Vectorization Of Scanned Image Of Engineering Drawing

Engineering drawing vectorization technology, to convert scanned image of engineering drawing into graphics file, can not only reduce storage space radically, but also reuse existed paper flexibly and effectively. This technology is helpful to three-dimensional reconstruction and has important practical values. The primitive region based vectorization method describes the overall structure of an image by primitive regions, and the adjacency graph which is built by linking primitive regions with physical positions. The method supplies advanced hierarchy and macrostructure, with distinct advantages in noise-rejection capability and recognition velocity.A new graphics distilling method, i.e., the primitive region based synthetical growth vectorization method, is proposed in this thesis. Based on the predecessors’work, this new method is developed by the guidance of visual physiology and cognitive psychology. It makes seed primitive regions judge synthetically according to both adjacent graphics at a higher level and adjacent pixels at a lower level and select a good path to grow to distill integrated graphics (lines and arcs). In addition, another method of synthetical growth to distill dashed lines and dash dot lines in term of key characteristics of graphics is depicted.In the latter half, the 1st edition of Scanned Image of Engineering Drawing Vectorization Software, Vector for short, is introduced. The software is designed by object-oriented technique. Because of limited precision of vectorization recognition technology, manual edit functions are added to furthest improve vectorization process. Except for main function modules, it includes the scanned image input module, the vector file output module and the human machine interface’s design module. The image recognition results demonstrate that this software is practical and effective. However, lines and arcs distilling are basic work of vectorization of scanned image of engineering drawing. The abundant structure and function information engineering drawings contain, such as logical relationship of graphics and between graphics and texts, will be the target of further research.