如何在OpenCV或OpenFrameworks中跟踪指尖？

import cv2
import numpy as np

# 初始化跟踪器
tracker = cv2.TrackerKCF_create()

# 读取视频
cap = cv2.VideoCapture('video.mp4')

# 读取第一帧图像
ret, frame = cap.read()

# 获取指尖的初始位置
x, y, w, h = cv2.selectROI(frame, False)

# 初始化跟踪器
tracker.init(frame, (x, y, w, h))

while True:
    # 读取下一帧图像
    ret, frame = cap.read()

    # 跟踪指尖
    success, bbox = tracker.update(frame)

    # 绘制跟踪结果
    if success:
        x, y, w, h = [int(v) for v in bbox]
        cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2, 1)
    else:
        cv2.putText(frame, "Tracking failure", (100, 80), cv2.FONT_HERSHEY_SIMPLEX, 0.75, (0, 0, 255), 2)

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

    # 等待用户输入
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

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