曲面立体线图的补线技术研究

Labeling and Completing Imperfect Line Drawing of Curved Objects

文中根据已有的曲面立体自然线图的标记原理,得到了曲面立体画隐线图的标记原理和方法。曲面立体的不完整线图中的L型节点是曲面立体完整线图中W型节点的退化。基于曲面立体画出隐藏线的完整线图标记原理和方法,详细分析并建立了曲面立体不完整线图中L型节点与曲面立体完整线图中W型节点的对应关系。提出了曲面立体不完整线图的标记和补线方法,结合算例详细论述了曲面立体不完整线图的标记和补线过程,从曲面立体不完整线图获得了合理的曲面立体完整线图。

The problem for recovering 3D shape from imperfect line drawing of curved objects is addressed in this paper. In section 2, the curve-surface line labeling techniques of Chakravarty's labeling scheme is extended to include invisible line. All possible configurations of imperfect line drawings of curved objects are studied and it is found that there are L junctions in imperfect line drawings of curved objects. Therefore it is necessary to take a close look at the behaviors of L junctions in imperfect line drawing of curved objects. W and Y junctions in imperfect line drawings of curved objects are the same as they are in perfect line drawing of curved objects. L junctions, however, are different because they could be degenerated from W and Y junctions. By exhausting all possible cases, it is found that the maximum number of L junctions for imperfect line drawings of curved objects is 28, and the 28 L junctions and their corresponding W and Y junctions from which these L junctions are degenerated are illustrated, they are shown in Table 1.In section 3, the general procedure for labeling and completing an imperfect line drawing is given; also it is shown how to utilize the line labeling and junction labeling information to predict and recover the missing line.