太赫兹共焦扫描成像中，由于太赫兹激光器不可能恒定输出和采集信号微弱等原因，成像质量有待提高。在消除激光抖动的背景抑制后进行了中值滤波、块匹配和三维滤波(BM3D)、非局部均值（NLM）滤波和中值非局部均值（MNLM）滤波等方法比较；同时研究了滤波参数对处理效果的影响。图像处理结果表明，对所考察图像应用所确定的滤波参数时，MNLM滤波稍好于NLM滤波，NLM滤波稍好于BM3D，中值滤波效果较差。

In the terahertz confocal scanning imaging, the imaging quality is to be improved for the reason that terahertz laser can not output the beam constantly and that the signal collected is weak, and so on. The comparison among median filtering, block-matching and three dimensional (3D) filtering (BM3D), non-local means filtering (NLM) and median non-local means filtering (MNLM) is made after eliminating the background suppression resulting from laser shaking. The influence of the filtering parameters on the processed effect is studied. The results of image processing show that on the condition of applying definitive filter parameters to the investigation images, MNLM′s effect is better than that of NLM′s, and NLM′s effect is better than BM3D′s, while median filtering′s effect is the worst.