| Rapid Prototyping and Manufacturing (RPM)technology is a high-tech developed in the late 80's, which integrates New Material Science, CAD, Numerical Control and Laser Technology. By using it, 3D objects with complex figure can be fabricated rapidly, easily and precisely. So it will be applied widely in biomedical engineering field. Computerized Tomography(CT) technology is always powerful means to examine bones with pathological changes and replace it. How to combine these two technologies well for fabricating artificial bone model and its substitute rapidly and precisely has become the focus of people's attention.For solving this problem,the technology of 3D reconstruction from CT images is researched in this dissertation, which is one of the key technologies to realize RPM. According to the 2D information of CT images, the regions of Interest were extracted by image segmentation and binary processing. Then, the 3D physical model could be made by the reconstruction of 3D surface model and translating it into standard data for RP.The main contents of 3D reconstruction from medical images include inputting of medical image,pre-processing,such as filtering and interpolating,segmenting and extracting tissues or organs of body, constructing 3D surface models.BMP file is used as the main file format of CT images image,and input module of it is exploited.Some filtering methods and interpolating methods are used to process the input data.Exact segmentation is a premise that 3D reconstruction can represent tissue and organ accurately. In this dissertation, an interactive threshold segmentation method is adopted based on grey-level information according to the characteristics of CT images. As a standard algorithm of surface rendering in 3D reconstruction, the basic principle of Marching Cube (MC) algorithm is analyzed in detail. The ambiguity problem in Marching Cube and its solution are also presented. At last , a RP-oriented bone 3D reconstruction system is designed and implemented on the platform of VC++6.0 through applying the principle of object-oriented programming and Model-View-Controller design pattern. The system provides the functions for inputting of medical images, pre-processing, exacting iso-surface and outputting of STL file. This software provides the functions for inputting of medical images,pro-processing,segmenting and interpolating,exacting iso-surface and outputting of STL file ,which is a interface of RP system. |
