Lancer de Faisceaux en Synthèse d'Images

Ray tracing is one of the most important rendering techniques used in computer graphics. However, this algorithm cannot resolve all the aliasing problems, particulary small objects, or small shadows are missed. Beam tracers can be considered as an extension of classical ray tracers. They replace the concept of infinitesimal ray by that of beam. The "pyramidal beam tracer" studied here has some advantages:

• complex and expensive computations of conventional beam-object intersection are entirely avoided, so an extension to some non polyhedral scenes such as CSG ones is possible;
• usual approximations or complex approaches for refraction computations are avoided;
• soft shadows due to large light sources are possible;
• objetcs preselection based on simple tests and regular spatial subdivision can decrease computational time.

Other applications of beam tracer are possible. We can use beam tracer in an exact visibility algorithm based on generalized maps. Beams are used to optimize this method and to determine precisely the position between two objetcs. In the case of a rendering process, beams can decrease the nomber of considered objets to determine the visibility, for example in a radiosity algorithm.

@PhdThesis\{Has98,
  author       = "Hasenfratz, Jean-Marc",
  title        = "Lancer de Faisceaux en Synth\`ese d'Images",
  school       = "Universit\'e de Limoges",
  month        = "Janvier",
  year         = "1998",
  note         = "Pages 140",
  keywords     = "beam tracing, ray tracing, ant",
  url          = "http://artis.inrialpes.fr/Publications/1998/Has98"
}