如何使用opencv在视频中仅检测左眼？

import cv2
import numpy as np

video = cv2.VideoCapture('video.mp4')

eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')

while True:
    ret, frame = video.read()
    if not ret:
        break
    
    # 将帧转换为灰度图像
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    
    # 检测左眼
    eyes = eye_cascade.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=5, minSize=(30, 30))
    
    # 绘制左眼检测框
    for (x, y, w, h) in eyes:
        cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2)
    
    # 显示处理后的帧
    cv2.imshow('Video', frame)
    
    # 按下'q'键退出循环
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# 释放视频对象和窗口
video.release()
cv2.destroyAllWindows()