树莓派上可用的人脸识别（官方程序，精度较低）

人脸检测器下载地址，与程序放在同一文件夹haarcascade_frontalface_default.rar

import cv2
import time

# 加载人脸检测器
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')

# 打开摄像头
cap = cv2.VideoCapture(0)

# 设置分辨率为 640x480
cap.set(3, 320)
cap.set(4, 240)

# 初始化帧率计数器
fps_start_time = time.time()
fps_counter = 0

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

    # 将图像转换为灰度
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # 使用人脸检测器检测人脸
    faces = face_cascade.detectMultiScale(gray, scaleFactor=1.3, minNeighbors=5, minSize=(30, 30))

    # 在检测到的人脸周围绘制矩形
    for (x, y, w, h) in faces:
        cv2.rectangle(frame, (x, y), (x+w, y+h), (255, 0, 0), 2)

    # 显示帧率
    fps_counter += 1
    if time.time() - fps_start_time >= 1:
        fps = fps_counter / (time.time() - fps_start_time)
        print(f"FPS: {fps:.2f}")
        fps_start_time = time.time()
        fps_counter = 0

    # 显示结果
    cv2.imshow('Face Detection', frame)

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

# 释放摄像头资源
cap.release()
cv2.destroyAllWindows()