| This paper studies the paper-engineering-drawing recognition and matching technology.In view of the engineering drawing recognition,using Hough transformation to achieve a straight line and circle’s recognition,and did some research vector quantization of drawing.According to the characteristic of engineering drawing,the matching of topological structure and the type and number of primitive types are proposed.This paper is divided into three parts:1.Scanning input and pretreatment of paper engineering drawings.By scanning equipment to convert paper drawings into a computer to recognize a bitmap,the bitmap is then pretreated(gray-scale transformation,decontamination filtering,Two valued,icon separation,etc.).2.The engineering drawing recognition and its vector.Using the appropriate vector method,the bitmap can be transformed into a vector map,so that the results of the vector in the CAD system output.For example,based on the thinning algorithm and the algorithm based on non-thinning.In this paper,how to use the Hof transform to identify the straight line and circular arc in the engineering drawing is introduced in detail.The vector transformation of the complex graph generated by MATLAB to the CAD graph is discussed.3.Matching of engineering drawings.The matching of engineering drawings can be attributed to the matching of images,which can be used to match the engineering drawings.According to the characteristics of engineering drawings,a new matching method is proposed,which is based on the matching of the topological structure and the type and number of elements.According to the rules,find out the feature points of the image,and then use these points to construct the topology structure of the engineering drawing,and finally use the principle of isomorphism identification to get the matching of the two drawings.Based on the type and quantity of the matching is to identify the elements as the foundation,so the recognition accuracy of the graphic elements is very high. |
