“Jeśli Len (i1.getbands ()) == 1” Kod odpowiedzi

Jeśli Len (i1.getbands ()) == 1

from PIL import Image

i1 = Image.open('./image_1.png')

for i in range(18):
	i2 = Image.open('./image_%s.png'% i)
	pairs = zip(i1.getdata(), i2.getdata())
	if len(i1.getbands()) == 1:
		# for gray-scale jpegs
		dif = sum(abs(p1-p2) for p1,p2 in pairs)
	else:
		dif = sum(abs(c1-c2) for p1,p2 in pairs for c1,c2 in zip(p1,p2))
	ncomponents = i1.size[0] * i1.size[1] * 3
	print ("Difference (percentage):", (dif / 255.0 * 100) / ncomponents)