Colour perception

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Presentation on Colour Perception in Visual Perception theory and application course @PSYC UBC
Spring 2011

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Colour perception

  1. 1. 2.1 Color PerceptionPSYC 579 Topic Presentation,University of British ColumbiaDiliara NasirovaSchool of Interactive Art and Technology,Simon Fraser UniversityJanuary 26, 2011
  2. 2. 2Outline1.  The Physical Description of Light■  Light Components■  Electromagnetic Spectrum2.  The Psychological Description of Color■  Color Space3.  Theories of Color Vision■  Trichromatic Theory■  Opponent Process TheoryDiliara Nasirova | PSYC 579 | Jan 26, 20114.  Basic Phenomena■  Color Blindness■  Color Afterimage■  Color Contrast5.  Application to Visual Design■  Color Specification Interfaces■  Color for Labeling
  3. 3. 3References1.  C. Ware, “Information Visualization: Perception for Design”, ch. 4 “Color”2.  SE. Palmer, “Vision Science”3.  E. Tufte, “Envisioning Information”, ch. 5 “Color and information”4.  P Rheingans. (1999). “Task-based Color Scale Design”5.  CA Brewer. (2005). “Designing Better Maps”, ch. 5 “Color Decisions forMapping”6.  C. Ware, “Visual Thinking for Design”, ch. 4 “Color”7.  M. Stone, “Color in Information Display” workshop, Vis08Diliara Nasirova | PSYC 579 | Jan 26, 2011
  4. 4. 4The Physical Description of LightLight ComponentsDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Sir Isaac Newton, 1666
  5. 5. 5The Physical Description of LightElectromagnetic SpectrumDiliara Nasirova | PSYC 579 | Jan 26, 2011
  6. 6. 6The Psychological Description of ColorColor Space•  All colors experiences can bedescribed in terms of threedimensions:■  Hue■  Value (lightness)■  Saturation (chroma)Diliara Nasirova | PSYC 579 | Jan 26, 2011
  7. 7. 7The Psychological Description of ColorColor Space•  Color space:■  A three dimensional coordinatesystem■  Each color can be represented as asingle point with a unique position.Diliara Nasirova | PSYC 579 | Jan 26, 2011
  8. 8. 8The Psychological Description of ColorColor Space•  Color solid: Subset of color spaceDiliara Nasirova | PSYC 579 | Jan 26, 2011LightnessHueSaturation
  9. 9. 9Theories of Color VisionTrichromatic Theory•  Trichromacy:Three color receptors (cones) inretinas that are active at normallight levels•  Young-Helmholtz TrichromaticTheoryDiliara Nasirova | PSYC 579 | Jan 26, 2011
  10. 10. 10The Physical Description of LightSpectral DiagramDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Human cone sensitivityfunctions.•  Cones sensitive to■  S (blue)■  M (green)■  L (red)
  11. 11. 11The Physical Description of LightSpectral Diagram: Short wavelength sensitive conesDiliara Nasirova | PSYC 579 | Jan 26, 2011Blue text on a dark backgroundis to be avoided. We have very fewshort-wavelength sensitive cones inthe retina and they are not verysensitive.Blue text on a dark backgroundis to be avoided. We have very fewshort-wavelength sensitive cones inthe retina and they are not verysensitive.
  12. 12. 12The Physical Description of LightSpectral Diagram: Short wavelength sensitive conesDiliara Nasirova | PSYC 579 | Jan 26, 2011Blue text on a dark backgroundis to be avoided. We have very fewshort-wavelength sensitive cones inthe retina and they are not verysensitive.Blue text on a dark backgroundis to be avoided. We have very fewshort-wavelength sensitive cones inthe retina and they are not verysensitive.
  13. 13. 13Theories of Color VisionOpponent Process Theory•  Ewald Hering Opponent ProcessTheory•  Six elementary colors arranged asopponent pairs along three axes:■  black-white,■  red-green,■  yellow-blue.Diliara Nasirova | PSYC 579 | Jan 26, 2011
  14. 14. 14Theories of Color VisionOpponent Process Theory: Physiological basis•  Input from the cones is processed into 3 distinct channelsDiliara Nasirova | PSYC 579 | Jan 26, 2011
  15. 15. 15Theories of Color VisionOpponent Process Theory: Scientific evidence1.  Unique Hues:black, white, red, green…Diliara Nasirova | PSYC 579 | Jan 26, 2011
