不同植被覆盖率地区遥感矿化蚀变提取研究

Study on Identification of Altered Wall-rock in Areas of Different Vegetation Coverages Based on Remote Sensing

从遥感图像上识别出的围岩蚀变信息往往是一种弱信息。地表植被和第四系覆盖的干扰,增加了遥感蚀变信息提取的难度。为了研究不同植被覆盖条件下的矿化蚀变信息提取方法,分别选取内蒙古西部戈壁荒漠基岩裸露区(温根地区)、中北部中覆盖草原区(达来庙地区)和东北部高覆盖森林草原区(颇格鲁山地区),利用TM数据进行遥感蚀变信息提取方法研究,得出以下结论:在基岩裸露地区,利用比值法、主成分分析法均能较好地提取出矿化蚀变信息;在中覆盖草原区,利用掩膜对图像进行预处理,再利用主成分分析法提取矿化信息效果比较好;在高覆盖森林草原区,利用掩膜技术和抑制植被信息方法对遥感数据进行综合处理,再利用比值—主成分分析方法能够提取部分矿化蚀变信息。这些方法对今后在类似地区开展遥感蚀变信息提取工作具有一定的指导意义。

Compared with other geological information,alteration is usually weak information,and because of the interference of the vegetation and coverage,the extraction of the alteration information by remote sensing is very difficult.In order to know how to get detail information about alteration in areas of different vegetation coverages through remote sensing,this paper chooses three areas to extract the alteration information,which are the exposed base rock area in the desert of east Inner Mongolia（Wengen District）,mid-coverage plain area in the middle-north Inner Mongolia （Dalaimiao District）,and high coverage forest and plain area in the northeast Inner Mongolia（Pogelu Mountain Area）.Based on the study of the method for extraction of alteration anomalies from the TM data,we can conclude that（1） in the exposed base rock area, band ratio process and principal component analysis are better in extraction of the alteration information;（2） in the mid-vegetation plain area,it is better to firstly pre-process by masking,and then use principal component analysis;（3） and in the high vegetation coverage forest and plain area,the alteration information can be partly extracted by the methods of de-vegetation,masking and ratio-principal component.This paper made some contributions for the alteration information extraction in areas of different vegetation coverages by remote sensing techniques.