1. Color Vsion
Sang Wook Hong

2. What is color good for? Segmenting objects from their backgrounds
Learning about the properties of objects
Signaling
Color coding

3. What is color good for? Segmenting objects from their backgrounds
Learning about the properties of objects
Signaling
Color coding

4. What is color good for? Segmenting objects from their backgrounds
Learning about the properties of objects
Signaling
Color coding

5. What is color good for? Segmenting objects from their backgrounds
Learning about the properties of objects
Signaling
Color coding

6. What is color good for? Segmenting objects from their backgrounds
Learning about the properties of objects
Signaling
Color coding
“Providing Jobs to researchers”

7. Where is Color?
In the ‘Light’?

8. Where is Color? Metamers: Two lights that have different wavelength
distributions but are perceptually identical
580
intensity
intensity
wavelength
wavelength

9. Where is Color? I Became a Father!
Color induction: Color appearance is affected by
nearby light
I Became a Father!

10. Where is Color?

11. Where is Color?

12. Where is Color? This isn't real... What is "real"? How do you
define "real"?
If you're talking about what
you can feel, what you can smell,
what you can taste and see,
then "real" is simply electrical
signals interpreted by your brain...

13. A I Where is Color? A Color is in the Brain
Perceived color is a neural representation for the light
reflected from a target object A I A I

14. Description of Color
Hue: The experience of a chromatic color such as red, green,
yellow, or blue or combinations of these colors
Saturation: The relative amount of whiteness in a chromatic
color
Brightness: Perceived light level

15. Description of Color

16. Source of Color Vision
Reflected light from objects

17. Source of Color Vision
Reflectance
Color Appearance

18. color vision depends on the activity of three different
Trichromatic Theory
Hermann von Helmholtz ( )
Actually, I just got the idea from
Thomas Young ( )
color vision depends on the activity of three different
receptor mechanisms

19. Trichromatic Theory
Color Matching Experiment

20. Trichromatic Theory Color Matching Experiment
“Our perception of color may
be determined by the ratio
of activity in three receptor
mechanisms with different
spectral sensitivities.”
Primary intensity
400
500
600
700

21. Neural Mechanism for Trichromatic Theory

22. Neural Mechanism for Trichromatic Theory
S M L
Yellow
Red
Blue
Gray

23. Neural Mechanism for Trichromatic Theory

24. Opponent Color Theory Ewald Hering (1834 - 1918)
Is there a color appearing bluish yellow
or yellowish blue?
Is there a color appearing reddish green
or greenish red?

25. Opponent Color Theory
Hue Cancellation Experiment: Jameson & Hurvich (1955)

26. Neural Mechanism for Opponent Theory
Electrophysiological recordings
from color and spatially opponent
midget ganglion cell in the monkey retina
Green On/Red OFF

27. Neural Mechanism for Opponent Theory

28. Neural Mechanism for Opponent Theory
Dacey (1996)
Bistratified ganglion cell
counter-phase modulation between blue and
red+green(luminance)
isolated S-cone modulation