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This paper introduces invariant transforms that preserve the ratio of either two or three co-linear points in the Desargues affine plane skew field. The results given here have a clean, geometric presentation based based Desargues affine…

General Mathematics · Mathematics 2025-10-22 Orgest Zaka , James F. Peters

The Delaunay triangulation (DT) is one of the most common and useful triangulations of point sets $P$ in the plane. DT is not unique when $P$ is degenerate, specifically when it contains quadruples of co-circular points. One way to achieve…

Computational Geometry · Computer Science 2015-10-16 Michael Khanimov , Micha Sharir

We introduce an (equi-)affine invariant diffusion geometry by which surfaces that go through squeeze and shear transformations can still be properly analyzed. The definition of an affine invariant metric enables us to construct an invariant…

Computer Vision and Pattern Recognition · Computer Science 2010-12-30 Dan Raviv , Alexander M. Bronstein , Michael M. Bronstein , Ron Kimmel , Nir Sochen

In this paper, we develop new affine-invariant algorithms for solving composite convex minimization problems with bounded domain. We present a general framework of Contracting-Point methods, which solve at each iteration an auxiliary…

Optimization and Control · Mathematics 2020-09-21 Nikita Doikov , Yurii Nesterov

Delaunay flip is an elegant, simple tool to convert a triangulation of a point set to its Delaunay triangulation. The technique has been researched extensively for full dimensional triangulations of point sets. However, an important case of…

Computational Geometry · Computer Science 2007-12-13 Siu-Wing Cheng , Tamal K. Dey

An extension of the restricted Delaunay-refinement algorithm for surface mesh generation is described, where a new point-placement scheme is introduced to improve element quality in the presence of mesh size constraints. Specifically, it is…

Computational Geometry · Computer Science 2016-06-28 Darren Engwirda , David Ivers

We investigate algorithms with predictions in computational geometry, specifically focusing on the basic problem of computing 2D Delaunay triangulations. Given a set $P$ of $n$ points in the plane and a triangulation $G$ that serves as a…

Computational Geometry · Computer Science 2026-01-14 Sergio Cabello , Timothy M. Chan , Panos Giannopoulos

This paper introduces advances in the geometry of the transforms for cross ratio of four points in a line in the Desargues affine plane. The results given here have a clean, based Desargues affine plan axiomatic's and definitions of…

General Mathematics · Mathematics 2025-04-11 Orgest Zaka , James F. Peters

Via circle pattern techniques, random planar triangulations (with angle variables) are mapped onto Delaunay triangulations in the complex plane. The uniform measure on triangulations is mapped onto a conformally invariant spatial point…

Mathematical Physics · Physics 2013-12-23 Francois David , Bertrand Eynard

Natural objects can be subject to various transformations yet still preserve properties that we refer to as invariants. Here, we use definitions of affine invariant arclength for surfaces in R^3 in order to extend the set of existing…

Computer Vision and Pattern Recognition · Computer Science 2010-12-30 Dan Raviv , Alexander M. Bronstein , Michael M. Bronstein , Ron Kimmel , Nir Sochen

An affine invariant point on the class of convex bodies in R^n, endowed with the Hausdorff metric, is a continuous map p which is invariant under one-to-one affine transformations A on R^n, that is, p(A(K))=A(p(K)). We define here the new…

Functional Analysis · Mathematics 2013-10-02 Mathieu Meyer , Carsten Schuett , Elisabeth M. Werner

We consider the problem of maintaining the Euclidean Delaunay triangulation $\DT$ of a set $P$ of $n$ moving points in the plane, along algebraic trajectories of constant description complexity. Since the best known upper bound on the…

Computational Geometry · Computer Science 2015-03-19 Pankaj K. Agarwal , Jie Gao , Leonidas J. Guibas , Haim Kaplan , Vladlen Koltun , Natan Rubin , Micha Sharir

Dense random sampling and surfacing of shapes encoded via implicit occupancy functions (OFs) are critical elements of many applications. Existing methods largely provide either one or the other of random sampling or mesh surfaces: ray…

Graphics · Computer Science 2026-05-06 Suzuran Takikawa , Leo Foord-Kelcey , Oliver Oxford , Nicholas Vining , Alla Sheffer

It is important that a spatial network's construction algorithm reproduces the structural properties of the original physical embedding. Here, we assess the Delaunay triangulation as a spatial network construction algorithm for seven…

Statistical Mechanics · Physics 2025-04-02 Eli Newby , Wenlong Shi , Yang Jiao , Salvatore Torquato , Réka Albert

In this paper, we present a novel affine-invariant feature based on SIFT, leveraging the regular appearance of man-made objects. The feature achieves full affine invariance without needing to simulate over affine parameter space. Low-rank…

Computer Vision and Pattern Recognition · Computer Science 2014-08-08 Chao Yang , Shengnan Caih , Jingdong Wang , Long Quan

Affine transformation is one of the most common transformations in nature, which is an important issue in the field of computer vision and shape analysis. And affine transformations often occur in both shape and color space simultaneously,…

Computer Vision and Pattern Recognition · Computer Science 2019-11-20 You Hao , Hanlin Mo , Qi Li , He Zhang , Hua Li

Two-dimensional Delaunay triangulation is a fundamental aspect of computational geometry. This paper presents a novel algorithm that is specifically designed to ensure the correctness of 2D Delaunay triangulation, namely the Polygonal…

Computational Geometry · Computer Science 2024-01-17 Sora Sawai , Kazuaki Tanaka , Katsuhisa Ozaki , Shin'ichi Oishi

Rotation-invariant recognition of shapes is a common challenge in computer vision. Recent approaches have significantly improved the accuracy of rotation-invariant recognition by encoding the rotational invariance of shapes as hand-crafted…

Computer Vision and Pattern Recognition · Computer Science 2025-03-17 Yanjie Xu , Handing Xu , Tianmu Wang , Yaguan Li , Yunzhi Chen , Zhenguo Nie

Let $P$ be a set of $n$ points in $\mathrm{R}^2$, and let $\mathrm{DT}(P)$ denote its Euclidean Delaunay triangulation. We introduce the notion of an edge of $\mathrm{DT}(P)$ being {\it stable}. Defined in terms of a parameter $\alpha>0$, a…

Computational Geometry · Computer Science 2015-04-28 Pankaj K. Agarwal , Jie Gao , Leonidas J. Guibas , Haim Kaplan , Natan Rubin , Micha Sharir

Image feature points are detected as pixels which locally maximize a detector function, two commonly used examples of which are the (Euclidean) image gradient and the Harris-Stephens corner detector. A major limitation of these feature…

Computer Vision and Pattern Recognition · Computer Science 2018-03-13 Stanley L. Tuznik , Peter J. Olver , Allen Tannenbaum
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