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Related papers: Denoising Sphere-Valued Data by Relaxed Total Vari…

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In this paper we propose a new approach for tomographic reconstruction with spatially varying regularization parameter. Our work is based on the SA-TV image restoration model proposed in [3] where an automated parameter selection rule for…

Numerical Analysis · Mathematics 2018-11-27 Yiqiu Dong , Carola-Bibiane Schönlieb

In this work, we propose a time-varying wave-shape extraction algorithm based on a modified version of the adaptive non-harmonic model for non-stationary signals. The model codifies the time-varying wave-shape information in the relative…

Signal Processing · Electrical Eng. & Systems 2023-09-28 Joaquin Ruiz , Gastón Schlotthauer , Leandro Vignolo , Marcelo A. Colominas

Designing a convolution for a spherical neural network requires a delicate tradeoff between efficiency and rotation equivariance. DeepSphere, a method based on a graph representation of the sampled sphere, strikes a controllable balance…

Machine Learning · Computer Science 2021-01-01 Michaël Defferrard , Martino Milani , Frédérick Gusset , Nathanaël Perraudin

Multi-channel sparse blind deconvolution, or convolutional sparse coding, refers to the problem of learning an unknown filter by observing its circulant convolutions with multiple input signals that are sparse. This problem finds numerous…

Machine Learning · Statistics 2021-04-07 Laixi Shi , Yuejie Chi

We present a framework for the optimal filtering of spherical signals contaminated by realizations of an additive, zero-mean, uncorrelated and anisotropic noise process on the sphere. Filtering is performed in the wavelet domain given by…

Signal Processing · Electrical Eng. & Systems 2021-02-09 Adeem Aslam , Zubair Khalid , Jason D. McEwen

Inverse problems generally require a regularizer or prior for a good solution. A recent trend is to train a convolutional net to denoise images, and use this net as a prior when solving the inverse problem. Several proposals depend on a…

Computer Vision and Pattern Recognition · Computer Science 2023-07-12 Kyle Luther , H. Sebastian Seung

Recovering a low-rank signal matrix from its noisy observation, commonly known as matrix denoising, is a fundamental inverse problem in statistical signal processing. Matrix denoising methods are generally based on shrinkage or thresholding…

Methodology · Statistics 2017-01-23 Santosh Kumar Yadav , Rohit Sinha , Prabin Kumar Bora

We study the theoretical properties of image denoising via total variation penalized least-squares. We define the total vatiation in terms of the two-dimensional total discrete derivative of the image and show that it gives rise to denoised…

Statistics Theory · Mathematics 2021-01-27 Francesco Ortelli , Sara van de Geer

Recovering a signal from its Fourier magnitude is referred to as phase retrieval, which occurs in different fields of engineering and applied physics. This paper gives a new characterization of the phase retrieval problem. Particularly…

Information Theory · Computer Science 2020-07-16 Wing Hong Wong , Yifei Lou , Stefano Marchesini , Tieyong Zeng

A multiscale representation-based denoising method for spherical data contaminated with Poisson noise, the multiscale variance stabilizing transform on the sphere (MS-VSTS), has been previously proposed. This paper first extends this…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 Jérémy Schmitt , Jean-Luc Starck , Jean-Marc Casandjian , Jalal Fadili , Isabelle Grenier

Diffuse Optical Tomography (DOT) is an emerging technology in medical imaging which employs light in the NIR spectrum to estimate the distribution of optical coefficients in biological tissues for diagnostic and monitoring purposes. DOT…

Numerical Analysis · Mathematics 2022-05-27 Alessandro Benfenati , Giuseppe Bisazza , Paola Causin

Many applications in science call for the numerical simulation of systems on manifolds with spherical topology. Through use of integer spin weighted spherical harmonics we present a method which allows for the implementation of arbitrary…

Computational Physics · Physics 2014-03-18 Florian Beyer , Boris Daszuta , Jörg Frauendiener , Ben Whale

Matrix-valued covariance functions are crucial to geostatistical modeling of multivariate spatial data. The classical assumption of symmetry of a multivariate covariance function is overlay restrictive and has been considered as unrealistic…

Statistics Theory · Mathematics 2017-11-28 Alfredo Alegría , Emilio Porcu , Reinhard Furrer

In this paper, we extend our research concerning the standard and linearized monotonicity methods for the inverse problem of the time harmonic elastic wave equation and introduce the modification of these methods for noisy data. In more…

Numerical Analysis · Mathematics 2025-04-07 Sarah Eberle-Blick

The goal of a denoising algorithm is to reconstruct a signal from its noise-corrupted observations. Perfect reconstruction is seldom possible and performance is measured under a given fidelity criterion. In a recent work, the authors…

Information Theory · Computer Science 2009-11-11 George Gemelos , Styrmir Sigurjonsson , Tsachy Weissman

Regularization is a critical technique for ensuring well-posedness in solving inverse problems with incomplete measurement data. Traditionally, the regularization term is designed based on prior knowledge of the unknown signal's…

Numerical Analysis · Mathematics 2024-12-16 Bosu Choi , Jihun Han , Yoonsang Lee

Denoising is of utmost importance for the visualization and processing of images featuring low signal-to-noise ratio. Total variation methods are among the most popular techniques to perform this task improving the signal-to-noise ratio…

Signal Processing · Electrical Eng. & Systems 2022-01-24 Gonzalo D. Maso Talou , Pablo J. Blanco

A fruitful approach for solving signal deconvolution problems consists of resorting to a frame-based convex variational formulation. In this context, parallel proximal algorithms and related alternating direction methods of multipliers have…

Other Computer Science · Computer Science 2015-05-28 Nelly Pustelnik , Jean-Christophe Pesquet , Caroline Chaux

A new parameter choice rule for inverse problems is introduced. This parameter choice rule was developed for total variation regularization in electron tomography and might in general be useful for $L^1$ regularization of inverse problems…

Numerical Analysis · Mathematics 2008-04-28 Hans Rullgård

In this paper we present a new regularization term for variational image restoration which can be regarded as a space-variant anisotropic extension of the classical isotropic Total Variation (TV) regularizer. The proposed regularizer comes…

Image and Video Processing · Electrical Eng. & Systems 2019-08-05 Luca Calatroni , Alessandro Lanza , Monica Pragliola , Fiorella Sgallari
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