python opencv运动检测

# -*- coding:utf-8 -*-__author__ = 'kingking'__version__ = '1.0'__date__ = '14/07/2017'import cv2import numpy as npimport timecamera = cv2.VideoCapture(0) # 参数0表示第一个摄像头# 判断视频是否打开if (camera.isOpened()):    print('Open')else:    print('摄像头未打开')background = cv2.imread('img.png',0)#读入一幅图像es = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (9, 4))while True:    # 按'q'健退出循环    key = cv2.waitKey(1) & 0xFF    # 读取视频流    grabbed, img = camera.read()    gray1 = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)    gray = cv2.GaussianBlur(gray1, (21, 21), 0)#可在这添加处理程序    #！！！等相机稳定后按下W选择背景    if key == ord('w'):        background = gray        print '背景已选定'    diff = cv2.absdiff(gray, background)    binary = cv2.threshold(diff, 25, 255, cv2.THRESH_BINARY)[1]#二值化阈值处理    dilation = cv2.dilate(binary, es, iterations=2) # 形态学膨胀<--可在这添加处理程序    contours, hierarchy = cv2.findContours(dilation.copy(), cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)    for c in contours:        # 对于矩形区域，只显示大于给定阈值的轮廓，所以一些微小的变化不会显示。        if cv2.contourArea(c) < 1500:             continue        (x, y, w, h) = cv2.boundingRect(c) # 该函数计算矩形的边界框        cv2.rectangle(img, (x, y), (x+w, y+h), (0, 255, 0), 2)    cv2.imshow('img', img)    cv2.imshow('dilation', dilation)    if key == ord('q'):        breakcamera.release()#ubuntu一定要释放相机资源否则要重启才能再次使用cv2.destroyAllWindows()