picture.py

import cv2

cam = cv2.VideoCapture(0)

cv2.namedWindow("take a picture") 
img_counter = 0
while True:
  ret, frame = cam.read()
  cv2.imshow("test", frame)
  if not ret:
    break
  k = cv2.waitKey(1)

  if k%256 == 27:
    print("Escape hit, closing...")
    break
  elif k%256 == 32:
    img_name = "opencv_frame_{}.png".format(img_counter)
    cv2.imwrite(img_name, frame)
    print("{} written!".format(img_name))
    img_counter += 1

cam.release()

cv2.destroyAllWindows()