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It is known that the continuous wavelet transform of a function $f$ decays very rapidly near the points where $f$ is smooth, while it decays slowly near the irregular points. This property allows one to precisely identify the singular…

Functional Analysis · Mathematics 2007-05-23 Gitta Kutyniok , Demetrio Labate

We summarise the construction of exact axisymmetric scale-discretised wavelets on the sphere and on the ball. The wavelet transform on the ball relies on a novel 3D harmonic transform called the Fourier-Laguerre transform which combines the…

Information Theory · Computer Science 2013-01-28 Boris Leistedt , Jason D. McEwen

We introduce a two-layer wavelet scattering network, for object classification. This scattering transform computes a spatial wavelet transform on the first layer and a new joint wavelet transform along spatial, angular and scale variables…

Computer Vision and Pattern Recognition · Computer Science 2014-03-11 Edouard Oyallon , Stéphane Mallat , Laurent Sifre

Synthetic turbulence models are a useful tool that provide realistic representations of turbulence, necessary to test theoretical results, to serve as background fields in some numerical simulations, and to test analysis tools. Models of 1D…

Fluid Dynamics · Physics 2016-11-15 Francesco Malara , Francesca Di Mare , Giuseppina Nigro , Luca Sorriso-Valvo

The 2-D discrete wavelet transform (DWT) can be found in the heart of many image-processing algorithms. Until recently, several studies have compared the performance of such transform on various shared-memory parallel architectures,…

Performance · Computer Science 2017-05-30 David Barina , Michal Kula , Michal Matysek , Pavel Zemcik

The major goal of the paper is to prove that discrete frames of (directional) wavelets derived from an approximate identity exist. Additionally, a kind of energy conservation property is shown to hold in the case when a wavelet family is…

Classical Analysis and ODEs · Mathematics 2018-03-06 Ilona Iglewska-Nowak

Convolutional Neural Networks (CNNs) have been providing the state-of-the-art performance for learning-related problems involving 2D/3D images in Euclidean space. However, unlike in the Euclidean space, the shapes of many structures in…

Computer Vision and Pattern Recognition · Computer Science 2019-04-02 Fenqiang Zhao , Shunren Xia , Zhengwang Wu , Dingna Duan , Li Wang , Weili Lin , John H Gilmore , Dinggang Shen , Gang Li

The shapelets method for image analysis is based upon the decomposition of localised objects into a series of orthogonal components with convenient mathematical properties. We extend the "Cartesian shapelet" formalism from earlier work, and…

Astrophysics · Physics 2009-11-10 Richard Massey , Alexandre Refregier

We introduce an innovative wavelet-based approach to dynamically adjust the local grid resolution to maintain a uniform specified error tolerance. Extending the work of Dubos and Kevlahan (2013), a wavelet multi-scale approximation is used…

Geophysics · Physics 2015-10-28 Matthias Aechtner , Nicholas Kevlahan , Thomas Dubos

Superpixel decomposition methods are generally used as a pre-processing step to speed up image processing tasks. They group the pixels of an image into homogeneous regions while trying to respect existing contours. For all state-of-the-art…

Computer Vision and Pattern Recognition · Computer Science 2025-09-18 Rémi Giraud , Vinh-Thong Ta , Nicolas Papadakis

In this article, we present an $O(N \log N)$ rapidly convergent algorithm for the numerical approximation of the convolution integral with radially symmetric weakly singular kernels and compactly supported densities. To achieve the reduced…

Numerical Analysis · Mathematics 2021-07-09 Awanish Kumar Tiwari , Ambuj Pandey , Jagabandhu Paul , Akash Anand

We present a versatile formulation of the convolution operation that we term a "mapped convolution." The standard convolution operation implicitly samples the pixel grid and computes a weighted sum. Our mapped convolution decouples these…

Computer Vision and Pattern Recognition · Computer Science 2019-06-27 Marc Eder , True Price , Thanh Vu , Akash Bapat , Jan-Michael Frahm

We investigate methods to calibrate the non-common path aberrations at an adaptive optics system having a wavefront-correcting device working at an extremely high resolution (larger than 150x150). We use focal-plane images collected…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Visa Korkiakoski , Christoph U. Keller , Niek Doelman , Matthew Kenworthy , Gilles Otten , Michel Verhaegen

We introduce a novel harmonic analysis for functions defined on the vertices of a strongly connected directed graph of which the random walk operator is the cornerstone. As a first step, we consider the set of eigenvectors of the random…

Functional Analysis · Mathematics 2021-11-02 Harry Sevi , Gabriel Rilling , Pierre Borgnat

In this paper, we propose a new method for the construction of multi-dimensional, wavelet-like families of affine frames, commonly referred to as framelets, with specific directional characteristics, small and compact support in space,…

Information Theory · Computer Science 2019-09-13 Nikolaos Atreas , Nikolaos Karantzas , Manos Papadakis , Theodoros Stavropoulos

Recently, the numerical schemes of the Fokker-Planck equations describing anomalous diffusion with two internal states have been proposed in [Nie, Sun and Deng, arXiv: 1811.04723], which use convolution quadrature to approximate the…

Numerical Analysis · Mathematics 2024-12-20 Jing Sun , Daxin Nie , Weihua Deng

Aperture array interferometers, such as that proposed for the Square Kilometre Array (SKA), will see the entire sky, hence the standard approach to simulating visibilities will not be applicable since it relies on a tangent plane…

Astrophysics · Physics 2008-09-11 J. D. McEwen , A. M. M. Scaife

2D convolution is a staple of digital image processing. The advent of large format imagers makes it possible to literally ``pave'' with silicon the focal plane of an optical sensor, which results in very large images that can require a…

Astrophysics · Physics 2015-05-26 Jeremy Kepner

Spectral graph convolution, an important tool of data filtering on graphs, relies on two essential decisions: selecting spectral bases for signal transformation and parameterizing the kernel for frequency analysis. While recent techniques…

Machine Learning · Computer Science 2025-05-15 Nian Liu , Xiaoxin He , Thomas Laurent , Francesco Di Giovanni , Michael M. Bronstein , Xavier Bresson

Image deblurring is a classical computer vision problem that aims to recover a sharp image from a blurred image. To solve this problem, existing methods apply the Encode-Decode architecture to design the complex networks to make a good…

Image and Video Processing · Electrical Eng. & Systems 2021-10-13 Wenbin Zou , Mingchao Jiang , Yunchen Zhang , Liang Chen , Zhiyong Lu , Yi Wu