讨论了在复杂背景条件下采用EMCCD实现光子计数成像的处理策略，提出了一种双重阈值滤波方法并通过实验验证了其有效性。根据EMCCD的成像模型，将EMCCD的输出图像表示为光子事件、偏置噪声和伪光子噪声事件的集合。通过采集多幅EMCCD的输出图像，将光子事件检测问题转化为标准的二元假设检测问题。利用贝叶斯判决，可以得到光子事件检测的最佳检测法则，使光子事件的误判代价达到最小，从而检测出光子事件及其空间分布特征。通过实验对比可以发现：提出的方法明显优于普通的累加积分方法，适合生物微光检测等超低照度条件下的成像领域。

In this paper, a double-threshold filter strategy was proposed and experimentally tested to improve the accuracy of photon counting imaging with an electron multiplying charge-coupled device, by taking into account the addition bias noise and Pseudo-photon noise during photon counting mode. Photon counting event detection was achieved by using amplitude threshold and frequency threshold filter to eliminate the bias noise and Pseudo-photon noise. Based on Bayesian estimation on multi-imaging, an optimal detection rule was found with minimum error cost. Experiment indicates that double-threshold filter strategy improves the photon detection accuracy than usual integrate method, and is suitable for imaging in ultra-low-light conditions such as biological dim light detection.