中文摘要：

为滤除激光扫描仪获取的林地采育作业环境的无效数据,从原始数据中抽取出目标立木的数据,需要对扫描仪获取的数据进行滤波处理。将差分方法应用于数据滤波,通过MATLAB编程实现滤波算法并对其关键阈值进行分析研究。结果表明,在32m的扫描范围、0.5度的分辨率的条件下,设定有效点个数为3～40个,阈值为200（mm）时,可以把目标立木从原始信号数据中有效过滤出来。

英文摘要：

To filter out useful data of standing tree from original data obtained by the laser scanner,data filtering is needed.The possibility of using difference calculation into data filter was studied.An algorithm was programed through MATLAB based on difference calculation,and it was then used to analyze the critical threshold of this algorithm.The result showed that the number of valid data point was between 3 and 40,and the critical threshold could be set as 200 millimeters in this experimental condition,with the scan scale,of 32 meters and the sensitivity of 0.5 degree,the standing tree could be filtered out efficiently.