histogram.py

from PIL import Image
import os
import math, operator

for root_n, dirs_n, filenames_n in os.walk('noisy'):
	for f_n in filenames_n:
		if f_n <> ".DS_Store":
			path_n = os.path.join(root_n, f_n)
			noisy = Image.open(path_n,'r')
			noisy_hist = noisy.histogram()
			for root, dirs, filenames in os.walk('covers'):
			    for f in filenames:
			    	if f <> ".DS_Store":
			    		path = os.path.join(root, f)
			        	cover = Image.open(path,'r')
			        	cover_hist = cover.histogram()
                        		rms = math.sqrt(reduce(operator.add,map(lambda a,b: (a-b)**2, noisy_hist, cover_hist))/len(noisy_hist))
       	                		if rms == 0.0:
			        		print("%s %s" % (f_n,f))
			        		break