【作者】 郝立巍；

【导师】 李树祥；

【作者基本信息】 第一军医大学 ， 生物医学工程， 2002， 硕士

【摘要】 在医院建立医学图像归档及通信系统(Picture Archiving and Communication System，PACS)的目的是为了利用先进的医学图像处理技术和计算机网络技术解决目前阻碍医院网络化信息管理的海量医学影像的获取、显示、存储、查询、保密、交换等问题。虽然近几年有很多研究人员进行了PACS系统的研究和设计，但是要真正建立一套完整和具有广泛适应性的解决方案而且适用于中国医院的PACS系统还一定的距离。 本研究受到军队“十五”重大课题资助的军队PACS关键技术研究项目的支持。我有幸参加并开展了比较深入的研究工作。 我调查了医院对PACS系统的用户需求，并在IMPAX2.0的开发中特别注意考虑临床用户的实际需要；在系统设计中还注意借鉴面向对象设计中最新的设计模式，增加了系统的可维护性。同时，我还提出了基于PACS环境的2个新的3D显示算法。一个是用于改善面显示的显示效果，另一个是利用微机的硬件环境，加速体绘制的计算速度。 本文主要分为以下三个部分： (1)IMPAX2.0的设计与实现。目前，PACS是现代医院实现信息化和网络化的一个研究热点。PACS系统旨在综合利用现代的数字化技术、图像技术、通信技术和计算机网络技术，取代医院目前对医学影像数据仍旧采用胶片的管理方式，解决目前不适应现代医院发展需要的医学影像图像的获取、显示、存储、查询、保密、交换等问题。本部分基于实验室以前关于DICOM标准和图像处理研究的技术积累，受到军队“十五”重大课题资助，主要研究和分析了IMPAX2.0的设计与实现，以及确实能够在医院发挥效能的PACS系统设计中应考虑与解决的关键问题与特色技术。 (2)基于法矢量进行低通滤波的面显示的平滑优化显示算法研究。在以前的三维显示研究中，采用表面矢量平滑的方法对三维重建后的数据显示取得了较好的效果，但也产生了表面特征和特征角等有用信息丢失的问题。本部分研究通过把表面法矢量视为离散矢量信号，引入信号处理中滤波器的方法来平滑表面法矢量。相对于以前三维表面数据场的平滑研究，不仅平滑迭代次数减少，而且更好地保留了有用的表面特征信息。 (3)基于一般微机硬件环境的体绘制实时显示加速研究。随着微机硬件技术的快速发展，微机系统正逐步取代昂贵的工作站系统，成为医学三维可视化的显示平台。目前在利用微机实现三维可视化的实用技术研究中，较多采用的是面显示方法。实际上，体绘制是有很多优点的，只是由于体绘制技术需要大量的三维插值运算，所以在一般微机硬件环境下实时体绘制显示比较困难。随着实际应用的日益增长的需求，新的显卡不断推出和改进，越来越多的微机显卡具有新的硬件构架，支持新的OpenGL规范。新的图形硬件渲染管道的硬件结构较之以前的硬件结构有了很大的不同和改进。本部分深入地分析了有关的微机显卡硬件结构的变化，并提出基于新的硬件结构的实时体绘制加速算法，不仅有更好的绘制效果，而且只需要更短的运算时间。更多还原

【Abstract】 The goal of PACS (Picture Archiving and Communication System) is to utilize the advanced technology of medical imaging and computer network to solve the problems of acquisition, storage, transmission, viewing, search and coding the huge amount of data of medical image to catch up with the rapid development of networklized information management of modern hospitals. The research and development of PACS has been carried on by many researchers and companies for years, but there are still problems hampering to build a really suitable PACS, which could really benefit the hospitals especially in China.To help hospitals with advanced science and technology related with PACS and to train doctors and technicians to work with and maintain a PACS, the PLA’s Key Lab. Of Medical Imaging, supported by PLA’s key research project of 10 Five-Year Plan, developed an advanced research system of PACS called IMPAX2.0. I had the honor to become a member of the group and did the research on the development of IMPAX2.0.The research work with this group became the main topics of the thesis. I investigated into the user’s requirements coming from different kinds of hospitals for PACS, and paid special attention to them in the designing and developing of IMPAX 2.0. At the same time, I proposed two new algorithms for visualization and display 3D image data in PACS environment. One is to improve the display quality of surface rendering, and the other is to speed the computation for volume rendering based on PC hardware architecture.The main topics discussed in the thesis consist of three parts:(1) The design and implementation of IMPAX2.0 based on accumulated research results of our lab. Recently, research and development of PACS is a hot-point in biomedical engineering and modernization of hospitals. The goal of PACS is to utilize the advanced technology of medical imaging and computer network to solve the problems of acquisition, storage, viewing, search, coding and delivery of medical images which delayed the development of modern hospitals. In this part, how to develop a PACS system that will soon be tested and run in a clinical environment is discussed.(2) A new isosurface smoothing algorithms is proposed. In former studyof 3D isosurface display, surface vector smoothing method is adopted. It can sometimes give good results, but some useful surface features and small feature angles might be lost in some cases. In this paper, the signal processing methods are introduced to improve the effect of display by regarding surface vectors as discrete vector signals and implementing low-pass filtering on them. Not only the number of smoothing iteration is reduced dramatically, but also useful surface features and small angles are better reserved.(3 ) Real-time volume rendering is studied based on modern PC hardware environment. It is a clear trend that PC hardware environment will become the basic platform for many visualization applications including PACS. Volume rendering on PC hardware environment is still in a cradle due to the large amount of trilinear interpolations. With more and more kinds of PC graphics cards supporting the specification of OpenGL1.3, there are many rendering pipeline hardware improvements in those new graphics cards. These hardware structure changes were introduced and then an improved texture mapping volume rendering algorithm based on the new hardware architecture is presented and implemented, which produced better results with less computing time.更多还原