针对浅水目标探测这一难题，设计了一种基于距离选通技术的水下成像系统。系统围绕532 nm NdYAG脉冲激光器和选通式增强型电荷耦合器件(ICCD)摄像机搭建而成，并且采用激光脉冲作为系统同步控制的触发信号。采用基于现场可编程门阵列(FPGA)技术设计的同步控制电路，进行了距离选通水下激光成像实验。实验结果表明，采用激光脉冲触发同步控制电路的方法，可有效抑制激光脉冲抖动对系统同步控制精度的影响，从而克服水体表面反射和后向散射对成像的影响，提高了成像质量。在有效衰减系数为0.52 m-1的湖泊中，系统的成像深度可达到水下7 m，对于浅水目标的探测、识别非常有效。

A range-gated underwater imaging system is designed for solving the problems in detection in shallow waters. The system is built around a pulsed 532 nm NdYAG laser and a self-made gated intensified charge-coupled device (ICCD) camera, and the laser pulse is used as the trigger for sync control of the system. The camera gating is timed to collect light reflected from the target to produce the target in the image. The range-gated underwater laser imaging experiment is done based on the sync control circuit designed by field programmable gate array (FPGA) technology. The experimental results indicate that the laser pulse jitter can be restrained by using laser pulse as trigger. As a result, water surface reflection and water backscattering are eliminated effectively and the imaging quality is enhanced. It is also proved that the imaging depth of the system is 7 m in the lake whose effective attenuation coefficient is 0.52 m-1, and the target can be effectively detected and recognized in shallow waters.