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Connecting cosmological simulations to real-world observational programs is often complicated by a mismatch in geometry: while surveys often cover highly irregular cosmological volumes, simulations are customarily performed in a periodic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Jordan Carlson , Martin White

In binary images, the distance transformation (DT) and the geometrical skeleton extraction are classic tools for shape analysis. In this paper, we present time optimal algorithms to solve the reverse Euclidean distance transformation and…

Computational Geometry · Computer Science 2007-05-24 David Coeurjolly , Annick Montanvert

For augmentation of the square-shaped image data of a convolutional neural network (CNN), we introduce a new method, in which the original images are mapped onto a disk with a conformal mapping, rotated around the center of this disk and…

Computer Vision and Pattern Recognition · Computer Science 2023-11-22 Oona Rainio , Mohamed M. S. Nasser , Matti Vuorinen , Riku Klén

The formula for the area of a rhumb polygon, a polygon whose edges are rhumb lines on an ellipsoid of revolution, is derived and a method is given for computing the area accurately. This paper also points out that standard methods for…

Geophysics · Physics 2024-10-24 Charles F. F. Karney

We consider the problem of checking whether an elliptic curve defined over a given number field has complex multiplication. We study two polynomial time algorithms for this problem, one randomized and the other deterministic. The randomized…

Number Theory · Mathematics 2007-05-23 Denis Charles

This paper aims to develop the mathematical representation of a surface generated by elliptical arcs joining the sides of a regular polygon to a point lying vertically upward on the central axis of the polygon. The volume of the…

History and Overview · Mathematics 2020-09-02 Shahid Saeed Siddiqi , Abdul Rauf Nizami

We begin by studying the surface area of an ellipsoid in n-dimensional Euclidean space as the function of the lengths of the semi-axes. We write down an explicit formula as an integral over the unit sphere in n-dimensions and use this…

Metric Geometry · Mathematics 2007-05-23 Igor Rivin

We write down estimates for the surface area, and more generally, integral mean curvatures of an ellipsoid E in n-dimensional Euclidean space in terms of the lengths of the major semi-axes. We give applications to estimating the area of…

Metric Geometry · Mathematics 2007-05-23 Igor Rivin

We introduce a fixed point iteration process built on optimization of a linear function over a compact domain. We prove the process always converges to a fixed point and explore the set of fixed points in various convex sets. In particular,…

Optimization and Control · Mathematics 2021-03-18 Pedro Felzenszwalb , Caroline Klivans , Alice Paul

The Integral Image algorithm is often applied in tasks that require efficient integration over images, such as object detection. In this paper we discuss theoretical aspects of the algorithm's continuous version. We suggest to define the…

Discrete Mathematics · Computer Science 2015-03-17 Amir Shachar

This article aims to provide a brief overview of both established and novel ellipsometry techniques, as well as their applications. Ellipsometry is an indirect optical technique in that information about the physical properties of a sample…

The efficient realization of linear space-variant (non-convolution) filters is a challenging computational problem in image processing. In this paper, we demonstrate that it is possible to filter an image with a Gaussian-like elliptic…

Computer Vision and Pattern Recognition · Computer Science 2016-11-17 Kunal Narayan Chaudhury , Arrate Munoz-Barrutia , Michael Unser

We introduce several possible generalizations of tomography for quadratic surfaces. We analyze different types of elliptic, hyperbolic and hybrid tomograms. In all cases it is possible to consistently define the inverse tomographic map. We…

Mathematical Physics · Physics 2009-11-13 M. Asorey , P. Facchi , V. I. Man'ko , G. Marmo , S. Pascazio , E. C. G. Sudarshan

A procedure to obtain differentiation matrices is extended straightforwardly to yield new differentiation matrices useful to obtain derivatives of complex rational functions. Such matrices can be used to obtain numerical solutions of some…

Numerical Analysis · Mathematics 2007-05-23 Rafael G. Campos , Claudio Meneses

In this note, we will consider two classical volume problems related to elliptic integrals. The first problem has a neat formula by means of elliptic integrals. We remade it with details. In the second problem, we found a messy formula. On…

General Mathematics · Mathematics 2021-07-16 Mehmet Kirdar

An accurate method for warping images is presented. Differently from most commonly used techniques, this method guarantees the conservation of the intensity of the transformed image, evaluated as the sum of its pixel values over the whole…

Computer Vision and Pattern Recognition · Computer Science 2022-10-12 Enrico Segre

In this article, we analyse the domain mapping method approach to approximate statistical moments of solutions to linear elliptic partial differential equations posed over random geometries including smooth surfaces and bulk-surface…

Numerical Analysis · Mathematics 2019-03-18 Lewis Church , Ana Djurdjevac , Charles M. Elliott

This paper presents an efficient reversible algorithm for linear regression, both with and without ridge regression. Our reversible algorithm matches the asymptotic time and space complexity of standard irreversible algorithms for this…

Data Structures and Algorithms · Computer Science 2021-12-01 Erik D. Demaine , Jayson Lynch , Jiaying Sun

This paper describes a 2-D graphics algorithm that uses shifts and adds to precisely plot a series of points on an ellipse of any shape and orientation. The algorithm can also plot an elliptic arc that starts and ends at arbitrary angles.…

Graphics · Computer Science 2021-06-14 Jerry R. Van Aken

Multidimensional imaging, capturing image data in more than two dimensions, has been an emerging field with diverse applications. Due to the limitation of two-dimensional detectors in obtaining the high-dimensional image data, computational…

Image and Video Processing · Electrical Eng. & Systems 2020-06-16 Didem Dogan , Figen S. Oktem