Filter black and white images from a directory

blackwhite_filter.py

# Filter black and white images from a directory
# walk the photos/ directory and copy bw photos
# to the bw/ directory.
# Runs in parallel to help with analyzing large
# batches of photos.

import colorsys
import multiprocessing
import os
import shutil
import sys
import traceback
from PIL import Image, ImageFile # pillow is the only external dependency

# Let PIL be flexible with corrupted image files
ImageFile.LOAD_TRUNCATED_IMAGES = True

# get list of files to be processed
jobs = []
for root, dirs, files in os.walk("photos"):
	for file in files:
		filename, file_extension = os.path.splitext(file)
		# skip movie files
		if file_extension.lower() == ".mov" or file_extension.lower() == ".mp4":
			sys.stderr.write("skipping {}\n".format(file))
			continue
		jobs.append([root, file])

def worker(job):
	# process job
	root, file = job
	try:
		#print(root + "/" + file)
		# iterate image pixels and count number of b/w pixels
		img = Image.open(root + "/" + file)
		bw_count = 0
		for x in range(img.width):
			for y in range(img.height):
				p = img.getpixel((x, y))
				h, l, s = colorsys.rgb_to_hls(*[c / 255 for c in p[:3]])
				# threshold for bw
				if (l >= .9 or l <= .1) and s <= .2:
					bw_count += 1
		# copy file to output if the image is >=95% black/white
		if bw_count / (img.width * img.height) >= .95:
			shutil.copyfile(root + "/" + file, "bw/" + file)
	except:
		# the main error this handles is "OSError: cannot identify image file",
		# which occurs with corrupted image files or non-image files
		sys.stderr.write("error with processing {}\n".format(file))
		traceback.print_exc()
	return file

if __name__ == '__main__': # windows support
	# setup the pool and start processing jobs
	print("processing with {} threads".format(multiprocessing.cpu_count()))
	with multiprocessing.Pool(processes=multiprocessing.cpu_count()) as pool:
		for i, f in enumerate(pool.imap_unordered(worker, jobs)):
			print("{:.02f}% {}/{} {}\033[K".format(100 * i / len(jobs), i, len(jobs), f), end="\r")