import cv2 
import sys 
import logging as log 
import datetime as dt 
from time import sleep 
 
cascPath = "haarcascade_frontalface_default.xml" 
faceCascade = cv2.CascadeClassifier(cascPath) 
 
# 打开视频捕获设备 
video_capture = cv2.VideoCapture(0) 
 
 
while True: 
 if not video_capture.isOpened(): 
  print('Unable to load camera.') 
  sleep(5) 
  pass 
 
 # 读视频帧 
 ret, frame = video_capture.read() 
 
 # 转为灰度图像 
 gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) 
 
 # 调用分类器进行检测 
 faces = faceCascade.detectMultiScale( 
  gray, 
  scaleFactor=1.1, 
  minNeighbors=5, 
  minSize=(30, 30), 
  #flags=cv2.cv.CV_HAAR_SCALE_IMAGE 
 ) 
 
 # 画矩形框 
 for (x, y, w, h) in faces: 
  cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2) 
 
 
 # 显示视频 
 cv2.imshow('Video', frame) 
 
 
 if cv2.waitKey(1) & 0xFF == ord('q'): 
  break 
 
 
# 关闭摄像头设备 
video_capture.release() 
 
# 关闭所有窗口 
cv2.destroyAllWindows()