Labeling And Adding Imperfect Line Drawing With Hidden-Part-Draw For Curved Surface Objects

A line drawing is the two-dimensional representation of a three-dimensional object. Line drawing plays an important role on exchanging information between man and man or man and computer. That is effortless for human to understand the projections of three-dimensional objects and scene, but not for computer. Investigating its reason, nothing but one is human have wide experience in distinguishing and judgment of constraint like parallel, vertical, intersection, angle, length and so on. It is impossible for computer to understand the projections with so little information about point and line. Therefore, in order to make computer understand the projections and then reason out the corresponding three-dimensional objects, some regulations and reasoning mechanisms must be laid down. It is a very important issue for computer to interprets the projections automatically in the field of computer vision and computer aided design.The research achievement of Computer interprets the Line drawing can be used in computer vision system, reverse engineering, the Internet and people-machine communication interface of the CAD system, shorten graph input time and alleviate people’s workload in people-machine communication.Line drawing labeling plays an important role in the three-dimensional line drawing interpretation as an effective assistant method. Line drawing labeling can eliminate some impossible object structure, and forecast the real three-dimensional object, thus reduced the work load about three-dimensional object’s quantitative analysis. The line drawings which the designer draws possibly are inaccurate or has mistakes, and as a result of many kinds of reasons just like texture, noise and light etc., the line drawing generally cannot be extracted accurately from the image. So carrying on the analysis and processing of the line drawing is of great importance.Based on line drawing labeling theory and rules and relevant basic assumptions,24kinds of junctions in line drawing are introduced in this paper, the corresponding relations between36kinds of L junctions and8kinds of dangling lines with24kinds of legitimate W and Y junctions were given. And the labeling and adding method about imperfect Line drawing with hidden-part-draw is introduced.Further research about imperfect Line drawing with hidden-part-draw is given at last. The corresponding relations between L junctions and dangling lines with legitimate Y and W junctions were given. Based on this theory, the methods about how to manage the imperfect Line drawing with hidden-part-draw are listed in this paper. A detailed discussion on the process of line drawing labeling and adding is given with examples. Finally, the imperfect line drawing is transformed into a proper line drawing.