Color Vsion Sang Wook Hong
What is color good for? Segmenting objects from their backgrounds Learning about the properties of objects Signaling Color coding
What is color good for? Segmenting objects from their backgrounds Learning about the properties of objects Signaling Color coding
What is color good for? Segmenting objects from their backgrounds Learning about the properties of objects Signaling Color coding
What is color good for? Segmenting objects from their backgrounds Learning about the properties of objects Signaling Color coding
What is color good for? Segmenting objects from their backgrounds Learning about the properties of objects Signaling Color coding “Providing Jobs to researchers”
Where is Color? In the ‘Light’?
Where is Color? Metamers: Two lights that have different wavelength distributions but are perceptually identical 530 + 620 580 intensity intensity wavelength wavelength
Where is Color? I Became a Father! Color induction: Color appearance is affected by nearby light I Became a Father!
Where is Color?
Where is Color?
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...
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
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
Description of Color
Source of Color Vision Reflected light from objects
Source of Color Vision Reflectance Color Appearance
color vision depends on the activity of three different Trichromatic Theory Hermann von Helmholtz (1821 - 1894) Actually, I just got the idea from Thomas Young (1773 - 1829) color vision depends on the activity of three different receptor mechanisms
Trichromatic Theory Color Matching Experiment
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
Neural Mechanism for Trichromatic Theory
Neural Mechanism for Trichromatic Theory S M L Yellow Red Blue Gray
Neural Mechanism for Trichromatic Theory
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?
Opponent Color Theory Hue Cancellation Experiment: Jameson & Hurvich (1955)
Neural Mechanism for Opponent Theory Electrophysiological recordings from color and spatially opponent midget ganglion cell in the monkey retina Green On/Red OFF
Neural Mechanism for Opponent Theory
Neural Mechanism for Opponent Theory Dacey (1996) Bistratified ganglion cell counter-phase modulation between blue and red+green(luminance) isolated S-cone modulation