python+opencv实现动态物体追踪

import cv2 import numpy as np camera=cv2.VideoCapture(0) firstframe=None while True:   ret,frame = camera.read()   if not ret:     break   gray=cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)   gray=cv2.GaussianBlur(gray,(21,21),0)   if firstframe is None:     firstframe=gray     continue      frameDelta = cv2.absdiff(firstframe,gray)   thresh = cv2.threshold(frameDelta, 25, 255, cv2.THRESH_BINARY)[1]   thresh = cv2.dilate(thresh, None, iterations=2)   # cnts= cv2.findContours(thresh.copy(),cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)      x,y,w,h=cv2.boundingRect(thresh)   frame=cv2.rectangle(frame,(x,y),(x+w,y+h),(0,0,255),2)   cv2.imshow("frame", frame)   cv2.imshow("Thresh", thresh)   cv2.imshow("frame2", frameDelta)   key = cv2.waitKey(1)&0xFF      if key == ord("q"):     break  camera.release() cv2.destroyAllWindows()