python  OpenCV怎么使用背景分离方法

from __future__ import print_functionimport cv2import argparseparser = argparse.ArgumentParser(            description='This program shows how to use background subtraction methods provided by OpenCV. You can process both videos and images.')parser.add_argument('--input', type=str, help='Path to a video or a sequence of image.', default='vtest.avi')parser.add_argument('--algo', type=str, help='Background subtraction method (KNN, MOG2).', default='MOG2')args = parser.parse_args()## [create]# create Background Subtractor objectsif args.algo == 'MOG2':    backSub = cv2.createBackgroundSubtractorMOG2()else:    backSub = cv2.createBackgroundSubtractorKNN()## [create]## [capture]capture = cv2.VideoCapture(args.input)if not capture.isOpened():    print('Unable to open: ' + args.input)    exit(0)## [capture]while True:    ret, frame = capture.read()    if frame is None:        break    ## [apply]    # update the background model    fgMask = backSub.apply(frame)    ## [apply]    ## [display_frame_number]    # get the frame number and write it on the current frame    cv2.rectangle(frame, (10, 2), (100,20), (255,255,255), -1)    cv2.putText(frame, str(capture.get(cv2.CAP_PROP_POS_FRAMES)), (15, 15),               cv2.FONT_HERSHEY_SIMPLEX, 0.5 , (0,0,0))    ## [display_frame_number]    ## [show]    # show the current frame and the fg masks    cv2.imshow('Frame', frame)    cv2.imshow('FG Mask', fgMask)    ## [show]    keyboard = cv2.waitKey(30)    if keyboard == 'q' or keyboard == 27:        break

# create Background Subtractor objects  KNN or MOG2if args.algo == 'MOG2':    backSub = cv2.createBackgroundSubtractorMOG2()else:    backSub = cv2.createBackgroundSubtractorKNN()

capture = cv2.VideoCapture(args.input)if not capture.isOpened:    print('Unable to open: ' + args.input)    exit(0)

# update the background model    fgMask = backSub.apply(frame)

 # get the frame number and write it on the current frame    cv2.rectangle(frame, (10, 2), (100,20), (255,255,255), -1)    cv2.putText(frame, str(capture.get(cv2.CAP_PROP_POS_FRAMES)), (15, 15),               cv2.FONT_HERSHEY_SIMPLEX, 0.5 , (0,0,0))

# show the current frame and the fg masks    cv2.imshow('Frame', frame)    cv2.imshow('FG Mask', fgMask)