为科学评价微光夜视仪的性能指标和作战效能，系统分析了微光夜视系统视距探测方程及微光助视效能，阐明了“微光增视可以提高观察距离多少倍”的说法不宜作为衡量助视效能的技术指标。定义并表征了微光助视效能的 4个特征参量：Em、Ex、Ey、Eb。靶场实验结果表明：当夜天环境照度为 0.6×10-3 lx时，微光夜视仪难以获得清晰的景物图像，通过微光助视，施加特征参量 Ex后，微光夜视仪处于理想的工作状态。

In order to properly evaluate the performance and efficacy of low light level(LLL) night vision systems, the visual range detecting equation and twilight aids effectiveness of LLL night vision system are analysed systematically. The results show that the “twilight aids can improve observation distance several times” should not be a technical indicator to determine the twilight aids effectiveness. The four characteristic parameters(Em、Ex、Ey、Eb) of twilight aids effectiveness are defined and characterized respectively. The target range experiment results show that LLL night vision system could not obtain a clear image of the scene when the environmental illuminance is 0.6×10-3 lx and the LLL night vision system can work normally under twilight aids applying characteristic parameter Ex. The four characteristic parameters of twilight aids effectiveness have the important guiding significance to research twilight aids technique.