view CT, only a few projection views are acquired, causing…

Image and Video Processing · Electrical Eng. & Systems 2024-02-28 Nadja Gruber , Johannes Schwab , Elke Gizewski , Markus Haltmeier

We analyze representative ill-posed scenarios of tomographic PIV with a focus on conditions for unique volume reconstruction. Based on sparse random seedings of a region of interest with small particles, the corresponding systems of linear…

Numerical Analysis · Mathematics 2012-09-20 Stefania Petra , Christoph Schnörr , Andreas Schröder

We consider the case in which a robot has to navigate in an unknown environment but does not have enough on-board power or payload to carry a traditional depth sensor (e.g., a 3D lidar) and thus can only acquire a few (point-wise) depth…

Robotics · Computer Science 2017-10-17 Fangchang Ma , Luca Carlone , Ulas Ayaz , Sertac Karaman

Intensively growing approach in signal processing and acquisition, the Compressive Sensing approach, allows sparse signals to be recovered from small number of randomly acquired signal coefficients. This paper analyses some of the commonly…

Signal Processing · Electrical Eng. & Systems 2018-02-21 Tamara Koljensic , Caslav Labudovic

In recent years, a number of works have studied methods for computing the Fourier transform in sublinear time if the output is sparse. Most of these have focused on the discrete setting, even though in many applications the input signal is…

Data Structures and Algorithms · Computer Science 2016-09-06 Eric Price , Zhao Song

Input space reconstruction is an attractive representation learning paradigm. Despite interpretability of the reconstruction and generation, we identify a misalignment between learning by reconstruction, and learning for perception. We show…

Computer Vision and Pattern Recognition · Computer Science 2024-02-20 Randall Balestriero , Yann LeCun

The need for tomographic reconstruction from sparse measurements arises when the measurement process is potentially harmful, needs to be rapid, or is uneconomical. In such cases, information from previous longitudinal scans of the same…

Image and Video Processing · Electrical Eng. & Systems 2019-09-13 Preeti Gopal , Sharat Chandran , Imants Svalbe , Ajit Rajwade

Recovering jointly sparse signals in the multiple measurement vectors (MMV) setting is a fundamental problem in machine learning, but traditional methods often require careful parameter tuning or prior knowledge of the sparsity of the…

Machine Learning · Computer Science 2026-02-02 Lakshmi Jayalal , Sheetal Kalyani

We propose a sparse reconstruction framework for solving inverse problems. Opposed to existing sparse regularization techniques that are based on frame representations, we train an encoder-decoder network by including an $\ell^1$-penalty.…

Numerical Analysis · Mathematics 2019-08-07 Daniel Obmann , Johannes Schwab , Markus Haltmeier

Sparse coding algorithms are about finding a linear basis in which signals can be represented by a small number of active (non-zero) coefficients. Such coding has many applications in science and engineering and is believed to play an…

Neural and Evolutionary Computing · Computer Science 2016-08-14 András Lőrincz , Zsolt Palotai , Gábor Szirtes

We propose a method to reconstruct sparse signals degraded by a nonlinear distortion and acquired at a limited sampling rate. Our method formulates the reconstruction problem as a nonconvex minimization of the sum of a data fitting term and…

Optimization and Control · Mathematics 2023-01-19 Arthur Marmin , Marc Castella , Jean-Christophe Pesquet , Laurent Duval

In this paper, we focus on approximating a natural class of functions that are compositions of smooth functions. Unlike the low-dimensional support assumption on the covariate, we demonstrate that composition functions have an intrinsic…

Numerical Analysis · Mathematics 2023-04-24 Chenguang Duan , Yuling Jiao , Xiliang Lu , Jerry Zhijian Yang , Cheng Yuan

This paper presents a novel projection-based adaptive algorithm for sparse signal and system identification. The sequentially observed data are used to generate an equivalent sequence of closed convex sets, namely hyperslabs. Each hyperslab…

Information Theory · Computer Science 2015-10-28 Yannis Kopsinis , Konstantinos Slavakis , Sergios Theodoridis

This thesis develops exact analytical tools to study strongly correlated stochastic systems, with a focus on extreme value statistics, gap statistics, and full counting statistics in multi-particle processes. A central contribution is the…

Statistical Mechanics · Physics 2025-08-19 Marco Biroli

Fusion frames are collection of subspaces which provide a redundant representation of signal spaces. They generalize classical frames by replacing frame vectors with frame subspaces. This paper considers the sparse recovery of a signal from…

Information Theory · Computer Science 2018-04-09 Ulaş Ayaz

Sparsity is a ubiquitous feature of many real world signals such as natural images and neural spiking activities. Conventional compressed sensing utilizes sparsity to recover low dimensional signal structures in high ambient dimensions…

Statistics Theory · Mathematics 2018-07-02 Abbas Kazemipour