The World Wide Web as a repository of information has had a great influence on our lives. This influence is increasing as the web introduces applications in addition to information. These applications have several advantages, such as world wide accessibility, distance group learning and collaboration. Furthermore, the web encourages training applications since it offers multi-media that can support all stages of training. On the other hand, the virtual reality technology has been utilised to provide new systematic training methods for surgical procedures. These solutions are usually expensive in terms of cost and computation. In this thesis we propose a novel solution to fulfill the training needs of radiologists performing one type of minimally invasive surgery known as interventional radiology. Our training method combines the capabilities of virtual reality to provide realistic simulation environment together with the web environment to provide platform independent, scalable and acc...

We present the combination of an interaction--rich virtual environment and a volume-rendering library which enables to work in an easier and more natural way on volume data. This paper describes how we combined these packages and points out the advantages of such a combination. We also give a short survey of the state of the art in volume rendering libraries and we explain why we selected SGI Volumizer as the volume rendering library for our volume VR system.

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Children television productions have been using puppets for a long time. Since the early days of computer animation, computer puppet simulation has been researched intensively. Complex motion capture equipment allows nowadays the real time mapping of movement for virtual puppets (performance animation). However, the costs of capturing equipment are too high and the difference in the workflow make it difficult for small production teams to access and use such technology. This paper presents a system for the real time simulation of elastic latex hand puppets which are used in television productions. After an analysis of the production processes of real puppets and of the materials used for their production, the paper describes the components of the system simulating them. The system connects a high resolution visual mesh to a three-layered 3D mass spring mesh, which is used for the elastic simulation. Polygonal mesh decimation of the puppet surface model is used as a basis for generating the elastic mesh. From the decimated mesh a new metod is proposed for generating the internal layers of the mass-spring mesh. A data handglove is used for transmitting forces to the elastic mesh, indirectly moving the surface of the virtual puppet in real time. Dataglove interaction maps in a natural way the hand movements of a puppeteer to the computer model. The tradeoffs of the implementation on low cost hardware and its efficiency are also discussed.

Virtual endoscopy is the navigation of a virtual camera through anatomy, computationally reconstructed from radiological data. Virtual endoscopy mimics physical minimally invasive surgical activity and is used for diagnosis (e.g., the detection of colon polyps), planning of endoscopic interventions, postoperative assessment of surgical success and training for inexperienced endoscopists. This thesis introduces STEPS, a virtual endoscopy system designed as a planning and training tool for endonasal transsphenoidal pituitary surgery, a method used to minimally invasively remove tumors of the pituitary gland. A rigid endoscope is inserted into the nose and advanced through intracranial cavities towards the bony wall covering the pituitary gland. This bone is then opened and the tumor is removed. STEPS reconstructs the boundaries of the investigated cavities primarily using iso-surfacing in original CT data. Presegmented objects of interest can be added to the scene and displayed behind the semi-transparent isosurface. These objects (e.g., the tumor, the pituitary gland and important blood vessels) provide an augmented picture of patient anatomy to guide the surgeon, aid in planning the endoscopic approach, and help the user find an ideal