DEVELOPMENT OF EXPERT SYSTEM FOR HIGH-SPEED 3D COMPUTED TOMOGRAPHY

本课题对共射束投影三维X射线计算机层析成像(CT)技术进行了实用化研究，开发了三维数据可视化系统。整个3-D数据只有在X射线源和探测器对旋转的情况下才能获得。3-D图像是从幻影和活体对象的投影中实验重建的。利用放大投影几何方法获得了高分辨率骨结构的三维图像，并对冠状动脉三维成像技术进行了研究。通过实验，用模拟退火法重建了血管的三维图像。利用该方法可以从静脉造影中获得冠状动脉图像，对心脏疾病的诊断具有重要的价值。提出了一种基于光学模型的体数据可视化方法，并在该系统中实现。光电混合处理使高速交互操作成为可能。操作员可以将CT数到光学常数之间的映射表进行更改，并且可以生成模糊曲面的图像。在实验中，根据CT数据重建了颅骨、肌肉、软组织和大脑的图像。通过该系统，很难通过常规方法进行三维观察，从而实现了这类受试者的三维结构的旋转可视化。

A practical investigation on 3-D X-ray computed tomography (CT) using con-beam projections is done and the system for the visualization of 3-D data is developed in this project. Whole 3-D data are acquired only with a rotation of a X-ray source and detector pair. 3-D images are experimentally reconstructed from the projections of phantoms and live subject. 3-D images of high-resolution bone structures are obtained using magnified projection geometry.The 3-D imaging technique of coronary artery is also investigated. The 3-D image of blood vessels is reconstructed using simulated annealing algorithm through the experiment. It is possible to image coronary artery from venography by this method, which is valuable for the diagnosis of heart disease.We construct the expert system to observe 3-D volume data that are acquirecd from 3-D CT systems. A new method for the visualization of volume data using optical model is developed and implemented in the system. High speed interactive operation is possible with electro-optical hybrid processing. The operator can change the mapping table between CT numbers to optical constants, and can generate images of fuzzy surfaces. In the experiment, the images of skull, muscle, soft tissues, and brain are reconstructed from CT data. 3-D structures of such subjects, which is difficult to observe three-dimensionally through conventional method, are visualized with rotation through this system.