text: import os
  import time
  import cv2
  import numpy as np
  from matplotlib import pyplot as plt
  
  img_list = os.listdir("img_file/")
  wrong_img = []
  for img_name in img_list[1:]:
  	path = "img_file/"+img_name
  	pic = cv2.imread(path, 0)
  
  	if type(pic) == "NoneType":
  		print(img_name)
  		cv2.imshow(" img ", pic)	
  		cv2.waitKey(0)
  # 	if (pic.shape[0] < 10 )or (pic.shape[1]< 10):
  # 		wrong_img.append(img_name)
  # print(wrong_img)
  