The Study Of Remote Sensing Alteration Information Extraction And Filtration Ways In Fuping County,Chiwawu Area

The alteration of the country rock is an important symbol for the occurrence of hydrothermal mineralization,and it is the main basis for seeking hydrothermal deposit.Because the distribution range of the alteration country rock is larger than that of the ore body,it can effectively guide the geological prospecting work.This study uses remote sensing technology to extract and filter the remote sensing information related to hydrothermal alteration minerals,it can provide the basis for field geology prospecting,that shows the important technology meaning and application meaning.The existing research results show that the use of principal component analysis method and band-ratio method to extract the remote sensing alteration information has been matured.However,according of typical alteration mineral diagnostic spectrum combination absorption valley,building the multi-combination ratio model and extracting the alteration remote sensing is very poor.In paper,based on analysis the geological mineralization data and typical alteration mineral diagnostic spectrum characteristics,the statistical analysis theory and remote sensing digital image processing theory,the TM and ASTER remote sensing data combination ratio and Principal Component Analysis(PCA)alteration remote sensing information extracting model has been build.The alteration remote sensing cutting threshold are determined by enhanced remote sensing gray value histogram.Based on this,according to the alteration mineral types,alteration mineral formation geology condition,geology mineral characteristics,remote sensing geology characteristics in the area,the multi-ways extracting multi-sources alteration remote sensing information are mutual validated and filtered.The alteration remote sensing information filter ways are studied in the area and five anomaly packets have been delineated by the enveloping line.The alteration remote sensing anomaly filter results show that the alteration remote sensing information by using the combination ratio extracting method are better than the single band ratio extracting method.Using gray value histogram different storage methods to determine the cutting threshold is feasible.Filtered and delineated anomaly packages by the enveloping line have a good consistency with known deposits and mineralization and field survey results.This study provides the foundation for the future extraction of altered remote sensing information and the screening of alteration anomalies,and geology mineral survey work arranging provide the new evidence.