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We develop an exact wavelet transform on the three-dimensional ball (i.e. on the solid sphere), which we name the flaglet transform. For this purpose we first construct an exact transform on the radial half-line using damped Laguerre…

Information Theory · Computer Science 2013-08-15 B. Leistedt , J. D. McEwen

In this paper, we investigate 1D elliptic equations $-\nabla\cdot (a\nabla u)=f$ with rough diffusion coefficients $a$ that satisfy $0<a_{\min}\le a\le a_{\max}<\infty$ and $f\in L_2(\Omega)$. To achieve an accurate and robust numerical…

Numerical Analysis · Mathematics 2024-11-01 Qiwei Feng , Bin Han

The generalized Morse wavelets are shown to constitute a superfamily that essentially encompasses all other commonly used analytic wavelets, subsuming eight apparently distinct types of analysis filters into a single common form. This…

Methodology · Statistics 2015-06-04 Jonathan M. Lilly , Sofia C. Olhede

This paper describes a method for extracting rapidly varying, superimposed amplitude- and frequency-modulated signal components. The method is based upon the continuous wavelet transform (CWT) and uses a new wavelet which is a modification…

Mathematical Physics · Physics 2009-11-07 J. D. Harrop , S. N. Taraskin , S. R. Elliott

Though widely used in image classification, convolutional neural networks (CNNs) are prone to noise interruptions, i.e. the CNN output can be drastically changed by small image noise. To improve the noise robustness, we try to integrate…

Computer Vision and Pattern Recognition · Computer Science 2021-09-01 Qiufu Li , Linlin Shen , Sheng Guo , Zhihui Lai

The recently proposed empirical wavelet transform was based on a particular type of filter. In this paper, we aim to propose a general framework for the construction of empirical wavelet systems in the continuous case. We define a…

Spectral Theory · Mathematics 2024-10-28 Jerome Gilles

The constant center frequency to bandwidth ratio (Q-factor) of wavelet transforms provides a very natural representation for audio data. However, invertible wavelet transforms have either required non-uniform decimation -- leading to…

Audio and Speech Processing · Electrical Eng. & Systems 2023-01-20 Nicki Holighaus , Günther Koliander , Clara Hollomey , Friedrich Pillichshammer

A sensitive porosity adjoint method (SPAM) for optimizing the topology of fluid machines has been proposed. A sensitivity function with respect to the porosity has been developed. In the first step of the optimization process, porous media…

Fluid Dynamics · Physics 2015-12-29 B. Philippi , Y. Jin

We present a volumetric mesh-based algorithm for parameterizing the placenta to a flattened template to enable effective visualization of local anatomy and function. MRI shows potential as a research tool as it provides signals directly…

Computer Vision and Pattern Recognition · Computer Science 2021-11-16 S. Mazdak Abulnaga , Esra Abaci Turk , Mikhail Bessmeltsev , P. Ellen Grant , Justin Solomon , Polina Golland

We investigate the problem of finding the optimal shape and topology of a system of acoustic lenses in a dissipative medium. The sound propagation is governed by a general semilinear strongly damped wave equation. We introduce a phase-field…

Optimization and Control · Mathematics 2021-09-29 Harald Garcke , Sourav Mitra , Vanja Nikolić

We revisit the feasibility approach to the construction of compactly supported smooth orthogonal wavelets on the line. We highlight its flexibility and illustrate how symmetry and cardinality properties are easily embedded in the design…

Optimization and Control · Mathematics 2020-05-13 Neil Dizon , Jeffrey Hogan , Scott B. Lindstrom

We axiomatically derive a family of wavelets for an orientation score, lifting from position space $\mathbb{R}^2$ to position and orientation space $\mathbb{R}^2\times S^1$, with fast reconstruction property, that minimise…

Differential Geometry · Mathematics 2025-10-24 Finn M. Sherry , Chase van de Geijn , Erik J. Bekkers , Remco Duits

We solve the ground state of the deuteron using a variational neural network ansatz for the wave function in momentum space. This ansatz provides a flexible representation of both the $S$ and the $D$ states, with relative errors in the…

Nuclear Theory · Physics 2024-04-19 J Rozalén Sarmiento , J W T Keeble , A Rios

In this paper we present and analyse a high accuracy method for computing wave directions defined in the geometrical optics ansatz of Helmholtz equation with variable wave number. Then we define an "adaptive" plane wave space with small…

Numerical Analysis · Mathematics 2021-07-22 Qiya Hu , Zezhong Wang

In this paper, we present a framework for multiscale topology optimization of fluid-flow devices. The objective is to minimize dissipated power, subject to a desired contact-area. The proposed strategy is to design optimal microstructures…

Computational Engineering, Finance, and Science · Computer Science 2023-09-18 Rahul Kumar Padhy , Krishnan Suresh , Aaditya Chandrasekhar

Orthogonal wavelet transforms are a cornerstone of modern signal and image denoising because they combine multiscale representation, energy preservation, and perfect reconstruction. In this paper, we show that these advantages can be…

Computation · Statistics 2026-03-04 Radhika Kulkarni , Brani Vidakovic

In this work, we propose a new detector function based on wavelet transform to discriminate between turbulent and non-turbulent regions in an intermittent velocity signal. The derivative-based detector function, which is commonly used in…

Fluid Dynamics · Physics 2023-01-02 Satyajit De , Aditya Anand , Sourabh S. Diwan

Image enhancement is a technique that frequently utilized in digital image processing. In recent years, the popularity of learning-based techniques for enhancing the aesthetic performance of photographs has increased. However, the majority…

Computer Vision and Pattern Recognition · Computer Science 2022-12-20 Zinuo Li , Xuhang Chen , Chi-Man Pun , Shuqiang Wang

The paper presents a versatile library of analytic and quasi-analytic complex-valued wavelet packets (WPs) which originate from discrete splines of arbitrary orders. The real parts of the quasi-analytic WPs are the regular spline-based…

Numerical Analysis · Mathematics 2019-07-04 Amir Averbuch , Pekka Neittaanmaki , Valery Zheludev

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