This document discusses several color models, including RGB, YIQ, CMY, and HSV. The RGB color model represents colors as combinations of red, green, and blue light and is based on how the eye perceives color. The YIQ color model was used in analog television broadcasting and is derived from RGB. The CMY color model uses cyan, magenta, and yellow as primary colors and is useful for color printing. Finally, the HSV color model represents color in terms of hue, saturation, and value in a cylindrical coordinate representation derived from the RGB color cube.

1. COLOR MODELS
Adri Jovin J.J.
Assistant Professor
Department of Information Technology
Sri Ramakrishna Institute of Technology
Coimbatore.

2. RGB Color Model
• Based on “tristimulus theory of vision”
– eyes perceive color through the stimulation of
three visual pigments in the cones of the retina
– peak sensitivity at wavelengths of about 630 nm
(red), 530 nm (green), and 450 nm (blue)
• Represented as a unit cube defined on R, G, B
axes
• Color Ck = RR + GG + BB
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3. RGB Color Model (Contd..)
"Cie Chart with sRGB gamut by spigget" by Spigget - Own work. Licensed
under Creative Commons Attribution-Share Alike 3.0 via Wikimedia
Commons -
http://commons.wikimedia.org/wiki/File:Cie_Chart_with_sRGB_gamut_
by_spigget.png#mediaviewer/File:Cie_Chart_with_sRGB_gamut_by_spig
get.png
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4. YIQ Color Model

R



R
G
0.299 0.587 0.144



0.299 0.587 0.144
0.596 0.275 0.321



Y
  





G



0.596 0.275 0.321




  



• National Television System Committee (NTSC)
color model for forming the composite video
signal
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









Y




B
I

Q
0.212 0.528 0.311










B
I
Q
0.212 0.528 0.311

5. YIQ Color Model (Contd…)
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"YIQ IQ plane" by Tonyle - Own work. Licensed under
Creative Commons Attribution-Share Alike 3.0 via
Wikimedia Commons -
http://commons.wikimedia.org/wiki/File:YIQ_IQ_plane.s
vg#mediaviewer/File:YIQ_IQ_plane.svg

6. CMY Color Model
• Defined with the primary colors cyan,
magenta, and yellow
• Useful for describing color output to hard-copy
devices
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7. CMY Color Model (Contd…)
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8. HSV Color Model
• Color parameters in this model are hue ( H ) ,
saturation( S ) and value( V )
• 3D representation is derived from RGB Cube.
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9. Reference
• Donald Hearn, Pauline Baker, Computer
Graphics – C Version, Second Edition, Pearson
Education, 2004.
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