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地球信息科学学报 >

2018 , Vol. 20 >Issue 11: 1644 - 1656

DOI: https://doi.org/10.12082/dqxxkx.2018.180195

遥感科学与应用技术

主成分分析技术在遥感蚀变信息提取中的应用研究综述

  • 吴志春 , 1, 2, 3, * ,
  • 叶发旺 4 ,
  • 郭福生 1, 2 ,
  • 刘文恒 3 ,
  • 李华亮 2, 3 ,
  • 杨羿 2
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  • 1. 东华理工大学放射性地质与勘探技术国防重点学科实验室,南昌 330013
  • 2. 东华理工大学地球科学学院,南昌 330013
  • 3. 东华理工大学江西省数字国土重点实验室,南昌 330013
  • 4.核工业北京地质研究院遥感信息与图像分析技术国家级重点实验室,北京 100029

作者简介：吴志春（1986-）,男,江西石城人,硕士,讲师,主要从事遥感地质解译、三维地质建模方面的教学与研究。E-mail:

收稿日期: 2018-04-18

  要求修回日期: 2018-09-04

  网络出版日期: 2018-11-20

基金资助

国家自然科学基金（41802247、41603031）

江西省教育厅科技项目（GJJ160584）

放射性地质与勘探技术国防重点学科实验室开放基金项目（RGET1305）

江西省数字国土重点实验室开放基金项目（DLLJ201614）

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A Review on Application of Techniques of Principle Component Analysis on Extracting Alteration Information of Remote Sensing

  • WU Zhichun , 1, 2, * ,
  • YE Fawang 3 ,
  • GUO Fusheng 1 ,
  • LIU Wenheng 2 ,
  • LI Hualiang 1, 2 ,
  • YANG Yi 1
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  • 1. Key Laboratory for Radioactive Geology and Exploration Technology, Fundamental Science for National Defense, East China University of Technology, Nanchang 330013, China
  • 2. School of Earth Sciences, East China University of Technology, Nanchang 330013, China
  • 3. Key Laboratory for Digital Land and Resources of Jiangxi Province, East China University of Technology, Nanchang 330013, China
  • 4. National Key Lab of Remote Sensing Information and Imagery Analysis, Beijing Research Insititute of Uranium Geology, Beijing 100029, China
*Corresponding author: WU Zhichun, E-mail:

Received date: 2018-04-18

  Request revised date: 2018-09-04

  Online published: 2018-11-20

Supported by

National Science Foundation of China, No.41802247, 41603031

The Scientific Research Fund of Jiangxi Provincial Education Department, No.GJJ160584

Key Laboratory for Radioactive Geology and Exploration Technology, Fundamental Science for National Defense, No.RGET1305

Key Laboratory for Digital Land and Resources of Jiangxi Province, No.DLLJ201614.

Copyright

《地球信息科学学报》编辑部 所有
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摘要

主成分分析是目前遥感蚀变异常信息提取常用方法之一,该方法具有对影像大气校正质量要求不高、实现简单、提取效果好、效果稳健等优点,广受地质工作者的青睐。根据输入影像的数量及类型、主成分分析的次数等,本文将主成分分析分为标准主成分分析、特征向量主成分分析、定向主成分分析、二次主成分分析、不同影像间的主成分分析等5种类型。其中,特征向量主成分分析又可细分为4个波段特征向量主成分分析和3个波段特征向量主成分分析。在上述分类的基础上,系统介绍了各种主成分分析及蚀变信息主分量的选择,尤其是对特征向量主成分分析的Crosta技术和定向主成分分析的软落叶技术进行了详细阐述。并以TM/ETM+、ASTER影像为例,对部分应用主成分分析提取蚀变异常信息的实例进行了分析,认为：在基岩裸露区,不同主成分分析都可以很好地提取铁化、泥化蚀变信息;在中、低植被覆盖区,采用标准主成分分析、Crosta技术、改进的Crosta技术、软落叶技术、“掩膜/抑制干扰信息+主成分分析”等方法可以有效地提取蚀变异常信息;高植被覆盖区多采用主成分分析生成的蚀变信息主分量进行彩色合成,再通过对彩色影像进行目视解译的方式判断蚀变的类型和范围。其中,“掩膜+Crosta技术”、“掩膜+软落叶技术”、二次主成分分析等方法在高植被覆盖区也可以取得较好的应用效果;对于干扰信息种类众多、岩性复杂的地区,可根据干扰信息、岩性种类划分成若干个小区,再根据每个小区实际情况采用不同的蚀变提取方法,最后将每个小区内提取的蚀变信息进行合并。

关键词： 主成分分析; 标准主成分分析; 特征向量主成分分析; 定向主成分分析; Crosta技术; 软落叶技术

本文引用格式

吴志春 , 叶发旺 , 郭福生 , 刘文恒 , 李华亮 , 杨羿 . 主成分分析技术在遥感蚀变信息提取中的应用研究综述[J]. 地球信息科学学报, 2018 , 20(11) : 1644 -1656 . DOI: 10.12082/dqxxkx.2018.180195

Abstract

The principle component analysis (PCA) technique, as one of the common method of extracting alteration information of remote sensing, is characterized by undemanding quality of atmospheric correction images, easily realization, effective, and steadily i.e., and is widely used by geologists. Based on the number and type of the input images and times of the PCA, this paper subdivided the PCA analysis into the standard principle component analysis (SPCA), feature oriented principal components selection (FPCS), directed principal component analysis (DPCA), the secondary principle component analysis and the principle component analysis of different images, of which the FPCS comprise four bands and three bands principle component analysis. Based on the above mentioned, every PCA and selection criteria have been systematically introduced, especially for the Crosta technique of the FPCS and the software defoliant technique of the DPCA. Images of TM/ETM+、ASTER are selected as examples to analyze the part of application techniques of PCA on extracting alteration information of remote sensing. The results indicate that different PCA all are in favor of extracting information of iron and clay alteration. The methods of SPCA, Crosta technique, modified Crosta technique, software defoliant technique and mask or inhibition of interference information+PCA have been effectively applicated in the medium-low vegetated-covered area. In contrast, in the high vegetated-cover area, the principle component of alteration information derived from PCA was adopted to conduct color composite. The resulted color images were then visual interpreted to estimate the type and extent of alteration. Among these techniques, the “Mask and Crosta technique”, the “Mask and software defoliant technique” and the secondary principle component analysis also can achieve good results in the high vegetated-cover area. For areas characterized by numerous kinds of interference information and complex lithology, firstly, it is practicable to divide the area into several sub-areas based on kinds of interference information and lithology; secondly, different methods of extracting alteration information should be proposed according to the features of every sub-areas; lastly, synthesizing alteration information extracted from every sub-areas.

Key words： Principal Component Analysis (PCA); Standard Principle Component Analysis (SPCA); Feature Oriented Principal Components Selection (FPCS); Directed Principal Component Analysis (DPCA); Crosta technique; software defoliant technique

1 前言

遥感技术具有宏观性好、速度快、成本低等优势,在矿产勘查过程中得到广泛应用。美国于1972年发射了首颗陆地卫星（Landsat 1）,迄今为止共发射了8个系列的陆地卫星（Landsat 1- Landsat 8）,获得了海量地球表面影像数据。这些数据免费供各国学者使用,从而在矿产资源、海洋资源、水资源的调查及各类专题图件（如地质图、地貌图、水文图）的绘制等方面得到广泛应用[1]。该类影像数据具有空间分辨率适中、波段多、波段光谱范围设置合理等特点,适用于矿产资源勘查中的岩性解译、构造解译和蚀变信息提取,尤其是在中等尺度下大面积快速提取铁化、泥化蚀变异常信息方面具有独特的优势。
绝大部分内生矿床都伴随着相应的围岩蚀变,这些蚀变通常是重要的找矿标志。随着遥感技术的发展,矿产勘查中遥感蚀变异常跟地球化学异常和地球物理异常一样成为一种具有独立性找矿标志的参数[2,3]。Landsat卫星影像数据是遥感蚀变异常提取中应用最为广泛的数据源之一,已有40多年的应用历史,取得了丰硕的研究成果。通常运用目视解译、图像处理可以有效、快速地提取遥感影像中的蚀变异常信息,常用的遥感蚀变提取图像处理方法主要有波段彩色合成、波段比值、主成分分析、光谱角、像元分解等。在这些方法中,主成分分析具有实现简单、速度快、效果好、稳健等优点[4,5,6],且处理过程中对影像数据大气校正质量要求不高,即使不进行大气校正直接应用都可取得较好的效果。因此,该技术广受地质工作者的青睐[7,8,9,10,11,12]。
随着主成分分析在矿产资源勘查中应用的不断深入,逐渐衍生出了许多细分方法,如标准主成分分析、特征向量主成分分析、定向主成分分析、不同影像间的主成分分析、二次主成分分析等。这些方法被广泛应用到不同地区和不同条件下遥感蚀变异常信息的提取上,但绝大多数仅在特定区域采用了1~2种方法,目前尚未见到有关于上述5种方法综合运用、系统总结的文献报道。鉴于主成分分析方法在遥感蚀变异常信息提取中的重要作用,有必要对上述5种方法进行系统归纳、总结。本文主要包括以下3个研究内容：① 对主成分分析技术方法进行归纳与分类;② 不同类型主成分分析的蚀变信息主分量的选择原则;③ 对不同类型主成分分析的应用效果进行总结,同时探讨针对复杂环境条件下遥感蚀变信息提取中所存问题的有效解决方法。

