@InProceedings{CoelhoOlivEspe:1998:TeCoLi,
               author = "Coelho, Paulo Sergio de Souza and Oliveira, Ant{\^o}nio A. F. de 
                         and Esperan{\c{c}}a, Claudio",
                title = "A technique for compensating light source direction in face 
                         recognition application",
            booktitle = "Proceedings...",
                 year = "1998",
               editor = "Costa, L. da F and Camara, G.",
         organization = "International Symposium on Computer Graphics, Image Processing and 
                         Vision, 11. (SIBGRAPI)",
            publisher = "Sociedade Brasileira de Computa{\c{c}}{\~a}o",
              address = "Porto Alegre",
                 note = "The conference was held in Rio de Janeiro, RJ, Brazil, from 
                         October 20 to 23.",
             keywords = "face recognition, light compensation, image databases.",
             abstract = "A process to obtain the directional component of the main light 
                         source illuminating a human face in an image is described. In the 
                         first step of this process, two measures using low resolution data 
                         are obtained from the image. The value of these measures is then 
                         compared with those obtained from a synthetic model illuminated 
                         from different directions. This process, however, is not 
                         sufficient to indicate a single direction as is proved using a 
                         simplified model for face parts. An additional step is required to 
                         break the tie by using high frequency data. Once the light 
                         direction is determined, correction values are added to the image 
                         pixels to obtain an approximation of the face imaged under 
                         standard illumination conditions thereby making recognition much 
                         easier.",
  conference-location = "Rio de Janeiro, RJ, Brazil",
      conference-year = "20-23 Oct. 1998",
         organisation = "SBC - Sociedade Brasileira de Computa{\c{c}}{\~a}o",
                  ibi = "83LX3pFwXQZeBBx/fL6Uj",
                  url = "http://urlib.net/ibi/83LX3pFwXQZeBBx/fL6Uj",
           targetfile = "sse067.pdf",
        urlaccessdate = "2024, May 03"
}