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Color: from craft to computation
 

Color: from craft to computation

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Keynote presented at this year's German Color Group Image Processing Workshop in Darmstadt.

Keynote presented at this year's German Color Group Image Processing Workshop in Darmstadt.

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    Color: from craft to computation Color: from craft to computation Presentation Transcript

    • COLOR:FROM CRAFTTO COMPUTATIONDr. Ján MorovičSenior Color Scientist, Hewlett–Packard CompanyDirector of CIE Division 8: Image TechnologyGerman Color Group’s 18th Image Processing Workshop (27/09/2012)© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • OUTLINE• I learned this color from my granny.• Science starts creeping in ...• Whoa! How do I do that in Excel?• Come on! Surely that’s not color?!• Are we done?© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • HEREDITARY COLOR• Oooooo, when I mix these I get a nice red!• But, when I try, it comes out brown?! :(• Master Leonardo taught me a lovely dragon’s blood! (Err, it just comes from a gum tree ...)• Poor Winifred was killed by orpiment † Trial and error, bad repeatability, superstition, health hazard© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • BUT: potential for great results!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • MAKE WAY FOR SCIENCE! Did you know that: • Color is dominant wavelength! • Color is spectral power distribution! • Color is cone response! • Memory colors are a special case! Sequence of firmly stated, but changing claims ... • There is no metamerism in trichromatic color reproduction!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • BUT: WE DO KNOW MORE• Deficient color vision • Color appearance • Color preference phenomena• Cone sensitivities • Color difference • Chromatic adaptation• Retinal center–surround • Metamerism organization • Color constancy • Colorant mixing• Opponent color signals • Color memory • Device characterization• Visual pathway • Color esthetics© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • AND WE CAN BUILD TOOLS• Color appearance models: CIECAM02 → “What will this surface look like under this light, against this background and seen from this distance?”• Color difference equations: CIEDE2000 → “How different is this pair of colors as compared to that other pair?”• Contrast sensitivity functions: CSFs → “How distinctly will I see a given difference when it occurs at a given spatial frequency?”• That let us provide solutions for: Process control (color characterization, calibration), color and image enhancement, color specification and communication, colorant recipe formulation, color management, color quantization for compression, color in machine vision, color in telemedicine, color in motion pictures© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • BUT, THESE TOOLS ARE SIMPLISTIC!• Color appearance models don’t follow physiology of human visual system → approximations with data–fitted parameters• Color difference, uniform color spaces, color rendering indices, chromatic adaptation functions use separate computational mechanisms → ought to derive from single, unified model of color perception• Most models and metrics could be worked out with a calculator and easily with Excel• AND: Computational capabilities have evolved far beyond spreadsheets!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • WHAT DO YOU MEAN“BIG DATA”? ?© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • THE COMPUTATIONAL REVOLUTION• iCAM• LAB2000HL• Metamer constrained color correction• Spectral printing• HANS© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • ICAM & LAB2000HL Spatial processing to account for (local) adaptation/ sharpening Color space uniformity not achievable using single set of formulæ. Fairchild & Johnson Lissner & Urban JEI, 2004© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. IEEE TIP, 2012
    • MCCC Scanner/camera characterization with one–to–many relationship between sensor RGB and all spectra that could have resulted in it: greater accuracy and level of realism P. Morovič & Finlayson JOSA, 2006© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • SPECTRAL PRINTING Urban Derhak JD, 2009 ICC DPD, 2011© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • HANS: WHO WHAT IS THAT? printer (inks, media, WS, FW, pipeline)! artist! Printing as mosaic assembly Separation: from ink amount selection to Neugebauer Primary (NP) statistics mosaic! print! Halftoning: from per ink continuous levels to discrete drops to single ink drop stack (NP) from local statistics J. Morovič, P. Morovič, et al. tesserae/ Neugebauer Primaries (NPs) / IEEE TIP, 2011 tiles! at-pixel ink drop states!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • HANS COLOR WORKFLOW LAB + spot colors! RGB/CMYK! ‘Upstream’/External workflow Source content (RGB, Contone Conventional! CMYK, Lab, spot colors, Color device color remains (un)tagged)! management! space! unchanged (ICC Color separation!color management Halftone Contone to device color ink space! Halftoning! ink space! data) ink channels! LAB + spot colors! RGB/CMYK! Source content (RGB, Color Contone device CMYK, Lab, spot colors, management! color space! Separation and (un)tagged)! halftoning ‘talk’ in HANS! Color more specific separation! Halftone Contone terms and can ink space! Halftoning! NPac space! ‘say’ new things/ ink channels! Neugebauer Primary channels! patterns. