The Expected Number of 3D Visibility Events Is Linear

Autor: Xavier Goaoc, Sylvain Petitjean, Vida Dujmović, Hazel Everett, Hyeon-Suk Na, Sylvain Lazard, Olivier Devillers
Přispěvatelé: Geometry, Algorithms and Robotics (PRISME), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), School of computer science [Ottawa] (SCS), Carleton University, Models, algorithms and geometry for computer graphics and vision (ISA), INRIA Lorraine, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université Henri Poincaré - Nancy 1 (UHP)-Université Nancy 2-Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS)-Université Henri Poincaré - Nancy 1 (UHP)-Université Nancy 2-Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS), School of Computing - Soongsil University, Séoul, Soongsil University, Seoul
Rok vydání: 2003
Předmět:
Zdroj: SIAM Journal on Computing
SIAM Journal on Computing, Society for Industrial and Applied Mathematics, 2003, 32 (6), pp.1586-1620. ⟨10.1137/S0097539702419662⟩
SIAM Journal on Computing, 2003, 32 (6), pp.1586-1620. ⟨10.1137/S0097539702419662⟩
ISSN: 1095-7111
0097-5397
DOI: 10.1137/s0097539702419662
Popis: In this paper, we show that, amongst $n$ uniformly distributed unit balls in $\mathbb{R}^3$, the expected number of maximal nonoccluded line segments tangent to four balls is linear. Using our techniques we show a linear bound on the expected size of the visibility complex, a data structure encoding the visibility information of a scene, providing evidence that the storage requirement for this data structure is not necessarily prohibitive. These results significantly improve the best previously known bounds of $O(n^{8/3})$ [F. Durand, G. Drettakis, and C. Puech, {ACM Transactions on Graphics}, 21 (2002), pp. 176--206]. Our results generalize in various directions. We show that the linear bound on the expected number of maximal nonoccluded line segments that are not too close to the boundary of the scene and tangent to four unit balls extends to balls of various but bounded radii, to polyhedra of bounded aspect ratio, and even to nonfat three-dimensional objects such as polygons of bounded aspect ratio. We also prove that our results extend to other distributions such as the Poisson distribution. Finally, we indicate how our probabilistic analysis provides new insight on the expected size of other global visibility data structures, notably the aspect graph.
Databáze: OpenAIRE