old_contents: import cv2
  import time
  
  # for debug
  # from IPython import embed
  # from IPython.terminal.embed import InteractiveShellEmbed
  # ishell = InteractiveShellEmbed()
  
  WIDTH = 320
  HEIGHT = 240
  
  # Capture Camera
  cap = cv2.VideoCapture(0)
  if cap.isOpened() is False:
      exit
      raise("Camera is not available.")
  
  # edge detection
  def edge(image):
      gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
      return cv2.Canny(gray_image, 100, 200)
  
  cap.set(3, WIDTH)
  cap.set(4, HEIGHT)
  
  last_sec = time.ctime()
  fps = 0
  
  while(cap.isOpened()):
      # read 1 frame
      ret, frame = cap.read()
      if ret == False:
          continue
  
      t = time.ctime()
      if t != last_sec:
          print("Fps", fps)
          fps = 0
          last_sec = t
  
      fps += 1
  
      # show edge detection
      cv2.imshow("edge", edge(frame))
  
      # exit if 'q' is pressed
      if cv2.waitKey(1) & 0xFF == ord('q'):
          break
  
  # close and finish
  cap.release()
  cv2.destroyAllWindows()
  
new_contents: import cv2
  import time
  
  # for debug
  from IPython import embed
  from IPython.terminal.embed import InteractiveShellEmbed
  ishell = InteractiveShellEmbed()
  
  WIDTH = 320
  HEIGHT = 240
  
  # Capture Camera
  cap = cv2.VideoCapture(0)
  if cap.isOpened() is False:
      exit
      raise("Camera is not available.")
  
  # edge detection
  def edge(image):
      gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
      return cv2.Canny(gray_image, 100, 200)
  
  cap.set(3, WIDTH)
  cap.set(4, HEIGHT)
  
  last_sec = time.ctime()
  fps = 0
  
  while(cap.isOpened()):
      # read 1 frame
      ret, frame = cap.read()
      if ret == False:
          continue
  
      t = time.ctime()
      if t != last_sec:
          print("Fps", fps)
          fps = 0
          last_sec = t
  
      fps += 1
  
      # show edge detection
      edge_image = edge(frame)
      #ishell()
      cv2.imshow("edge", edge(frame))
  
      # exit if 'q' is pressed
      if cv2.waitKey(1) & 0xFF == ord('q'):
          break
  
  # close and finish
  cap.release()
  cv2.destroyAllWindows()
  
subject: Enable ipython shell