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We describe a polynomial time algorithm that takes as input a polygon with axis-parallel sides but irrational vertex coordinates, and outputs a set of as few rectangles as possible into which it can be dissected by axis-parallel cuts and…

Computational Geometry · Computer Science 2025-01-08 David Eppstein

We consider drawings of trees in which all edges incident to leaves can be extended to infinite rays without crossing, partitioning the plane into infinite convex polygons. Among all such drawings we seek the one maximizing the angular…

Computational Geometry · Computer Science 2007-05-23 Josiah Carlson , David Eppstein

This paper presents Polylidar, an efficient algorithm to extract non-convex polygons from 2D point sets, including interior holes. Plane segmented point clouds can be input into Polylidar to extract their polygonal counterpart, thereby…

Computational Geometry · Computer Science 2020-07-24 Jeremy Castagno , Ella Atkins

We consider a natural variation of the concept of stabbing a segment by a simple polygon: a segment is stabbed by a simple polygon $\mathcal{P}$ if at least one of its two endpoints is contained in $\mathcal{P}$. A segment set $S$ is…

Computational Complexity · Computer Science 2014-06-23 José Miguel Díaz-Báñez , Matias Korman , Pablo Pérez-Lantero , Alexander Pilz , Carlos Seara , Rodrigo I. Silveira

We introduce series-triangular graph embeddings and show how to partition point sets with them. This result is then used to improve the upper bound on the number of Steiner points needed to obtain compatible triangulations of point sets.…

Computational Geometry · Computer Science 2007-05-23 Jeff Danciger , Satyan L. Devadoss , Don Sheehy

Motivated by indoor localization by tripwire lasers, we study the problem of cutting a polygon into small-size pieces, using the chords of the polygon. Several versions are considered, depending on the definition of the "size" of a piece.…

Computational Geometry · Computer Science 2020-06-29 Esther M. Arkin , Rathish Das , Jie Gao , Mayank Goswami , Joseph S. B. Mitchell , Valentin Polishchuk , Csaba D. Toth

In general dimension, there is no known total polynomial algorithm for either convex hull or vertex enumeration, i.e. an algorithm whose complexity depends polynomially on the input and output sizes. It is thus important to identify…

Computational Geometry · Computer Science 2021-04-26 Ioannis Z. Emiris , Vissarion Fisikopoulos , Bernd Gärtner

In this paper, we establish two necessary conditions for a joint triangulation of two sets of $n$ points in the plane and conjecture that they are sufficient. We show that these necessary conditions can be tested in $O(n^3)$ time. For the…

Discrete Mathematics · Computer Science 2011-02-08 Ajit Arvind Diwan , Subir Kumar Ghosh , Partha Pratim Goswami , Andrzej Lingas

We prove that almost every triangle can be dissected only into $n^2$ triangles which have to be equal one another. Moreover, such a dissection is unique for every $n$. It turns out that to solve this "simple" problem it is convenient to use…

Metric Geometry · Mathematics 2021-02-23 Andrey Ryabichev

We describe an algorithm for computing the separating common tangents of two simple polygons using linear time and only constant workspace. A tangent of a polygon is a line touching the polygon such that all of the polygon lies to the same…

Computational Geometry · Computer Science 2015-11-13 Mikkel Abrahamsen

We present a new and simple randomized algorithm for constructing the Delaunay triangulation using nearest neighbor graphs for point location. Under suitable assumptions, it runs in linear expected time for points in the plane with…

Computational Geometry · Computer Science 2009-12-13 Kevin Buchin

This paper introduces a Delaunay triangulation algorithm based on the external incremental method. Unlike traditional random incremental methods, this approach uses convex hull and points as basic operational units instead of triangles.…

Computational Geometry · Computer Science 2025-03-20 Yifeng Cai

We study the problem of partitioning a polygon into the minimum number of subpolygons using cuts in predetermined directions such that each resulting subpolygon satisfies a given width constraint. A polygon satisfies the unit-width…

Computational Geometry · Computer Science 2025-09-15 Jaehoon Chung , Kazuo Iwama , Chung-Shou Liao , Hee-Kap Ahn

This paper uses mathematics to analyze the challenges of geometrically noisy environments on triangulation. Given widely accepted algorithmic triangulation methods, such as O (n ln n) or a simpler O (n^3) method, we can mathematically prove…

Computational Geometry · Computer Science 2023-11-21 Noah M. Kenney

Tightness is a generalisation of the notion of convexity: a space is tight if and only if it is "as convex as possible", given its topological constraints. For a simplicial complex, deciding tightness has a straightforward exponential time…

Computational Geometry · Computer Science 2018-10-24 Bhaskar Bagchi , Benjamin A. Burton , Basudeb Datta , Nitin Singh , Jonathan Spreer

More than 25 years ago Chazelle~\emph{et al.} (FOCS 1991) studied the following question: Is it possible to cut any set of $n$ lines in ${\Bbb R}^3$ into a subquadratic number of fragments such that the resulting fragments admit a depth…

Computational Geometry · Computer Science 2017-04-07 Mark de Berg

We show that Delaunay triangulations and compressed quadtrees are equivalent structures. More precisely, we give two algorithms: the first computes a compressed quadtree for a planar point set, given the Delaunay triangulation; the second…

Computational Geometry · Computer Science 2012-08-27 Maarten Löffler , Wolfgang Mulzer

Ear recognition task is known as predicting whether two ear images belong to the same person or not. In this paper, we present a novel metric learning method for ear recognition. This method is formulated as a pairwise constrained…

Computer Vision and Pattern Recognition · Computer Science 2018-03-28 Ibrahim Omara , Hongzhi Zhang , Faqiang Wang , Wangmeng Zuo

Cochlear implantation is currently the most effective treatment for patients with severe deafness, but mastering cochlear implantation is extremely challenging because the temporal bone has extremely complex and small three-dimensional…

Image and Video Processing · Electrical Eng. & Systems 2022-11-15 Xin Hua , Zhijiang Du , Hongjian Yu , Jixin Ma , Fanjun Zheng , Cheng Zhang , Qiaohui Lu , Hui Zhao

We prove that every 2-dimensional polygonal complex, where each polygon is given a constant curvature metric and belongs to one of finitely many isometry classes can be triangulated using only acute simplices. There is no requirement on the…

Computational Geometry · Computer Science 2022-10-18 Florestan Brunck