Quick and dirty thing I hacked together for finding lightning in night-time video. It just measures the average brightness of each image of a video (you first rip the video to a sequence of images with ffmpeg), then symlinks the brightest frames into a subdirectory called "brightest".

lightning_anal.py

from PIL import Image, ImageStat

import os
import sys
import shutil
import glob

import argparse
import operator

def brightness( im_file ):
   im = Image.open(im_file).convert('L')
   stat = ImageStat.Stat(im)
   return stat.mean[0]


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Look for lightning in images')
    parser.add_argument('directory')
    args = parser.parse_args()
    d = args.directory
    print(f"Operating in {d}")

    print(f"Finding all files in {d}")
    stats = {}

    os.chdir(args.directory)
    for f in glob.glob("*.png"):
        img_brightness = brightness(f)
        stats[f] = img_brightness
        # print("%s\t%s"%(f,img_brightness))
        
    min_b_key =  min(stats.items(), key=operator.itemgetter(1))[0]
    max_b_key =  max(stats.items(), key=operator.itemgetter(1))[0]

    min_b_val = stats[min_b_key]
    max_b_val = stats[max_b_key]
    print(f"MIN:\t{min_b_key}\t{min_b_val}")
    print(f"MAX:\t{max_b_key}\t{max_b_val}")

    threshold = (min_b_val+max_b_val)/2.0
    print(f"AVG:\t{threshold}")

    brighter_than_average = {k: v for k,v in stats.items() if v > threshold }
    
    # print(brighter_than_average)

    print("Brightest Images:")
    s = sorted(brighter_than_average, key=brighter_than_average.get,reverse=True)
    if not os.path.exists("brightest"):
        os.mkdir("brightest")
    for fn in s:      
        os.symlink(
            os.path.join(os.getcwd(),fn),
            os.path.join(os.getcwd(),"brightest",fn)
        )
    print ("Done.")