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我们推导了从三维人体中识别器官的基本步骤。该方法包括基于CT值的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)用样条曲线表示中心线，(2)用Beje曲线表示器官表面，(3)形状特征集，(4)关键切片上的结构。它们分别用于识别(1)纵隔大血管、(2)肺区、(3)支气管、(4)肺内动脉和静脉，并在实验中证明了它们的有效性。对相关领域的研究现状进行了详细的综述。(3)对本课题组以往在三维数字几何方面的工作进行了系统化，并以专著和教科书的形式出版。将视觉专家系统IMESS扩展到三维图像处理。(4)明确了CAD概念CAD的概念，将其分为三种类型：通用CAD、专用CAD和日常使用CAD。(5)虚拟人体和MR医学我们提出MR(混合现实)医学是虚拟人体和用于诊断和治疗的真实人体的统一。作为其核心技术，开发了虚拟内窥镜系统和基于导航的内窥镜系统。

(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.