Sang Wook Hong

Segmenting objects from their backgrounds

Learning about the properties of objects

Signaling

Color coding

Segmenting objects from their backgrounds

Learning about the properties of objects

Signaling

Color coding

Segmenting objects from their backgrounds

Learning about the properties of objects

Signaling

Color coding

Segmenting objects from their backgrounds

Learning about the properties of objects

Signaling

Color coding

Segmenting objects from their backgrounds

Learning about the properties of objects

Signaling

Color coding

“Providing Jobs to researchers”

In the ‘Light’?

Metamers: Two lights that have different wavelengthdistributions but are perceptually identical

580530 + 620

wavelength

intensity

wavelength

intensity

Color induction: Color appearance is affected by nearby light

This isn't real...This isn't real...

What is "real"? How do you What is "real"? How do you define "real"? define "real"? If you're talking about what If you're talking about what you can feel, what you can smell, you can feel, what you can smell, what you can taste and see, what you can taste and see, then "real" is simply electrical then "real" is simply electrical signals signals interpretedinterpreted by your brain... by your brain...

Color is in the Brain

Perceived color is a neural representation for the lightreflected from a target object

A I AI

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 chromaticcolor

Brightness: Perceived light level

Reflected light from objects

Reflectance Color Appearance

Hermann von Helmholtz (1821 - 1894)

Actually, I just got the idea fromThomas Young (1773 - 1829)

color vision depends on the activity of three different receptor mechanisms

Color Matching Experiment

Color Matching Experiment

400 500 600 700

Pri

mar

y in

tens

ity “Our perception of color may

be determined by the ratio

of activity in three receptor

mechanisms with different

spectral sensitivities.”

S MM L

Blue

Red

YellowYellow

Gray

Is there a color appearing bluish yellow or yellowish blue?

Is there a color appearing reddish green or greenish red?

Ewald Hering (1834 - 1918)

Hue Cancellation Experiment: Jameson & Hurvich (1955)

Electrophysiological recordings from color and spatially opponent

midget ganglion cell in the monkey retinaGreen On/Red OFF

+M-L

Bistratified ganglion cell

Dacey (1996)

counter-phase modulation between blue andred+green(luminance)

isolated S-cone modulation