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • BUT WHY BOTHER? Alternative basic Alternative basic ink combinations:! Print color! NPacs:! • Vastly increased space of addressable halftone 2! 6086! (in 4D)! (in 34=81D)! patterns, each having specific properties (grain, ink use, …): knD v. nD 3000x possible patterns (same • Starting point for color)! W=70%! optimization selection of the C1=2%! pattern per color that has M1=5%! ‘best’ properties. Y1=5%! W=79%! K1=6%! • Access to increased color Y1=2%! C1M1=1%! gamut (convex combinations) W=77%! K1=14%! C1K1=2%! C=34%! C=7%! included! C1=1%! Y1K1=2%! M1K1=3%! M=27%! Y=1%! Y1=2%! C2=1%! Y1K1=2%! Y=28%! K=27%! K1=20%! K2=2%! C2=4%!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • CMY METAMERS (TRICHROMACY?!) 12% W 0% W 35% C 51% C 0% M 0% M 29% Y 0% Y 24% CM 4% CM 0% CY 3% CY 0% MY 42% MY 0% CMY 0% CMY© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • 20% LESS INK + 10% MORE GAMUT +10% !60 !60 !40 !40 !20 !20 0 0 a* a* 20 20 40 40 60 60 !40 !20 0 20 40 60 80 !40 !20 0 20 40 60 80 b* b* CMYKcm @ 2dpp = 729 NPs Light ink use: current vs HANS© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • WAIT! YOU CAN DO OTHER STUFF WITH COLOR?• Cost: HANS, K as function of CSF• Ease of use: color personalization• Productivity: profiling chart optimization• Reliability: closed loop system, auto-calibration/profiling/configuration• Encryption?!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • SPATIAL BLACK GENERATIONKisilev et al.CIC, 2011© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • COLOR ME EASY printers/media photos Personalize Color Output for P Printer/Media Video 1: Video 2: Adjust each image Encode adjustment as individually for print modified ICC profile New Media/Printer? New Media/Printer? Adjust all photos... Adjust profile(s) only.P. Morovič et al.CGIV, 2012© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • FASTER WITH LESS ∆E2000 profiling color samplesJ. Morovič et al.IEEE TIP, 2010© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • SAME, SAME & NOT DIFFERENT Densitometer integrated in print carriage → print carriagecalibration without need of expert knowledge or external devices (1997) Mirror Electronics GreatgMacbeth/Xrite spectrophotometerintegrated in printhead-shaped enclosure, part of Photodiode print carriage → 2x color consistency versus Array densitometer HolographicBuilt–in, ‘Green Button,’ single–click, high quality Grating (gallery print) ICC profiling with robust defaults → Test Chart consistent & accurate color •  ICC Profiling •  Calibration Shutter withHP Z–series Designjet printers White Tile Lenssince 2006 White LED© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • IT’S ALL GARBLED UP!? 1. Photographer contacts PSP Photograher to have his photos printed... Print Service Provider 3. PSP sends encryption profile to photographer 5. Photographer sends encrypted photos to PSP 4. Photographer converts photos to encrypted space 6. PSP sends scrambled 2. Print service provider image to correct printer to retrieves scrambling ICC be printed (correct profile from printer of unscramling profile is photographers choice applied internally) (unscrambling internal to printer) device X provides public key represent & decode & encode interpret device A LABX device X using public using private key ICC key ICC device B LABY device Y represent & decode & encode interpret device Y provides public key P. Morovič et al. CIC, 2010© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • THE FUTURE OF COLOR “You cant connect the dots looking forward; you can only connect them looking backwards.” –Steve Jobs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “The only way you can predict the future is to build it.” –Alan Kay© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • WHAT SHALL WE BUILD?• Color as color: larger gamut, more resolution, better detail, better re–rendering, controlled color on new materials and under new conditions; pro performance for consumers at consumer prices; done properly in new applications (medicine, motion pictures, data visualization & analysis) • But: do we need it? Yes! Customers may not ask for it, but will appreciate and demand it once they see it (à la Ford’s faster horses v. cars)• Hidden color: cheaper HW/materials/resources, faster setup and performance, easier use and application to new contexts (e.g., 3D printing), more predictable, more consistent• Good color can also be like good typography – invisible.© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • ACKNOWLEDGEMENTS • Peter Morovič • Albert Serra • Marc Rossinyol • Jordi Arnabat • Rafa Gimenez • Santi Reyero • Juan Manuel García–Reyero • Ramon Pastor • Ingeborg Tastl • Marti Rius • Jep Tarradas • John Recker • Jordi Vilar • Johan Lammens • Angel Albarran • Yvan Richard • Philipp Urban • Carlos Amselem • Patrick Chase© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
    • THANK YOU!© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.