A Critical Review of the Preetham Skylight Model

Georg Zotti, Alexander Wilkie, Werner Purgathofer
A Critical Review of the Preetham Skylight Model
In WSCG , pages 23-30. January 2007.

Information

Abstract

The Preetham skylight model is currently one of the most widely used analytic models of skylight luminance in computer graphics. Despite its widespread use, very little work has been carried out to verify the results generated by the model, both in terms of the luminance patterns it generates, and in terms of numerical reliability and stability.

We have implemented the model in Mathematica, visualise and discuss those parameter ranges which exhibit problematic behaviour, and compare the computed luminance values with references from literature, especially the 15 standard skylight distributions of the CIE 2003 Standard General Sky.

We also performed luminance measurements on real cloudless skies, and compare these measurements to the predictions of the model.

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BibTeX

@inproceedings{zotti-2007-wscg,
  title =      "A Critical Review of the Preetham Skylight Model",
  author =     "Georg Zotti and Alexander Wilkie and Werner Purgathofer",
  year =       "2007",
  abstract =   "The Preetham skylight model is currently one of the most
               widely used   analytic models of skylight luminance in
               computer graphics.   Despite its widespread use, very little
               work has been carried out to verify the results generated by
               the model, both in terms of the luminance patterns it
               generates, and in terms of numerical reliability and
               stability.  We have implemented the model in Mathematica,
               visualise and discuss those parameter ranges which exhibit
               problematic behaviour, and compare the computed luminance
               values with references from literature, especially the 15
               standard skylight distributions of the CIE 2003 Standard
               General Sky.  We also performed luminance measurements on
               real cloudless skies, and compare these measurements to the
               predictions of the model.",
  month =      jan,
  booktitle =  "WSCG ",
  editor =     "Vaclav Skala",
  isbn =       "978-80-86943-02-2",
  location =   "Plzen",
  publisher =  "University of West Bohemia",
  pages =      "23--30",
  keywords =   "Verification, Skylight",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2007/zotti-2007-wscg/",
}