Opt Lett. 2018 Jul 1;43(13):3088-3091. doi: 10.1364/OL.43.003088.
Critical to navigation, situational awareness, and object identification is the ability to image through turbid water and fog. To date, the longest imaging ranges in such environments rely on active illumination and selection of ballistic photons by means of time gating. Here we show that the imaging range can be extended by using time-gated holography in combination with multi-frame processing. Instead of simply summing the intensity of the frames, we use the complex fields retrieved through digital holographic processing and coherently add the frames. We demonstrate imaging through extended bodies of turbid water and fog at one-way attenuation lengths of 13 and 13.6, respectively. Compared to equivalent traditional time-gated systems, gated holography and coherent processing require 20× less laser illumination power for the same imaging range.
对导航、态势感知和目标识别至关重要的是能够在浑浊水和雾中进行成像。迄今为止，在这种环境中最长的成像距离依赖于主动照明和通过时间门控选择弹道光子。在这里，我们展示了通过使用时门控全息术结合多帧处理，可以扩展成像范围。我们没有简单地对帧的强度求和，而是使用通过数字全息处理检索到的复场，并相干地添加帧。我们演示了通过分别具有 13 和 13.6 的单程衰减长度的扩展浑浊水和雾体进行成像。与等效的传统时门控系统相比，门控全息术和相干处理对于相同的成像范围需要 20 倍的激光照明功率。