2 蚀变矿物反射光谱特征

目标蚀变矿物具有特征反射波谱是遥感蚀变异常信息提取的前提与基础。可见光-近红外区（0.4~1.3 μm）诊断性波谱由Fe、Cu、Mn、Ni、Cr等过渡性元素电子跃迁产生,短波红外区（1.3~2.5 μm）诊断性波谱主要由CO32-、OH-等阴离子基团和水分子的振动产生。造岩矿物中的Si、Al、Mg、O等元素在可见光-短波红外区不具有诊断性波谱,这些元素的诊断性波谱主要集中在热红外区[13,14,15]。
根据Landsat卫星所携带的传感器的不同,获取的影像数据可以分为MSS、TM、ETM+、OIL共4类（图1）。MSS数据只可以提取铁化蚀变,而TM、ETM+和OIL数据则可以提取铁化、泥化蚀变,其中TM、ETM+数据在铁化、泥化蚀变信息提取方面更有效。在可见光-短波红外区间内,ETM+数据比TM数据仅多了一个全色波段,其他波段完全一致。下文将用TM代替ETM+。
Fig. 1 Comparision of spatial resolution and spectral resolution of each band of MSS, TM, ETM+ and OIL images

图1 MSS、TM、ETM+和OIL各波段空间分辨率、光谱分辨率比较

铁化蚀变矿物包括铁的氧化物、铁的氢氧化物和铁的硫化物,如赤铁矿（Fe2O3）、针铁矿（FeO（OH））、黄钾铁矾（KFe3（SO4）2（OH）6）等。在可见光-近红外区（0.4~1.3 μm）,反射率具有明显的吸收谷和反射峰,在0.5 μm和0.9 μm处附近表现为吸收谷,分别对应于TM1和TM4,TM3则表现为相对反射峰（图2）。0.9 ~1.3 μm,随波长的增加铁化蚀变矿物反射率急剧上升,到1.3 μm达到最高值。在短波红外区,铁化蚀变矿物反射率基本呈高值平稳状态,变化较小,不具有诊断性波谱特征。根据铁化蚀变矿物的波谱特征,可运用反射峰对应的波段除以吸收谷对应的波段的方式来增强铁化蚀变信息[16,17,18,19,20],如TM3/1,TM5/1,TM5/4等。
Fig. 2 Mineral spectral curves of iron alteration

图2 铁化蚀变矿物光谱曲线

泥化蚀变是指OH-、CO32-等基团振动产生的蚀变异常,蚀变矿物主要有明矾石、伊利石、蒙脱石、高岭石、方解石等。泥化蚀变矿物在1.5~2.5 μm 范围内,随波长的增加反射率快速减低,并在2.150-2.450 μm范围内产生系列特征吸收谱带（图3）。-OH、-CO3在短波红外区产生的特征吸收谱带的位置与-OH、-CO3连接的金属离子类型有密切关系,如Al-OH（2.22 μm）、Si-OH（2.23 μm）、Fe-OH（2.25 μm）、Mg-OH（2.33 μm）和X-CO3（2.33~2.35 μm）类蚀变矿物诊断性吸收谷位置各不相同[21,22]。TM影像在短波红外区光谱分辨率较低,无法有效区分泥化蚀变矿物的具体类型,只能作为大类进行提取。泥化蚀变在TM5波谱范围表现为强反射,在TM7波谱范围表现为强吸收,常用TM5和TM7的差异来识别泥化蚀变异常。
Fig. 3 Mineral spectral curves of clay alteration

图3 泥化蚀变矿物光谱曲线

3 主成分分析的分类及其应用

在前人研究基础上,本文依据主成分分析时输入影像的数量及类型、主成分分析的次数等将主成分分析细分为：标准主成分分析、特征向量主成分分析、定向主成分分析、二次主成分分析、不同影像间的主成分分析5种类型。

3.1 标准主成分分析

标准主成分分析（Standard Principal Component Analysis,SPCA）遥感蚀变异常信息提取,是对多光谱影像在可见光-短波红外区的所有波段（或包含热红外波段）一同进行主成分分析,生成一系列主分量,然后根据目标蚀变波谱特征和特征向量矩阵确定蚀变信息所在主分量,最后运用彩色合成、密度分割、非监督分类、C-A分形、主分量门限化等处理方法凸显主分量中的蚀变异常信息[23,24]。
主成分分析过程遵循能量守恒定律,变换前后的信息总量相等,且变换后各主分量之间互不相关。单个主分量的信息量取决于对应的特征值的大小,特征值越大,主分量信息量越大。主分量按特征值的大小依次排列,信息主要集中在前几个主分量影像中。例如,对TM影像进行标准主成分分析,生成的主分量影像中,PC1、PC2和PC3信息量之和一般超过85%,最后一个主分量中大部分为噪声,有用信息较少。主成分分析将具有相关性的波段转换成完全独立的主分量影像,变换后的主分量影像更易于地质解译和解释[25,26]。各主分量与原始波段的相关性则由特征向量载荷因子决定,载荷因子的符号指示主分量与对应波段的正、负相关性,载荷因子数值的大小则表示主分量与对应波段相关性大小。载荷因子为正值时,主分量与对应波段呈正相关,为负值时,则呈负相关;载荷因子数值越大,表明主分量与该波段相关性越大,数值越小,则相关性越小。
标准主成分分析生成的主分量中,PC1与所有波段呈正相关,为各波段的总体特征,主要为各波段的反射率大小。除PC1之外的主分量总是以一部分波段特征为主[27]。可见光波段与近红外-短波红外波段在PC2对应的特征向量载荷因子符号总是相反,PC2主要反映的是这2个光谱范围波段的反射率差,即光谱曲线的斜率变化[28,29]。PC3一般与TM4波段相关系数较高,主要呈现的是植被信息。与原始波段彩色合成相比较,运用PC1、PC2、PC3进行彩色合成的图像,具有信息量大、色彩丰富等特征,更有利于岩性、构造、蚀变的解译和地物的识别。朱谷昌等[30]在湖南大坊红土型金矿区利用RGB（PC1,PC2,PC3）影像成功解译出铁化、泥化蚀变区,在该彩色影像中铁化蚀变区呈红色色调,泥化蚀变区呈黄褐色色调,金矿有利找矿区呈“黄褐色+红色”色调,成功圈定了金矿有利找矿区。陈松岭等[31]在乌拉山哈达门沟金矿和内蒙古麦汉山常山壕金矿区运用PC1/PC2增强钾化、褐铁矿化等蚀变信息,运用PC1/PC4增强碳酸盐化、绿泥石化、绢云母化等蚀变信息,识别出了与金矿化有关的蚀变异常信息。
泥化蚀变矿物在TM5为反射峰,TM7为吸收谷（图3）。泥化蚀变信息主分量与TM5和TM7对应的特征向量载荷因子符号应相反[32]。当TM5对应的特征向量载荷因子符号为正,TM7对应的符号为负时,泥化蚀变对应于蚀变信息主分量影像亮值区,否则对应于暗值区。由于标准主成分分析生成的主分量较多,可能同时存在多个主分量满足这一条件。该种情况下,就需要对蚀变信息主分量进行确定,通常有以下3种方法：① 多个主分量对应的蚀变都位于亮值区或暗值区时,可将多个蚀变信息主分量影像做加法运算,生成一个新的影像,将该影像作为蚀变信息主分量;② 既有蚀变位于亮值区的主分量,又有蚀变位于暗值区的主分量,运用蚀变位于亮值区的主分量影像与蚀变位于暗值区的主分量影像做减法运算,生成的影像中蚀变位于亮值区。③ 多个满足条件的主分量中,仅有一个主分量与TM5、TM7对应的特征向量载荷因子数值较大,其余主分量对应的特征向量载荷因子数值都很小,这时可直接选择特征向量载荷因子数值较大的主分量作为蚀变信息主分量,其他主分量中包含的蚀变信息可忽略不计。铁化蚀变信息主分量的选择与泥化蚀变信息主分量的选择方法相同,在此不再赘述。
TM影像标准主成分分析,蚀变异常信息往往处于信息量较少的PC4和PC5中。利用这2个主分量与其他的主分量进行彩色合成,生成的彩色影像可以有效呈现综合蚀变异常信息[33,34,35]。马建文和Slaney[25]通过对RGB（PC5,PC4,PC3）影像进行目视解译及监督分类、非监督分类等处理,在环境复杂的加拿大北部地区提取了含金硅化、绢云母化蚀变带,指导了地质勘查工作,并将该方法成功运用于辽宁二道沟、新疆、内蒙古等地的蚀变异常信息提取[26,36]。邓素贞等[37]利用RGB（PC4,PC5,PC2）影像解译出了河北张家口东部下双台金矿区与铁矿、金矿有关的蚀变信息,在该彩色影像中与铁矿相关的铁氧化物蚀变呈浅白色斑块,与金矿有关的蚀变呈淡紫色-粉红色团块,这有效指导了该地区矿山外围找矿。也有研究人员运用蚀变信息主分量与蚀变吸收谷波段、反射峰波段合成的彩色图像解译出了干旱基岩裸露区的蚀变异常信息[38,39]。

