blog: scale images with multiprocessing

blog_mproc-img-scale.py

import os, tqdm, glob
import multiprocessing as mproc

ls_images = glob.glob("plant-pathology/train_images/*.jpg")
print(f'found images: {len(ls_images)}')

def _convert(pimg: str):
    # it can be replaced by opencv implementation...
    os.system(f'convert -resize 640 point {pimg} {pimg}')

nb_cpu = mproc.cpu_count()
pbar = tqdm.tqdm(total=len(ls_images), desc=f"Convert {nb_cpu}CPUs")
pool = mproc.Pool(processes=nb_cpu)
for _ in pool.imap(_convert, ls_images):
    pbar.update()
pool.close()
pool.join()