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The wavelet transform has been used for numerous studies in astrophysics, including signal--noise periodicity and decomposition as well as the signature of differential rotation in stellar light curves. In the present work, we apply the…

Solar and Stellar Astrophysics · Physics 2010-09-28 D. B. de Freitas , I. de C. Leão , B. L. Canto Martins , J. R. De Medeiros

This paper investigates the nonparametric estimation of a heteroskedastic variance function on the sphere in a regression framework, assuming the variance belongs to a Besov regularity class. A needlet-based estimator is proposed, combining…

Statistics Theory · Mathematics 2026-01-08 Claudio Durastanti , Radomyra Shevchenko

The cosmic microwave background radiation is supposed to be Gaussian and this hypothesis is in good agreement with the recent very accurate measurements. Nonetheless a tiny amount of non-Gaussianity is predicted by the standard inflation…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-06 Davide Pietrobon

We suggest a two-dimensional wavelet devised to deduce the large-scale structure of a physical field (e.g., the Galactic magnetic field) from its integrals along straight paths from irregularly spaced data points to a fixed interior point…

Astrophysics · Physics 2009-11-07 R. Stepanov , P. Frick , A. Shukurov , D. Sokoloff

To improve diagnostic accuracy of breast cancer detection, several researchers have used the wavelet-based tools, which provide additional insight and information for aiding diagnostic decisions. The accuracy of such diagnoses, however, can…

Methodology · Statistics 2022-01-25 Minkyoung Kang , William Auffermann , Brani Vidakovic

Wavelets are waveform functions that describe transient and unstable variations, such as noises. In this work, we study the advantages of discrete and continuous wavelet transforms (DWT and CWT) of microlensing data to denoise them and…

Instrumentation and Methods for Astrophysics · Physics 2023-10-06 Sedighe Sajadian , Hossein Fatheddin

Texture classification is an important and challenging problem in many image processing applications. While convolutional neural networks (CNNs) achieved significant successes for image classification, texture classification remains a…

Computer Vision and Pattern Recognition · Computer Science 2017-07-25 Shin Fujieda , Kohei Takayama , Toshiya Hachisuka

In this review, we give an overview of some of the major aspects of data reduction and analysis for the cosmic microwave background (CMB). Since its prediction and discovery in the last century, the CMB radiation has proven itself to be one…

Astrophysics · Physics 2009-09-29 Matthieu Tristram , Ken Ganga

The field of gamma-ray astronomy has seen important progress during the last decade, yet there exists so far no common software framework for the scientific analysis of gamma-ray telescope data. We propose to fill this gap by means of the…

Functional data analysis is ubiquitous in most areas of sciences and engineering. Several paradigms are proposed to deal with the dimensionality problem which is inherent to this type of data. Sparseness, penalization, thresholding, among…

Methodology · Statistics 2018-09-05 Rodney V. Fonseca , Aluísio Pinheiro

This paper reviews the application of a novel methodology for analysing the isotropy of the universe by probing the alignment of local structures in the CMB. The strength of the proposed methodology relies on the steerable wavelet filtering…

Astrophysics · Physics 2009-11-11 P. Vielva , Y. Wiaux , E. Martinez-Gonzalez , P. Vandergheynst

The cosmic microwave background (CMB) has been a treasure trove for cosmology. Over the next decade, current and planned CMB experiments are expected to exhaust nearly all primary CMB information. To further constrain cosmological models,…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Benjamin Beringue , P. Daniel Meerburg , Joel Meyers , Nicholas Battaglia

We investigate the use of wavelet transforms in detecting and characterising non-Gaussian structure in maps of the cosmic microwave background (CMB). We apply the method to simulated maps of the Kaiser-Stebbins effect due to cosmic strings…

Astrophysics · Physics 2009-10-31 MP Hobson , AW Jones , AN Lasenby

Needlets have been recognized as state-of-the-art tools to tackle spherical data, due to their excellent localization properties in both spacial and frequency domains. This paper considers developing kernel methods associated with the…

Machine Learning · Computer Science 2015-09-11 Shaobo Lin

We describe an assembly of numerical tools to model the output data of the Planck satellite. These start with the generation of a CMB sky in a chosen cosmology, add in various foreground sources, convolve the sky signal with arbitrary, even…

Astrophysics · Physics 2009-11-11 Martin Reinecke , Klaus Dolag , Reinhard Hell , Matthias Bartelmann , Torsten Ensslin

Deep learning image classifiers usually rely on huge training sets and their training process can be described as learning the similarities and differences among training images. But, images in large training sets are not usually studied…

Image and Video Processing · Electrical Eng. & Systems 2020-05-19 Roozbeh Yousefzadeh

Segmentation, a useful/powerful technique in pattern recognition, is the process of identifying object outlines within images. There are a number of efficient algorithms for segmentation in Euclidean space that depend on the variational…

Computer Vision and Pattern Recognition · Computer Science 2019-11-12 Xiaohao Cai , Christopher G. R. Wallis , Jennifer Y. H. Chan , Jason D. McEwen

Recently, Computer-Aided Diagnosis (CAD) systems have emerged as indispensable tools in clinical diagnostic workflows, significantly alleviating the burden on radiologists. Nevertheless, despite their integration into clinical settings, CAD…

Image and Video Processing · Electrical Eng. & Systems 2024-06-27 Muwei Jian , Hongyu Chen , Zaiyong Zhang , Nan Yang , Haorang Zhang , Lifu Ma , Wenjing Xu , Huixiang Zhi

The analysis of gravitational-wave (GW) signals is one of the most challenging application areas of signal processing. Wavelet transforms are specially helpful in detecting and analyzing GW transients and several analysis pipelines are…

General Relativity and Quantum Cosmology · Physics 2024-05-27 Andrea Virtuoso , Edoardo Milotti

We describe S2LET, a fast and robust implementation of the scale-discretised wavelet transform on the sphere. Wavelets are constructed through a tiling of the harmonic line and can be used to probe spatially localised, scale-depended…

Information Theory · Computer Science 2013-10-29 B. Leistedt , J. D. McEwen , P. Vandergheynst , Y. Wiaux