当光微弱到以单个光子发射时，成像系统只有利用光子计数模式才能探测到单光子信息。采用基于碰撞电离效应的全固态雪崩光电二极管作为探测元件，构成微光环境下的光子计数成像实验系统。该系统的硬件主要由雪崩光电二极管构成的单光子计数器、计算机、微光照度计、2维电控导轨、控制器、暗箱等组成。控制器的软件在Altera公司Quartus环境下设计，主要完成导轨运动的控制；上位机软件采用VC++编程实现系统的数据采集处理、系统功能控制和光子计数图像显示等。该系统为全固态结构，工作电压小于35 V，暗计数率小于4 Hz。所建光子计数成像系统在10－5lx微光环境下实现了目标的探测成像。

When light is so weak that a single photon is emitted, the single photon can be detected only in photon counting mode. The avalanche photodiode(APD) based on impact ionization effect is used as detector to construct an experimental system of photon counting imaging in low light level environment. The hardware of the system is composed of a single photon counter based on APD, a computer, a low light level illuminometer, two two-dimensional guides, a controller, an obscure box, and so on. The software of the controller is programmed in Altera’s Quartus environment. It controls the movement of the guides. Human machine interface is developed by VC++ software, with the functions of data acquisition and processing, system functions control, and photon counting image display. The photon counting imaging system is all solid, the operation voltage is less than 35 V, and the dark count rate is less than 4 Hz. The detection and imaging of target achieved at 10－5 lx low light level by the system.(2010ZYTS033)