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Green-Red Color Contrast Improvement
The document discusses the feasibility and effects of green-red color contrast improvement, focusing on various lighting techniques and their impacts on visual perception. It includes results from tests conducted with observers that highlight preferences for different types of lamps and their effectiveness in enhancing color vividness and contrast for individuals with color deficiencies. The findings suggest that specific lighting can significantly improve color perception and perceived brightness.
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Green-Red Color Contrast Improvement
- 1. Green-Red Color ContrastImprovement: Feasibility, Effect and Interpretation Dr. Katalin Tóth GE Lighting Global Lighting Training & Six Sigma Manager 18 September
- 2. Same effect withartifictial illumination:
- 3. Standard CFL Reveal CFL
- 4. Booth test Standard FL 300lux Reveal ® 260 lux 35 Questions: Answer of 31 observers 30 1, Which is more colourful 25 2, Where are the contrasts sharper 20 1 booth 3, Where is the white brighter 15 2 booth 4, Where is the overall brightness higher 10 5 0 1 2 3 4
- 5. Pattern recognition ofcolor deficient individuals Standard FL 300lux Reveal® 260 lux Correct answers for Ishihara test Standard Reveal Individual #1 9 12 Individual #2 16 18 Individual #3 13 21 Individual #4 18 20
- 6. Human Perception • 2 booths • 3 images • 26 individuals • Luminance set equal in both booths • Compare right lamp with left lamp • Difference was calibrated to the Inc-Reveal pair. Lamp pairs tested: Y: 1 Inca. Std. FL_1 R Ⓡ Preference scores: right vs. left 2 FL_2 R Ⓡ FL_1 RⓇ 3 FL Std FL_1 R Ⓡ 4 FL Standard Inca. Reveal Ⓡ 5 FL Standard Inca. Standard Left one Right one 6 FL_2 Reveal Ⓡ Inca. Standard preferred preferred 7 FL_2 Reveal Ⓡ FL Standard 8 FL_2 Reveal Ⓡ Inca. Reveal Ⓡ -5 0 +5 9 FL_1 Reveal Ⓡ Inca. Reveal Ⓡ 10 Inca Standard Inca. Reveal Ⓡ
- 7. Preference of Reveal®-like performanceconfirmed Left lamp Negligible Right lamp preferred Difference preferred Individual 95% CI Pair Mean --------+---------+---------+---------+--- 1 Inc Std. FL_1 RⓇ 0.577 (--*---) 2 FL_2 R Ⓡ FL_1 RⓇ-0.000 (---*---) 3 FL Std. FL_1 RⓇ 0.654 (--*---) 4 FL Std. Inc. RⓇ 0.679 (---*---) 5 FL Std. Inc. Std.-0.103 (--*---) 6 FL_2 RⓇ Inc. Std.-0.551 (--*---) 7 FL_2 RⓇ FL Std. -0.526 (---*--) 8 FL_2 RⓇ Inc. RⓇ -0.026 (--*---) 9 FL_1 RⓇ Inc. RⓇ 0.051 (--*---) 10 Inc. Std. Inc. RⓇ 0.808 (--*---) --------+---------+---------+---------+--- -0.400 0.000 0.400 0.800
- 8. Current metrics forquality of light Standard CFL Reveal® Improved visual Incandescent clarity Reveal® FL Ra 80 78 72 R9 -12 14 23 LPW 65 13 60 Do they reflect perception test results?
