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Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering)  2007, Vol. 8 Issue (8): 1210-1217    DOI: 10.1631/jzus.2007.A1210
Information Science     
A new algorithm for computing the convex hull of a planar point set
LIU Guang-hui, CHEN Chuan-bo
College of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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Abstract  When the edges of a convex polygon are traversed along one direction, the interior of the convex polygon is always on the same side of the edges. Based on this characteristic of convex polygons, a new algorithm for computing the convex hull of a simple polygon is proposed in this paper, which is then extended to a new algorithm for computing the convex hull of a planar point set. First, the extreme points of the planar point set are found, and the subsets of point candidate for vertex of the convex hull between extreme points are obtained. Then, the ordered convex hull point sequences between extreme points are constructed separately and concatenated by removing redundant extreme points to get the convex hull. The time complexity of the new planar convex hull algorithm is O(nlogh), which is equal to the time complexity of the best output-sensitive planar convex hull algorithms. Compared with the algorithm having the same complexity, the new algorithm is much faster.

Key wordsComputational geometry      Convex hull      Extreme points      Ordered convex hull point sequence     
Received: 07 November 2006     
CLC:  TP391  
Cite this article:

LIU Guang-hui, CHEN Chuan-bo. A new algorithm for computing the convex hull of a planar point set. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2007, 8(8): 1210-1217.

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http://www.zjujournals.com/xueshu/zjus-a/10.1631/jzus.2007.A1210     OR     http://www.zjujournals.com/xueshu/zjus-a/Y2007/V8/I8/1210

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