3.2 特征向量主成分分析

根据目标蚀变矿物波谱特征,选择3~4个诊断性波谱对应的波段进行主成分分析,提取目标蚀变异常信息,该方法称之为特征向量主成分分析 （Feature Oriented Principal Components Selection,FPCS）。根据主成分分析输入波段数量的不同,笔者进一步将该方法细分为4个波段特征向量主成分分析和3个波段特征向量主成分分析。
3.2.1 4个波段特征向量主成分分析
1989年Crosta和Moore首次运用PCA（TM1,TM3,TM4,TM5）和PCA（TM1,TM4,TM5,TM7）对巴西米纳斯吉拉斯州西部的亚热带地区残积土壤进行铁化、泥化蚀变信息填图[40]。此后,英国国家遥感中心Loughlin教授运用Crosta和Moore提出的蚀变信息提取技术在美国西南部大盆地（Great Basin）地区提取矿化蚀变信息,取得很好的应用效果,并将该技术称之为Crosta技术[41,42]。此后,Crosta技术广泛应用于TM/ETM+影像的铁化、泥化蚀变信息的提取[27,43-52]。
进行PCA（TM1,TM3,TM4,TM5）、PCA（TM1,TM4,TM5,TM7）处理,可分别生成4个主分量。根据目标蚀变光谱特征,可以确定蚀变信息主分量。当铁化蚀变信息主分量与TM3、TM5对应的特征向量载荷因子符号为正,与TM1、TM4对应符号为负时,铁化蚀变异常位于主分量亮值区,否则位于暗值区。当泥化蚀变信息主分量与TM1、TM5对应的特征向量载荷因子符号为正,与TM4、TM7对应符号为负时,泥化蚀变异常位于亮值区,否则处于暗值区[7,53]。蚀变信息主分量通常为PC4,有时候也有可能为PC3[54]。对蚀变信息主分量进行非监督分类、C-A分形、主分量门限化等处理进行量化分级,不同强度的蚀变信息赋予不同的颜色,使蚀变分布范围、蚀变强弱一目了然[5,12,45,55-59]。
吴志春等[60]在青海玉树干旱基岩裸露区利用Crosta技术提取的蚀变信息与已知的84个矿床（点）吻合率高达88%。铁化蚀变与泥化蚀变重叠部位,与矿床（点）吻合度更高,且这些矿床（点）多为多种蚀变类型共生的多金属矿床（点）。赵小星[61]在西藏桑木岗地区利用Crosta技术提取的铁化、泥化蚀变信息与矿床（点）、水系沉积物异常、自然重砂异常高度吻合。以多元数据为依据,圈定了Ⅰ级找矿远景区5个,Ⅱ级、Ⅲ级找矿远景区各1个,指导了该地区的铅锌、铜等多金属找矿。
除了对蚀变主分量进行量化分级之外,运用蚀变信息主分量与其他主分量进行彩色合成,也是一种有效呈现蚀变强度、分布范围的有效方法。如朱谷昌等[30]在湖北蛇屋山红土型金矿区运用RGB（PC1,PC2,PC4）影像解译出了与金成矿有关的蚀变信息。将铁化蚀变信息主分量、泥化蚀变信息主分量、铁化蚀变信息主分量和泥化蚀变信息主分量的算术平均值生成的影像分别赋给红、绿、蓝通道,生成Crosta彩色图[62,63,64,65]。在该彩色图中,强铁化蚀变区呈红色色调,强泥化蚀变区呈绿色色调,强铁化蚀变与强泥化蚀变叠合区呈白色色调。Crosta彩色图,不仅能够同时显示铁化、泥化蚀变及2种蚀变叠合区的范围,还能够从颜色和色调上区分出这 2种蚀变的强度。燕守勋等[63]通过青海东昆仑、内蒙赤峰、新疆东天山、西昆仑、东非等地的700多个矿床（点）与Crosta彩色图叠合显示,发现矿床（点）与Crosta彩色图中的蚀变区吻合度高,铁、铅锌、金、铜、钼矿多位于强铁化蚀变的暗红色色调区,内生铜矿位于2种蚀变叠合部位。
在影像中,植被、第四系、水体、云、阴影等属于强信息,岩石围岩蚀变属于微弱信息,微弱的蚀变信息往往会被强信息所掩盖,因此遥感蚀变信息提取过程中易受这些强信息的干扰或抑制。Crosta技术是对整幅影像进行统计分析,提取的蚀变信息中也就掺杂了些干扰信息,一定程度上会降低蚀变信息的精度。采用“掩膜+主成分分析”的方法,可以一定程度上降低干扰信息对蚀变信息提取的影 响[20,66-67],但是掩膜会丢失掩膜区内的一切影像信息。当干扰信息覆盖面积较大,且干扰信息不强时,可用“抑制干扰信息+主成分分析”的方法代替“掩膜+主成分分析”法。根据干扰信息和蚀变信息的波谱特征,采用避开干扰信息诊断性波谱所在波段、抑制干扰信息、增强蚀变信息等方法,改进Crosta技术（表1）。若研究区内干扰信息种类多、岩性复杂,可根据干扰信息、岩性种类将研究区划分成若干个小区[66,67,68,69],针对每个小区内的地物光谱特征选用合适的Crosta技术,可以在很大程度上提高蚀变信息提取的精度。
Tab. 1 Modified Crosta technique

表1 改进的Crosta技术

技术方法 提取的蚀变类型及应用效果
PCA（TM2,TM4,TM5,TM7） 提取泥化蚀变和碳酸盐化蚀变[70]
PCA（TM1,TM4/3,TM5,TM7） RGB（PC1,PC3,PC4）影像合成,图像中含钾长石斑晶花岗岩和含金钾化硅化蚀变带呈鲜红色,可清楚辨别。通过对PC1和PC4二维散点投图,可将含钾长石斑晶花岗岩、含金钾化硅化蚀变带进一步分离[71]。该方法在加拿大北部冰川、森林覆盖区,中国河北等金矿区得到较好应用[26]
PCA（TM1+TM2,TM4/3,TM5,TM7） 干旱基岩裸露区,可以同时提取铁化、泥化蚀变信息,提取的蚀变信息与已知矿床、矿（化）点吻合度高[55,72-73]。在北祁连山西段疏勒河以东约9000 km2范围内,提取的蚀变异常与已知的103个矿床（点）吻合度高达83.5%[55]。在东天山戈壁地区的石英滩至赤湖地区约33 000 km2范围内,提取的蚀变异常与已知的122个矿床（点）吻合度达86%[72]
PCA（TM1,TM4,TM5/7,TM7） 在基岩裸露区,运用TM5/7代替TM5,增强了泥化蚀变信息,扩大了泥化蚀变与植被之间的光谱差异[59,74]。吴浩等[59]有效提取了青海省五龙沟金矿区的泥化蚀变信息,提取的蚀变信息在野外得到验证
PCA（TM1,TM3/1,TM4,TM5） 在基岩裸露区,运用TM3/1代替TM3,增强了铁化蚀变信息,扩大了铁化蚀变与植被之间的光谱差异。在青海省五龙沟金矿区提取的铁化蚀变,受断裂构造控制明显,与成矿物质来源和运移通道相吻合,提取的蚀变信息可作为该区的金矿找矿标志[59]
PCA（TM2,TM3,TM4,TM5/1） 提取褐铁矿化蚀变异常。提取的蚀变异常信息与金矿体、水系沉积物Au和Cu异常相吻合[70]
3.2.2 3个波段特征向量主成分分析
3个波段特征向量主成分分析多用于具体蚀变类型的提取,如Al-OH类、Fe-OH类、Mg-OH类、X-CO3类蚀变等[75,76]。针对某一蚀变诊断性吸收谷,选择吸收谷、吸收谷两肩对应的波段进行主成分分析的一种方法。该方法需要影像具有较高的光谱分辨率,如ASTER影像的短波红外区。高岭石、蒙脱石、明矾石、伊利石等Al-OH类蚀变矿物在2.2 μm附近处具有强的诊断性吸收谷,吸收谷位置与ASTER6相对应,两肩对应的波段分别为ASTER5和ASTER7,运用PCA（ASTER5,ASTER6,ASTER7）提取Al-OH类蚀变矿物信息。黄钾铁矾、皂石等Fe-OH类蚀变矿物在2.25 μm处附近具有诊断性吸收谷,吸收谷位置与ASTER7相对应,两肩对应的波段分别为ASTER6和ASTER7,运用PCA（ASTER6,ASTER7,ASTER8）可以提取该类蚀变。绿泥石、绿帘石、滑石等Mg-OH类蚀变矿物和方解石、白云石等X-CO3类蚀变矿物诊断性吸收谷位置处于2.35 μm附近,与ASTER8光谱范围相对应,两肩对应的波段分别为ASTER7和ASTER9,可用PCA（ASTER7,ASTER8,ASTER9）提取这些蚀变信息。
3个波段特征向量主成分分析,PC3为蚀变信息主分量。PC3对应的特征向量载荷因子符号中,与左肩波段、右肩波段对应的符号相同,并与吸收谷波段对应的符号相反。当吸收谷波段的特征向量符号为负时,蚀变位于亮值区,否则蚀变位于暗值区。运用该方法能够简单、快速、有效地提取不同蚀变类型,这为矿床蚀变分带、蚀变定量研究提供了新的手段。

