Research On 3D Reconstruction Technology And Its Application In The Aircraft Lofting Design

The 3D reconstruction technology of the target solids has been one of the important branches in the field of computer vision. Based on the engineering views it has been deeply studied and probed from the problem of the 3D reconstruction for aircraft in this paper.2D engineering drawings, being the input of 3D reconstruction system, contains both geometrical information such as shapes & sizes and topological information like the connectivity of points, edges and faces of the target solid. The loss of topological information aggravates the complexity of 3D reconstruction process.Thus the focus of 3D reconstruction turns out to be the recovery of lost topological information during projection.Due to including a lot of disturbed drawing-elements pretreatment of engineering views is first needed to answer the purpose of purifying input noise and making the input data more favorable to compter.The target objects are divided into two categories: planar surface and curved surface solids. Planar surface solids are reconstructed using Constructive Solid Geometry(CSG) theme with improved auxiliary line technique. Adding auxiliary line to the 2D drawing speeds the identification and extraction of primitives, and could also eliminate gost figures. Solids with sectional views such as full section, half section and offset section are also discussed and perfectly settled.Skewed symmetry detection has been introduced to the problem of reconstruction of quadric surface solids.First, skewed symmetry axes of projection curvs are detected.Then the edges of skewed symmetry polygon, which form the skewed symmetry polygon, are extracted out of those skewed symmetry axes. The algebraic equation of projection curves are obtained using'five point'method. A transform technique is then carried out to get parametric expression of projection curve. The quanric curve is obtained after projection matching. Target object finally emerges after a rotating procedure. The validity of target object is proved by back projection of target object. As the skewed symmetry detection technique has no restriction on the disposal of solids, thus the reconstruction domain is enlarged.A cubic parametric H-spline is constrcted and used in aircraft profile design.Exaples have shown its advantages such as excellent bulge keeping and easy shape control.Examples include the reconstruction of aircraft ponents and the whole aircraft itself. All the programs are written by C/C++ language.