摘要
目前,光谱波段比值法可以用于岩性信息提取与识别。以新疆北山坡北造山带辉长岩、橄榄岩、橄榄辉长岩以及闪长岩为研究对象,深入分析这四种岩性在VNIR(可见光-近红外)-SWIR(短波红外)谱域的光谱差异。基于辉长岩、橄榄辉长岩、橄榄岩以及闪长岩在2 300 nm附近存在-OH的吸收特征,建立了第8波段的相对吸收深度RBD_8;基于橄榄辉长岩、橄榄岩以及闪长岩在400~700 nm出现的弱吸收特征,建立比值指数RI_(21)来反映四种岩性含Fe^(3+)矿物的丰度;基于四种岩性在1 100 nm附近都存在由Fe^(2+)引起的宽而强的吸收谱带,建立了比值指数RI54来估计Fe^(2+)含量。利用RBD_8、RI_(21)以及RI_(54)三个比值指数分别对影像进行增强处理,并对增强后的影像进行RGB彩色合成,不仅识别和提取出辉长岩、橄榄岩、橄榄辉长岩和闪长岩,还有效区分出片岩以及碳酸盐岩等岩性信息。
At present,the spectral bands ratio method can be used for extracting and recognizing the lithologic information. In this paper,the gabbro,peridotite,olive gabbro,and diorite in the north slope of north orogenic belt in Xinjiang are selected as the research object,we deeply analyze the difference of the four kinds of lithology in VNIR-SWIR spectrum domain. On account of the- OH absorption characteristic of the gabbro,olive gabbro,and peridotite diorite in the near 2 300 nm spectrum,we establish the relative absorption depth data of band 8,which is called RBD_8. On the strength of the weak absorption characteristics of the olive gabbro,peridotite diorite and between 400 nm to 700 nm in the spectrum,we establish the RI_（21） ratio index to reflect theabundance of the four kinds of lithologies,which contain Fe3＋. Because of the wide and strong absorption band of the four kinds of lithology near 1 100 nm in the spectrum caused by Fe2＋,we establish the ratio index,which is called as RI_（54） to estimate the content of Fe^（2＋）. Using ratio indexes RBD_8,RI_（21） and RI_（54） to enhance the image,respectively,we enhance image for the RGB color composite. We not only identify and extract the gabbro,peridotite,olive gabbro,and diorite,but also effectively distinguish the lithology information between schist and carbonate rock. Because of the wide and strong absorption band of the four kinds of lithology near 1 100 nm in the spectrum caused by Fe^（2＋）,we establish the ratio index which is called RI_（54） to estimate thecontent of Fe2＋.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2016年第3期938-944,共7页
Journal of Jilin University：Earth Science Edition
基金
中国地质调查局项目(12120113100100)~~
关键词
波段比值
相对吸收深度
ASTER
岩性提取
bands ratio
relative absorption-band depth
ASTER
lithology extraction
