由于传统的显微镜成像需要精确的光学聚焦过程，很难检测到在水体中运动的肝吸虫尾蚴，更难以对其进行连续的动态观测.针对此问题，提出了利用单光束同轴数字全息视频技术对在水体中运动的肝吸虫尾蚴进行连续动态观测的方法，研究了其中的动态跟踪聚焦算法和视频处理算法.利用上一帧再现像中尾蚴的中心位置作为下一帧全息再现中聚焦窗口的中心位置，使聚焦窗口始终跟随观测的尾蚴移动，从而保证处理全息视频时每一帧再现像都能准确自动聚焦，使再现视频中肝吸虫尾蚴始终处于清晰状态.进行了肝吸虫尾蚴观测实验，得到肝吸虫尾蚴在水体中运动的全息再现视频，并对其运动轨迹进行了跟踪，总结了肝吸虫尾蚴在水体中的运动规律.实验结果表明，利用数字全息技术拍摄一张数字全息图即可观察到水体中不同位置的肝吸虫尾蚴，检测更加方便高效;本文提出的数字全息视频成像技术能实现对水体中的肝吸虫尾蚴或其它浮游生物进行连续动态观测.

The traditional microscope is not suitable to observe the liver fluke cercariae moves in water, because it needs an optical focusing process. A continuous dynamic observation method for liver fluke cercariae based on digital inline holographic video was proposed. The dynamic tracking focus and video processing algorithms were studied. The center of the liver fluke cercariae in the reconstructed image was used as the center of focusing window in the reconstructing for next frame of holographic video, so the focusing window followed the liver fluke cercariae all the time. Thus ensuring each frame of reconstructed video was in focused accurately, so that the liver fluke cercariae in the video was always in a clear state. The observation of liver fluke cercariae experiment was carried out. The holographic reconstructed video of liver fluke cercariae swiming in the water was obtained. The liver fluke cercariae law of motion was summed up by tracked it’s trajectory in the water. The experimental results show that capture a digital hologram can observed fluke cercariae at different positions in water use the digital holography technology, which makes detection more convenient and efficient, and the proposed digital holographic video imaging technology can achieve the continuous dynamic observation of the liver fluke cercariae or other plankton in water.