Delaunay triangulation

About: Delaunay triangulation is a research topic. Over the lifetime, 5816 publications have been published within this topic receiving 126615 citations. The topic is also known as: Delone triangulation.

Delaunay graphs of point sets in the plane with respect to axis-parallel rectangles

Abstract: Given a point set P in the plane, the Delaunay graph with respect to axis-parallel rectangles is a graph defined on the vertex set P, whose two points p,q ∈ P are connected by an edge if and only if there is a rectangle parallel to the coordinate axes that contains p and q, but no other elements of P. The following question of Even et al. [ELRS03] was motivated by a frequency assignment problem in cellular telephone networks. Does there exist a constant c > 0 such that the Delaunay graph of any set of n points in general position in the plane contains an independent set of size at least cn? We answer this question in the negative, by proving that the largest independent set in a randomly and uniformly selected point set in the unit square is O(n log2 log n/log n), with probability tending to 1. We also show that our bound is not far from optimal, as the Delaunay graph of a uniform random set of n points almost surely has an independent set of size at least cn/ log n. We give two further applications of our methods. 1. We construct 2-dimensional n-element partially ordered sets such that the size of the largest independent sets of vertices in their Hasse diagrams is o(n). This answers a question of Matousek and Přivětivý [MaP06] and improves a result of Křiž and Nesetřil [KrN91]. 2. For any positive integers c and d, we prove the existence of a planar point set with the property that no matter how we color its elements by c colors, we find an axis-parallel rectangle containing at least d points, all of which have the same color. This solves an old problem from [BrMP05].

Surface reconstruction using umbrella filters

Abstract: We present a new approach to surface reconstruction in arbitrary dimensions based on the Delaunay complex. Basically, our algorithm picks locally a surface at each vertex. In the case of two dimensions we prove that this method gives indeed a reconstruction scheme. In three dimensions we show that for smooth regions of the surface this method works well and at difficult parts of the surface yields an output well-suited for postprocessing. As a postprocessing step we propose a topological clean up and a new technique based on linear programming in order to establish a topologically correct surface. These techniques should be useful also for many other reconstruction algorithms.

An upper bound for conforming Delaunay triangulations

Abstract: A plane geometric graph C in R2conforms to another such graph G if each edge of G is the union of some edges of C. It is proved that for every G with n vertices and m edges, there is a completion of a Delaunay triangulation of O(m2n) points that conforms to G. The algorithm that constructs the points is also described.

Computing two-dimensional Delaunay triangulation using graphics hardware

Abstract: This paper presents a novel approach to compute, for a given point set S in R2, its Delaunay triangulation T (S). Though prior work mentions the possibility of using the graphics processing unit (GPU) to compute Delaunay triangulations, no known implementation and performance have been reported. Our work uncovers various challenges in the use of GPU for such a purpose. In practice, our approach exploits the GPU to assist in the computation of a triangulation T of S that is a good approximation to T (S). From that, the approach employs the CPU to transform T ' to T (S). As a major part of the total work is done by the GPU with parallel computing capability, it is a fast and practical approach, particularly for a large number of points (millions with the current state-of-the-art GPU). For such cases, our current implementation can run up to 53% faster on a Core2 Duo machine when compared to Triangle, the well-known fastest Delaunay triangulation implementation.