title =      "Adaptive Global Visibility Sampling",
  author =     "Ji{\v r}{\' i} Bittner and Oliver Mattausch and Peter
               Wonka and Vlastimil Havran and Michael Wimmer",
  year =       "2009",
  abstract =   "In this paper we propose a global visibility algorithm which
               computes from-region visibility for all view cells
               simultaneously in a progressive manner. We cast rays to
               sample visibility interactions and use the information
               carried by a ray for all view cells it intersects. The main
               contribution of the paper is a set of adaptive sampling
               strategies based on ray mutations that exploit the spatial
               coherence of visibility. Our method achieves more than an
               order of magnitude speedup compared to per-view cell
               sampling. This provides a practical solution to visibility
               preprocessing and also enables a new type of interactive
               visibility analysis application, where it is possible to
               quickly inspect and modify a coarse global visibility
               solution that is constantly refined. ",
  pages =      "94:1--94:10",
  month =      aug,
  number =     "3",
  event =      "ACM SIGGRAPH 2009",
  journal =    "ACM Transactions on Graphics",
  volume =     "28",
  location =   "New Orleans, LA",
  keywords =   "visibility, visibility sampling, occlusion culling, PVS",
  URL =        "http://www.cg.tuwien.ac.at/research/publications/2009/BITTNER-2009-AGVS/",