视频在opencv对象检测30秒后冻结

Question

我正在使用opencv做一个项目。但是，即使对于简单的代码，视频也能正常工作约30秒。然后冻结和计算机挂起。这是驱动程序v4l的问题。我想要连续播放视频。我的代码：

import cv2
import numpy as np

flag = 1
capture = cv2.VideoCapture(0)

while True:
    _,img = capture.read()
    simg = cv2.blur(img, (5,5))
    simg = cv2.GaussianBlur(simg,(5,5),0)
    simg = cv2.medianBlur(simg,5)

    frame1 = cv2.rectangle(simg,(200,200),(400,400),(0,255,0))
    frame2 = simg[200:400,200:400]

    hsv = cv2.cvtColor(frame2, cv2.COLOR_BGR2HSV)

    # define range of blue color in HSV
    lower_yellow = np.array([20,100,100])
    upper_yellow = np.array([30,255,255])

    # Threshold the HSV image to get only yellow colors
    mask = cv2.inRange(hsv, lower_yellow, upper_yellow)


    img_mom = cv2.moments(mask,0)
    area = img_mom['m00']

    if((area > 800000) and flag==1):
        print 'found'
        flag=0
        print area

    cv2.imshow('2',simg)
    cv2.imshow('area',frame2)
    cv2.imshow('3',mask)
    k = cv2.waitKey(20) & 0xFF
    if k == 27:
        break


cv2.destroyAllWindows()

我该怎么办？