- 9. Human photoreceptors Rods: • Achromatic night vision • 1 type Cones: • Daytime, achromatic and chromatic vision • 3 types Long-wavelength Middle-wavelength Short-wavelength sensitive (L) or sensitive (M) or sensitive (S) or „red” cone „green” cone „blue” cone
- 10. Why do wehave rods and cones Our vision has to operate over an enormous range of 1012 levels To cover that range we have two different types of photoreceptors: • Rods that are optimized for low light levels • Cones that are optimized for higher light levels GE inside use only
- 11. Rod and conedistribution • 0.3mm of eccentricity is about 1 deg of visual angle (eccentricity angle) • 120 million rods (absent in the central of fovea (0.3mm fovea centralis), max at 20 deg • At night you have to look away from things to see them in more details • 6-7 million cones (concentrated in the fovea) • During the day you have to look at things directly to see them in detail GE inside use only
- 12. Spectral sensitivity, univariance •Probability of photon absorption depends upon wavelength • But response is independent of photon wavelength • Change in output could be caused by change in intensity or a change in color • Each photoreceptor is „color blind”, being unable to distinguish between colour and intensity changes • All the photoreceptor effectively does is to count photons GE inside use only
- 13. Color is encodedby the relative cone outputs Blue light Red light Green light Purple light Yellow light White light GE inside use only
- 14. Post receptorial colorvision M L S M L Trichomatic stage _ + _ Color opponent stage M-L S-(M+L) CRG CBY Chromatic pathways GE inside use only
- 15. Type of colordeficiency
- 16. Trichomatic stage Spectral responsecurves of cone cells Color opponent stage CBY=S-(L+M) CRG= L-M Neural opponent signals GE inside use only
- 17. Reveal Performance Incandescent Lamps 1.00 0.90 0.80 Relative intensity 0.70 0.60 0.50 0.40 Warm white Incandescent Reveal 0.30 Reveal® • filters out yellow (560-620nm) 0.20 0.10 0.00 350 450 550 650 750 Wavelength (nm) Fluorescent lamps 1.0 0.9 0.8 Fluorescent spectrum: Relative Intensity 0.7 Triphos 0.6 Test#4 0.5 • minimizes addition of yellow 0.4 0.3 Looks like small change in spectrum 0.2 0.1 Significant effect in color perception 0.0 17 / 350 450 550 650 750 By Katalin Toth/ Wavelength (nm) September 27, 2012
- 18. Emission spectra Reveal® Standard GE inside use only
- 19. RG neural opponentsignal adapted to standard FL RG neural opponent signal adapted to Reveal® FL Resulting increased green-red contrast, gamut and better color rendering for red color GE inside use only
- 20. Protanomal’s RG neuralopponent signal adapted to Reveal® FL ® GE inside use only
- 21. 30 SPD of 25 Inca. 20 CIE color-matching 15 SPD*x-bar SPD*y-bar functions 2 SPD*z-bar 10 1.8 1.6 5 1.4 0 380 399 418 437 456 475 494 513 532 551 570 589 608 627 646 665 684 703 722 741 760 1.2 x-bar 1 y-bar z-bar 0.8 0.6 0.4 25 0.2 0 20 380 399 418 437 456 475 494 513 532 551 570 589 608 627 646 665 684 703 722 741 760 15 SPD*x-bar SPD*y-bar 10 SPD*z-bar 5 SPD of Reveal Incan .0 21 / 380 399 418 437 456 475 494 513 532 551 570 589 608 627 646 665 684 703 722 741 760 By Katalin Toth/ September 27, 2012
- 22. 400 350 300 SPD of Standard CFL 250 SPD*x-bar 200 SPD*y-bar SPD*z-bar 150 100 CIE color-matching functions 50 2 0 1.8 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 1.6 1.4 1.2 x-bar 1 y-bar z-bar 0.8 0.2 0.6 0.18 0.4 0.16 0.2 0 0.14 380 399 418 437 456 475 494 513 532 551 570 589 608 627 646 665 684 703 722 741 760 0.12 SPD*x-bar 0.1 SPD*y-bar 0.08 SPD*z-bar 0.06 546 Hg line 0.04 0.02 SPD of Reveal CFL 0 22 / 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 By Katalin Toth/ September 27, 2012
- 23. Color contrast improvementsummary: • Make colour more vivid: increased chroma • Improve green-red contrast • Good for person with certain type colour- deficiency • Increase perceived illumination level 23 / By Katalin Toth/ September 27, 2012
- 24. Thank you foryour attention! 24 / By Katalin Toth/ September 27, 2012