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Uniform Color Spaces Based on CIECAM02 and IPT Color Difference Equations

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Uniform Color Spaces Based on CIECAM02 and IPT Color Difference Equations Rochester Institute of Technology RIT Scholar Works Theses 11-1-2008 Uniform color spaces based on CIECAM02 and IPT color difference equations Yang Xue Follow this and additional works at: https://scholarworks.rit.edu/theses Recommended Citation Xue, Yang, "Uniform color spaces based on CIECAM02 and IPT color difference equations" (2008). Thesis. Rochester Institute of Technology. Accessed from This Thesis is brought to you for free and open access by RIT Scholar Works. It has been accepted for inclusion in Theses by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. Uniform Color Spaces Based on CIECAM02 and IPT Color Difference Equations by Yang Xue A thesis submitted for partial fulfillment of the requirements for the degree of Master in the Chester F. Carlson Center for Imaging Science of the College of Science Rochester Institute of Technology November 2008 Signature of the Author_____________________________________________________ Accepted By_____________________________________________________________ Coordinator, M.S. Degree Program Date i CHESTER F. CARLSON CENTER FOR IMAGING SCIENCE COLLEGE OF SCIENCE ROCHESTER INSTITUTE OF TECHNOLOGY ROCHESTER, NEW YORK CERTIFICATE OF APPROVAL M.S. DEGREE THESIS The M.S. Degree Thesis of Yang Xue has been examined and approved by the thesis committee as satisfactory for the thesis requirement for the Master of Science degree in Imaging Science. ________________________________ Prof. Roy S.Berns, Thesis Advisor ________________________________ Prof. Mark D. Fairchild, Committee Member ________________________________ Prof. Mitchell R. Rosen, Committee Member ii THESIS RELEASE PERMISSION ROCHESTER INSTITUTE OF TECHNOLOGY COLLEGE OF SCIENCE CHESTER F. CARLSONCENTER FOR IMAGING SCIENCE Title of Thesis: Uniform Color Spaces Based on IPT and CIECAM02 Color Difference Equations I, Yang Xue, hereby grant permission to the Wallace Memorial Library of R.I.T. to reproduce my thesis in whole or in part. Any reproduction will not be for commercial use or profit. Signature:_____________________________________ Date:_________________________________________ iii Uniform Color Spaces Based on CIECAM02 and IPT Color Difference Equations Yang Xue Submitted for partial fulfillment of the requirements for the degree of Master in the Chester F. Carlson Center for Imaging Science of the College of Science Rochester Institute of Technology November, 2008 ABSTRACT Color difference equations based on the CIECAM02 color appearance model and IPT color space have been developed to fit experimental data. There is no color space in which these color difference equations are Euclidean, e.g. describe distances along a straight line. In this thesis, Euclidean color spaces have been derived for the CIECAM02 and IPT color difference equations, respectively, so that the color difference can be calculated as a simple color distance. Firstly, the Euclidean line element was established, from which terms were derived for the new coordinates of lightness, chroma, and hue angle. Then the spaces were analyzed using performance factors and statistics to test how well they fit various data. The results show that the CIECAM02 Euclidean color space has performance factors similar to the optimized CIECAM02 color difference equation. To statistical significance, the CIECAM02 Euclidean color space had superior fit to the data when compared to the CIECAM02 color difference equation. Conversely, the IPT Euclidean color space performed poorer than the optimized IPT color difference equation. The main reason is that the line element for the lightness vector dimension could not be directly calculated so an approximation was used. To resolve this problem, a new IPT color difference equation should be designed such that line elements can be established directly. iv ACKNOWLEDGEMENTS I would like to express my gratitude to my advisor, Prof. Roy.S Berns, for his very helpful and invaluable support and guidance to my research. Without his constructive advice and encouragement, I would not finish my thesis. I also want to thank my committee member: Prof. Mark Fairchild and Prof. Mitch Rosen. Thanks for their helps in my study in RIT and taking time to review my thesis. This research was supported by the E. I. du Pont de Nemours and Company Graduate Fellowship in Color Science. Their support is greatly appreciated. I am very honored to have opportunity to study in Munsell Color Science Laboratory. Being a member in this big family is an unforgettable memory in my life. My special thanks to everyone in MCSL: the faculty, staff, and my officemates. Lastly, and most importantly, my deepest thanks are given to my parents and my husband. Thanks for their understanding, support, and endless love. I love you all and you are the most important part in my life. v Table of Contents 1 Introduction............................................................................................................................1 2. Background ............................................................................................................................4 2.1 IPT Color Space ...........................................................................................................................7 2.2 CIECAM02 Color Space .............................................................................................................8 2.2.1 Forward Model...................................................................................................................................... 8 2.2.2 Inverse Model ..................................................................................................................................... 13 2.3 Color-Difference Equations with Improved Performance .....................................................16 2.3.1 CIE94.................................................................................................................................................. 16 2.3.2 CIEDE2000......................................................................................................................................... 18 2.3.3 DIN99 ................................................................................................................................................. 21 2.3.4 Modification of CIECAM02............................................................................................................... 22 2.4 Euclidean Spaces........................................................................................................................23 2.4.1 A Euclidean Color Space by Thomsen ............................................................................................... 23 2.4.2 Euclidean Color Space based on DIN99............................................................................................. 24 3. RIT-Dupont Dataset.............................................................................................................28 3.1 Background.................................................................................................................................28 3.2 Color-Difference Ellipsoids .......................................................................................................33 3.3 CIECAM02.................................................................................................................................36 3.4 IPT...............................................................................................................................................39 4. Qiao and Berns Dataset .......................................................................................................44 4.1 Background.................................................................................................................................44 4.2 Plots of Qiao Experimental Results in Color Spaces ..............................................................46 5. Hung and Berns Dataset......................................................................................................50 5.1 Background.................................................................................................................................50 5.2 Hung Data Plots in CIELAB, CIECAM02, and IPT Color Spaces.......................................51 5.3 Conclusion...................................................................................................................................53 6. Optimizing Color-Difference Formula ...............................................................................54 6.1 Background.................................................................................................................................54 6.2 CIECAM02.................................................................................................................................55 6.3 IPT...............................................................................................................................................61 7. Euclideanization...................................................................................................................65 7.1 Theory .........................................................................................................................................65 7.2 Derivation of CIECAM02 Euclidean .......................................................................................68 7.3 Derivation of IPT Euclidean .....................................................................................................72
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