Question

I am looking to isolate “brown” colors by rgb values. Not just 1 brown color, but the wide spectrum of colors that are perceived as brown – tan, suede, dirt, etc.

Any ideas on how to do this? I’m thinking that maybe if Red is less than 128, and Green is between 70 and 138, and blue is less than 128, than it appears brown. Something along those lines.

Answer 1

A really simple heuristic would be something like, in pythony pseudocode

def isBrown(red, green, blue):

  # Kind of maximum lightness
  if blue > parameter_1
    return False

  # how green or red tinted can it be
  if absolute_value(red - green) > parameter_2:
    return False

  # Light brown is just yellow or orange
  if maximum_of(red, green) > parameter_3:
    return False
  else:
    return True

The tune parameters 1 through 3 until it works nicely. Perhaps replace if absolute_value(red - green) > parameter_2: with if absolute_value(red - green*parameter_2b) > parameter_2a: so that more greeny or reddy ones are selected depending on parameter_2b. Perhaps change maximum_of to something else. etc. etc.