基于Python的OpenCV与face_recognition库的人脸识别代码

下面是一个基于Python的OpenCV和face_recognition库的简单人脸识别代码示例：

import cv2
import face_recognition

# 加载已知的人脸图像和对应的名字
obama_image = face_recognition.load_image_file("obama.jpg")
obama_face_encoding = face_recognition.face_encodings(obama_image)[0]
biden_image = face_recognition.load_image_file("biden.jpg")
biden_face_encoding = face_recognition.face_encodings(biden_image)[0]
known_face_encodings = [
    obama_face_encoding,
    biden_face_encoding
]
known_face_names = [
    "Barack Obama",
    "Joe Biden"
]

# 打开摄像头
cap = cv2.VideoCapture(0)

while True:
    # 读取一帧图像
    ret, frame = cap.read()

    # 转换为RGB图像
    rgb_frame = frame[:, :, ::-1]

    # 检测人脸
    face_locations = face_recognition.face_locations(rgb_frame)
    face_encodings = face_recognition.face_encodings(rgb_frame, face_locations)

    # 遍历每个检测到的人脸
    for (top, right, bottom, left), face_encoding in zip(face_locations, face_encodings):
        # 判断是否和已知人脸匹配
        matches = face_recognition.compare_faces(known_face_encodings, face_encoding)
        name = "Unknown"

        # 如果匹配到了已知人脸，则获取对应的名字
        if True in matches:
            first_match_index = matches.index(True)
            name = known_face_names[first_match_index]

        # 在图像上绘制人脸矩形和名字
        cv2.rectangle(frame, (left, top), (right, bottom), (0, 0, 255), 2)
        cv2.rectangle(frame, (left, bottom - 35), (right, bottom), (0, 0, 255), cv2.FILLED)
        font = cv2.FONT_HERSHEY_DUPLEX
        cv2.putText(frame, name, (left + 6, bottom - 6), font, 1.0, (255, 255, 255), 1)

    # 显示图像
    cv2.imshow('Video', frame)

    # 按下q键退出
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# 释放摄像头和窗口资源
cap.release()
cv2.destroyAllWindows()

注意，这个代码示例需要在已经安装了face_recognition库和OpenCV库的Python环境中运行，还需要把`obama.jpg`和`biden.jpg`两个已知人脸图像放在代码所在目录下。