Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Green-Red Color Contrast Improvement

823 views

Published on

Dr. Katalin Toth's presentation about the green-red colour contrast improvement at the conference Strategies in Light Europe 2012 in MÜnchen, Germany.

Published in: Technology, Design
  • Be the first to comment

  • Be the first to like this

Green-Red Color Contrast Improvement

  1. 1. Green-Red Color Contrast Improvement:Feasibility, Effect and InterpretationDr. Katalin TóthGE LightingGlobal LightingTraining & Six Sigma Manager 18 September
  2. 2. Same effect with artifictial illumination:
  3. 3. Standard CFL Reveal CFL
  4. 4. Booth test Standard FL 300lux Reveal ® 260 lux 35Questions: Answer of 31 observers 301, Which is more colourful 252, Where are the contrasts sharper 20 1 booth3, Where is the white brighter 15 2 booth4, Where is the overall brightness higher 10 5 0 1 2 3 4
  5. 5. Pattern recognition of color 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. 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. 7. Preference of Reveal®-likeperformance confirmed 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. 8. Current metrics for quality of light Standard CFL Reveal® Improved visual Incandescent clarity Reveal® FLRa 80 78 72R9 -12 14 23LPW 65 13 60Do they reflect perception test results?
  9. 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. 10. Why do we have rods and conesOur vision has to operate over an enormous range of1012 levelsTo 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. 11. Rod and cone distribution• 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. 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. 13. Color is encoded by the relative cone outputs Blue light Red light Green light Purple light Yellow light White light GE inside use only
  14. 14. Post receptorial color visionM L S M L Trichomatic stage _ + _ Color opponent stage M-L S-(M+L) CRG CBY Chromatic pathways GE inside use only
  15. 15. Type of color deficiency
  16. 16. Trichomatic stageSpectral response curves of cone cells Color opponent stage CBY=S-(L+M) CRG= L-MNeural opponent signals GE inside use only
  17. 17. Reveal Performance Incandescent Lamps 1.00 0.90 0.80Relative 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. 18. Emission spectra Reveal® Standard GE inside use only
  19. 19. RG neural opponent signaladapted tostandard FLRG neural opponent signaladapted toReveal® FLResulting increased green-redcontrast, gamut and bettercolor rendering for red colorGE inside use only
  20. 20. Protanomal’s RG neural opponent signaladapted to Reveal® FL ® GE inside use only
  21. 21. 30 SPD of 25 Inca. 20CIE color-matching 15 SPD*x-bar SPD*y-barfunctions 2 SPD*z-bar 101.81.6 51.4 0 380 399 418 437 456 475 494 513 532 551 570 589 608 627 646 665 684 703 722 741 7601.2 x-bar 1 y-bar z-bar0.80.60.4 250.2 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. 22. 400 350 300 SPD of Standard CFL 250 SPD*x-bar 200 SPD*y-bar SPD*z-bar 150 100CIE color-matching functions 50 2 01.8 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 7601.61.41.2 x-bar 1 y-bar z-bar0.8 0.20.6 0.180.4 0.160.2 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. 23. Color contrast improvement summary:• 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. 24. Thank you for your attention! 24 / By Katalin Toth/ September 27, 2012

×