在微光成像系统中，为了克服限制微光像增强器和红外成像器件灵敏度提高的技术瓶颈，应用了由探测器输出的光子个数推断出目标特征的光子计数技术。采用雪崩光电二极管作为探测器，将其工作状态设置在盖革模式下。通过分析和计算，雪崩光电二极管可以实现单光子数量级的高灵敏度探测。根据夜天光的光谱分布特点和典型目标的反射特性，仿真得到了在晴朗星光环境下雪崩光电二极管与绿色植被、混凝土和暗绿色涂层的光谱匹配因子分别为：0.4972，0.5021和0.4979。提高了夜天光近红外辐射的利用率，为构建以雪崩光电二极管为核心的夜视系统提供了一定的理论依据。

In order to overcome the technical bottleneck which limits the increase of sensitivity of the low light level (LLL) image intensifier and the infrared imaging device, the photon counting technique is applied to the LLL imaging system, which can deduce the characteristics of the objects according to the number of the photon that the detector outputs. The avalanche photodiode (APD) is used for detector and is operated in Geiger mode. It is proved that APD has high sensitivity in the order of a single photon by analyses and calculations. Under the clear starlight night sky illumination, the spectral response characterization of the APD with green vegetation, concrete, and dark green paint is studied. The spectral matching factors are 0.4972, 0.5021 and 0.4979, respectively. The utilization rate of the infrared radiation highly increases in the night sky. These results can be used to provide the theoretical basis for the night vision system construction based on APD.