OpenCV访问当前帧和上一帧

import cv2

# 创建VideoCapture对象，参数为摄像头索引或视频文件路径
cap = cv2.VideoCapture(0)

# 读取第一帧
ret, frame = cap.read()

# 初始化上一帧
prev_frame = None

while True:
    # 读取当前帧
    ret, frame = cap.read()
    
    if not ret:
        break
    
    # 在此处进行当前帧的处理
    
    # 如果有上一帧
    if prev_frame is not None:
        # 在此处进行上一帧和当前帧之间的处理
        
        # 示例：计算当前帧和上一帧的差异图像
        diff = cv2.absdiff(frame, prev_frame)
        cv2.imshow('Difference', diff)
    
    # 显示当前帧
    cv2.imshow('Frame', frame)
    
    # 按下q键退出循环
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    
    # 更新上一帧
    prev_frame = frame

# 释放VideoCapture对象和窗口
cap.release()
cv2.destroyAllWindows()