3.3 定向主成分分析

当对多个影像进行主成分分析时,影像的波谱信息常存在于排序靠前的主分量中,但是主分量中的特征波谱信息常会被噪声干扰。当参与主成分分析的影像较多时,生成的主分量也较多,蚀变信息主分量的选择和结果的解释也更困难。根据目标蚀变特征波谱差异,仅选择2个最能代表目标特征波谱信息的波段进行主成分分析,该方法称为定向主成分分析（Directed Principal Component Analysis, DPCA）。定向主成分分析是基于2个输入影像的相关性统计,当2个影像相关性较大时,2个影像中相关的信息位于PC1中,因此,PC1包含了2个影像的绝大部分信息,主要是2个影像的空间信息。PC2为2个影像相关性差的信息,更多的是波谱信息。输入的2个影像相关性越强,PC1包含的信息量越大,PC2所含信息量就越少。定向主成分分析是对2个输入影像的线性变换,蚀变信息主分量更易于判别,结果更容易解释。
定向主成分分析波段的选择,一方面要避免背景信息、干扰信息与目标蚀变信息波谱差异过小,另一方面要尽可能凸显目标蚀变信息波谱差异,体现目标蚀变信息的波谱特征。2个波段中,通常一个为目标蚀变反射峰对应的波段,另一个为吸收谷对应的波段,这样目标蚀变的波谱差异能够达到最大。对于具有诊断性吸收谷或反射峰的蚀变异常信息,定向主成分分析较标准主成分分析、选择主成分分析更能够增强波段间的光谱差异[8,77]。生成的主分量中,PC1与2个波段都呈正相关,该主分量为2个波段共有的信息。PC2与2个波段的相关性相反,为蚀变信息主分量。当PC2与目标蚀变反射峰波段呈正相关时,蚀变信息位于PC2中的亮值区,否则位于暗值区。
根据铁化蚀变和泥化蚀变光谱特征,在基岩裸露区可用PCA（TM3,TM1）、PCA（TM5,TM1）、PCA（TM5,TM4）提取铁化蚀变信息,PCA（TM5,TM7）提取泥化蚀变[63,78],但对于植被覆盖区的蚀变提取效果不佳。针铁矿、赤铁矿、黄钾铁矾等铁化蚀变矿物与绿色植被在TM1和TM5波段处的反射率基本相似,在TM3处铁化蚀变矿物的反射率稍强于绿色植被（图1）,因此运用PCA（TM3,TM1）、PCA（TM5,TM1）要从植被信息中分离出铁化蚀变信息难度较大。在短波红外区,绿色植被和泥化蚀变矿物反射率都是呈下降趋势,波谱形态基本相似（图2）。在短波红外区,虽然不同的泥化蚀变矿物在不同位置具有典型的诊断性吸收谷,但对于TM7的波谱范围而言,无法对其进行有效区别。因此,运用PCA（TM5,TM7）也难以准确区分泥化蚀变和绿色植被。
针对植被覆盖区定向主成分分析无法有效提取蚀变异常信息的问题,Frazer和Green[79]对定向主成分分析进行了改进,提出一种“波段比值+主成分分析”的组合方法,即用波段比值获取的目标蚀变影像和植被指数影像代替原始波段进行主成分分析。该方法常用于植被覆盖区的蚀变信息提取,因此该方法被称为软落叶技术（Software Defoliant Technique）。TM5/7亮值区为植被信息,次亮值区为泥化蚀变信息,但两者一定程度上能够区分。TM4/3为植被指数,植被在该比值影像中的亮度值远大于泥化蚀变的亮度值。进行PCA（TM5/7,TM4/3）处理,PC1与TM5/7、TM4/3呈正相关,主要为植被信息,PC2与TM5/7、TM4/3对应的2个特征向量符号相反,主要为泥化蚀变信息[2,80]。同理,PCA（TM3/1,TM4/3）、PCA（TM5/1,TM4/3）、PCA（TM5/4,TM4/3）可用于提取中、低植被覆盖区的铁化蚀变异常信息[81]。高植被覆盖区的蚀变信息提取难度较大,将掩膜技术与软落叶技术结合使用效果会更好[8,82-84]。

3.4 二次主成分分析

从主成分分析生成的主分量中选择部分主分量与其他影像再次进行主成分分析,从第二次主成分分析获得的主分量中选取蚀变信息主分量,该方法称之为二次主成分分析。一景影像中包含了岩石、土壤、植被、水体、蚀变等众多信息,很多情况下直接运用标准主成分分析、特征向量主成分分析、定性主成分分析等方法提取蚀变异常信息效果并不理想。虽然“掩膜+主成分分析”的方法能在一定程度上降低了干扰因素对蚀变信息提取的影响,可以准确提取非掩膜区的蚀变异常信息,但是当影像中干扰信息种类多、覆盖面积大时,大面积掩膜处理,丧失了蚀变信息提取的目的。在此种情况下,一次单一方法的使用难以奏效,需要多种方法组合使用或一种方法多次使用,蚀变信息才能从众多信息中“剥离”出来。
韩先菊等[85]对波段比值、Crosta法、二次主成分分析、彩色合成等方法组合应用,提取了新疆西准噶尔托里金成矿带与金成矿密切相关的热液蚀变,并得到野外实地验证。陈勇敢等[86]对（TM5+TM3）/（TM7+TM4+TM1）、TM3/1、TM5/7、PCA（TM1,TM3,TM4,TM5）处理获得的铁化蚀变信息主分量、PCA（TM1,TM4,TM5,TM7）处理获得的泥化蚀变信息主分量5个影像进行二次主成分分析,提取了甘肃省陇南阳山金矿区与金成矿相关的蚀变异常信息。杨波等[87]运用（TM5+TM3+TM2）-（TM7+TM4+TM1）、TM3/1、TM5/4、TM5/7、PCA（TM1,TM4,TM5,TM7）提取的泥化蚀变信息主分量、PCA（TM1,TM3,TM4,TM5）提取的铁化蚀变信息主分量进行二次主成分分析,有效降低了各种干扰因素的影响,增强了弱蚀变信息,余凤鸣和王磊[88]运用该方法在湖北武当地区提取的蚀变信息也得到较好验证,提取的蚀变信息与已知矿化蚀变带吻合度高达80%。

3.5 不同影像间的主成分分析

ASTER影像在2.150~2.450 μm范围内有5个波段,具有较高的光谱分辨率,能够区分Al-OH（2.17~2.21 μm）、Fe-OH（2.21~2.30 μm）、Mg-OH（2.30~2.40 μm）、X-CO3（2.30~2.350 μm）等蚀变类型,而TM、ETM+影像在该范围内仅有1个波段,只能识别泥化蚀变大类。ASTER影像在可见光光谱范围内,仅有绿光波段（ASTER1）和红光波段（ASTER2）,缺少蓝光波段,而蓝光波段正是铁化蚀变诊断性吸收谷对应的重要波段。TM1为蓝光波段,正好可以弥补ASTER影像的不足。Honarmand 等[75]运用PCA（TM1,TM3,ASTER6,ASTER7）、PCA（TM1,TM3,ASTER4,ASTER5）、PCA（TM1,TM3,ASTER8,ASTER9）很好识别出了不同铁化蚀变类型组合。
在同一景影像内提取蚀变信息时,主成分分析对影像大气校正和辐射校正要求不高,仅对原始影像稍作拉伸处理即可。对涉及多景影像、多种影像类型提取蚀变信息时,需要对影像进行辐射校正,即将影像的灰度值转换成辐亮度值或反射率值。

4 结论

综上所述,主成分分析提取遥感蚀变异常信息,具有对影像大气校正质量要求不高、实现简单、速度快、效果好、应用稳健等优点,该技术广受地质工作者的青睐。本文对该方法进行了详细的种类划分,并对不同地质条件下的蚀变信息提取方法进行了总结,具体结论如下：
（1）主成分分析根据输入影像的数量及类型、主成分分析的次数等,本文将其分为5种类型：标准主成分分析、特征向量主成分分析、定向主成分分析、二次主成分分析、不同影像间的主成分分析。其中,又将特征向量主成分分析细分为2种类型：3个波段特征向量主成分分析和4个波段特征向量主成分分析。
（2）在基岩裸露区,不同主成分分析都可以很好地提取铁化、泥化蚀变信息。在中、低植被覆盖区,采用Crosta技术、改进的Crosta技术、软落叶技术、“掩膜/抑制干扰信息+主成分分析”等方法可以更有效地提取蚀变异常信息。高植被覆盖区的蚀变信息提取难度较大,多采用主成分分析生成的蚀变信息主分量进行彩色合成,再通过对彩色影像进行目视解译的方式判断蚀变的类型和范围。另外,“掩膜+Crosta技术”、“掩膜+软落叶技术”、二次主成分分析等方法在高植被覆盖区也能较好地提取蚀变信息。
（3）当研究区内干扰信息种类众多、岩性复杂时,可根据干扰信息、岩性种类将研究区划分成若干个小区。根据每个小区实际情况采用不同的方法,再将每个小区内提取的蚀变信息进行合并。该种处理方法可在一定程度上提高复杂区的遥感蚀变提取的可靠性和准确性。

The authors have declared that no competing interests exist.

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陈松岭,卢福宏,高光明,等.华北地台北缘内蒙古段金矿围岩蚀变的遥感识别[J].国土资源遥感,2001,54(2):13-18.

[ Chen S L, Lu F H, Gao G M, et al.Remote sensing extraction of altered information related to gold mineralization, Inner Mongolia section, north margin of north China plate[J]. Remote Sensing for Land & Resources, 2001,54(2):13-18. ]

[32]
刘刚. 东昆仑五龙沟金矿围岩蚀变的遥感识别[J].国土资源遥感,2002,55(4):60-61.The Alteration Information of the Wulonggou gold deposit was extracted with Principal Component Image Processing Method. This Method is effective, as evidenced by field survey and the concordance between the image altered zone and the real mineralization zone.

DOI

[ Liu G.Remote sensing extraction of alteration information related to the Wulonggou gold deposit, east Kunlun mountains[J]. Remote Sensing for Land & Resources, 2002,55(4):60-61. ]

[33]
Ranjbar H, Honarmand M, Moezifar Z.Application of the Crosta technique for porphyry copper alteration mapping, using ETM+ data in the southern part of the Iranian volcanic sedimentary belt[J]. Journal of Asian Earth Sciences, 2004(24):237-243.Many of the known porphyry copper deposits in Iran are situated in the Central Iranian volcanic Belt. The area under study is located in the southern part of this belt and covers an area of about 6600 km. The climate in the area is semi-arid. Given the poor soil development and poor vegetation cover but abundant outcrops, the arid/semi-arid part of the belt is most suitable for remote sensing study. Enhanced Thematic Mapper plus (ETM) images have been used for alteration mapping. Crosta method was found useful for enhancing the areas in which the regolith contains a high proportion of hydroxyl and iron oxide minerals. The Crosta method has been used on selected 4 and 6 bands. Areas with iron oxide and hydroxyl minerals have been enhanced by using six bands of ETM data.