  16. 16. 16Theories of Color VisionOpponent Process Theory: Scientific evidence2.  Naming and Cross-Cultural Naming:“yellowish green”, but no “yellowish blue”Diliara Nasirova | PSYC 579 | Jan 26, 2011
  17. 17. 173.  Neurophysiology: cells in visualcortexes of monkeys that haveproperties of opponencyDiliara Nasirova | PSYC 579 | Jan 26, 2011Theories of Color VisionOpponent Process Theory: Scientific evidence
  18. 18. 183.  Categorical Colors:■  Evidence that confusionbetween colors is affected bycolor categoriesDiliara Nasirova | PSYC 579 | Jan 26, 2011Theories of Color VisionOpponent Process Theory: Scientific evidence
  19. 19. 19Diliara Nasirova | PSYC 579 | Jan 26, 2011Theories of Color VisionOpponent Process Theory: Scientific evidence
  20. 20. 20Theories of Color VisionOpponent Process Theory: Color Channels Properties•  Chromatic channels carry ~1/3the amount of detail carried bythe black–white channel.•  Difficult to read the text whereluminance is equal, despite alarge chromatic differenceDiliara Nasirova | PSYC 579 | Jan 26, 2011
  21. 21. 21Theories of Color VisionOpponent Process Theory: Color Channels PropertiesDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Form: Form perception processed mainly through the luminance channelFloor, Duomo di Siena
  22. 22. 22Theories of Color VisionOpponent Process Theory: Color Channels PropertiesDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Form: Pseudocolor sequences for maps
  23. 23. 23Basic PhenomenaColor ContrastDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Colors are perceived relative to their overall context
  24. 24. 24Basic PhenomenaColor Blindness•  ~10% of the male and ~1% of the female population have some form ofcolor vision deficiency.OriginalDeuteranope (r/g)Protanope (r/g)Tritanope (y/b)
  25. 25. 25Basic PhenomenaColor BlindnessDiliara Nasirova | PSYC 579 | Jan 26, 2011
  26. 26. 26Basic PhenomenaColor BlindnessDiliara Nasirova | PSYC 579 | Jan 26, 2011Normalvision: nonumberColor blindvision: “45”
  27. 27. 27Basic PhenomenaColor AfterimageDiliara Nasirova | PSYC 579 | Jan 26, 2011
  28. 28. 28Basic PhenomenaColor AfterimageDiliara Nasirova | PSYC 579 | Jan 26, 2011.
  29. 29. 29Basic PhenomenaColor Afterimage•  BMW commercial:http://www.huffingtonpost.com/2010/12/16/bmw-ad-vide-burns-logo-into-eyes-_n_797981.htmlDiliara Nasirova | PSYC 579 | Jan 26, 2011
  30. 30. 30Application to Visual DesignColor Specification InterfacesDiliara Nasirova | PSYC 579 | Jan 26, 2011•  One of the most widely used colorinterfaces in computer graphics isbased on the HSV color spacesaturationhue value
  31. 31. 31Application to Visual DesignColor Specification InterfacesDiliara Nasirova | PSYC 579 | Jan 26, 2011
  32. 32. 32Application to Visual DesignColor for Labeling•  Labeling: nominal informationcoding•  Color can be extremely effectiveas a nominal code.Diliara Nasirova | PSYC 579 | Jan 26, 2011
  33. 33. 33Application to Visual DesignColor for Labeling•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  ConventionsDiliara Nasirova | PSYC 579 | Jan 26, 2011
  34. 34. 34Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  Conventions
  35. 35. 35Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  Conventions
  36. 36. 36Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  Conventions
  37. 37. 37Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  Conventions
  38. 38. 38Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  Conventions
  39. 39. 39Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  Perceptual factors to be considered:1.  Distinctness2.  Unique hues3.  Contrast with background4.  Color blindness5.  Number6.  Field size7.  Conventions
  40. 40. 40Application to Visual DesignColor for LabelingDiliara Nasirova | PSYC 579 | Jan 26, 2011•  12 colors recommended for use in coding.
  41. 41. 41Conclusion

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