利用python如何实现一个人脸识别功能

import cv2

filepath = "img/xingye-1.png"
img = cv2.imread(filepath) # 读取图片
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # 转换灰色

# OpenCV人脸识别分类器
classifier = cv2.CascadeClassifier(
  "C:\Python36\Lib\site-packages\opencv-master\data\haarcascades\haarcascade_frontalface_default.xml"
)
color = (0, 255, 0) # 定义绘制颜色
# 调用识别人脸
faceRects = classifier.detectMultiScale(
  gray, scaleFactor=1.2, minNeighbors=3, minSize=(32, 32))
if len(faceRects): # 大于0则检测到人脸
  for faceRect in faceRects: # 单独框出每一张人脸
    x, y, w, h = faceRect
    # 框出人脸
    cv2.rectangle(img, (x, y), (x + h, y + w), color, 2)
    # 左眼
    cv2.circle(img, (x + w // 4, y + h // 4 + 30), min(w // 8, h // 8),
          color)
    #右眼
    cv2.circle(img, (x + 3 * w // 4, y + h // 4 + 30), min(w // 8, h // 8),
          color)
    #嘴巴
    cv2.rectangle(img, (x + 3 * w // 8, y + 3 * h // 4),
           (x + 5 * w // 8, y + 7 * h // 8), color)

cv2.imshow("image", img) # 显示图像
c = cv2.waitKey(10)

cv2.waitKey(0)
cv2.destroyAllWindows()

# -*- coding:utf-8 -*-
# OpenCV版本的视频检测
import cv2


# 图片识别方法封装
def discern(img):
  gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
  cap = cv2.CascadeClassifier(
    "C:\Python36\Lib\site-packages\opencv-master\data\haarcascades\haarcascade_frontalface_default.xml"
  )
  faceRects = cap.detectMultiScale(
    gray, scaleFactor=1.2, minNeighbors=3, minSize=(50, 50))
  if len(faceRects):
    for faceRect in faceRects:
      x, y, w, h = faceRect
      cv2.rectangle(img, (x, y), (x + h, y + w), (0, 255, 0), 2) # 框出人脸
  cv2.imshow("Image", img)


# 获取摄像头0表示第一个摄像头
cap = cv2.VideoCapture(0)
while (1): # 逐帧显示
  ret, img = cap.read()
  # cv2.imshow("Image", img)
  discern(img)
  if cv2.waitKey(1) & 0xFF == ord('q'):
    break
cap.release() # 释放摄像头
cv2.destroyAllWindows() # 释放窗口资源