用opencv调用电脑摄像头
import cv2
cap=cv2.VideoCapture(0,cv2.CAP_DSHOW)
while cap.isOpened():
ret,frame=cap.read()
frame = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
cv2.imshow("Video", frame)
if cv2.waitKey(1) & 0xFF == ord('q'): #ord("q")表示按下q键退出
break
cap.release()
cv2.destroyAllWindows()