距离选通技术对后向散射抑制作用的理论分析

 从辐射度学的基本理论出发，建立了单CCD像元的距离选通激光主动成像模型。而后考虑成像质量，借助单CCD像元信噪比和图像均方差误差两个指标，阐明了距离选通技术是抑制后向散射、增大成像距离、提高图像质量的有效手段。最后从模型出发，导出了距离选通技术在激光主动成像中应用时一些关键参数的选取原则:(1) 尽可能减小激光脉冲宽度，以克服后向散射的影响；（2） 要能够达到尽可能远的观测距离，在激光功率一定的条件下，激光占空比越大越好；（3）在激光满足一定条件的情况下，脉冲频率越高越好。

Analysis of back-scattering restraining of range-gated imaging technique

On the basis of active imaging model of CW laser and range-gated,it is proved that range-gated technique is an effective method for restraining the influence of back-scattering in terms of single CCD cell SNR(single noise ratio) and image MSE(mean square error).Range-gated technique can enlarge the imaging distance and improve the image quality.Based on the model,some principles to select key parameters of range-gated are figured out.These principles are:(1) the laser pulse width is as short as possible for both increasing the single CCD cell SNR and improving the image quality,(2) the laser duty cycle is as big as possible in a certain power of laser for longer imaging distance,(3) the laser pulse frequeney is as high as possible in some cases.