@Article{braquelaire-97, author = "Braquelaire, Jean Pierre. and Luc Brun", title = "Comparison and Optimization of Methods of Color Image Quantization", journal = "IEEE Transactions on Image Processing", year = 1997, volume = 6, number = 7, pages = "1048-1052", month = "july", url= {article(.ps.gz) :=http://www.greyc.ensicaen.fr/~luc/ARTICLES/articleIEEE.ps.gz, article(.ps) :=http://www.greyc.ensicaen.fr/~luc/ARTICLES/articleIEEE.ps.gz}, theme= {quantification}, abstract = "Color image quantization is the process of reducing the number of colors in a digital color image has been widely studied for the last fifteen years. In this paper the different steps of clustering methods are studied. The methods are compared step by step and some optimizations of the algorithms and data structures are given. A new color space called $H1H2H3$ is introduced which improves quantization heuristics. A low-cost quantization scheme is proposed." } @InProceedings{braquelaire-95-1, author = "Braquelaire, Jean Pierre and Luc Brun", title = "Quantification de couleurs par partition dynamique", booktitle = "Actes de la journ{'e}e Couleur et Informatique Graphique", year = 1995, address = "Lille ", month = "Mars", url = {article(.ps.gz):=http://www.greyc.ensicaen.fr/~luc/ARTICLES/articleLILLE.ps.gz}, theme = {quantification}, abstract = "La quantification de couleurs est un probl{`e}me qui bien qu'il admette d'autres applications a pris de plus en plus d'importance au fur et {`a} mesure du d{'e}veloppement des {'e}crans couleurs. Nous proposons dans ce papier diverses am{'e}liorations des algorithmes de type partitionement dynamique permettant de diminuer l'erreur de quantification et de r{'e}duire l'occupation m{'e}moire." } @InProceedings{braquelaire-94-1, author = "Braquelaire, Jean Pierre and Luc Brun", title = "Une am{'e}lioration des m{'e}thodes de quantification de couleur par partition dynamique", pages = "247-261", booktitle = "Deuxi{`e}mes journ{'e}es de l'association francc{a}ise d'informatique graphique ", year = 1994, organization = "A.F.I.G", address = "Toulouse", theme = {quantification}, abstract = "La quantification de couleurs est un probl{`e}me qui bien qu'il admette d'autres applications a pris de plus en plus d'importance au fur et {`a} mesure du d{'e}veloppement des {'e}crans couleurs. Ce papier se propose de revoir les principes des techniques de quantification par partitionnement. Nous d{'e}gagerons de ceux-ci quelques id{'e}es fortes qui nous permettront de proposer un nouvel algorithme qui, s' inscrivant dans la continuit{'e} des algorithmes d{'e}j{`a} d{'e}velopp{'e}s, affiche des performances tant en qualit{'e} qu'en espace m{'e}moire et temps de calcul tout {`a} fait int{'e}ressantes." } @PhdThesis{brun-02-9, author = {Luc Brun}, title = {Traitement d'images couleur et pyramides combinatoires}, school = {Universit{'e} de Reims}, year = 2002, theme = {topologie,hierarchical,couleur,quantification,inversion}, type = {Habilitation {`a} diriger des recherches}, abstract = "We describe in this thesis three key steps of image processing algorithms. We first study the reflexion models which describe the image formation process. These models are used to obtain a segmentation of the image into materials and to reconstruct the surface of some of the regions previously segmented. The materials studded for the reconstruction stage are metallic ones. We also study quantization and inverse colormap operations. These operations are used to display an image onto low cost terminals. Such processes may also be applied into the image compression or image segmentation framework. We finally describe a new hierarchical model based on a topological representation of an image partition. The model named Combinatorial Pyramid is the only hierarchical model currently developed which allows to encode all the topological information.", url= {pdf:=http://www.greyc.ensicaen.fr/~luc/ARTICLES/hdr.pdf,ps.gz:=http://www.greyc.ensicaen.fr/~luc/ARTICLES/hdr.ps.gz} } @InBook{brun-02, author = {Luc {B}run and Alain Tr{'e}meau}, title = {Digital Color Imaging Handbook}, chapter = {9 : Color quantization}, pages = {589-637}, publisher = {CRC Press}, year = 2002, theme = {quantification,couleur}, series = {Electrical and Applied Signal Processing}, } @InProceedings{brun-00-2, author = {Luc {B}run and Myriam Mokhtari}, title = {Two High Speed Color Quantization Algorithms}, booktitle = {Proceedings of CGIP'2000}, pages = {116-121}, year = 2000, editor = {C{'e}padu{`e}s}, address = {Saint Etienne}, month = {October}, url = {article (.ps):=http://www.greyc.ensicaen.fr/~luc/ARTICLES/cgip.ps, slides(PPT):=http://www.greyc.ensicaen.fr/~luc/ARTICLES/cgip.ppt}, abstract = " Color image quantization has been widely studied for the last fifteen years. Most of existing quantization algorithms use pure top-down or bottom-up approaches, in this paper we present a two-pass quantization method using a split stage followed by a merge one. The split stage uses a uniform quantization algorithm to generate $N$ initial clusters. These clusters are then combined during the merge stage into $K<<N$ final clusters. Finally, these clusters are used by an inverse colormap algorithm to create the output image. Two different inverse colormap algorithms are proposed leading to two quantization algorithms. These quantization algorithms are more efficient than pure split or pure merge algorithms. Moreover, the difference between the number of clusters produced by the split stage and the number of final clusters allows users to control efficiently the quality/time ratio.", theme={quantification} }