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The problem of constructing an orthogonal set of eigenvectors for a DFT matrix is well studied. An elegant solution is mentioned by Matveev in his paper "Interwining relations between the Fourier transfom and discrete Fourier transform, the…

Numerical Analysis · Computer Science 2017-12-20 Vadim Zaliva

Recent progress in image deblurring techniques focuses mainly on operating in both frequency and spatial domains using the Fourier transform (FT) properties. However, their performance is limited due to the dependency of FT on stationary…

Computer Vision and Pattern Recognition · Computer Science 2024-09-04 Subhajit Paul , Sahil Kumawat , Ashutosh Gupta , Deepak Mishra

The Fourier transform is approximated over a finite domain using a Riemann sum. This Riemann sum is then expressed in terms of the discrete Fourier transform, which allows the sum to be computed with a fast Fourier transform algorithm more…

Numerical Analysis · Mathematics 2015-08-07 Jeremy Axelrod

The algorithm behind the Fast Fourier Transform has a simple yet beautiful geometric interpretation that is often lost in translation in a classroom. This article provides a visual perspective which aims to capture the essence of it.

Signal Processing · Electrical Eng. & Systems 2018-06-25 Jithin Donny George

Performance of neural networks can be significantly improved by encoding known invariance for particular tasks. Many image classification tasks, such as those related to cellular imaging, exhibit invariance to rotation. We present a novel…

Machine Learning · Statistics 2018-06-01 Benjamin Chidester , Minh N. Do , Jian Ma

The notion of fractional Fourier transform (FrFT) has been used and investigated for many years by various research communities, which finds widespread applications in many diverse fields of research study. The potential applications…

Signal Processing · Electrical Eng. & Systems 2018-03-21 Sanjay Kumar

The setting is the representation theory of a simply connected, semisimple algebraic group over a field of positive characteristic. There is a natural transformation from the wall-crossing functor to the identity functor. The kernel of this…

Representation Theory · Mathematics 2010-02-09 Kevin J. Carlin

This paper presents a family of Fourier eigenfunctions indexed by the space dimension d. These eigenfunctions are radial and built upon some generalized exponential integral function. For d=1,2,3, they are integrable or square integrable…

Classical Analysis and ODEs · Mathematics 2024-11-28 Rodolphe Garbit , Julien-Bilal Zinoune

In some of the problems, complicated functions of the Z-transform variable, $z$, appear which either cannot be inverted analytically or the required calculations are quite tedious. In such cases numerical methods should be used to find the…

Numerical Analysis · Mathematics 2014-09-08 Farshad Merrikh-Bayat

The windowed quadratic phase Fourier transform (WQPFT) combines the localization capabilities of windowed transforms with the phase modulation structure of the quadratic phase Fourier transform (QPFT). This paper investigates fundamental…

Functional Analysis · Mathematics 2025-07-09 Sarga Varghese , Manab Kundu

Differential equation discovery, a machine learning subfield, is used to develop interpretable models, particularly in nature-related applications. By expertly incorporating the general parametric form of the equation of motion and…

Machine Learning · Computer Science 2024-02-23 Alexander Hvatov , Roman Titov

Object orientation provides a flexible framework for the implementation of the convolution of arbitrary distributions of real-valued random variables. We discuss an algorithm which is based on the discrete Fourier transformation (DFT) and…

Computation · Statistics 2014-08-07 Peter Ruckdeschel , Matthias Kohl

Many signals on Cartesian product graphs appear in the real world, such as digital images, sensor observation time series, and movie ratings on Netflix. These signals are "multi-dimensional" and have directional characteristics along each…

Methodology · Statistics 2017-12-22 Takashi Kurokawa , Taihei Oki , Hiromichi Nagao

With the help of a simple model, we analyze Scanning Tunneling Microscopy images of simple and double moir\'e patterns resulting from misoriented bi- and tri-layers graphene stacks. It is found that the model reproduces surprisingly well…

Mesoscale and Nanoscale Physics · Physics 2014-09-11 Frédéric Joucken , Fernande Frising , Robert Sporken

We solve the problem of Fourier transformation for the one-dimensional $q$-deformed Heisenberg algebra. Starting from a matrix representation of this algebra we observe that momentum and position are unbounded operators in the Hilbert…

High Energy Physics - Theory · Physics 2008-02-03 J. Schwenk

Ptychography is a popular imaging technique that combines diffractive imaging with scanning microscopy. The technique consists of a coherent beam that is scanned across an object in a series of overlapping positions, leading to reliable and…

Numerical Analysis · Mathematics 2024-08-08 Ricardo Parada , Samy Wu Fung , Stanley Osher

Time independent convolution yields circulant matrices whose eigenvectors are the Fourier exponentials with the eigenvalues being the Fourier transform of the mask. The case of time dependent convolution, the non-stationary case, no longer…

General Mathematics · Mathematics 2025-03-18 Peter Zizler

The search for a canonical set of eigenvectors of the discrete Fourier transform has been ongoing for more than three decades. The goal is to find an orthogonal basis of eigenvectors which would approximate Hermite functions -- the…

Classical Analysis and ODEs · Mathematics 2015-02-02 Alexey Kuznetsov

In the article, we discuss the architecture of the polynomial neural network that corresponds to the matrix representation of Lie transform. The matrix form of Lie transform is an approximation of the general solution of the nonlinear…

Neural and Evolutionary Computing · Computer Science 2019-08-19 Andrei Ivanov , Alena Sholokhova , Sergei Andrianov , Roman Konoplev-Esgenburg

This paper presents a systematic methodology based on the algebraic theory of signal processing to classify and derive fast algorithms for linear transforms. Instead of manipulating the entries of transform matrices, our approach derives…

Information Theory · Computer Science 2020-01-29 Markus Pueschel , Jose M. F. Moura