Computer Interpretation And Noise Correction Of Line Drawings For Representing Planar Objection

Computer interpretation of line drawings is an important research topic in computer vision and reverse engineering. People use line drawings to describe3-D objects in many cases, while a line drawing is composed by some straight line segments, it contains a lot of information of3-D objects. It has long been committed to2-D expression of the3-D objects in Descriptive Geometry which has formed a mature theory and methods, but its inverse problem3-D reconstruction of two-dimensional line drawings is studied much more late Humans can use their highly developed visual system to obtain the three-dimensional information expressed by line drawings, But the computer is a specific、unambiguous and accurately system, there may be a variety of understanding. In addition, line drawings corresponding3-D objects may not exit because of the unavoidable external factors. Therefore, the primary task is to make the information of line drawings to be Specific、unambiguous and accuracy.In this thesis, the main work can be divided into three parts:The first part is to extract information of line drawings drawn by CAD software by ObjectARX application based on VC++platform. The second part is line drawings interpretation based on line-line constraints. The third part is to correct line drawings with noise, to make the original line drawings closest to the real projection of3-D entity. In addition, This thesis described markup theory and method of the dimensional manifold line drawings. Discussed the Expression advantages and disadvantages of the2-D straight line in line drawings and3-D space straight line.proposed a differential method of polygon convex-concave property.Innovation of the paper:the method of interpreting line drawing in this paper make full use of characteristics of the linear elements which is facilitate to extract、simple to express. comparing with the point-line and point-face constraints to interpret line drawings,the line-line method not only has small error but also have simple operation and high accuracy. In addition, for the line drawing with noise,we set a reasonable assessment function and proposed an error correction algorithm based on iterative feedback technology. The experiment proved its rationality.