用数字全息进行动态观测时, 由于不同物体记录距离不同, 且不断地变化, 再现像不能始终处于清晰状态。本文提出了利用同轴数字全息视频技术实现在三维空间内对运动物体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观测物体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目标移动, 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, 使再现视频中要观测的目标始终处于清晰状态。采用上一帧的聚焦距离为下一帧再现距离的搜索中心、避免处理不同全息图时的重复运算等方式来提高数字全息视频的处理速度。实验结果表明, 本文提出的数字全息视频成像技术能实现在三维空间内对某一特定运动物体进行连续动态观测。

In dynamic digital holography, due to different objects at different distances recorded, and constantly changing, the reconstructed image was not always in a clear state. A continuous dynamic observation method based on digital in-line holographic video was proposed. The dynamic tracking focus and video processing algorithms were studied. The center of the measured object in the reconstructed image was used as the center of focusing window in the reconstructing for next frame of holographic video. The focusing window always follows the moving target all the time. Thus ensuring each frame of reconstructed video was in focused accurately, so that the observed target in the video was always in a clear state. In order to improve the processing speed of digital holographic video, the focused distance on a frame was used as the search center of reconstructed distance to avoid repeated operation when dealing with different holograms. Experimental results show that the proposed digital holographic video imaging technology can achieve the moving objects in three-dimensional space of continuous dynamic observation.