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Virtual Colon Flattening

by A. Vilanova Bartroli, R. Wegenkittl, A. König, E. Gröller and E. Sorantin
Published in VisSym '01 Joint Eurographics - IEEE TCVG Symposium on Visualization, Conference Proceedings, pages 127-136, May 2001.

This page assembles some animations results of work that is part of our research topic ``Visualization of Medical Data''. The figures are provided in GIF or JPG format and the movies are MPEG1 compressed (mpg).



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Abstract of the Paper:

We present a new method to visualize virtual endoscopic views. We propose to flatten the organ by the direct projection of the surface onto a set of cylinders. Two sampling strategies are presented and the introduced distortions are studied. A non-photorealistic technique is presented to enhance the perception of the images. Finally, an approximate but real-time endoscopic fly-through is possible by using the data obtained by the projection technique.



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Download the paper (.ps.zip) (~953KB)



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Animations

Figures in the paper

[Fig. 1]
 		Figure 1 :
Illustration of the possible undersampling and double counting of polyps due to intersections of the cross-sections in high curvature areas. The dash cross-section line produces a double counting of the polyp.
[Fig. 2]
 		Figure 2 :
Illustration of the projection procedure. A region of the surface is projected to the cylinder $C(h,\alpha)$. Then the cylinder is mapped to the image I(u,v)
[Fig. 3]
 		Figure 3 :
a) Constant angle sampling: it is shown that different surface lengths are represented by the same length in the cylinder.
b)Perimeter sampling: same length but different angle.
[Fig. 4a][Fig. 4b]
[Fig. 4a][Fig. 4b] 		Figure 4a and Figure 4b :
a) Resulting image of the projection technique using constant angle sampling.
b) Same camera position as a) but with a perimeter sampling.
The bottom images show a grid which was generated by fixing a constant angle value.
[Fig. 5a][Fig. 5b]
[Fig. 5c][Fig. 5d] 		Figure 5a, Figure 5b, Figure 5c and Figure 5d:
For the same camera position and using constant angle sampling:
a) depth image
b) shaded image
c) level lines with hue shift color coded
d) combination of the level lines and shaded image.
[Fig. 6a][Fig. 6b] Figure 6a and Figure 6b:
a) Endoscopic view backprojecting the lines using the depth information and the camera frame.
b) Endoscopic view using the backprojection of the generated shaded stripes.
[Fig. 7a][Fig. 7b]
[Fig. 7c][Fig. 7d]
[Fig. 7e][Fig. 7f]
[Fig. 7g]
[Fig. 7h][Fig. 7i]
 Figure 7a, Figure 7b, Figure 7c, Figure 7d, Figure 7e, Figure 7f, Figure 7g, Figure 7h and Figure 7i :
Cadaveric colon CT data set 381x120x632:
a) Outside view and camera position for c) and d).
b) Endoscopy view moving the camera in a) a bit backwards.
c) Constant angle sampling showing 2 polyps.
d) The same as c) but with level lines enhancement.
e) and f) Constant angle sampling from another camera positions showing polyps.
g) The same as f) but with perimeter sampling.
Colon CT dataset 256x256x311:
h) Constant angle sampling.
i) The same camera position as h) but with perimeter sampling.



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This page was last updated by Anna Vilanova on August 29, 2001.
If you have any comments, please send a message to anna@cg.tuwien.ac.at.