人脸识别Demo

1.安装opencv（也可以使用whl安装网上教程很多，我遇见了平台不符的错误）

pip install opencv-python

2.重点数一下，分类器，很多人使用pip安装可能找不到分类文件

pip show opencv-python

结果如下

Name: opencv-python
Version: 4.2.0.34
Summary: Wrapper package for OpenCV python bindings.
Home-page: https://github.com/skvark/opencv-python
Author: None
Author-email: None
License: MIT
Location: c:\users\lql\appdata\local\programs\python\python37-32\lib\site-packages
Requires: numpy
Required-by:

看Location的链接。
3.一个网上的小demo(其他博主的）

import cv2 as cv
import numpy as np
 
 
def face_detect_demo(image):
    gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
    face_detector = cv.CascadeClassifier("C:/Users/lql/AppData/Local/Programs/Python/Python37-32/Lib/site-packages/cv2/data/haarcascade_frontalface_alt.xml")
    faces = face_detector.detectMultiScale(gray, 1.1, 2)
    for x, y, w, h in faces:
        cv.rectangle(image, (x, y), (x+w, y+h), (0, 0, 255), 2)
    cv.imshow("result", image)
 
print("--------- Python OpenCV Tutorial ---------")
capture = cv.VideoCapture(0)
cv.namedWindow("result", cv.WINDOW_AUTOSIZE)
while(True):
    ret, frame = capture.read()
    frame = cv.flip(frame, 1)
    face_detect_demo(frame)
    c = cv.waitKey(10)
    if c == 27: # ESC
        break
cv.waitKey(0)
 
cv.destroyAllWindows()

cv.CascadeClassifier一个关键的函数(目前还是应用层面，拿来主义先用着，以后再研究，哈哈哈)

注意：文件的路径是"/",而不是"\"