# -*- coding: utf-8 -*-
import os
import cv2
import sys
import importlib
importlib.reload(sys)


def CatchUsbVideo(window_name, camera_idx):
 cv2.namedWindow(window_name)
 # 视频来源,可以来自一段已存好的视频,也可以直接来自USB摄像头
 cap = cv2.VideoCapture(camera_idx)
 # 告诉OpenCV使用人脸识别分类器
 classfier = cv2.CascadeClassifier(os.getcwd()+"\\haarcascade\\haarcascade_frontalface_alt2.xml")
 # 识别出人脸后要画的边框的颜色,RGB格式
 color = (0, 255, 0)
 count = 0

 while cap.isOpened():
 ok, frame = cap.read() # 读取一帧数据
 if not ok:
 break
 # 将当前帧转换成灰度图像
 grey = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
 # 人脸检测,1.2和2分别为图片缩放比例和需要检测的有效点数
 faceRects = classfier.detectMultiScale(grey, scaleFactor=1.2, minNeighbors=3, minSize=(32, 32))
 if len(faceRects) > 0: # 大于0则检测到人脸
 count=count+1
 return count


if __name__ == '__main__':
 result = CatchUsbVideo("识别人脸区域", os.getcwd()+'\\video\\xiaojiejie.mp4')
 if result > 0:
 print('视频中有人!!')
 else:
 print('视频中无人!!')