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Proceedings Paper

Direct Visualization Of Surfaces From Computed Tomography Data
Author(s): Marc Levoy
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Paper Abstract

The application of direct volume visualization techniques to the presentation of CT data is explored. No surface detection or fitting of geometric primitives is involved. Images are formed by directly shading each data sample and projecting it onto the picture plane. The visualizations in this study are based on a hybrid physical model incorporating aspects of both surfaces and semi-transparent gels. Using a surface model, shading calculations are performed at every voxel with local gradient vectors serving as surface normals. In a separate step, surface classification and enhancement operators are applied to obtain a partial opacity for every voxel. Independence of shading and classification calculations insures an undistorted presentation of 3-D shape. The use of non-binary classification operators insure that small or poorly defined features are not lost. The resulting colors and opacities are merged from back to front along view rays using volumetric compositing, an approximation to the visibility calculations required to render a semi-transparent gel. The technique is simple and fast, yet produces images exhibiting smooth surface silhouettes and few other aliasing artifacts. The use of selective blurring and super-sampling to further improve image quality is also described.

Paper Details

Date Published: 27 June 1988
PDF: 14 pages
Proc. SPIE 0914, Medical Imaging II, (27 June 1988); doi: 10.1117/12.968719
Show Author Affiliations
Marc Levoy, University of North Carolina (United States)


Published in SPIE Proceedings Vol. 0914:
Medical Imaging II
Samuel J. Dwyer; Roger H. Schneider; Roger H. Schneider; Samuel J. Dwyer; Samuel J. Dwyer; Roger H. Schneider, Editor(s)

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