用python写一个人脸识别的代码

当然可以！要实现人脸识别，你需要用到OpenCV和face_recognition这两个库，具体代码可参考以下示例：

import cv2
import face_recognition

video_capture = cv2.VideoCapture(0)

# 加载参考照片
obama_image = face_recognition.load_image_file("obama.jpg")
# 获取参考照片特征
obama_face_encoding = face_recognition.face_encodings(obama_image)[0]

known_face_encodings = [
    obama_face_encoding
]

known_face_names = [
    "Barack Obama"
]

while True:
    # 读取视频帧
    ret, frame = video_capture.read()

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

    # 识别人脸
    face_locations = face_recognition.face_locations(rgb_frame)
    face_encodings = face_recognition.face_encodings(rgb_frame, face_locations)

    for (top, right, bottom, left), face_encoding in zip(face_locations, face_encodings):
        # 判断是否与参考照片匹配
        matches = face_recognition.compare_faces(known_face_encodings, face_encoding)
        name = "Unknown"

        # 如果匹配，则显示姓名
        if True in matches:
            first_match_index = matches.index(True)
            name = known_face_names[first_match_index]

        # 在画面中标出人脸位置及姓名
        cv2.rectangle(frame, (left, top), (right, bottom), (0, 0, 255), 2)
        cv2.putText(frame, name, (left + 6, bottom - 6), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255), 1)

    # 显示结果
    cv2.imshow("Video", frame)

    # 按q键退出程序
    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

# 释放资源
video_capture.release()
cv2.destroyAllWindows()

希望对你有所帮助！