说明： 对关键帧采用分水岭算法（OpenCV中有封装好的分水岭算法函数，但建议实现经典的分水岭算法），生成分割图像。
显示原视频、关键帧和分水岭分割后结果。 (Watershed algorithm is used for key frames (OpenCV has a wrapped watershed algorithm function, but it is recommended to implement the classical watershed algorithm) to generate segmented images.
Display the original video, key frames and watershed segmentation results.)
