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We describe the construction of a spherical wavelet analysis through the inverse stereographic projection of the Euclidean planar wavelet framework, introduced originally by Antoine and Vandergheynst and developed further by Wiaux et al.…

Astrophysics · Physics 2011-10-28 J. D. McEwen , M. P. Hobson , D. J. Mortlock , A. N. Lasenby

The continuous wavelet transform (CWT) is very useful for processing signals with intricate and irregular structures in astrophysics and cosmology. It is crucial to propose precise and fast algorithms for the CWT. In this work, we review…

Instrumentation and Methods for Astrophysics · Physics 2024-08-28 Yun Wang , Ping He

A directional spherical wavelet analysis is performed to examine the Gaussianity of the WMAP 1-year data. Such an analysis is facilitated by the introduction of a fast directional continuous spherical wavelet transform. The directional…

Astrophysics · Physics 2008-03-04 J. D. McEwen , M. P. Hobson , A. N. Lasenby , D. J. Mortlock

A new construction of a directional continuous wavelet analysis on the sphere is derived herein. We adopt the harmonic scaling idea for the spherical dilation operator recently proposed by Sanz et al. but extend the analysis to a more…

Astrophysics · Physics 2011-10-28 J. D. McEwen , M. P. Hobson , A. N. Lasenby

A fast algorithm is developed for the directional correlation of scalar band-limited signals and band-limited steerable filters on the sphere. The asymptotic complexity associated to it through simple quadrature is of order O(L^5), where 2L…

Astrophysics · Physics 2011-02-11 Y. Wiaux , L. Jacques , P. Vielva , P. Vandergheynst

Finding a computationally efficient algorithm for the inverse continuous wavelet transform is a fundamental topic in applications. In this paper, we show the convergence of the inverse wavelet transform.

Functional Analysis · Mathematics 2010-09-01 Wenchang Sun

We review scale-discretized wavelets on the sphere, which are directional and allow one to probe oriented structure in data defined on the sphere. Furthermore, scale-discretized wavelets allow in practice the exact synthesis of a signal…

Information Theory · Computer Science 2013-12-10 J. D. McEwen , P. Vandergheynst , Y. Wiaux

Dense pixelwise prediction such as semantic segmentation is an up-to-date challenge for deep convolutional neural networks (CNNs). Many state-of-the-art approaches either tackle the loss of high-resolution information due to pooling in the…

Computer Vision and Pattern Recognition · Computer Science 2018-08-07 Lingni Ma , Jörg Stückler , Tao Wu , Daniel Cremers

We propose fast, exact and efficient algorithms for the convolution of two arbitrary functions on the sphere which speed up computations by a factor \order{\sqrt{N}} compared to present methods where $N$ is the number of pixels. No…

Astrophysics · Physics 2009-10-31 Benjamin D. Wandelt , Krzysztof M. Gorski

A new method is presented for the construction of a natural continuous wavelet transform on the sphere. It incorporates the analysis and synthesis with the same wavelet and the definition of translations and dilations on the sphere through…

Astrophysics · Physics 2007-05-23 J. L. Sanz , D. Herranz , M. Lopez-Caniego , F. Argueso

Due to the emergence of new high resolution numerical weather prediction (NWP) models and the availability of new or more reliable remote sensing data, the importance of efficient spatial verification techniques is growing. Wavelet…

Atmospheric and Oceanic Physics · Physics 2017-04-05 Michael Weniger , Florian Kapp , Petra Friederichs

We propose a transform for signals defined on the sphere that reveals their localized directional content in the spatio-spectral domain when used in conjunction with an asymmetric window function. We call this transform the directional…

Information Theory · Computer Science 2013-04-23 Z. Khalid , R. A. Kennedy , S. Durrani , P. Sadeghi , Y. Wiaux , J. D. McEwen

We construct a directional spin wavelet framework on the sphere by generalising the scalar scale-discretised wavelet transform to signals of arbitrary spin. The resulting framework is the only wavelet framework defined natively on the…

Information Theory · Computer Science 2017-06-06 Jason D. McEwen , Boris Leistedt , Martin Büttner , Hiranya V. Peiris , Yves Wiaux

The symplectic wavelet transformation [Opt. Lett. 31 (2006) 3432], which is related to quantum optical Fresnel transform, is developed to the symplectic-dilation mixed wavelet transform (SDWT). The SDWT involves both a real-variable…

Quantum Physics · Physics 2009-11-13 Hong-yi Fan , Shu-guang Liu , Li-yun Hu

In the general context of complex data processing, this paper reviews a recent practical approach to the continuous wavelet formalism on the sphere. This formalism notably yields a correspondence principle which relates wavelets on the…

Astrophysics · Physics 2007-08-14 Y. Wiaux , J. D. McEwen , P. Vielva

We propose a novel algorithm for computing the Walsh-Hadamard Transform (WHT) which consists entirely of Haar wavelet transforms. We prove that the algorithm, which we call the Cascading Haar Wavelet (CHW) algorithm, shares precisely the…

Data Structures and Algorithms · Computer Science 2017-06-28 Andrew Thompson

One of the key challenges in the area of signal processing on graphs is to design transforms and dictionaries methods to identify and exploit structure in signals on weighted graphs. In this paper, we first generalize graph Fourier…

Computer Vision and Pattern Recognition · Computer Science 2019-02-28 Jiasong Wu , Fuzhi Wu , Qihan Yang , Youyong Kong , Xilin Liu , Yan Zhang , Lotfi Senhadji , Huazhong Shu

The polar wavelet transform (PWT) has been proven to be a powerful mathematical tool for signal and image processing in recent years. Due to the increasing demand for directional representations of signals in engineering, it is impossible…

General Mathematics · Mathematics 2023-12-13 Hui Zhao , Bing-Zhao Li

Wavelet scattering networks, which are convolutional neural networks (CNNs) with fixed filters and weights, are promising tools for image analysis. Imposing symmetry on image statistics can improve human interpretability, aid in…

Computer Vision and Pattern Recognition · Computer Science 2021-04-26 Andrew K. Saydjari , Douglas P. Finkbeiner

We show that continuous transform with the complex Morlet wavelet is easily performed if we replace the integration of the fast-oscillation function by the solution of the diffusion differential equations. The most important advantage of…

Astrophysics · Physics 2007-05-23 E. B. Postnikov , A. Loskutov
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