Advanced Raycasting for Virtual Endoscopy on Consumer Graphics Hardware

Information

• Publication Type: Master Thesis
• Workgroup(s)/Project(s):
  • Visualization Group
• Date: 2005
• First Supervisor:
  • Katja Bühler
  • Markus Hadwiger
  • Eduard Gröller

Abstract

Volume rendering techniques for medical applications face a number of problems that restrict the applicable techniques to a handful of established algorithms. Developing a virtual endoscopy application further narrows the choice due to the very specific demands of such a system. First, being able to move the viewpoint into the dataset and providing correct renderings incorporating the wide field of view optical endoscopy cameras usually deliver is a challenging task at a time when many of the available professional solutions like TeraRecon’s VolumePro boards are still restricted to orthogonal rendering. Second, the extreme perspective distortion of the image leads to an amplification of visible sampling artefacts, making it necessary to employ special techniques to deal with this problem. Third, highly interactive framerates are not a welcomed feature but an absolute necessity, since the possible intra-operative environment makes immediate response to certain actions essential. And last, correct visualization and intersection of the endoscopic tools have to be ensured in order to provide the surgeon with an adequate representation of the environment. In the past, there has always been a trade-off between functionality, interactivity and high-quality renderings resulting in systems either being able to produce interactive visualizations that lack the necessary detail and correctness of the representation, or high-quality renderings that have to be generated off-line in a tedious process that makes real-time adaptations impossible. This thesis presents an approach that attempts to meet all the demands on a virtual endoscopy system by creating a rendering framework that allows for interactive framerates for almost every possible dataset, quality setting and rendering mode. To achieve this, a number of specialized techniques is incorporated that extend the basic rendering pipeline in numerous ways. As virtually all of the different approaches to real-time visualization of volume datasets, raycasting on consumer graphics hardware faces its own problems and pitfalls. This is why separate sections of this thesis are dedicated to solutions to these problems that make the approach as versatile as possible. Finally, results and real-life images of the raycaster are presented, which is already used in medical practice in pre-operative planning for neuro-surgery.

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BibTeX

@mastersthesis{scharsach-2005-adv,
  title =      "Advanced Raycasting for Virtual Endoscopy on Consumer
               Graphics Hardware",
  author =     "Henning Scharsach",
  year =       "2005",
  abstract =   "Volume rendering techniques for medical applications face a
               number of problems that restrict the applicable techniques
               to a handful of established algorithms. Developing a virtual
               endoscopy application further narrows the choice due to the
               very specific demands of such a system. First, being able to
               move the viewpoint into the dataset and providing correct
               renderings incorporating the wide field of view optical
               endoscopy cameras usually deliver is a challenging task at a
               time when many of the available professional solutions like
               TeraRecon’s VolumePro boards are still restricted to
               orthogonal rendering. Second, the extreme perspective
               distortion of the image leads to an amplification of visible
               sampling artefacts, making it necessary to employ special
               techniques to deal with this problem. Third, highly
               interactive framerates are not a welcomed feature but an
               absolute necessity, since the possible intra-operative
               environment makes immediate response to certain actions
               essential. And last, correct visualization and intersection
               of the endoscopic tools have to be ensured in order to
               provide the surgeon with an adequate representation of the
               environment. In the past, there has always been a trade-off
               between functionality, interactivity and high-quality
               renderings resulting in systems either being able to produce
               interactive visualizations that lack the necessary detail
               and correctness of the representation, or high-quality
               renderings that have to be generated off-line in a tedious
               process that makes real-time adaptations impossible. This
               thesis presents an approach that attempts to meet all the
               demands on a virtual endoscopy system by creating a
               rendering framework that allows for interactive framerates
               for almost every possible dataset, quality setting and
               rendering mode. To achieve this, a number of specialized
               techniques is incorporated that extend the basic rendering
               pipeline in numerous ways. As virtually all of the different
               approaches to real-time visualization of volume datasets,
               raycasting on consumer graphics hardware faces its own
               problems and pitfalls. This is why separate sections of this
               thesis are dedicated to solutions to these problems that
               make the approach as versatile as possible. Finally, results
               and real-life images of the raycaster are presented, which
               is already used in medical practice in pre-operative
               planning for neuro-surgery.",
  address =    "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria",
  school =     "Institute of Computer Graphics and Algorithms, Vienna
               University of Technology ",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2005/scharsach-2005-adv/",
}