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Home , Brightness, CIECAM02, CIELUV, Colorimetry, Lightness

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 • 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 Sources (CIECAM16) Chroma (C) Colourfulness (M) Saturation (s) angle (h)

X Y Z Ref. w w w LA Yb Surround: Hue composition (H) Average, Dim and Dark Colour appearance attributes

• • • 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. effect 2. Hunt effect 3. Stevens effect 4. Surround effect 5. Lightness contrast effect Chromatic Adaptation

Green

Open end - SE Open circle - A 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), 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 , 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- (a) Lightness (J’) Redness Greenness -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 and 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 for image signals including high dynamic range and wide , 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 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!

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