激光成像跟踪系统是实现空间远距离暗目标跟踪的一种极具潜力的手段，而目标在激光照射下的图像将受到激光散斑的调制作用，影响目标的识别及目标的定向精度。对激光照射下的目标图像的统计特性进行了理论分析，提出了一种对原始图像依次实施灰度线性变换、中值滤波和Lee滤波的组合数值滤波器对图像噪声进行抑制。处理的结果表明，采用上述组合方法，图像的噪声指数可从0.67降至0.22，同时边缘保持度可达0.96，为后续的图像处理提供了必要的条件。

Laser imaging tracking system is a potential way of tracking dark target in distance especially in space, but target image under the illumination of laser is modulated by the laser speckle and it will affect the identification and orient precision of target. Analysis of the statistical characteristic of laser imaging is given, then a combined numerical filter that utilize gray level linear transformation, median filtering and Lee filtering acting on the original image in turn is provided to reduce the image noise. The results indicate that the noise coefficient reduces from 0.67 to 0.22, and edge-preserving degree is up to 0.96, respectively, and it makes a necessary basis for the followed image processing.