opencv 背景减除

import cv2
cap = cv2.VideoCapture('people.mp4')
fgbg = cv2.bgsegm.createBackgroundSubtractorMOG()
while(1):
    ret, frame = cap.read()
    fgmask = fgbg.apply(frame)
    cv2.imshow('frame',fgmask)
    cv2.waitKey(1)

cap.release()
cv2.destroyAllWindows()

import cv2
cap = cv2.VideoCapture('people.mp4')
fgbg = cv2.createBackgroundSubtractorMOG2()
while(1):
    ret, frame = cap.read()
    fgmask = fgbg.apply(frame)
    cv2.imshow('frame',fgmask)
    k = cv2.waitKey(30) & 0xff
    if k == 27:
        break
cap.release()
cv2.destroyAllWindows()

import cv2
cap = cv2.VideoCapture('people.mp4')
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(3,3))
fgbg = cv2.bgsegm.createBackgroundSubtractorGMG()
while(1):
    ret, frame = cap.read()
    fgmask = fgbg.apply(frame)
    fgmask = cv2.morphologyEx(fgmask, cv2.MORPH_OPEN, kernel)
    cv2.imshow('frame',fgmask)
    k = cv2.waitKey(30) & 0xff
    if k == 27:
        break
cap.release()
cv2.destroyAllWindows()