Python extract colour from image (tested on Arduino OpenWRT)

gistfile1.txt

from PIL import Image
from math import pow
import colorsys
import urllib, cStringIO

T = 500
URL = 'http://iot.merfobrienzi.it/img.jpg'
basewidth = 80

# http://blog.soulwire.co.uk/code/actionscript-3/colourutils-bitmapdata-extract-colour-palette
class Color:
    def __init__(self, t):
        self.t = t
        self.r = t[0]
        self.g = t[1]
        self.b = t[2]

    def toHex(self):

        def f(x): 
            n = hex(x)[2:]
            if len(n)==1:
                n = '0'+n
            return n

        return f(self.r) + f(self.g) + f(self.b)

    def __str__(self):
        return str(self.r) +','+ str(self.g) +','+ str(self.b)

def similar(c1, c2, tolerance=T):
    distance = 0
    distance += pow(c1.r - c2.r, 2)
    distance += pow(c1.g - c2.g, 2)
    distance += pow(c1.b - c2.b, 2)
    return distance <= tolerance

def different(c1, cs, tolerance=T):
    for c2 in cs:
        if similar(c1,c2, tolerance):
            return False
    return True

def uniqueColours(cs, maximum, tolerance=T):
    uniques = []
    for c in cs:
        if different(c, uniques, tolerance):
            uniques.append(c)

        if len(uniques) > maximum:
            break
    return uniques

if __name__ == "__main__":

    # http://stackoverflow.com/a/7391991/433685

    f = cStringIO.StringIO(urllib.urlopen(URL).read())
    im = Image.open(f)

    # http://stackoverflow.com/a/451580/433685
    #wpercent = (basewidth/float(im.size[0]))
    #hsize = int((float(im.size[1])*float(wpercent)))
    #im = im.resize((basewidth,hsize), 0)
    im = im.resize((19,1), 0)

    #im = Image.open("img.jpg")
    im.convert("RGB")

    colors = {}
    for color in im.getdata():
        colors[color] = colors.get(color, 0) + 1

    colorlist = colors.items();
    colorlist = [ (Color(c[0]), c[1]) for c in colorlist]

    #colorlist = sorted(colorlist, key=lambda tup: tup[1])

    #cs = [t[0] for t in colorlist]
    #u = uniqueColours(cs, 17)

    #u = sorted(u, key=lambda c: colorsys.rgb_to_hsv(c.r, c.g, c.b)[2])

    u = [t[0] for t in colorlist]
    s = ''.join([c.toHex() for c in u] )
    print s

    #pl= Image.new('RGB', (20, 1))
    #tpls = [c.t for c in u]
    #pl.putdata(tpls)
    #pl.show()