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为了减少由于不同岩性的反射率值差异而造成提取到错误的蚀变信息,采用先进星载热发射和反射辐射仪(advanced spaceborne thermal emission and reflection radiometer,ASTER)数据,以内蒙古昌特敖包地区为研究区,先开展岩性分区,再利用主成分分析和阈值分割的方法提取矿化蚀变信息,并进行了方法对比与野外验证工作.褐铁矿化蚀变信息验证点共12个,不分区直接提取的信息有6个与验证点吻合,分区后提取的信息有8个点与验证点吻合;绿泥石化蚀变信息验证点共5个,不分区直接提取的信息有2个与验证点吻合,分区后提取的信息有4个点与验证点吻合.研究结果表明,针对不同岩性存在的反射率差异,造成高背景值地区提取出较多的非矿致异常信息,而低背景值地区弱信息被噪声淹没的现象,该方法能够减少不同岩性产生的反射率差异.
In order to reduce the false alteration information caused by the difference of reflectivity of different lithology, the data of advanced spaceborne thermal emission and reflection radiometer (ASTER) For the study area, lithology zoning was carried out firstly, then the mineralization alteration information was extracted by principal component analysis and threshold segmentation method, and the method comparison and field verification were carried out.The alluvial mineralization alteration information verification points were altogether 12, There are 6 information extracted directly without partition, which is consistent with the verification point. There are 8 information extracted from the partition and verified point coincide with each other. There are 5 verification points of chlorite alteration information, 2 information extracted without partition, The verification points are consistent and the information extracted after partitioning has 4 points which are in agreement with the verification points.The results show that for the difference of reflectivity of different lithology, more non-mine induced abnormal information is extracted in high background areas and low The background value of weak information in the area is submerged by noise. This method can reduce the difference of reflectivity caused by different lithologies.