Which is most accurate way to distinguish one of 8 colors?

Question

Imagine we how some basic colors:

RED = Color ((196, 2, 51), \"RED\")
ORANGE = Color ((255, 165, 0), \"ORANGE\")
YELLOW = Color ((255, 205, 0), \"YELLOW\")
GREEN         


        

Answer 1

Use rgb_to_hsv to convert. Then match the color with the closet hue

For your example it would be RED because the hue matches exactly

>>> from colorsys import rgb_to_hsv
>>> rgb_to_hsv(192,2,51)
(0.83333333333333337, 0, 192)
>>> rgb_to_hsv(206, 17, 38)
(0.83333333333333337, 0, 206)
>>> 

Here's an example of how to find the closest match

>>> from colorsys import rgb_to_hsv
>>> 
>>> colors = dict((
...     ((196, 2, 51), "RED"),
...     ((255, 165, 0), "ORANGE"),
...     ((255, 205, 0), "YELLOW"),
...     ((0, 128, 0), "GREEN"),
...     ((0, 0, 255), "BLUE"),
...     ((127, 0, 255), "VIOLET"),
...     ((0, 0, 0), "BLACK"),
...     ((255, 255, 255), "WHITE"),))
>>> 
>>> color_to_match = (206,17,38)
>>> 
>>> print min((abs(rgb_to_hsv(*k)[0]-rgb_to_hsv(*color_to_match)[0]),v) for k,v in colors.items())
(0.0, 'RED')