中文摘要：

设计了一种多次渐进滤波方法,通过反复选取地面点,不断更正误选点,最终得到较正确的地面点数据。试验表明,该方法能有效地克服地陷点带来的问题,得到了更加精确的数字地面模型。

英文摘要：

A gradually multi-filtering method is put forward,through which the wrong selected points are removed again and again.The method is tested with a group of LiDAR data.Experimental results indicate that this method can gain more accurate DTM.