摘要
研究标记符合人们画图习惯的立体线图。建立了一种新的标记方法 ,给出了立体线图标记规则。立体线图中的节点是由三面角构成的顶点的投影。对画出隐藏线的立体线图 ,合法的节点标记形式有 2 4种 ,对没有画出隐藏线的立体线图 ,Huffman和 Clowes的 1 2种合法节点形式是新的2 4种合法节点形式的特殊情况。新的标记方法对平面立体、曲面立体以及由平面立体和曲面立体组合而成的复杂立体的投影线图都是适用的。
Although line drawings consist of only line segments on a plane, they convey much information about the three-dimensional object structures. For a computer interpreting line drawings, some intelligent mechanism is required to extract three-dimensional information from the two-dimensional line drawings. In this paper, a new labeling theory and method are proposed for the two-dimensional line drawing of a three-dimensional object with trihedral vertices. Three rules for labeling a line drawing are established in section 1. There are 24 kinds of possible junctions for hidden-part-draw natural line drawings, in which there are 6 possible Y-junctions and 18 possible W-junctions. The labeling theory of Huffman-Clowes is the special case of our new labeling theory for hidden-part-eliminated natural line drawings. Our labeling theory and method can discriminate between correct and incorrect hidden-part-draw natural line drawings. The hidden-part-draw natural line drawings can be labeled correctly by our labeling theory and method, whereas the labeling theory of Sugihara can only label the hidden-part-draw unnatural line drawings in which some visible lines must be drawn as hidden lines, and some invisible lines must be drawn as continuous lines. Our labeling theory and method are efficient for the line drawings of polyhedrons and objects with curved surfaces.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2002年第4期677-679,共3页
Journal of Northwestern Polytechnical University
