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Cylindrical Approximation of Tubular Organs for Virtual Endoscopy

by A. Vilanova, E. Gröller and A. König
Published in Computer Graphics and Imaging 2000, Conference Proceedings, pages 283-289. IASTED/ACTA Press, November 2000.

This page assembles some results (figures) of work that is part of our research topic ``Visualization of Medical Data''. The figures are provided in GIF or JPG format.

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Abstract of the Paper:

Virtual endoscopy is a promising medical application of volume visualization techniques. A virtual endoscopy system requires high quality and perspective projection rendering, as well as real-time navigation. In this paper the generation of a cylindrical structure for tubular shaped organs (i.e. colon, aorta) is presented. This structure represents an approximation of the real organ. The cylindrical structure will be used to accelerate high quality volume rendering.

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Figures in the paper

	Figure 2 : Sketch representation of a 2D cut of an organ. It shows the wall and the cavity of the organ together with a possible wall interval definition.
	Figure 3 : Surface of a segmented trachea together with its skeleton.
	Figure 7 : Illustration of the volume rendering algorithm using the cylindrical approximation structure.

	Figure 1a and Figure 1b and Figure 1c: Surface of the segmented organ together with the cylindrical approximation: a) (left) CT colon data. b) (middle) The same CT colon data as in a but using a) different wall thickness. c) (right) CT kidney data set. The segmented organ is the aorta.
	Figure 4a and Figure 4b and Figure 4c: Canal Surfaces: a) (left) 1-parameter spheres family. b) (middle) Circles of intersection. c) (right) Canal surface.
	Figure 5a and Figure 5b and Figure 5c: Surface of the segmented organ together with the cylinder axis generation based on the central path: a) (left) Central path. b) (middle) Central path, cylinder axes generated from curvature information. The circle shows an area where an axis is outside of the organ. c) (right) Central path, cylinder axes generated according to distance errors.
	Figure 6a and Figure 6b and Figure 6c: Illustration of the axes generation algorithm using the distance error information. Aj is the axis generated in iteration j; Pi denote the central path points. The central path is drawn as a discontinuous line and the current sub-path is painted in grey. 3 iterations of the algorithm are shown. In this example the final valid axis would be A1.
	Figure 8a and Figure 8b and Figure 8c: Virtual endoscopy of a 200x115x300 CT dataset of a colon : a) (left) Outside view of the segmented object surface together with the camera and the cylindrical approximation. b) (middle) Endoscopic view of the cylindrical structure and a surface based rendering. The polygons have been generated using marching cubes. c) (right) Endoscopic view using direct volume rendering and the cylindrical approximation.
	Figure 9a and Figure 9b and Figure 9c: Virtual endoscopy of a 205x83x105 CT dataset of a trachea: a) (left) Outside view of the Segmented object surface together with the camera and the cylindrical approximation. b) (middle) Endoscopic view of the cylindrical structure and a surface based rendering. The polygons have been generated using marching cubes. c) (right) Endoscopic view using direct volume rendering and the cylindrical approximation.