基于断层图象三维重建的体视化技术研究与应用

【作者】 杨淑莹；

【导师】 游泽清；

【作者基本信息】 天津师范大学 ， 教育技术学， 2001， 硕士

【摘要】 体视化是科学可视化的一个重要组成部分，它是在吸收计算机图形学、计算机视觉和计算机图象处理等学科有关知识的基础上发展起来的。而这三方面的内容又是计算机应用方面非常重要的分支，因其涉及的内容较深，理论性强，算法多，因此，它常被视为代表计算机专业应用的水平。国际上对体视化的研究与应用如火如茶，我国在这一领域的研究工作起步较晚。本论文在断层图象三维重构方面做了系统地阐述和探讨，主要论述了将一系列二维CT扫描图象经过旋转、平移、滤波、插值、锐化等处理后，提取不同物体的边界数据，形成三维体数据，实现物体三维重建，并实现对体数据进行显示、平移、旋转、缩放、投影等功能，根据软件编程实现这些功能的基础上，对三维体视化处理的各种算法进行总结。 断层影象三维重建的实现方法，主要围绕图象处理、图形变换、实现三维立体还原的方法及图象压缩等方面展开探讨。在图象处理方面，论述了断层图象中定位点提取、图象几何变换、靶区边界提取、图象纵横方向的剖面显示、图象的平滑、图象的锐化、边缘检测与边缘提取等算法；在图形变换方面，讨论了二维图形的几何变换（平移、旋转、缩放），平面数据三维化、立体模型的创建、三维图形的几何变换、曲线拟合、隐藏线和隐藏面的处理、着色处理等算法及其实现原理；并且介绍了用OpenGL开发实现断层图象三维重建系统的设计思想，包括用OpenGL实现坐标变换、立体建模、用OpenGL实现立体旋转、投影等功能；还介绍了将图象BMP文件压缩为JPEG文件的方法，其中包括色彩模型原理、DCT（离散余弦变换）、Zig-Zag变换、量化、AC编码、DC编码、采样系数、JPG文件的解码等实现原理。 目前，国内各医院对肿瘤病人的化疗方法各不相同，资金雄厚的医院采用进口软件进行设计；大多数医院应用国产软件，这些软件厂家主要有北京大恒公司，深圳的威达医疗公司，而这两家的软件在医生进行治疗方案设计时，是在图象平面上进行射野，但不能在全方位立体显示模式下进行放射和计量的设计，造成关键部位不能准确判断。而这也正是医生最需要的关键地方。这些正是本项目要解决和达到的目标。本论文主要论述了将一系列二维CT扫描图象经过校正、锐化等处理后，提取不同物体的边界数据，形成三维体数据，实现物体三维重建，并实现对体数据进行显示、平移、旋转、缩放、投影等功能。 本论文主要以医学领域中的应用为背景，通过对医学领域中体视化的研究与应用，以期对计算机图形学、计算机视觉和计算机图象处理等学科进行深入的研究。通过该项目的体视化技术研究与开发，可以为观察者在进行手术治疗之前、放射治疗之前提供模拟演示功能。并可为医学院教学提供虚拟现实的教学和实验环节。同时提高医用领域的临床水平和教学水平。更多还原

【Abstract】 VOLUME VISUALIZATION is developed in the base of some knowledge in computer graphics, computer vision and computer image manipulation. The content is a very important branch in computer application, as well as. These aspects involve deeper content, have stronger theory and more arithmetic. So it often stands for the level of computer specialty application. Internationally, the research and application of volume visualization is very popular, but the research and application in china appears later. The systematic theory in 3D reconstruction of faultage images is discussed in this paper. The principle, realization arithmetic, realization method and application about spacial 3D volume visualization are brought forward and summed up. The realization method of 3D reconstruction in faultage images is discussed in this paper. First,surrounding images manipulation , graphics translation, the 3D shape reconstruction , image compression, and so on are mainly expounded. In the aspect of images manipulation, the arithmetic of anchor point picking-up, image geometry translation, object identifying boundary picking-up, image section plane displaying in length and width, image smoothness, image sharpening, boundary picking-up in faultage images are discoursed. Second,in the side of graphics translation, the arithmetic and its realization principle of 2D geometry translation (level shift, circumrotation, zoom), plane data 3D, the 3D shape’s establishing, 3D geometry translation, curve, concealing lines and concealing surface processing, colour processing are researched and sunixnarized. Third, the design idea of using OpenGL to exploit and realize 3D reconstruction system of faultage images is introduced,. The idea includes using OpenGL to realize the function of coordinate translation, the 3D modeling, the 3D circumrotation and projection. Fouth, the method of compress- -ing the image BMP files to JPEG files is introduced in this paper.It involves the color model principle, DCT (disperse cosine translation), Zig-Zag translation, quantify, AC encoding, DC encoding, sampling coefficient, the decoding of JPG files. This thesis is written chiefly according to the background of medicine field’s application, the research and application of volume visualization deeply deal with computer graphics, computer vision and computer images manipulation. Though the research it can accelerate the improvement of our national computer application level at these aspects. Through the research and exploitation of volume visualization technology , we can offer demo function for the observer before the operation treatment and the X-adiation treatment. We can also provide the practice’s teaching and experimental teaching method to medical college students. At the same time, the application can help doctor 7 ,k7 improve the sense’ and accurately 1ocate cancer p1ace.Presently, ho.pit.l, have not the software of comP1ete CT 3DreconSboion and X-radial spatial 3D distributng display yet. Using X- radialtredriellt has already become prevalent operation method. Bot, The 3Ddistributing circumstance of radial wraPping target section, section shaPe, radialintensity X- radial time, radial angle, bedstead direchon and other a series ofwork are very difficult to be imagined. Merely relying on doctors directjudgement lacks definite science. Through the research and exp1oitation ofvoIume visual ization techno1ogy, it sure1y can he1p the physician s更多还原