地球化学异常提取的自适应衬值滤波法

A SELF-ADAPTIVE METHOD OF CONTRAST FILTERING FOR EXTRACTING GEOCHEMICAL ANOMALY

地球化学数据分布,特别是微量元素的频率分布,是正向偏斜的,其异常下限的计算也是基于对数正态分布。当定性分析元素的分布状态时,大部分样本分布状态的结果是可以接受的,但是当定量计算异常下限时,一定要结合具体样本的实际分布情况。引入g-h分布函数对样本数据进行拟合,根据所得到的参数确定异常下限,将异常下限与标准离差分割开来。结合子区中位数衬值滤波法,对个旧及其外围成矿区的化探数据进行处理,同时自适应的调节滤波窗口大小,提取化探异常,从而对预测靶区进行圈定。

Geochemical data distribution,especially the frequency distribution of trace elements,are positively deflective,and the calculation of the threshold is based on abnormal lognormal distribution.When qualitative analysis is conducted,the distributionof most of the sample is acceptable.But when quantitative analyzing lower limit of anomalies,the calculation must be in combination with the actual distribution of samples.This paper introduces the g-h distribution function to fit the sample data and ascertain the threshold according to the parameters.In combination with the sub-region median contrast filtering raised by Shi Changyi,the authors processed geochemical data of Gejiu and its peripheral areas and adjusted the size of the filter window by self-adapting,extracting the geochemical anomalies and delineating the targets.