DOI

[34]
Mokhtari Z, Boomeri M, Bagheri S.Digital image processing and analysis techniques for detection of hydrothermal alteration zones: A case study in Siah-Jangal area, north of Taftan volcano, southeastern Iran[J]. J Indian Soc Remote Sens, 2015,43(2):363-377.Hydrothermal alteration zones have significant role in prospecting of porphyry mineral deposits. In this research, Image processing techniques were applied on the digital subset ETM鈥+鈥塪ata covered the Siah-Jangal area. These techniques generated several products of enhanced satellite imagery, such as colour composite images, ratio images and principal component analysis images. These techniques have been successfully used in mapping of hydrothermal alteration and mineralization zones in the study area. The colour composite and band ratio methods show very clearly the hydrothermal altered zones of clay minerals and iron oxides in and around the Siah-Jangal area. The principal component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and iron-oxide mineral zones as well. The Crosta method has been used on selected 6 (standard method of PCA), 4 and 3 bands. There is no significant difference of the hydroxyl images in the Band ratio and PC methods. But the best results, in terms of mapping the distribution of iron oxide alteration, were obtained using the band ratio and Crosta methods on 3 bands. The results indicate that methods is promising for identifying alteration zones and can assist exploration geologists to find new prospects of porphyry copper and gold deposits in the other virgin regions before costly detailed ground investigations.

DOI

[35]
Masoumi F, Eslamkish T, Honarmand M, et al.A comparative study of Landsat-7 and Landsat-8 data using image processing methods for hydrothermal alteration mapping[J]. Resource Geology, 2016,67(1):72-88.Comparing spaceborne satellite images of Landsat‐8 Operational Land Imager (OLI) and Landsat‐7 Enhanced Thematic Mapper plus (ETM+) was undertaken to investigate the relative accuracy of mapping hydrothermal alteration minerals. The study investigated the northern part of Rabor, which contains copper mineralization occurrences, and is located in the Kerman Cenozoic magmatic assemblage (KCMA), Iran. Image processing methods of band ratio, principal component analysis (PCA), and spectral angle mapper (SAM) were used to map the distribution of hydrothermally altered rocks associated with the porphyry copper mineralization. The band ratio combination of both sensors for mapping altered areas showed similar outcomes. PCA exposed variations in the spatial distribution of hydroxyl‐bearing minerals. The representation of hydrothermal areas using OLI data was more satisfactory than when using ETM+ data. SAM analysis found similar results for mapping hydroxyl‐bearing zones. Verification of the results came through ground investigation and laboratory studies. Rock samples (02=0256) were collected to validate results using thin sections, X‐ray diffraction (XRD) and spectral analyses. Field observations and laboratory analysis revealed that phyllic and propylitic alterations dominate the alteration zones in the study area. Argillic and iron oxides/hydroxides alterations were observed to a lesser degree. The results indicate that alteration maps prepared by OLI data using PCA for visual interpretation are more suitable than those of ETM+ due to a higher radiometric resolution and lower interference between vegetation and altered areas. As the spectral bandwidth of ETM+ band 7 covers absorption feature of propylitic alteration, better mapping of propylitic alterations is achieved using ETM+ data. SAM analysis of both datasets found similar results for mapping hydroxyl‐bearing zones. Propylitic alteration was mapped by ETM+ data better than OLI data. Color composite of band ratios show similar results for mapping alterations whereas PCA found that OLI data were suitable than ETM+ data.

DOI

[36]
马建文. 利用TM数据识别二道沟金矿地表地质特征[J].国土资源遥感,1994,47(4):20-22.

[ Ma J W.Using TM data to identify surficial geological feature of the gold deposit[J]. Remote Sensing for Land & Resources, 1994,47(4):20-22. ]

[37]
邓素贞,贺佳惠,王永军. ETM数据在金矿化蚀变信息提取中的应用研究——以张家口下双台地区为例[J].国土资源遥感,2010,54(4):56-59.金矿遥感探测之关键在于成矿构造及铁氧化物、含羟基蚀变矿物信息的提取。以张家口下双台地区 为研究区，利用ENVI4．0图像处理软件，通过“多元数据分析＋比值＋主成分变换＋密度分割＋分类”等方法，从Landsat-7ETM数据中提取矿化 蚀变信息并抑制植被波谱干扰，方法快速、准确、有效。结果表明，利用该方法获得的矿化蚀变信息与已知矿点有很大的一致性，该方法是可行的。

DOI

[ Deng S Z, He J H, Wang Y J.The application of ETM data to the extraction of gold mineralization and alteration information: A case study of Xiashuangtai area in Zhangjiakou[J]. Remote Sensing for Land & Resources, 2010,54(4):56-59. ]

[38]
何国金,胡德永,陈志军,等.从TM图像中直接提取金矿化信息[J].遥感技术与应用,1995,10(3):51-54.lt;p>以内蒙古撰山子试区为例，阐明了&ldquo;徽差信息处理&rdquo;的主要观点，墓于这种认识直接从TM图像中提取到的金矿化性变信息，为撰山子金矿区及其外围找矿提供了丰富准确的指示性信息，取得了显著的经济效益和良好的社会效益。</p>

[ He G J, Hu D Y, Chen Z J, et al.Extraction gold mineralized information directly from TM image[J]. Remote Sensing Technology and Application, 1995,10(3):51-54. ]

[39]
施炜,刘建民,王润生.内蒙古东部喀喇沁旗地区金矿围岩蚀变遥感信息提取及成矿预测[J].地球学报,2007,28(3):291-298.内蒙古东部喀喇沁旗地区位于燕 山造山带东段的成矿带之上,金矿资源丰富。本文运用遥感技术,结合野外调查,对这一地区金矿围岩矿化异常信息进行了提取和分析。研究表明,本区现有矿床分 布与明显受区域构造控制,区内金矿床围岩蚀变以硅化和含铁矿物为主,粘土矿物蚀变较少。区内主要发育3个成矿带,即南北各存在一个近E-W向的成矿带,喀 喇沁旗东南发育一个NE-SW向的成矿带,且明显受断裂控制。成矿有利区主要位于本区东南部,且在本区南部NE-SW向断裂和近EW向断裂交汇地带围岩蚀 变信息较强,可能为富矿部位。研究表明围岩蚀变遥感异常组合信息能直观地指示出成矿的可能部位,对金矿床的勘查工作具有一定的指导意义。

DOI

[ Shi W, Liu J M, Wang R S.The extraction of wall rock alteration information related to gold deposits in Harqin Banner area of eastern Inner Mongolia by using ETM+ remote sensing technique[J]. Acta Geoscientica Sinica, 2007,28(3):291-298. ]

[40]
Crosta A P, Moore J.Enhancement of Landsat Thematic Mapper imagery for residual soil mapping in SW Minais Gerais State, Brazil: A prospecting case history in greenstone belt terrain[C]. Proceedings of the 7th(ERIM) Thematic Conference: Remote Sensing for Exploration Geology, 1989:1173-1187.

[41]
Loughlin W P.Geological exploration in the western United States by use of airborne scanner imagery[C]. IMM Conference: Remote Sensing, an Operational Technology for the Mining and Petroleum Industries, London, 1990:223-241.

[42]
Loughlin W P.Principal component analysis for alteration mapping[J]. Photogrammetric Engineering & Remote Sensing, 1991,57(9):1163-1169.

[43]
Aydal D, Ardal E, Dumanlilar O.Application of the Crosta technique for alteration mapping of granitoidic rocks using ETM+ data: Case study from eastern Tauride belt (SE Turkey)[J]. International Journal of Remote Sensing, 2007,28(17):3895-3913.The present study particularly focuses on the determination of alteration products of the granitoid associations by remote sensing techniques. Widespread magmatism has occurred in the Malatya‐Elaz0306 area of the eastern Tauride belt in south east Turkey as a consequence of plate convergence and continental collision. The development of the magmatism in the study area can be subdivided into two separate phases, the Baskil and the Bilaser Tepe complexes. Based on the petrographic and bulk‐rock geochemical data, the Baskil granitoids are classified as quartz‐diorite, quartz‐monzodiorite and tonalite, whereas the Bilaser Tepe granitoids are classified as granodiorite and dacite‐porphyry. Both the Baskil and Bilaser Tepe granitoids have peraluminous and metaluminous compositions. The Crosta method is found to be very useful for enhancing the altered areas with hydroxyl and iron oxide minerals. The Crosta method is applied to six (1, 2, 3, 4, 5 and 7) and two sets of four (1, 3, 4, 5 and 1, 4, 5, 7) bands of ETM+ data. However, the areas with potassic, phyllic, argillic and propylitic alteration zones are enhanced much better by using six bands of Landsat 7 ETM+ data. The alteration differences of these two magmatic groups are also tested with the Crosta technique using four band combinations. Although no distinct difference is observed on the hydroxyl image, a clear difference is observed between the two magmatites on the iron oxide image. The present study shows that the Crosta technique is not only generating hydroxyl and iron oxide images, but also differentiates between two magmatite groups of different ages and genesis.

DOI

[44]
韩玲,谢秋昌.利用遥感技术对新疆西天山地区矿化蚀变信息的提取[J].遥感信息,2007,6:49-51.

[ Han L, Xie Q C.Remote sensing for extracting mineralizing alteration information in Chagannur areas of west Tianshan, Xinjiang[J]. Remote Sensing Information, 2007,6:49-51. ]

[45]
高景刚,薛春纪,吴淦国,等.基于知识的蚀变遥感异常信息快速提取及找矿应用实践[J].遥感学报,2008,12(1):186-192.本文以新疆卡拉先格尔成矿带内新发现的哈腊苏铜矿化区为例,进行ETM 矿化蚀变遥感异常信息快速提取研究.分别在ETM 1,ETM 2,ETM 3,ETM 4,ETM 5和ETM 7等6个波段图像和增强图像(比值图像、主成分分析图像)上已知蚀变岩分布区及地质背景进行像元光谱采样,并分析蚀变岩在ETM 的6个波段图像及铁染异常和羟基异常图像上的光谱特征,进而发现蚀变岩与矿区地层区分的光谱知识.利用矿区成矿地质特征和典型矿床成矿模型建立遥感地质找矿模型,发现遥感地质控矿特征.在此基础上建立了基于知识规则的在ETM 图像上提取蚀变遥感异常信息模型,利用ERDAS IMAGING V8.7图像处理系统中的专家分类器模块快速提取该区蚀变遥感异常信息,实现了地质与遥感在图像处理平台上的有机结合.经实际验证,其结果与实际情况基本吻合,并且新发现铜矿化带一处,可为与该区地质背景类似的新疆阿勒泰南缘开展铜矿普查勘探提供参考依据.

