Study Of Recognition Aircraft Based On Model

Today, aircraft recognizing become more important in field of national defence and civil aviation due to the development of economy and technology and local confliction. It has gained a great deal of achievement in identifying aircraft automatically from airphoto and remote sensing image. But the deeper study is necessary in many fields. The reason is not only the variety of complex object, but also the insufficiency of knowledge to human vision mechanism.Presently, there are three methods of 3D object recognition: based on the theory of vision calculate, based on initiative vision and based on model. In this paper,recognition aircraft is based on model--it is realized through matching the singleimage with 2D model.A new algorithm about adaptive data sampling based on vertical distance has been proposed, furthermore, a modeling method applying this algorithm for complex surface objects has been addressed in this paper. This process is as follows: firstly, the data of different section contour and of section line have been obtained by reverse-engineering; Secondly, Non-Uniform B-Spline approximation algorithm is used to fit the discrete data; Then the data have been optimized and reduced by adopting adaptive sampling of key points of the fitted curve based on vertical distance, sequently the adaptive sampling data is transformed into the format of the .ibl file of the famous 3-D design software Pro/E. therefore we reconstruct the surface and a model is generated; Lastly, The effectiveness of the adopted algorithm and modeling approach are demonstrated by the experiments.In part of recognition, two problems are studied. First, shape descriptors, which are invariant under affine transformation, are proposed to describe the polygon. Second, a new algorithm for recognizing aircrafts from a single image is presented. The polygon is employed to present the aircraft contour approximately, and the aircraft can be recognized by recognizing the characteristic polygon. Then the shape descriptors are introduced to describe the polygon. The shape descriptors are thenumber of the polygon's vertices, and the triangles areas ratio vector of the longest line hemline. The database of the aircraft's each pose is established to overcome the image differences which are produced by the occlusion of the aircraft's components in different pose. The aircraft is recognized by search for the database of the aircraft's each pose. The recognition method is a process from simple to complex, thus many redundancies calculation are avoided. The experiment results show the algorithm is efficient and feasible.This thesis is supported by Graduation Seed Fund of Northwestern PoIytechnicalUniversity(Z20030060)...