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The majority of document image analysis systems use a document skew detection algorithm to simplify all its further processing stages. A huge amount of such algorithms based on Hough transform (HT) analysis has already been proposed.…

Computer Vision and Pattern Recognition · Computer Science 2019-12-06 Pavel Bezmaternykh , Dmitry Nikolaev

The principle of translation equivariance (if an input image is translated an output image should be translated by the same amount), led to the development of convolutional neural networks that revolutionized machine vision. Other…

Computer Vision and Pattern Recognition · Computer Science 2025-05-29 Zachary Schlamowitz , Andrew Bennecke , Daniel J. Tward

We consider the linearized electrical impedance tomography problem in two dimensions on the unit disk. By a linearization around constant coefficients and using a trigonometric basis, we calculate the linearized Dirichlet-to-Neumann…

Numerical Analysis · Mathematics 2017-06-08 Stefan Kindermann

The discrete Hartley transform (DHT) is a useful tool for medical image coding. The three-dimensional DHT (3D DHT) can be employed to compress medical image data, such as magnetic resonance and X-ray angiography. However, the computation of…

Signal Processing · Electrical Eng. & Systems 2022-06-02 V. A. Coutinho , F. M. Bayer , R. J. Cintra

The polar coordinate transformation (PCT) method has been extensively used to treat various singular integrals in the boundary element method (BEM). However, the resultant integrands of the PCT tend to become nearly singular when (1) the…

Computational Engineering, Finance, and Science · Computer Science 2015-11-16 Junjie Rong , Lihua Wen , Jinyou Xiao

Simplified solutions of the Cox-Thompson inverse quantum scattering method at fixed energy are derived if a finite number of partial waves with only even or odd angular momenta contribute to the scattering process. Based on new formulae…

Mathematical Physics · Physics 2011-11-28 Tamas Palmai , Miklos Horvath , Barnabas Apagyi

We develop a new approach for estimating the expected values of nonlinear functions applied to multivariate random variables with arbitrary distributions. Rather than assuming a particular distribution, we assume that we are only given the…

Numerical Analysis · Mathematics 2020-06-25 Deanna Easley , Tyrus Berry

In this article we present an improved exact inversion formula for the 3D cone beam transform of vector fields. It is well known that only the solenoidal part of a vector field can be determined by the longitudinal ray transform of a vector…

Numerical Analysis · Mathematics 2016-03-10 Alexander Katsevich , Dimitri Rothermel , Thomas Schuster

This work derives an application from the identities of arXiv:hep-th/0602028 in order to invert four point functions in defect conformal field theories. For this, a recursion relation is established and the O(N) model with a line defect is…

High Energy Physics - Theory · Physics 2024-03-11 Georgios Sakkas

Approximate methods have been considered as a means to the evaluation of discrete transforms. In this work, we propose and analyze a class of integer transforms for the discrete Fourier, Hartley, and cosine transforms (DFT, DHT, and DCT),…

Signal Processing · Electrical Eng. & Systems 2020-07-07 R. J. Cintra

We present a new computed tomography (CT) method for inverting the Radon transform in 2D. The idea relies on the geometry of the flat torus, hence we call the new method Torus CT. We prove new inversion formulas for integrable functions,…

Functional Analysis · Mathematics 2020-10-23 Joonas Ilmavirta , Olli Koskela , Jesse Railo

We discuss efficient algorithms for the accurate forward and reverse evaluation of the discrete Fourier-Bessel transform (dFBT) as numerical tools to assist in the 2D polar convolution of two radially symmetric functions, relevant, e.g., to…

Computational Physics · Physics 2016-11-08 O. Melchert , M. Wollweber , B. Roth

The goal of this paper is to reconstruct spatially distributed dielectric constants from complex-valued scattered wave field by solving a 3D coefficient inverse problem for the Helmholtz equation at multi-frequencies. The data are generated…

Numerical Analysis · Mathematics 2016-12-14 Michael V. Klibanov , Dinh-Liem Nguyen , Loc H. Nguyen , Hui Liu

This article pursues a statistical study of the Hough transform, the celebrated computer vision algorithm used to detect the presence of lines in a noisy image. We first study asymptotic properties of the Hough transform estimator, whose…

Statistics Theory · Mathematics 2007-06-13 Alexander Goldenshluger , Assaf Zeevi

This paper proposes using sketch algorithms to represent the votes in Hough transforms. Replacing the accumulator array with a sketch (Sketch Hough Transform - SHT) significantly reduces the memory needed to compute a Hough transform. We…

Computer Vision and Pattern Recognition · Computer Science 2018-11-16 Levi Offen , Michael Werman

Single photons provide excellent quantum information carriers, but current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed single photons, while…

Quantum Physics · Physics 2012-02-07 N. K. Langford , S. Ramelow , R. Prevedel , W. J. Munro , G. J. Milburn , A. Zeilinger

Single-photon subtraction plays important roles in optical quantum information processing as it provides a non-Gaussian characteristic in continuous-variable quantum information. While the conventional way of implementing single-photon…

Quantum Physics · Physics 2017-07-21 Young-Sik Ra , Clément Jacquard , Adrien Dufour , Claude Fabre , Nicolas Treps

Recently, experiments have been reported where researchers were able to perform high dynamic range (HDR) tomography in a heuristic fashion, by fusing multiple tomographic projections. This approach to HDR tomography has been inspired by HDR…

Information Theory · Computer Science 2021-05-11 Matthias Beckmann , Ayush Bhandari , Felix Krahmer

The discrete cosine transform (DCT) is a central tool for image and video coding because it can be related to the Karhunen-Lo\`eve transform (KLT), which is the optimal transform in terms of retained transform coefficients and data…

Image and Video Processing · Electrical Eng. & Systems 2026-01-28 A. P. Radünz , L. Portella , R. S. Oliveira , F. M. Bayer , R. J. Cintra

Few of the known quantum algorithms can be reliably executed on a quantum computer. Therefore, as an extension, we propose a Parallel Quantum Hough transform (PQHT) algorithm that we execute on a quantum computer. We give its implementation…

Image and Video Processing · Electrical Eng. & Systems 2023-11-21 Frank Klefenz , Nico Wittrock , Frank Feldhoff