DOI

[ Gao J G, Xue C J, Wu G G, et al.Method of fast extracting alteration remote sensing abnormal information based on knowledge and prospecting application[J]. Journal of Remote Sensing, 2008,12(1):186-192. ]

[46]
Kalelioglu O, Zorlu K, Kurt M A, et al.Delineating compositionally different dykes in the Uluksla basin (Central Anatolia, Turkey) using computer-enhanced multi-spectral remote sensing data[J]. International Journal of Remote Sensing, 2009,30(11):2997-3011.

DOI

[47]
张佩民,张建国,杨自安,等.滇东罗平县雄武镇地区遥感蚀变信息提取及成矿预测[J].地质通报,2009,28(6):769-775.

[ Zhang P M, Zhang J G, Yang Z A, et al.Remote sensing alteration information extraction and metallogenic prognosis of Xiongwu Town area, Luoping County, eastern Yunnan Province, China[J]. Geological Bulletin of China, 2009,28(6):769-775. ]

[48]
王润生,熊盛青,聂洪峰,等.遥感地质勘查技术与应用研究[J].地质学报,2011,85(11):1699-1743.遥感的发展极大地拓宽了人类的视野和视觉能力，以其宏观性、综合性、多尺度、多层次的特点，已成为地质研究和地质勘查不可缺少的方面军，在地质调查、矿产勘查、地质环境评价、地质灾害监测和基础地质研究等方面都发挥了越来越大的作用。随着传感器分辨率（空间、光谱、时间、辐射）的不断提高，特别是高光谱和干涉雷达技术的发展，不仅极大地提高了遥感的观测尺度、对地物的分辨本领和识别的精细程度，而且使遥感地质发生了由宏观探测到微观探测，由定性解译到定量反演的质的飞跃，将遥感地质和应用都推向一个新的高度。本文首先简要介绍了遥感技术的发展及其意义，遥感地质找矿的原理、方法和遥感找矿模型，然后分别从岩矿波谱、遥感图像处理、多光谱蚀变异常提取、高光谱矿物识别与填图、InSAR地表形变调查与监测、遥感找矿模型、遥感地质灾害调查与监测7个方面介绍了遥感的基本原理、主要的技术方法、技术特点和技术关键、主要的应用领域，以及取得的一些研究成果和应用实例

[ Wang, R S, Xiong S Q, Nie H F, et al. Remote sensing technology and its application in geological exploration[J]. Acta Geologica Sinica, 2011,85(11):1699-1743. ]

[49]
钱建平,张渊,赵小星,等.内蒙古东乌旗遥感构造和蚀变信息提取与找矿预测[J].国土资源遥感,2013,25(3):109-117.lt;p>为了研究内蒙古东乌旗Pb-Zn-Ag多金属成矿区的找矿远景,在对Landsat7 ETM<sup>+</sup>数据进行几何纠正、大气校正和去干扰等预处理的基础上,对多波段假彩色合成图像做滤波处理以增强区域构造信息、进行线性构造解译; 运用分形几何学原理和计盒维数法求取线性构造分维值,得到线性构造的统计自相似性和分形特征; 采用主成分分析和阈值分割法对图像进行铁染、羟基蚀变信息提取; 最后根据区内线性构造、遥感蚀变信息、岩体分布特征、区域地球化学异常和已知矿床(点)分布资料综合分析,圈定出3个级别的7个找矿预测区,再次证实了基于遥感图像的线性构造和遥感蚀变异常信息可以作为找矿预测的标志。</p>

DOI

[ Qian J P, Zhang Y, Zhao X X, et al.Extraction of linear structure and alteration information based on remote sensing image and ore-prospecting prognosis for Dongwu Banner, Inner Mongolia[J]. Remote Sensing for Land and Resources, 2013,25(3):109-117. ]

[50]
夏清,杨武年,赵妮.青藏大陆北缘喷山耦合带库斯拉甫地区遥感蚀变信息提取[J].国土资源遥感,2014,26(1):127-131.lt;p>新疆库斯拉甫地处青藏大陆北缘西昆仑复合造山带与塔里木大陆南缘的碰撞结合带，具备良好的成矿地质条件；但自然环境恶劣，可进入条件差，有不少重要地质现象和找矿信息若采用常规地质调查方法难以获取。许多应用实践已经证明，日趋成熟的遥感技术能够很好地弥补这方面的不足。以库斯拉甫地区为研究区，以ETM<sup>+</sup>图像为数据源，在ENVI软件环境下，综合运用比值运算、掩模处理、主成分分析和密度分割等方法对遥感数据进行处理，提取出研究区近矿围岩蚀变信息；并通过与研究区已有矿点信息和化探异常信息进行叠置分析，对提取的遥感蚀变信息进行验证。结果表明，利用上述方法提取羟基蚀变信息是可行的，可为研究区今后开展大范围地质找矿提供依据。</p>

DOI

[ Xia Q, Yang W N, Zhao N.Extraction of remote sensing alteration information of Kosrap area in northern basin-mountain coupling zone of Tibetan Plateau[J]. Remote Sensing for Land and Resources, 2014,26(1):127-131. ]

[51]
吴小娟,温静,肖晨超,等.基于多源遥感数据的矿物蚀变信息提取——以西藏甲玛铜多金属矿为例[J].地质力学学报,2015,21(2):228-240.This paper extracted the altered minerals in Jiama copper polymetallic deposit by two methods: bands algebraic operation and principal component analysis with ETM+(TM) data and Aster data and got the distribution map of altered minerals by fusing alteration information.ETM+(TM) data is suitable to recognize hydroxyl group, iron and carbonate and can offer basic remote sensing technology. Aster data can extract more minerals, such as dolomite, limonite, chlorite, muscovite and kaolinite. By comparing with the geological data and actual exploration results, the extraction results of mineral alteration are effective and reliable.

DOI

[ Wu X J, Wen J, Xiao C C, et al.Extraction of altered mineral information based on multi-source remote sensing data: A case study of Jiama Copper polymetallic deposit[J]. Journal of Geomechanics, 2015,21(2):228-240. ]

[52]
Sojdehee M, Rasa I, Nezafati N, et al.Application of spectral analysis to discriminate hydrothermal alteration zones at Daralu copper deposit, SE Iran[J]. Arabian Journal of Geosciences, 2016,9(1):1-12.ABSTRACT A number of geoids with various data and names have been determined up to present day in Turkey. In this paper, all Turkish geoids have been reviewed. For this purpose, ten local geoid models have been examined. These are 1976 Turkish Geoid (TG-76), Turkish Geoid-1991 (TG-91), Turkish Doppler Geoid-1992 (TDG-92), Turkish PseudoWGS84Doppler Geoid-1992 (TPDG-92), Turkish Astrogeodetic Geoid-1994 (TAG-94), Turkish GPS/Leveling Geoid, Updated Turkish Geoid-1999 (TG-99A), Turkish Geoid-2003 (TG-03), Turkish Geoid-2009 (TG-09), and Turkish Hybrid Geoid-2009 (THG-09). Within the numerical applications carried out, 30 test benchmarks of the Turkish National Fundamental GPS Network have been selected and geoid heights from each geoid model over these points have been calculated. Later, all of the models have been compared with each other in terms of the criteria based on their developments and geoid height differences have been calculated using local models at the test points. Through these comparisons, the causes of the inconsistencies between the various geoid models are explored while their overall accuracy is determined as well.

DOI

[53]
Pazand K, Sarvestani J F, Ravasan M R S. Hydrothermal alteration mapping using ASTER data for reconnaissance porphyry copper mineralization in the Ahar area, NW Iran[J]. Indian Society of Remote Sensing, 2013,41(2):379-389.The Ahar area is located in East Azarbaijan province, and covers an area of about 2,500 km 2 . Spectral mapping techniques were applied on VNIR and SWIR of ASTER data for discriminating between hydrothermal alteration zones and the identification of high potential mineralized lithological unit associated with hydrothermal porphyry copper mineralization in the Ahar. In this research to remove atmospheric and topographic effects from ASTER data, the log-residual method (LRM) was used. Four methods, Relative Band Depth Ratios (RBD), Principal Component Analysis (PCA), Minimum Noise Fraction (MNF) and matched filtering (MF), were used to processing and interpretation of remote sensing data in the study area. Results show that ASTER images provide preliminary mineralogy information and geo-referenced alteration maps at low cost and with high accuracy for reconnaissance porphyry copper mineralizations.

DOI

[54]
毛晓长,刘文灿,杜建国,等.ETM+和ASTER数据在遥感矿化蚀变信息提取应用中的比较——以安徽铜陵凤凰山矿田为例[J].现代地质,2005,19(2):309-314.lt;p>在利用遥感技术找矿中，矿化蚀变信息识别与提取起着重要作用。选择具有典型蚀变特征的安徽铜陵凤凰山矿田作为研究区，从分析地物波谱，尤其是岩矿光谱特征出发，根据ETM+和ASTER数据的光谱特征，采用主成分分析（PCA），设计了相应的粘土矿化蚀变信息提取方案，成功地进行信息提取。对两者的提取结果进行比较后表明，ASTER数据较之ETM数据在粘土类矿化蚀变信息提取中具有更大的优势。</p>

DOI

[ Mao X C, Liu W C, Du J G, et al.Comparison between ETM+ and ASTER data for extraction of alteration information: A case study of Fengshuangshan ore field, Tongling, Anhui Province[J]. Geoscience, 2005,19(2):309-314. ]

[55]
张玉君,杨建民.基岩裸露区蚀变岩遥感信息的提取方法[J].国土资源遥感,1998,51(2):46-53.

