Study of Theory and Algorithms for Model Based General Purpose CAD Systems of Three-dimenisional Images in Medicine

(1)基于模型的器官提取方法推导了从三维人体中识别器官的基本方法。该方法包括使用CT值的逐体素区域生长和基于预先存储在系统中的形状模型的模型匹配。模型描述为：（1）样条曲线的中心线表达，（2）Beje曲线的器官表面表达，（3）形状特征集，（4）关键切片上的结构。将其分别应用于（1）纵隔大血管的识别、（2）肺区的识别、（3）支气管的识别和（4）肺内主动脉和静脉的识别，实验证明了其有效性。通过使用Hill Cribming算法最小化在3D图像上定义的能量函数来执行数十个模型匹配。(2)详细调查了相关领域的技术现状。(3)三维图像处理算法本研究小组过去关于三维数字几何的工作被系统化并作为专著和教科书出版。将视觉专家系统IMPRESS扩展到三维图像处理。(4)将CAD概念分为通用CAD、专用CAD和日常使用CAD三种类型。(5)虚拟人体与MR医学我们提出了MR医学（mixed reality medicine，混合现实），将虚拟人体与真实的人体统一起来进行诊断和治疗。虚拟内窥镜系统和基于导航的内窥镜系统作为其基本技术得到了发展。

(1) Procedures for model-based extraction of organs We derived basic procedures for recognizing organs from three-dimensional human body. The method consists of the voxel-wise region growing using CT values and model matching based on shape models stored in the system beforehand. Models were described in terms of (1) center line expression by spline curves, (2) Beje curves expression of the surface of organs, (3) sets of shape features, and (4) structure on key-slices. These were applied to recognition of (1) large vessels in mediastinum, (2) lung areas, (3) bronchus, and (4) discriminating aorta and veins in lung, respectively and their effectiveness was shown experimentally. By several tens ofModel matching was performed by minimizing the energy function defined on 3D images using hill cribming algorithm.(2) Survey States of arts in the relating fields was surveyed in detail.(3) Three-dimensional image processing algorithm Past work of this research groups on three-dimensional digital geometry was systematized and published as a monograph and textbook. The vision expert system IMPRESS was extended to three dimensional image processing.(4) CAD concept CAD concept was clarified by dividing three types : general purpose CAD, speical purpose CAD, and daily use CAD.(5) Virtualized human body and MR medicine We proposed the MR (mixed reality) medicine as the unification of the virtualized human body and the real human body for diagnosis and treatment. As its element technology, virtualized endoscope system and navigation-based endoscope system were developed.