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Radial basis functions for color conversion

dc.contributor.authorQiao, Yue, author
dc.contributor.authorKirby, Michael, advisor
dc.date.accessioned2024-03-13T20:12:30Z
dc.date.available2024-03-13T20:12:30Z
dc.date.issued2008
dc.description.abstractThe most difficult and challenging task in color printing is to reduce costs while maintaining superior quality. This dissertation proposes significant enhancements to printer color conversion techniques including accurate nonlinear models that incorporate perceptual color difference metrics, lossless gray component replacement (GCR) transformations, optimized toner saving algorithms and numerical/perceptual based gamut mapping methods. Radial Basis Functions (RBFs) combined with the Lp norm approximation with emphasis on L1, L2, and L∞ were developed for color conversion. The exchange algorithm was employed in the L∞ and L1 approximations with RBFs that satisfy the Haar condition. Both the Barrodale and Phillips (BP) algorithm for solving the dual problem and the Bartels and Conn's (BC) algorithm for solving the primal were extended to multidimensional color conversion. A new approach for lossless GCR was achieved by finding one dimensional color manifolds in the CMIYK color space using multidimensional optimization techniques. We proposed objective functions for toner savings, cost savings, etc., with no quality degradation. The color conversion with the toner/ink limitation problem was solved via both L1 and L∞ approximation algorithms in the neutral and saturated color regions respectively. The L1 algorithm was a modified Barrodale and Roberts (BR) primal algorithm with an added constraint, while the L∞ algorithm was developed based on the BP dual algorithm which extended the three-stage algorithm to a four-stage algorithm. A novel gamut mapping algorithm was developed based on the numerical model guided by a perceptual color difference model. The direction of the gamut mapping is not fixed as in other methods. The algorithm transformed a connected out-of-gamut colors to connected colors around the boundary of the device gamut. The out-of-gamut colors in a small neighborhood vary continuously and smoothly. Our results indicated that the color conversion quality was significantly improved. The lossless GCR algorithm is accurate and efficient. Both the BP and BC algorithms for solving the toner/ink limitation are able to convert colors from CIELab to CMY with any given toner/ink limitation. We foresee this research will have significant impact on the color reproduction industry.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierETDF_Qiao_2008_3400387.pdf
dc.identifier.urihttps://hdl.handle.net/10217/237914
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.rights.licensePer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.
dc.subjectcolor conversion
dc.subjectgray component replacement
dc.subjectradial basis functions
dc.subjectapplied mathematics
dc.titleRadial basis functions for color conversion
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineMathematics
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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