DOI

[ Zhang Y J, Yang J M.The method of abstracting remote sensing information of alterated rocks in the uncovered bedrocks area[J]. Remote Sensing for Land and Resources, 1998,51(2):46-53. ]

[56]
马文征,王铁军.内蒙古西乌珠穆沁旗地区围岩蚀变的遥感信息提取[J].地质找矿论丛,2010,25(3):265-270.Mask technique is applied to eliminate interfere factors at surface and principal component transfer technique is used to enhance the alteration information and the alteration information is extracted by using false color composite and unsuperised classification techniques.

DOI

[ Ma W Z, Wang T J.Remote sensing information extraction of wall rock alteration in Xi Ujimqin Banner, Inner Mongolia[J]. Contributions to Geology and Mineral Resources Research, 2010,25(3):265-270. ]

[57]
段宗恩,朱谷昌,张思颖,等.哈密黑山口地区遥感蚀变信息提取特征波段优选研究[J].地质与勘探,2012,48(4):823-828.在遥感蚀变信息提取研究中,特征波段的选取是主要的技术关键。本文以新疆哈密市黑山口地区为 研究区,利用ETM卫星遥感数据,在光谱数据空间几何结构特征分析的基础上,通过对七个多光谱波段的回归偏度分析,评价蚀变信息的客观存在性,从而选取出 针对不同蚀变类型的特征波段,然后采用主成分分析、最优密度分割等方法,提取出矿化蚀变信息,并对结果信息进行了评价。通过野外地质调查和光谱测量的实地 验证,提取的蚀变信息与实地情况吻合性好,取得了较理想的效果。结论认为,次级断裂构造带上含矿化蚀变的铁镁质岩体找矿前景较好。

[ Duan Z E, Zhu G C, Zhang S Y, et al.Selection of characteristic bands in alteration information extraction from remote sensing images for the Heishankou area, Hami, Xinjiang[J]. Geology and Exploration, 2012,48(4):823-828. ]

[58]
Asl R A, Afzal P, Adib A, et al.Application of multifractal modeling for the identification of alteration zones and major faults based on ETM+ multispectral data[J]. Arabian Journal of Geosciences, 2015(8):2997-3006.The aim of this study is to investigate the reconnaissance of alteration zones and faults in Hashtjin 1:100,000 sheet (NW Iran) using concentration-area (C-A) fractal model based on remote sensing data, which has been extracted from enhanced thematic mapper (ETM)+ multispectral images. There are Oligocene volcano-plutonic rocks and Tarom-Hashtjin metallogenic zone with Cu, Au, and Pb-Zn occurrences in the studied area. The concentration-area (C-A) fractal model proposed in this paper for the interpretation of pixel value distribution spatial patterns based on the extracted data from ETM+ multispectral images. The pixel values were calculated by the PCA (principal component analysis) method for iron oxides and argillic alteration. Furthermore, the sharpen-filtering has been applied to calculate the value pixels for the main fault zone in the Hashtjin area. The C-A model can be used to establish power-law relationships between the area and the pixel value. The log-log C-A plots show multifractal nature for iron oxides, argillic alteration zones, and faults. Results obtained by the fractal model reveal that alteration zones and major faults have a NNW-SSE trend. The alteration zones and major faults have a strong correlation with the geological map of the area.

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[59]
吴浩,徐元进,范高晶,等.奇异值分解在ETM+遥感蚀变信息提取中的应用——以青海省五龙沟金矿勘查区为例[J].地理与地理信息科学,2016,32(2):40-45.

[ Wu H, Xu Y J, Fan G J, et al.Using ETM+ data for extraction of alteration information based on singular value decomposition: A case study of Wulonggou gold deposit, Qinghai[J]. Geography and Geo-information Science, 2016,32(2):40-45. ]

[60]
吴志春,郭福生,刘林清,等.青海玉树地区遥感找矿蚀变异常提取与成矿预测[J].东华理工大学学报(自然科学版),2011,34(3):271-277.遥感找矿蚀变异常提取是当今综合找矿的重要手段之一。以青海玉树地区的遥感找矿蚀变异常提取 为例，运用主成分分析、波段比值、波段比值的主成分分析复合法、无损线性拉伸、掩膜、密度分割等方法，解决了第四系和植被对遥感蚀变异常提取的干扰的问 题。在该工作区内共圈出了6个I级找矿远景区，3个Ⅱ级找矿远景区，7个Ⅲ级找矿远景区；遥感蚀变异常区与全部矿床、矿（化）点吻合率高达88．1％，与 含铜、含铅、含锌、含铁的金属矿床、矿（化）点吻合率分别为93．22％，75．76％，78．26％，100％。

DOI

[ Wu Z C, Guo F S, Liu L Q, et al.Alterations anomaly abstraction of mineral survey with remote sensing and metallogenic prognosis in Yushu, Qinghai[J]. Journal of East China University of Technology (Natural Science), 2011,34(3):271-277. ]

[61]
赵小星. 西藏桑木岗地区遥感线性构造和蚀变信息提取与找矿预测[J].现代地质,2017,31(4):851-859.利用西藏桑木岗地区ETM+遥感数据,通过主成分分析、卷积滤波和形态学分析、假彩色合成等方法对线性构造做了增强处理,并进行目视解译.根据蚀变矿物特有的光谱特征,通过彩色合成、直方图拉伸进行信息增强处理,运用主成分分析方法对研究区铁染、羟基蚀变信息进行提取.比较线性构造和铁染、羟基蚀变信息可知,线性构造密集区与铁染、羟基蚀变异常区基本吻合,均呈近EW向展布,与区域构造、成矿构造格局一致,区内80％以上的已知矿点分布于铁染、羟基蚀变异常区.综合分析线性构造、遥感蚀变异常、区域地质、地球化学、已知矿床(点)等地学信息,圈定了3级7个成矿远景区,其中一级远景区是最有前景的异常区.

[ Zhao X X.Extraction of linear structure and alteration information based on remote sensing images and ore-prospecting prognosis for Sangmugang in Tibet[J]. Geoscience, 2017,31(4):851-859. ]

[62]
Tangestani M H, Moore F.Iron oxide and hydroxyl enhancement using the Crosta method: A case study from the Zagros belt, Fars Province, Iran[J]. International Journal of Applied Earth Observation and Geoinformation, 2000,2(2):140-146.Following preliminary reports on the probable occurrence of iron ore in the Mashayekh-Nowdan area, west of Shiraz, principal components analysis on 6 and 4 Landsat-TM bands was tested by the Crosta method for the enhancement and discrimination of iron oxide stained and hydroxyl-bearing areas in the region. Eigenvector loadings of visible and infrared bands of TM bands 1, 3, 4, 5, and 7 show that in each case the first principal component (PC 1) indicates albedo, PC2 indicates the difference between visible and infrared bands, and PC3 indicates vegetation. Features with lower importance such as iron oxide or hydroxyl-bearing minerals are concentrated in subsequent principal components. PC4 of unstretched data transformation on bands 1, 4, 5, and 7 indicates the hydroxyl-bearing and carbonate exposures; and on bands 1, 3, 4, and 5, it indicates iron oxides. Color composites of hydroxyl and iron oxide images enhance the iron oxide exposures, but not as clearly in the case of hydroxyls, because of some spectral behavior similarities with carbonates.

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[63]
燕守勋,武晓波,周朝宪,等.遥感和光谱地质进展及其对矿产勘查的实践应用[J].地球科学进展, 2011,26(1):13-29.lt;p>根据2009年Economic Geology 出版的专辑Remote Sensing and Spectral Geology,近年来发表的相关文献以及研究和应用的实践，对遥感与光谱地质进行了综述。内容从测谱学、TM/ETM和ASTER宽波段遥感应用，到地面和航空高光谱遥感应用与热红外遥感。传统的信息填图主要是解译，现代遥感不仅能提取地质和蚀变信息，还能进行其他手段无法进行的有效填图，结合地球物理、地球化学、野外和实验室光谱等，还能加深对矿床成因的理解。现代光谱地质结合XRF和GPS能够对矿物和蚀变带原地定量填图。TM/ETM从铁氧化物和含羥基矿物来提取矿化蚀变信息，大区域快速圈定成矿靶区。ASTER在粘土区SWIR的5个波段，提供了区分粘土矿物类型和一些硫酸盐、碳酸盐的能力，可以区分粘土、高级粘土、绢英岩和青盘岩，以及方解石和白云石。短波区的3个铁波段可以区分黄钾铁矾与赤铁矿和褐铁矿。障碍是需要校正到反射率来区分这些矿物组合，没有辅助数据很难做到这点，这极大地限制了该仪器作为常规勘探工具的能力。Crosta提供了多元统计方法对蚀变带填图，不需要大气校正。ASTER有5个热波段，像元大、信/噪比低。有能力对硅质岩和碳酸盐填图，但噪音多，并不总是有效。航空高光谱具有矿物填图的实用信/噪比。但航天高光谱Hyperion的信/噪比不能满足勘探和填图的要求。热红外是正在发展、尚未应用的勘探工具，其前景是可对硅质、硅酸盐类和碳酸盐填图。高分辨率遥感图像也为矿区快速评价、矿产勘查以及矿山建设提供了有效的技术支持。最后，结合国内外研究进展，讨论了勘查中的数据选择，给出了建设性的结论。</p>

DOI

[ Yan S X, Wu X B, Zhou C X, et al. Remote sensing and spectral geology and their applications to mineral exploration[J]. Advances in Earth Science, 2011,26(1):13-29. ]

[64]
Mia M B, Fujimitsu Y.Mapping hydrothermal altered mineral deposits using Landsat 7 ETM+ image in and around Kuju volcano, Kyushu, Japan[J]. Journal of Earth System Science, 2012(4):1049-1057.To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7 ETM+ image in and around Kuju volcano is the prime target of our study. The Kuju volcano is a mountainous composite which consists of hornblende-andesite lava domes and associated lava flows. We used the colour composite, band ratio, principal component analysis, least square fitting and reference spectra analysis methods. The colour composite and band ratio methods showed very clearly the hydrothermal altered deposits of clay minerals, iron oxides and ferric oxides around the fumaroles. The principal component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and iron-oxide mineral deposits of this region concentrating around the fumaroles. Least square fitting method illustrated the goethite, hematite and clay alteration region. Finally the target detection method for reference spectral analysis by using ENVI 4.3 detected the representative hydrothermal altered minerals around Kuju volcano fumaroles area. Therefore, all the methods showed high efficiency for mapping hydrothermal altered deposits especially iron-oxide minerals such as hematite, goethite and jarosite, which are alteration products of hydrothermal sulfides around the fumaroles.

