用opencv进行人脸识别

import cv2
import numpy as np

cap = cv2.VideoCapture(0) # 使用第1个摄像头
face_cascade = cv2.CascadeClassifier(r'haarcascade_frontalface_default.xml') # 加载人脸特征库
face_cascade.load('D:/opencv/sources/data/haarcascades/haarcascade_frontalface_default.xml') #此为特征库的存放路径（从下载的opencv文件里面找）
while(True):
    ret, frame = cap.read() # 读取一帧的图像
    # gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # 转灰
    gray = cv2.cvtColor(frame, 0)  # 图像颜色不变

    faces = face_cascade.detectMultiScale(gray, scaleFactor = 1.15, minNeighbors = 5, minSize = (5, 5)) # 检测人脸
    for(x, y, w, h) in faces:
        cv2.rectangle(gray, (x, y), (x + w, y + h), (0, 255, 0), 2) # 用矩形圈出人脸

    cv2.imshow('Face Recognition', gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release() # 释放摄像头
cv2.destroyAllWindows()