The basic idea of it is finding a available data segment first,then using principle of error assess area to find desultory point weeding them and comeback the available data by retrospect at last.

• 其基本思想是:先找到有效数据段,利用误差评定区域原则找到杂散点,最后剔除掉杂散点,同时采用回朔法恢复有效数据点。