Reconstructing Three-dimensional Object Structure Chart To Organize And Correction Technology Research

A line drawing is the two-dimensional representation of a three-dimensional object. It is an important problem in computer vision and computer aided design that machine interprets line drawing automatically.As a result of many kinds of reasons, the line drawings which the designer draws the line drawing possibly are inaccurate or has mistakes, or the line drawing generally cannot be extracted accurately from the image, so the line drawing designer draws or extracted from the image which input into the computer is generally disorderly, such as it has the missing lines or the excessive lines phenomenon. Therefore, need to carry on the analysis and processing of the line drawing, causing the line drawing is the three-dimensional object's real projection as far as possible, such as deleting the lines which are excessive, adding the lines which are missing, reorganizing the lines which positions are not correct and so on. Make sure that the following work of computer interpretation the line drawing, reconstruct the three-dimensional object structure to carry on smoothly.The line drawing interpretation mainly divided into two aspects: qualitative analysis and quantitative analysis. The labeling and completing of the line drawing belong to the qualitative analysis of line drawing interpretation. Distinguishing the constraint relations of lines and surfaces in the line drawing and reconstructing the three-dimensional object structure belong to the quantitative analysis of line drawing interpretation. This thesis discussed these two aspects of the line drawing interpretation.According to the 24 kinds of legitimate junction patterns of completed line drawings with hidden-part-drawn of planar objects, the corresponding relations between 36 kinds of L junctions and 8 kinds of I junctions with 24 kinds of legitimate W and Y junctions were given. Simultaneously, the complete algorithms of L junctions, I junctions, isolated lines, PEAK junctions as well as T junctions in the phase of processing incomplete line drawing were also given.According to the line expression principle, Line expression method in two-dimensional and three-dimensional have been given, the three-dimensional line expression method under the axonometric projection may produce contradiction, the general solution has been given in this thesis.