Little Script for my old webcam to make timelapse shots with an appealing brightness by adjusting the exposure

analyzePicture.py

#!/usr/bin/env python
from PIL import Image
from PIL import ImageStat
import sys
import os.path
import subprocess
import sched,time
import math

steps = 1


def analyze(img):
  global exposure
  global analyzing
  analyzing = True
  if exposure > 6000:
    exposure = 6000
  if exposure < 0:
    exposure = 0
  brightness = getBrightness(img)
  print("################ brightness = "+str(brightness)+" ################")
  print("################ exposure = "+str(exposure)+" ################")
  if exposure == 0 :
    exposure = 1
  # if brightness < 50:
  if brightness < 100 and exposure < 6000:
    if brightness > 95:
      print("Bild dunkel - erhoehe Belichtungszeit um 1")
      exposure += 1
    elif brightness <= 95 and brightness > 40:
      print("Bild zu dunkel - erhoehe Belichtungszeit um 50")
      exposure += 50
    elif brightness <= 40:
      print("Bild viel zu dunkel - verdopple Belichtungszeit")
      exposure = exposure*2
      
    #zu dunkel
    # if brightness < 40 and exposure < 6000:
    #   print("Bild viel zu dunkel - verdopple Belichtungszeit")
    #   exposure = exposure * 2
    # elif brightness >= 40 and brightness < 95 and exposure < 6000:
    #   exposure += 50
    # elif brightness >= 95 and exposure < 6000:
    #   print("Bild zu dunkel - erhoehe Belichtungszeit")
    #   exposure+=steps
    deleteImage(img)
    img = renameFile(img,int(exposure))
    takePicture(img,exposure)
    analyze(img)
  elif brightness > 140 and exposure > 0:
    if brightness < 145:
      print("Bild hell - verringere Belichtungszeit um 1")
      exposure -= 1
    elif brightness >= 145 and brightness < 160:
      print("Bild zu hell - verringere Belichtungszeit um 50")
      exposure -= 50
    elif brightness >= 160:
      print("Bild viel zu hell - halbiere Belichtungszeit")
      exposure = int(math.floor(exposure/2))
    # if brightness > 230 and exposure > 0:
    #   exposure = math.floor(exposure/2)
    # #zu hell
    # elif brightness <= 160 and brightness > 145 and exposure > 0:
    #   exposure -= 50
    # elif brightness <= 145 and exposure > 0:
    #   exposure-=steps
    deleteImage(img)
    img = renameFile(img,exposure)
    takePicture(img,exposure)
    analyze(img)
  else:
  	print("error mode setting exposure to 6000")
  	exposure = 6000
  analyzing = False


def deleteImage(img):
  os.remove(os.path.dirname(os.path.realpath(__file__))+"/"+img)

def takePicture(img,exposure):
  abspath = os.path.dirname(os.path.realpath(__file__))+"/"+img
  # fswebcam --no-banner -r 1280x720 --set Exposure=$initExposure  "$filename"
#  command = "fswebcam --no-banner -r 1280x720 --set Exposure="+str(exposure)+" "+abspath
  command = "fswebcam -r 1280x720 --set Exposure="+str(exposure)+" "+abspath

  # command = os.path.dirname(os.path.realpath(__file__))+"/capture.sh "+str(exposure)+" "+abspath
  process = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
  process.wait()

def renameFile(img,exposure):
  file = img.split("e")
  left = file[0]
  result = left+"e"+str(exposure)+".jpg"
  return result

def getBrightness(img):
  abspath = os.path.dirname(os.path.realpath(__file__))+"/"+img
  if not os.path.isfile(abspath):
    print(img+" is not a file")
    return
  print("Analyzing "+img)
  i = Image.open(abspath).convert('L')
  brightness = ImageStat.Stat(i)
  return brightness.mean[0]

def getFilename(exposure):
  t = time.strftime("%Y-%m-%d_%H:%M:%S")
  file = t+"-e"+str(exposure)+".jpg"
  return file

def doLoop():
  global analyzing
  global exposure
  if not analyzing:
    img = getFilename(exposure)
    takePicture(img,exposure)
    analyze(img)



def main(argv1,argv2):
  try:
    while True:
      doLoop()
      time.sleep(int(argv2))
  except KeyboardInterrupt:
    print("I WANT TO BREAK FREEE  -  KeyboardInterrupt")
    return


# argv1 = initial Exposure
# argv2 = capture interval
if len(sys.argv) <= 1:
  sys.exit("Wrong param")
exposure = int(sys.argv[1])
analyzing = False
main(sys.argv[1],sys.argv[2])


# ok brightness at 100-140