@inproceedings{Sousa:1999:OMB,
  citeseer = {http://citeseer.nj.nec.com/526382.html},
  www = {http://www.dgp.toronto.edu/gi99/papers/100},
  author = {Sousa, Mario Costa and John W. Buchanan},
  booktitle = GI1999,
  optstatus = {doi},
  url = {http://www.graphicsinterface.org/proceedings/1999/100/},
  abstract = {In this paper we present a blender and eraser model that extends
              our graphite pencil and paper model. This blender and eraser model
              enhances the rendering results producing realistic looking
              graphite pencil tones and textures. Our model is based on
              observations on the absorptive and dispersive properties of
              blenders and erasers interacting with lead material deposited over
              drawing paper. The parameters of our model are the particle
              composition of the lead over the paper, the texture of the paper,
              the position and shape of the blender and eraser, and the pressure
              applied to them. We demonstrate the capabilities of our approach
              with a variety of pencil swatches and compare them to digitized
              pencil drawings. We also present automatic and interactive
              image-based rendering results implementing traditional graphite
              pencil tone rendering methods.},
  localfile = {papers/Sousa.1999.OMB.pdf},
  address = {Toronto},
  title = {{O}bservational {M}odel of {B}lenders and {E}rasers in
           {C}omputer-{G}enerated {P}encil {R}endering},
  optmonth = jun,
  doi = {http://doi.acm.org/10.1145/351631.351678},
  year = {1999},
  organization = {Canadian Computer-Human Communications Society},
  pages = {157--166},
}