ASTER Image Alteration Minerals Information Extraction Based on Different Lithology Backgrounds

In order to reduce the incorrect alteration information extraction caused by the different reflectance values in the different lithologies, this paper explores alteration minerals information extraction by using ASTER (advanced spaceborne thermal emission and reflection radiometer) data, and taking Mongolia Changte'aobao region of Inner Mongolia as the study area. The alteration information has been extracted by segmenting the different lithologies firstly, and conducting the principal component analysis and threshold segmentation methods. It is found that there are 12 limonitization information verification points, of which 6 points match the information extracted directly without segmenting and 8 points match after segmenting; In addition, there are 5 Chloritization information verification points, of which 2 match directly and 4 after segmenting respectively. The results show that the reflectivity of different lithologies is different, resulting in extracting extra information in the high value background region and weak information submerged by noise in the area of low background values, and this method can effectively reduce the reflectance differences in different lithologies.