C o l o u r a p p e a r a n c e Ming Ronnier Luo Z h e j i a n g U n i v e r s i t y , Hangzhou, China Scope • CIE Colorimetry • Colour appearance models • Recent developments ICC DevCon 2020 Ming Ronnier Luo 2 Scope CIE Colorimetry Colour appearance models Recent developments CIE 015:2018 Colorimetry 4th Edition s10() m10() l10() 2.5 z () 2.0 1.5 x ( ) y ( ) 1.0 Tristimulus values Tristimulus 0.5 CMF 0.0 380 480 580 680 780 2o & 10o Wavelength ( nm ) SPD Spectral r L* D65 & A hab 120 CIELUV 100 CIELAB XYZ 80 b* 60 40 SPD b* 20 a* CIEDE2000 CIE LEDs 0 -60 -40 -20 0 20 40 60 80 100 120 CIECAM02 -20 -40 -60 a* CAM02-UCS C*ab CIE 015:2018 Colorimetry 4th Edition New CIE LED illuminants 0.35 0.6 0.3 0.5 0.25 0.4 0.2 0.3 Target 0.15 Target 0.2 0.1 0.05 0.1 0 0 360nm 410nm 460nm 510nm 560nm 610nm 660nm 710nm 760nm 360nm 410nm 460nm 510nm 560nm 610nm 660nm 710nm 760nm wavelength wavelength LED-B1 LED-B2 LED-B3 LED-B4 LED-B5 LED-BH1 LED-RGB1 LED-V1 LED-V2 Colour Appearance Model Lightness (J) Redness-Greenness (a) Yellowness-Blueness (b) X Y Z CIECAM02 Light Sources (CIECAM16) Chroma (C) Colourfulness (M) Saturation (s) Hue angle (h) X Y Z Ref. w w w LA Yb Surround: Hue composition (H) white Average, Dim and Dark Colour appearance attributes • Lightness • Brightness • Chroma • Colourfulness • Saturation • Hue angle • Hue composition 1. M. R. Luo, et. al. Quantifying colour appearance: Part I CRA 16 (1991) 166-180. 2. M. R. Luo, et. al. Quantifying colour appearance: Part II CRA 16 (1991) 181-197. 3. M. R. Luo, et al., Quantifying colour appearance: Part III CRA 18 (1993) 98-113. 4. M. R. Luo, et al., Quantifying colour appearance: Part IV CRA 18 (1993) 191-209. 5. M. R. Luo, et al., Quantifying colour appearance: Part V CRA 20 (1995) 18-35. Relationship between the absolute and relative colour appearance attributes Brightness Lightness = Brightnesswhite Colourfuln ess Chroma = Brightnesswhite Colourfuln ess Chroma Brightness Saturation = = white Brightness Lightness Brightnesswhite Chroma = Lightness Visual Phenomena 1. Chromatic adaptation effect 2. Hunt effect 3. Stevens effect 4. Surround effect 5. Lightness contrast effect Chromatic Adaptation Green Red Open end - SE Open circle - A Blue Hunt Effect 180 160 C*=80 140 120 C*=60 100 80 C*=40 60 C*=20 40 20 C*=0 0 -2 -1 0 1 2 3 4 5 6 log 10Lw Stevens Effect 800 700 L*=80 600 500 L*=60 400 L*=40 300 L*=20 200 100 L*=0.01 0 -2 -1 0 1 2 3 4 5 6 log10Lw CIE Colour Appearance Models • CIECAM97s • CIE TC1-34 Testing colour appearance models • M. R. Luo and R. W. G. Hunt, The structures of the CIE 1997 colour appearance model (CIECAM97s), Color Res. Appl., 23 138-146 (1998). • CIECAM02 • CIE TC8-01 Colour Appearance Modelling for Colour Management Applications, Scottsdale, Arizona, USA (1998-2002) • N. Moroney, M. D. Fairchild, R.W.G. Hunt, C Li, M. R. Luo and T. Newman, The CIECAM02 Color Appearance Model, CIC2002, Scottsdale, Arizona, pp23-27. • CIECAM16 • CIE JTC10 A new colour appearance model for colour management systems: CIECAM16, （Jiju, South Korea 2017- 2020). • C. J. Li. Z. Li, Z. Wang, Y. Xu, M. R. Luo, G. H. Cui, M. Melgosa, M. H. Brill, and M. R. Pointer, Comprehensive color solutions, CAM16, CAT16 and CAM16-UCS, Col., Res. and Appl., (2017), pp42703-718. Uniform Colour Spaces 120 100 b* b 100 80 80 60 60 40 40 20 20 a 0 a* 0 -20 -20 -40 -40 -60 -60 -60 -40 -20 0 20 40 60 80 100 120 -60 -40 -20 0 20 40 60 80 100 CIELAB CAM02-UCS M. R. Luo, G. Cui, C. Li, Uniform Colour Spaces Based on CIECAM02 Colour Appearance Model, Color Res. Appl. 31 (2006) 320-330. Scope CIE Colorimetry Colour appearance models Recent developments CIECAM Input and output parameters Related Red-Green (a) Lightness (J’) Redness Greenness Yellow-blue (b) Red-Green (a’) X Y Z Brightness (Q) Yellow-blue (b’) Lightness (J) Colourfulness (M’) Achromatic Hue angle (h) signal Colourfulness (M) Chroma (C) DJ’, DM’, DH, DEJ’a’b’ Saturation (s) Yellowness Blueness Hue angle (h) Hue composition (H) Unrelated Brightness (Qun) Colourfulness (Mun) White amount (Wun) Hue Surround: Angle subtense Xw Yw Zw LA Yb Average, Dim (q) and Dark Recent developments Incomplete chromatic adaptation CAT02- Incomplete adaptation Zhai et al, OE 26(2018)7724-39 Zhu et al, CRA(DOI/10.1002/Col.22500) 1 surface 0.8 self-luminous projector Present result 0.6 D 0.4 0.2 0 2500 5000 7500 10000 CCT/K D=F{1-(1/3.6)e[(-La-42)/92] } 2 2 D=a0+a1du’+a2dv’+a3sqrt(du’ +dv’ ) D= Function (Surround, La, [CCT, Duv] or [u’v’], Area, Time, media) Y. Zhu, M. Wei, M. R. Luo, Effects of Adapting Chromaticities and Luminance on Color Appearance on Computer Displays Using Memory, Color Res. and Appl., 000-000 Simultaneous colour contrast 1 ∆H 0.5 0 ∆h -180 -120 -60 0 60 120 180 -0.5 -1 modeling_7° modeling_15° 20 Result (ΔL*) result 15 10 5 0 Background（ΔL*） -100 -50 0 50 100 -5 -10 Y. Zhu and M. R. Luo, (O) Proposed Modification to the CAM16 Colour Appearance Model to Predict the Simultaneous Colour Contrast Effect, 27th Color and Imaging Conference (2019), Paris, 2019, pp190-194. Whiteness-Depth Blackness-Vividness 3 2 r = -0.82 Whiteness 1 0 -1 -2 British Observer Response Observer British -3 0 20 40 60 80 100 Depth (Dab*) Saturation Whiteness 3 2 r = -0.86 1 Blackness 0 -1 -2 Blackness Observer ResponseBritish -3 0 20 40 60 80 100 Vividness (Vab*) Y. J. Cho, L. C. Ou and M. R. Luo, A cross-culture comparison of saturation, vividness, blackness and whiteness scales, Color Res and Appl.,42(2017)203-215 Meaningful colour appearance scales Wang and Luo, R&A, 10(2018)458-470 80 PR650 70 Whiteness – Depth 60 L* 50 Blackness - Vividness 40 Caucasian Oriental 30 South Asian 20 0 10 20 30 40 C*ab Back yard of CII (Derby) Point 1~10 sky Point 11~20 plants Point 21~30 building Jzazbz Model for HDR/WCG M. Safdar, G. Cui, Y. J. kim and M. R. Luo, Perceptually uniform color space for image signals including high dynamic range and wide gamut, Optics Express, 25(2017), pp15131-15151. COMBVF Ellipses CIELAB CAM16-UCS 100 40 30 50 20 10 M b b* 0 0 -10 -20 -50 -30 -40 -50 0 50 100 -40 -20 0 20 40 a a* M IPT J a b z z z 5 0.15 4 0.1 3 2 0.05 z b T 1 0 0 -1 -0.05 -2 -0.1 -3 -0.1 -0.05 0 0.05 0.1 0.15 -2 0 2 4 a P z Hung & Berns Data Hue Linearity - WCG Unitary Hue Data Other Hue Data UCS’s performance Rescaled Chromatic discrimination ellipses in J a b z z z Rescaled Chromatic discrimination ellipses in CAM02-UCS b b z M 0.15 40 30 0.1 2 20 1 푁 퐴푖 σ푖=1 − 1 0.05 푁 퐵푖 10 a a 푳풐풄풂풍 = × 100% (8) z M 1 -0.15 -0.1 -0.05 0.05 0.1 0.15 -0.05 -10 -20 1 2 -0.1 푁 ҧ σ푖=1 푆푖 − 푆 -30 푁 퐺푙표푏푎푙 = × 100% (9) -0.15 ҧ -40 푆 Rescaled Chromatic discrimination ellipses in IC C T P Rescaled Chromatic discrimination ellipses in CIELAB C T b* -0.3 100 Colour Spaces Local (%) Global (%) -0.2 CIELAB 222 48 50 -0.1 CAM02-UCS 138 31 -0.3 -0.2 -0.1 0.1 0.2 0.3 a* ICTCP 175 59 C P -100 -50 50 100 Jzazbz 160 67 0.1 -50 0.2 0.3 -100 CIECAM Input and output parameters 1D-scales 2D-scales Redness Greenness Related X Y Z UCS Vividness (V) Brightness (Q) Depth (D) Achromatic Lightness (J) signal Lightness (J’) Saturation (s) Colourfulness (M) Colourfulness (M’) Blackness (K) Chroma (C) Hue angle (h) Whiteness (W) Yellowness Saturation (s) Blueness DJ’, DM’, DH, DEJ’a’b’ Hue angle (h) Clarity (Cl) Hue composition (H) Y Xw Yw Zw LA b Surround: Angle subtense Average, Dim (q) and Dark Colou reproduction • Spectral (R%) • Relative Colorimetric (XYZ) • Absolute Colorimetric (XL YL ZL) • Appearance (JCh, QMh) • Preference (JCh, QMh) Go beyond colour! CMF CIE 2015 2o & 10o colorimetry SPD Spectral D65 & A reflectance Translucency XYZ CIEDE2000 CIELAB CIELUV CAM16 Total ZCAM Appearance Gloss CAT16 (D) CAM02-UCS 2D colour appearance Jzazbz Unrelated Spatial colour differences Texture colours Colour HDR/WCG contrast Conclusions • Colour appearance models • viewing parameters, Correlates, Visual phenomena • Recent developments • CAT-D • Colour contrast • 2D-colour appearance scales 1 0.8 • Jzazbz UCS 0.6 0.4 • HDR and WCG applications 0.2 0 • Hue linearity 380 480 580 680 Thanks for your attention! Cel.zju.edu.cn [email protected].