Color Space

Mechanism

visible spectrum

Human eyes have two kinds of light sensitive cells, rod cell and cone cell.
Cone cell can detect light in the visible spectrum.
But human only have three types of cone cell, which are red, green, blue.
Thus, when there are lots of lights combined with different wavelength, human brain will interpolate the color between red and blue.
However, if a wavelength of a light is combined with red and blue, the problem is that the color should not be green.
To deal with this problem, human brain create Magenta.

Reference: 这个世界上根本不存在紫色！ ( 眼见为识)

Rod cell is sensitive to luminance.
When there is dark, rod cell can see boundary of objects.

sensitivity

Green > Red > Blue

Color Space

Like coordinate systems may be Cartesian coordinate system or Polar coordinate system.
Color Space also has lots of coordinate systems.

RGB-CMYK

RGB color model is an additive color model.

CMYK is a subtractive color model,

CIE Space

CIE (International Commission on Illumination) is human color vision.

YUV Space

Due to rod cell, human eye is more sensitive at grayscale.
Thus, in traditional camera space will try to seprate gray and other color.

RGB and YUV is able to calculate by martix.
https://en.wikipedia.org/wiki/YUV

HSL, HSV Space

A little like YUV. HSL and HSV also has an axis is lightness.
In HSL or HSV, the H is Hue which using 0 to 360 degree to represent all colors. S is Saturation.
L is Lightness.

CIE-LAB space

A little like YUV, LAB space also has an L-axis is lightness.
AB is like XY coordination.
The most important is that it is also CIE, human eye sensitive.

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tags:

• [[Color]]
• [[Biology]]
• [[Physics]]
• [[眼见为识]]

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