@techreport{TR-IC-02-11,
  number = {IC-02-11},
  author = {A.X. Falcão and L.M. Rocha and J.K. Udupa},
  title = {Shear-Warp Shell Rendering},
  month = {September},
  year = {2002}, 
  institution = {Institute of Computing, University of Campinas},
  note = {In English, 20 pages.
    \par\selectlanguage{english}\textbf{Abstract}
     In Medical Imaging, shell rendering (SR) and shear-warp rendering
     (SWR) are two ultra-fast and effective methods for volume
     visualization. We have previously shown the fact that, typically,
     SWR can be on the average 1.38 times faster than SR, but it
     requires from 2 to 8 times more memory space than SR. In this
     paper, we propose an extension of the compact shell data
     structure utilized in SR to allow shear-warp factorization of the
     viewing matrix in order to obtain speed up gains for SR, without
     paying the high storage price of SWR. The new approach is called
     shear-warp shell rendering (SWSR). The paper describes the
     methods, points out their major differences in the computational
     aspects, and presents a comparative analysis of them in terms of
     speed, storage, and image quality. The experiments involve hard
     and fuzzy boundaries of 10 different objects of various sizes,
     shapes, and topologies, rendered on a 1GHz Pentium-III PC with
     512MB RAM, utilizing surface and volume rendering strategies. The
     results indicate that SWSR offers the best speed and storage
     characteristics compromise among these methods. We also show that
     SWSR improves the rendition quality over SR, and provides
     renditions similar to those produced by SWR.
  }
}