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| Content Provider | ACM Digital Library |
|---|---|
| Author | Baltsan, A Sharir, A |
| Abstract | We consider the problem of computing the Euclidean shortest path between two points in three-dimensional space which must avoid the interiors of k given disjoint convex polyhedral obstacles, having altogether n faces. Although this problem is hard to solve when k is arbitrarily large, it had been efficiently solved by Mount [Mo84] (cf. also Sharir and Schorr [SS84]) for k = 1, i.e. in the presence of a single convex polyhedral obstacle, in time &Ogr;(n2log n). In this paper we consider the generalization of this technique to the cases k = 2 and k > 2. In the first part of this presentation we describe an algorithm which calculates shortest paths amidst two convex polyhedral obstacles in time &Ogr;(n3α(n)&Ogr;(α(n)7)log n), where α(n) is the functional inverse of Ackermann's function (and is thus extremely slowly growing). This result is achieved by constructing a new kind of Voronoi diagram, called peeper's Voronoi diagram, which is introduced and analyzed here. In the second part we show that shortest paths amidst k > 2 disjoint convex polyhedral obstacles can be calculated in time polynomial in the total number n of faces of these obstacles (but exponential in the number of obstacles). This is a consequence of the following result: Let K be a 3-D convex polyhedron having n vertices. Then the number of shortest-path edge sequences on K is polynomial in n (specifically &Ogr;(n7)), where a shortest-path edge sequence &xgr; is a sequence of edges of K for which there exist two points X, Y on the surface S of K such that &xgr; is the sequence of edges crossed by the shortest path from X to Y along S. |
| Starting Page | 193 |
| Ending Page | 206 |
| Page Count | 14 |
| File Format | |
| ISBN | 0897911946 |
| DOI | 10.1145/10515.10537 |
| Language | English |
| Publisher | Association for Computing Machinery (ACM) |
| Publisher Date | 1986-08-01 |
| Publisher Place | New York |
| Access Restriction | Subscribed |
| Content Type | Text |
| Resource Type | Article |
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