实现人脸识别的python库有很多，这里以OpenCV和face_recognition为例，具体实现步骤如下：

1. 安装OpenCV和face_recognition库

pip install opencv-python

pip install face_recognition

2. 获取人脸图像并存储

import cv2

# 打开摄像头

cap = cv2.VideoCapture(0)

while True:

    # 读取一帧图像

    ret, frame = cap.read()

    # 显示图像

    cv2.imshow('video', frame)

    # 按下q键退出

    if cv2.waitKey(1) & 0xff == ord('q'):

        break

# 释放摄像头资源

cap.release()

cv2.destroyAllWindows()

3. 对图像进行人脸检测

import face_recognition

# 将图像转为RGB格式

rgb_frame = frame[:, :, ::-1]

# 检测人脸位置

face_locations = face_recognition.face_locations(rgb_frame)

4. 对每个人脸进行识别

# 加载预先训练好的人脸数据

known_image = face_recognition.load_image_file("known_face.jpg")

known_encoding = face_recognition.face_encodings(known_image)[0]

# 对检测到的每个人脸进行识别

for face_location in face_locations:

    # 提取人脸编码

    unknown_encoding = face_recognition.face_encodings(rgb_frame, [face_location])[0]

    # 比对人脸

    results = face_recognition.compare_faces([known_encoding], unknown_encoding)

    if results[0]:

        # 识别成功

        print("This is known_face.")

    else:

        # 识别失败

        print("Unknown face.")

完整代码如下：

import cv2

import face_recognition

# 加载预先训练好的人脸数据

known_image = face_recognition.load_image_file("known_face.jpg")

known_encoding = face_recognition.face_encodings(known_image)[0]

# 打开摄像头

cap = cv2.VideoCapture(0)

while True:

    # 读取一帧图像

    ret, frame = cap.read()

    # 将图像转为RGB格式

    rgb_frame = frame[:, :, ::-1]

    # 检测人脸位置

    face_locations = face_recognition.face_locations(rgb_frame)

    # 对每个人脸进行识别

    for face_location in face_locations:

        # 提取人脸编码

        unknown_encoding = face_recognition.face_encodings(rgb_frame, [face_location])[0]

        # 比对人脸

        results = face_recognition.compare_faces([known_encoding], unknown_encoding)

        if results[0]:

            # 识别成功

            cv2.rectangle(frame, (face_location[3], face_location[0]), (face_location[1], face_location[2]), (0, 255, 0), 2)

            cv2.putText(frame, "Known Face", (face_location[3], face_location[2] + 20), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (0, 255, 0), 2)

        else:

            # 识别失败

            cv2.rectangle(frame, (face_location[3], face_location[0]), (face_location[1], face_location[2]), (0, 0, 255), 2)

            cv2.putText(frame, "Unknown Face", (face_location[3], face_location[2] + 20), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (0, 0, 255), 2)

    # 显示图像

    cv2.imshow('video', frame)

    # 按下q键退出

    if cv2.waitKey(1) & 0xff == ord('q'):

        break

# 释放摄像头资源

cap.release()

cv2.destroyAllWindows()