Algorithm to expand regions represented by linear quadtrees
Algorithm to expand regions represented by linear quadtrees
复制标题
扩展线性四叉树表示的区域的算法
DOI：
10.1016/0262-8856(88)90022-4
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
H. Samet
中科院分区：
文献类型：
--
作者：
C. Shaffer;H. Samet
提出了一种算法，该算法将由线性四叉树表示的图像中的任何“黑色”像素的指定距离内的那些“白色”像素变为“黑色”。此功能对于回答地理信息系统中的查询非常有用，例如“查找洪泛平原五英里内的所有麦田”。该算法的工作原理是计算大的白色节点到附近黑色像素的棋盘距离，并根据需要将它们保留为白色，将它们变为黑色或在每个子象限上重复该过程。小的白色节点是给定半径内的先验节点，不需要进一步计算。因此，只有一小部分四叉树的节点需要大量的处理。该算法很容易适用于多色图像处理所有非白色的颜色为“黑色”。
An algorithm is presented that changes to ‘black’ those ‘white’ pixels within a specified distance of any ‘black’ pixel in an image represented by a linear quadtree. This function is useful for answering queries in a geographic information system such as ‘Find all wheat fields within five miles of a flood plain.’ The algorithm works by computing the chessboard distance to nearby black pixels for large white nodes, and either leaves them white, changes them to black or repeats the process on each subquadrant, as required. Small white nodes are a priori within the given radius and require no further calculation. Thus only a small percentage of the nodes of the quadtree need extensive processing. The algorithm is easily applied to multicoloured images by treating all nonwhite colours as ‘black’.