RECOGNIZING POLYHEDRONS FROM AN AXONONMETRIC DRAWING ON PRINCIPLE OF HOMOGRAPH

摘要

In this paper, two problems are researched. First, the definition of homograph is given based on affine invariants, and the recognizing method of the homographs is proposed. Second, a new algorithm for recognizing polyhedrons from an axonometric drawing based on Principle of Homograph is presented. The obtained homographs can be employed to distinguish surfaces with different characteristics and to classify the surfaces of polyhedron. Matching process is limited in homographs, resulting in a great reduction in searching area and computation time. The topological structure is introduced to analyze homograph qualitatively, the algorithm is insensitive to noises and robust. The geometrical structure is employed to analyze homograph quantitatively, the fine discrimination between polyhedrons can be shown. Our algorithm can not only recognize objects of different shape, but also distinguish between objects that are of the same shape but their size and scale different. Our algorithm is implemented in computer simulations. Comparing with other algorithms, a better recognized result is obtained by using of our algorithm.