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Let $P$ be a set of $n$ points in $\mathbb{R}^3$ in general position, and let $RCH(P)$ be the rectilinear convex hull of $P$. In this paper we obtain an optimal $O(n\log n)$-time and $O(n)$-space algorithm to compute $RCH(P)$. We also…

Computational Geometry · Computer Science 2022-09-14 Pablo Pérez-Lantero , Carlos Seara , Jorge Urrutia

We describe convex hulls of the simplest compact space curves, reducible quartics consisting of two circles. When the circles do not meet in complex projective space, their algebraic boundary contains an irrational ruled surface of degree…

Algebraic Geometry · Mathematics 2017-01-24 Evan D. Nash , Ata Firat Pir , Frank Sottile , Li Ying

Using Quadrics as the object representation has the benefits of both generality and closed-form projection derivation between image and world spaces. Although numerous constraints have been proposed for dual quadric reconstruction, we found…

Computer Vision and Pattern Recognition · Computer Science 2025-03-04 Xiaolong Yu , Junqiao Zhao , Shuangfu Song , Zhongyang Zhu , Zihan Yuan , Chen Ye , Tiantian Feng

Inspired by the classical fractional cascading technique, we introduce new techniques to speed up the following type of iterated search in 3D: The input is a graph $\mathbf{G}$ with bounded degree together with a set $H_v$ of 3D hyperplanes…

Computational Geometry · Computer Science 2025-04-11 Peyman Afshani , Yakov Nekrich , Frank Staals

Recently, Convolutional Neural Networks have shown promising results for 3D geometry prediction. They can make predictions from very little input data such as a single color image. A major limitation of such approaches is that they only…

Computer Vision and Pattern Recognition · Computer Science 2017-11-08 Christian Häne , Shubham Tulsiani , Jitendra Malik

Computing the convex hull of a planar $n$-point set $P$ is one of the most fundamental problems in computational geometry. It has an $\Omega(n \log n)$ lower bound in the algebraic computation tree model, and many convex hull algorithms…

We present a mathematical and algorithmic scheme for learning the principal geometric elements in an image or 3D object. We build on recent work that convexifies the basic problem of finding a combination of a small number shapes that…

Computer Vision and Pattern Recognition · Computer Science 2016-07-05 Alireza Aghasi , Justin Romberg

We present a new fully dynamic algorithm for maintaining convex hulls under insertions and deletions while supporting geometric queries. Our approach combines the logarithmic method with a deletion-only convex hull data structure, achieving…

Computational Geometry · Computer Science 2026-04-02 Ivor van der Hoog , Henrik Reinstädtler , Eva Rotenberg

Convex hulls are a fundamental geometric tool used in a number of algorithms. A famous paper by Akl and Toussaint in 1978 described a way to reduce the number of points involved in the computation, which is since known as the Akl-Toussaint…

Computational Geometry · Computer Science 2013-04-10 Jean Souviron

Finding the coordinate-wise maxima and the convex hull of a planar point set are probably the most classic problems in computational geometry. We consider these problems in the self-improving setting. Here, we have $n$ distributions…

Computational Geometry · Computer Science 2014-04-29 Kenneth L. Clarkson , Wolfgang Mulzer , C. Seshadhri

We propose a cut-based algorithm for finding all vertices and all facets of the convex hull of all integer points of a polyhedron defined by a system of linear inequalities. Our algorithm DDM Cuts is based on the Gomory cuts and the dynamic…

Combinatorics · Mathematics 2020-10-27 S. O. Semenov , N. Yu. Zolotykh

3D printing of surfaces has become an established method for prototyping and visualisation. However, surfaces often contain certain degenerations, such as self-intersecting faces or non-manifold parts, which pose problems in obtaining a 3D…

Computational Geometry · Computer Science 2024-05-28 Christian Amend , Tom Goertzen

We present a novel GPU-accelerated implementation of the QuickHull algorihtm for calculating convex hulls of planar point sets. We also describe a practical solution to demonstrate how to efficiently implement a typical Divide-and-Conquer…

Computational Geometry · Computer Science 2018-05-21 Jiayin Zhang , Gang Mei , Nengxiong Xu , Kunyang Zhao

A common representation of a three dimensional object in computer applications, such as graphics and design, is in the form of a triangular mesh. In many instances, individual or groups of triangles in such representation need to satisfy…

Optimization and Control · Mathematics 2019-04-08 Valentin R. Koch , Hung M. Phan

A quadratically constrained quadratic program (QCQP) is an optimization problem in which the objective function is a quadratic function and the feasible region is defined by quadratic constraints. Solving non-convex QCQP to global…

Optimization and Control · Mathematics 2018-12-27 Asteroide Santana , Santanu S. Dey

We study the convex hulls of trajectories of polynomial dynamical systems. Such trajectories include real algebraic curves. The boundaries of the resulting convex bodies are stratified into families of faces. We present numerical algorithms…

Dynamical Systems · Mathematics 2024-01-26 Daniel Ciripoi , Nidhi Kaihnsa , Andreas Löhne , Bernd Sturmfels

Segmentation of overlapping convex objects has various applications, for example, in nanoparticles and cell imaging. Often the segmentation method has to rely purely on edges between the background and foreground making the analyzed images…

Computer Vision and Pattern Recognition · Computer Science 2019-06-05 Sahar Zafari , Mariia Murashkina , Tuomas Eerola , Jouni Sampo , Heikki Kälviäinen , Heikki Haario

This work proposes a new formulation to the long-standing problem of convex decomposition through learning feature fields, enabling the first feed-forward model for open-world convex decomposition. Our method produces high-quality…

Computer Vision and Pattern Recognition · Computer Science 2026-03-11 Yuezhi Yang , Qixing Huang , Mikaela Angelina Uy , Nicholas Sharp

Given a set of $n$ points $P$ in the plane, the first layer $L_1$ of $P$ is formed by the points that appear on $P$'s convex hull. In general, a point belongs to layer $L_i$, if it lies on the convex hull of the set $P \setminus…

Computational Geometry · Computer Science 2017-03-17 Raimi A. Rufai , Dana S. Richards

We present a novel 2D convex hull peeling algorithm for outlier detection, which repeatedly removes the point on the hull that decreases the hull's area the most. To find k outliers among n points, one simply peels k points. The algorithm…

Computational Geometry · Computer Science 2025-09-29 Vinesh Sridhar , Rolf Svenning