Studies On R-V Conversion Of Engineering Drawing

The Raster to Vector conversion of engineering drawings is an important graphics and image processing technique for the engineering drawings recognition system. Engineering drawing recognition technique aims at converting scanned engineering drawing images into vector formats compatible with CAD systems. Getting a vectorization result with sufficient accuracy is the basis for further drawing interpretation. Unfortunately, none drawing conversion systems can achieve the satisfactory recognizing accuracy. Research on improving input data qualities from vectorization system is the key for enhancing performance of Raster to Vector conversion systems. In this dissertation, revolving this subject development vectorization engineering drawings the earlier period processing engineering research, associating engineering drawings intelligence input and recognition system, the author presents two algorithms, the view compartmentalized algorithm which based on the threshold connected region and layering algorithm based on the borderline point matching.The modules of engineering drawings automatic region compartmentalized based on the drawing rules and intelligence layering based on linear attribute were designed using the algorithms.The modules act as the prefixal modules engineering drawings intelligence input and recognition system.Enables the system through these two modules to have the high grade data-input, thus not only increased R - V conversion precision, but also provides in semantic for the following intelligent recognition and the three dimensional reconstruction the instruction.The basic idear of the view compartmentalized algorithm which based on the threshold connected region is according as drawing rules and their semantemes, to recognize and to mark the basic views, technical requirement as well as other views from the overall engineering drawings.The basic idear of layering algorithm based on the borderline point matching is intelligence layering by linear attribute can use contour tracing technology, according to engineering drawings linear width characteristic, through the borderline point matching algorithm, to obtain goal object boundary point matching couples in the drawing. Then the line width parameter characteristic factor introduced, fuzzy pattern recognition method utilized, the outline information and the linear width information obtained in the picking course carried on the fuzzy distinction, the graph element can be realized to outline layer or assistance layer marking.The practices indicated that the algorithms is proposed in this paper has a higher correct rate, a good anti-noise ability, and no distortion etc. Especially for the complex drawings the algorithms obtain the well effect.