IES TM Evaluating Light Source Color Rendition

Átírás

1 IES TM Evaluating Light Source Color Rendition

2 "Original"

3 "CRI = 80" Desaturated

4 "CRI = 80" Saturated

5 More metrics Color Fidelity Color Discrimination Color Preference

6 Metrics/Measures R f (IES TM-30-15) R g (IES TM-30-15) CRI R a (CIE ) CRI R 9 (CIE ) CCT u'v' D uv Criteria K 5000 K Standards ANSI C ANSI/IES RP-1-12 ISO (CIE S 008) Design Guidance IES DG-1 TM-30 is a method that includes several related measures. TM-30 is not a required standard, and does not provide design guidance or criteria.

7 IES Method for Color Rendition Color Fidelity Color Gamut Graphics The accurate rendition of color so that they appear as they would under familiar (reference) illuminants Fidelity Index (R f ) (0-100) The average level of saturation relative to familiar (reference) illuminants. Gamut Index (R g ) ~ when R f > 60 Visual description of hue and saturation changes. Color Vector Graphic

8 Samples

9 Uniformity

10 Fidelity Index: R f a' Reference Source Test Source Average similarity in appearance of test and reference sources Analogous to CIE R a, greater accuracy Scores 0 to 100 Scale similar to CIE R a, but high scores harder to achieve Equal weight to all directions of shift Should not be expected to correlate with any single object

11 Relative Gamut Index: R g b' a' b' a' An R g value greater than 100 indicates an average increase in saturation and an R g value less than 100 indicates an average decrease in saturation.

12 Limits

13 Color Vector Graphic Gamut is not a dimension of perception. It is best interpreted with reference to a complementary graphic. Color Vector Graphic Color Distortion Graphic R f = 81 R g = 101 CCT = 2496 K R a = 88 (Source No. 286)

14 R f, R g and Color Vector Graphic CCT = 3500 K, R f = 100, R g = R g R f

15 R f, R g and Color Vector Graphic CCT = 3500 K, R f = 65, R g = R g R f

16 R f, R g and Color Vector Graphic CCT = 3500 K, R f = 65, R g = R g R f

17 Halogen MR16, 3000 K R f = 99 R g = 99 R f,skin = 99 CCT D uv R a R 9 = = = = 2988 K

18 Neodymium Incandescent R f = 86 R g = 109 R f,skin = CCT D uv R a R 9 = = = = 2757 K

19 High Pressure Sodium (Source No. 56) R f = 32 R g = 61 R f,skin = 34 CCT D uv R a R 9 = = = = 1967 K

20 F32T8 835 R f = 80 R g = 102 R f,ski n = CCT D uv R a R 9 = = = = 3480 K

21 Ceramic Metal Halide, 3000 K R f = 79 R g = 100 R f,skin = CCT D uv R a R 9 = = = = 3080 K

22 Original Desaturated Red- Enhanced CRI = 95 CRI = 80 CRI = 80 R f = 93 R g = 100 R f = 78 R g = 90 R f = 78 R g =

23 IES R f versus CIE R a IES R f Filament Daylight Models Narrowband Fluorescent Broadband Fluorescent HID Hybrid LED Color Mixed LED Phosphor LED CIE R a ~16 point spread in R f scores at R a = ~80 23

24 CRI = 80 + Hue Shift R f = 75, R g =

25 CRI = 80 - Hue Shift R f = 75, R g =

26 CRI = 80 Saturated R f = 75, R g =

27 CRI = 80 Desaturated R f = 75, R g = 80 60

28 Színinger-különbség számítások 1976 előtt kb. 30 különböző CIELAB, CIELUV CMC(l:c) CIE94 CIEDE2000

29 Számítás E ab 2 ( a) ( b) ( L 2 ) 2 E u v ' 2 ( u') ( v') ( L) ' 2 2

30 CIE 1994 colour difference E * 94 L * C * H ab k S k S k S L L C C H k parametric factors, industry dependent 2 2 * 2 ab S weighting functions, depend on location in colour space: H 1/ 2 S L = 1; S C = 1 + 0,045 C* ab ; S H = 1 + 0,015 C* ab

31 CIEDE2000 referencia paraméterek CCT D65 megvilágítás 1000 lx háttér neutrális szürke, L' = 50 megfigyelési mód közvetlen méret >4 minták elkülönítése nincs E* ab 0-5 homogén megvilágítás

32 CIEDE2000 #1 a' = a*(1+g) b* a* b' a' G = 0,5[1-(C* ab,m7 /(C* ab,m )) 0,5 ] b' = b* C* ab,m = (C* ab,b + C* ab,s )/2

33 0,6 G 0,4 0, C* ab

34 CIEDE2000 #2 (a', b')-chroma C' = (a' 2 + b' 2 ) 0,5 (a', b')-hue-angle chroma-diference h' = tan -1 (b'/a') C' = C' b - C' s hue-difference H'= 2(C' b C' s ) 0,5 sin( h'/2) onde h' = h' b - h' s

35 CIEDE2000 #3 S L = 1 + 0,015(L' m -50) 2 /[20+(L' m -50) 2 ] 0,5 L' = L* L' m = (L' b +L' s )/2

36 S L 2,0 1,5 1,0 0,5 0, L*

37 CIEDE2000 #4 S C = 1 + 0,045 C' m C' m = (C' b + C' s )/2 S C C' m

38 CIEDE2000 #5 S H = 1 + 0,015 C' m T T = 1-0,17 cos(h' m -30) + 0,24 cos(2h' m ) + 0,32 cos(3h' m +6) - 0,20 cos(4h' m -63) h' m = (h' b +h' s )/2

39 3 S H C' m T

40 T 2 1,6 1,2 0,8 0,4 0 R Y G B h'

41 S H 2,5 2 1,5 1 C' = 50 C' = 20 C' = 5 0,5 0 R Y G B h'

42 CIEDE2000 #6 b* a*

43 R T C' H' R T = - sin(2 Q) R C Q 30 exp[ - ((h' m -275)/25) 2 ] R C = 2(C' m7 /(C' m )) 0,5

44 0,5 0-0,5 R Y G B R T -1 C' = 5-1,5-2 C' = 20 C' = 50 h'

45 CIE 2000 ( L' C' H') E 00 = [( L'/k L S L ) 2 + ( C'/k C S C ) 2 + ( H' /k H S H ) 2 + R T ( C' /k C S C )( H' /k H S H )] 0,5 k L, k C, k H = faktorok

46 Gyakorlati összefoglaló CIEDE2000 ipari alkalmazásra lett kifejlesztve kis és közepes színkülönbségekhez jobb, mint a CMC(l:c) és a CIE94 teszt fázisban van, az eredményeket a CIE gyűjti a jövőben kiváltja majd a CMC(l:c) t az ISO szabványban

47 Advanced colorimetry Colour appearance models chromatic adaptation vonkries transformation CIE (Nayatani) proposal Bradford transformation Hunt model CIECAM97s model Colour management

48 Metamerism Different spectra, identical tristimulus values Metamerism indices: Illuminant Observer Radiance factor Sample 1 Sample Wavelength, nm

49 CIE Whiteness formulae Whiteness: W Y + 800(x n -x) (y n - y) Tint: T W 1000 (x n -x) + 650(y n - y)

50 Signal colours