Enhancing Depth-Perception with Flexible Volumetric Halos

Information

• Replaced by: bruckner-2007-EDF
• Publication Type: Technical Report
• Workgroup(s)/Project(s):
  • ExVisation: Expressive Visualization of Volumetric Data
• Date: April 2007
• Number: TR-186-2-07-04
• Keywords: illustrative visualization, halos, volume rendering

Abstract

Volumetric data commonly has high depth complexity which makes it difficult to judge spatial relationships accurately. There are many different ways to enhance depth perception, such as shading, contours, and shadows. Artists and illustrators frequently employ halos for this purpose. In this technique, regions surrounding the edges of certain structures are darkened or brightened which makes it easier to judge occlusion. Based on this concept, we present a flexible method for enhancing and highlighting structures of interest using GPU-based direct volume rendering. Our approach uses an interactively defined halo transfer function to classify structures of interest based on data value, direction, and position. A feature-preserving spreading algorithm is applied to distribute seed values to neighboring locations, generating a controllably smooth field of halo intensities. These halo intensities are then mapped to colors and opacities using a halo profile function. Our method can be used to annotate features at interactive frame rates.

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BibTeX

@techreport{TR-186-2-07-04,
  title =      "Enhancing Depth-Perception with Flexible Volumetric Halos",
  author =     "Stefan Bruckner and Eduard Gr\"{o}ller",
  year =       "2007",
  abstract =   "Volumetric data commonly has high depth complexity which
               makes it difficult to judge spatial relationships
               accurately. There are many different ways to enhance depth
               perception, such as shading, contours, and shadows. Artists
               and illustrators frequently employ halos for this purpose.
               In this technique, regions surrounding the edges of certain
               structures are darkened or brightened which makes it easier
               to judge occlusion.  Based on this concept, we present a
               flexible method for enhancing and highlighting structures of
               interest using GPU-based direct volume rendering. Our
               approach uses an interactively defined halo transfer
               function to classify structures of interest based on data
               value, direction, and position. A feature-preserving
               spreading algorithm is applied to distribute seed values to
               neighboring locations, generating a controllably smooth
               field of halo intensities. These halo intensities are then
               mapped to colors and opacities using a halo profile
               function. Our method can be used to annotate features at
               interactive frame rates.",
  month =      apr,
  number =     "TR-186-2-07-04",
  address =    "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria",
  institution = "Institute of Computer Graphics and Algorithms, Vienna
               University of Technology ",
  note =       "human contact: technical-report@cg.tuwien.ac.at",
  keywords =   "illustrative visualization, halos, volume rendering",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2007/TR-186-2-07-04/",
}