Compare images in two directories, showing difference/ディレクトリを探索して画像を比較し、差分画像を出力する

gistfile1.py

# coding: utf-8
from __future__ import print_function
from os import walk
from os.path import join, splitext
from PIL import Image, ImageChops


def compare_images(dir1, dir2):
    for dirname, subdirnames, filenames in walk(dir1):
        for filename in filenames:
            path1 = join(dirname, filename)
            path2 = dir2+path1[len(dir1):]
            body, ext = splitext(path1)
            if ext.lower()[1:] in ['jpg', 'png', 'gif']:
                img1 = Image.open(path1)
                img2 = Image.open(path2)
                if not img1.tobytes()==img2.tobytes():
                    print('Image %s and %s are not identical.' %(path1, path2))
                    (w1, h1), (w2, h2) = img1.size, img2.size
                    w, h = max(w1, w2), max(h1, h2)
                    d = Image.new('RGB', (w, h*3))
                    d.paste(img1, (0, h*0))
                    d.paste(img2, (0, h*1))
                    d.paste(
                        ImageChops.subtract_modulo(img1.convert('L'), img2.convert('L')).convert('RGB'),
                        (0, h*2))
                    d.show()


if __name__=='__main__':
    import sys
    from argparse import ArgumentParser, Action
    from os.path import isdir
    parser = ArgumentParser()
    parser.add_argument('dir1')
    parser.add_argument('dir2')
    parsed = parser.parse_args()
    for argname in ['dir1', 'dir2']:
        if not isdir(getattr(parsed, argname)):
            sys.stderr.write('%sERROR: %s not exists.\n' %(parser.format_usage(), argname))
            sys.exit(-1)
    compare_images(parsed.dir1, parsed.dir2)