@inproceedings{Drbohlav-BMVC05,
  IS = { zkontrolovano 27 Jan 2009 },
  UPDATE  = { 2008-12-29 },
  author =	 {Drbohlav, Ond{\v r}ej and Chantler, Mike},
  title =	 {Two-image comparison under variable illumination
                  revisited},
  year =	 {2005},
  pages =	 {189-198},
  booktitle =	 {BMVC 2005: Proceedings of the British Machine Vision
                  Conference},
  publisher =	 {BMVA},
  address =	 {London, UK},
  isbn =	 {1-901725-29-4},
  venue =	 {Oxford, UK},
  organization = {BMVA},
  annote = {We present a new theory that shows that two images of the
    same object taken under two different light directions can be made
    virtually identical by filtering each image by a directional
    derivative filter. The direction and magnitude of the derivative
    is generally different for each image, and depends on illumination
    directions used. The method requires the object surface to be of
    uniform Lambertian reflectance and a shallow relief, and the light
    directions used to be sufficiently inclined from the surface
    macro-normal. For a specific case when the surface consists of
    spherical patches, the two images can be made identical, for any
    two light directions used provided that none of them is
    perpendicular to the viewing axis. We provide some simple
    experiments which illustrate the validity of this theory.},
book_pages  = { 951 },
editor      = { Clocksin, WF and Fitzgibbon, AW and Torr, PHS },
project     = { UK_Photex },
}