Inverse colormap operation

@Article{brun-99,


author = {Luc {B}run and Claude Secroun},
title = {A fast algorithm for inverse color map computation},
journal = {Computer Graphics Forum},
year = 1998,
volume = 17,
number = 4,
pages = {263-271},
theme = {inverse},
month = {December},
url = {article:=http://www.greyc.ensicaen.fr/~luc/cgf.ps.gz},
abstract = "The inverse colormap operation is the process
which allows an image to be displayed with a
limited set of colors. In order to obtain minimal
visual distortion between the input image and the
displayed image, inverse colormap algorithms
associate each color with its nearest
representative. The method presented in this paper
is based on a Karhunen-Lo{`e}ve transformation,
which allows us to efficiently approximate the 3D
Voronoi diagram implicitly used by inverse color
map algorithms by its 2D projection into the plane
defined by the first two eigenvectors of the
covariance matrix and then performing an
additional correction step. The complexity of our
algorithm is independent of the size of the
colormap. Moreover, its results are equal or quite
close to the optimal solution."

 } 

@InProceedings{brun-97-3,


author = {Luc {B}run and Claude Secroun},
title = {Une nouvelle m{'e}thode d'inversion de tables de couleurs},
booktitle = {journ{'e}es de l'association francc{a}ise
d'informatique graphique },
year = 1997,
address = {Rennes},
theme = {inverse},
organization = {A.F.I.G.},
url= {article(.ps):=http://www.greyc.ensicaen.fr/~luc/ARTICLES/afig97.ps.gz}
abstract = "L'inversion de la table de couleurs est un processus
permettant de cr{'e}er une image {`a} partir d'une
image d'entr{'e}e et d'un ensemble de couleurs
appel{'e} la table de couleurs ou l'ensemble des
couleurs repr{'e}sentatives. Afin de diminuer la
distance visuelle entre l'image d'entr{'e}e et l'image
r{'e}sultat, ce processus affecte {`a} chaque couleur
de l'image originale sa couleur la plus proche dans
la table de couleurs. La m{'e}thode que nous allons
pr{'e}senter est bas{'e}e sur une projection de
l'ensemble des couleurs de l'image sur un plan
discret. L'utilisation de ce plan nous permet
d'approximer efficacement le diagramme de Voronoi 3D
sous-jacent aux m{'e}thodes d'inversion de table de
couleurs."

 }