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[65]
Eldosouky A M, Abdelkareem M. Elkhateeb S O.Integration of remote sensing and aeromagnetic data for mapping structural features and hydrothermal alteration zones in Wadi Allaqi area, south eastern desert of Egypt[J]. Journal of African Earth Science, 2017(130):28-37.Remote sensing and aeromagnetic data provided significant information for detecting potential areas of mineralization in Wadi Allaqi in the South Eastern Desert of Egypt. Application of band ratios and Crosta technique of Principal Component Analysis (PCA) using Landsat-8 successfully highlighted the hydrothermal alteration zones and the structural elements represented by lithologic contacts and faults/fracture zones. Structural lineaments were also successfully extracted using remote sensing and aeromagnetic data. Center for Exploration Targeting (CET) Grid analysis and CET Porphyry Analysis techniques were applied for constructing the structural complexity heat map and probable near circular features of porphyry intrusions respectively. Combining data of lineaments, alteration zones and porphyry intrusions after obtaining a consequence of each map allowed predicting and mapping areas of probable high mineral resources. Overlaying the present sites of mineralization on the final map validated the prepared mineral predictive map. Overall results clearly revealed that areas of high structural complexity, fractures/faults density are in agreement with the detected areas of hydrothermal alterations which also matched with the known mineralization mines in the study area.

DOI

[66]
张国荣,芦青山,费一清. ETM+数据在甘肃省肃北县黑刺沟一带蚀变遥感异常信息提取中的应用[J].大地构造与成矿学,2010,34(3):386-390.遥感卫星的多光谱数据应用于找矿已取得显著的成效,ETM^＋数据因涵盖波长范围宽、波段 多、价格合理等因素,而逐渐广泛应用。笔者利用ETM^＋数据到黑刺沟一带进行蚀变遥感异常提取,提取的蚀变异常与野外地质情况吻合性好,分别提取了铁染 和黏土化蚀变遥感异常,并采用了掩膜技术消除了云、冰雪、盐碱地、盐碱滩和植被的干扰。

DOI

[ Zhang G R, Lu Q S, Fei Y Q.Application of ETM+ data to alteration remote sensing anomaly extraction in the Heicigou area of Subei County, Gansu[J]. Geotectonica et Metallogenia, 2010,34(3):386-390. ]

[67]
费一清,李永庆.基于ETM数据的蚀变遥感异常信息提取及成矿区预测研究[J].遥感技术与应用,2011,26(4):482-488.<p>遥感成矿探测技术关键在于成矿构造及蚀变矿物信息的提取。以甘肃酒泉党河&mdash;南山地区为研究区,基于ETM数据和ASTER遥感数据,利用主成分变换、掩膜分析、阈值分割等方法,从Landsat\|7 ETM数据中提取矿化蚀变信息并预测可能成矿的区域。该方法准确、有效地消除了云、雪等干扰信息,利用该方法获得的矿化蚀变信息与已知矿点有很好的一致性,因此用该方法提取蚀变信息是可行的。</p>

[ Fei Y Q, Li Y Q.Extraction of remote sensing alteration information and analysis of metallogenic prognosis based on ETM: A case study of Danghe-Nanshan area in Gansu[J]. Remote Sensing Technology and Application, 2011,26(4):482-488. ]

[68]
彭光雄,王明艳,何皎.基于局部可变窗口的Crosta蚀变信息提取技术——以莫海拉亨为例[J].大地构造与成矿学,2013,37(3):553-560.针对常规Crosta技术的不足，本文提出一种基于局部可变窗口的改进方法。改进方法利用局部可变窗口将整幅影像划分为若干个独立统计分析单元，并且在每个独立单元内部排除水体、云、冰雪等干扰信息，然后再进行主成分分析和矿化蚀变异常组分的判断与选择。本次研究以莫海拉亨铅锌矿区为例，利用改进方法进行了矿化蚀变的信息提取和遥感找矿实例分析。结果表明，改进的Crosta方法能有效降低环境噪声，对干扰信息有较强的筛选过滤功能，同时对弱蚀变信息有较强的识别能力。褐铁矿化和硅化是矿区主要的矿化蚀变类型，断裂对成矿的控制作用明显。位于断裂带以及断裂交汇的部位，且铁帽、碳酸盐化和硅化遥感异常重叠的区域是重要的遥感找矿标志。

DOI

[ Peng G X, Wang M Y, He J.An improved Crosta technique based on local variable window for alteration information extraction: A case study of the Mohailaheng area[J]. Geotectonica et Metallogenia, 2013,37(3):553-560. ]

[69]
于岩,李建国,陈圣波,等.基于不同岩性背景的遥感影像蚀变矿物信息提取[J].地球科学——中国地质大学学报,2015,40(8):1391-1395.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.

DOI

[ Yu Y, Li J G, Chen S B, et al.ASTER image alteration minerals information extraction based on different lithology background[J]. Earth Science (Journal of China University of Geosciences), 2015,40(8):1391-1395. ]

[70]
丛丽娟,胡凤翔,杨俊才,等.内蒙古朱拉扎嘎金矿ETM+数据提取蚀变异常方法研究[J].现代地质,2007,21(4):725-732.lt;p>中国西北部大部分地区属于荒漠景观区，自然条件恶劣，常规的地质、物探、化探找矿工作难度大，如何借助遥感技术进行矿产资源勘查，是地质工作者积极探索的方向之一。本次工作选择内蒙古阿拉善盟朱拉扎嘎金矿作为实验区，利用卫星遥感ETM<sup>+</sup>数据进行蚀变异常提取方法研究。从蚀变矿物的波谱特征出发，对Crosta法则进行改造，建立了适合本区的异常提取模型：铁化蚀变异常提取以Band 2、 Band 3 、Band 4 、Band 5/Band 1主成分分析为核心技术；含羟基和碳酸盐化蚀变异常提取以Band 2、Band 4、 Band 5 、Band 7主成分分析为核心技术。运用该模型完成了矿区及其外围蚀变异常提取工作，经过地面光谱验证，检测到铁化、含羟基和碳酸盐化蚀变矿物，认为提取方法合理，提取结果可信。本次研究工作可以为矿区外围找矿提供新方法，为推广和应用遥感技术在荒漠景观区找矿提供参考。</p>

DOI

[ Cong L J, Hu F X, Yang J C, et al.Study on abnormal extracting of altered rocks using ETM+ data in Zhulazhaga gold deposit, Alashan region, Inner Monogolia[J]. Geoscience, 2007,21(4):725-732. ]

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马建文,张齐道.利用TM数据提取含金蚀变带的方法研究——以冀北东卯地区为例[J]. 国土资源遥感, 1994(2):41-45.卫星遥感技术是一种利用电磁波作载体从高空探测地面信息的技术。在遥感地质找矿中，环境因素对成矿条件信息的增强和提取来说可以认为是干扰因素。这种环境干扰因素在空间上可分为集中分布的和分散分布的两类。本文是用图像分割的方法从ＴＭ的７个波段原始数据中去掉集中分布的环境因素，用ＰＣ统计数据的二维散点图所表达的数据特征，把地质目标信息和分散分布的环境干扰因素分开，实现排除二类环境干扰因素，从而增强提取含金蚀变带信息的目的。

DOI

[ Ma J W, Zhang Q D.Study on the method of identifying hydrothermally altered rocks using TM data[J]. Remote Sensing for Land & Resources, 1994(2):41-45. ]

[72]
杨建民,张玉君,陈薇,等.ETM+(TM)蚀变遥感异常技术方法在东天山戈壁地区的应用[J].矿床地质,2003,22(3):278-286.文章将蚀变遥感异常作为矿产资源综合评价与定位预测的主要参数, 对在东天山戈壁地区的石英滩至赤湖地区3.3万余平方千米的范围内开展的ETM+(TM)遥感勘察结果进行了蚀变异常提取,并依此进行了矿产资源快速评价 与定位预测,还对部分异常点进行了实地查证.研究区内已知矿床、矿(化)点122个,遥感异常与其中105个互洽,吻合率86%,与已知矿床的吻合率为 100%.经首批地面查证扩大了一处已知金矿点的找矿范围.

DOI

[ Yang J M, Zhang Y J, Chen W, et al.Application of ETM+(TM) remote sensing alteration anomaly extraction technique to Gobi area, east Tianshan mountains[J]. Mineral Deposits, 2003,22(3):278-286. ]

[73]
张楠楠,周可法,孙莉,等.遥感蚀变地质特征提取研究——以新疆康古尔地区为例[J].新疆地质,2008,26(1):39-42.围岩蚀变范围比矿体的范围大一至几十倍，与原岩有很明显的差异特征．应用遥感技术在卫星图像上提取出这种特征，是寻找矿床或矿集区行之有效的方法之一．依据蚀变矿物光谱行为造成的蚀变岩光谱特征，利用遥感数据和典型岩石的多元分析，对蚀变矿物成份和光谱数据间的关系作出定性和定量分析，建立适合研究区的遥感矿化蚀变主分量门限化信息提取模型．研究以主分量门限化模型为基础，在新疆康古尔地区进行了模型应用研究，结果表明此模型在采集岩石光谱数据较困难时可以达到一定提取效果，为该区的地质找矿提供思路．

DOI

[ Zhang N N, Zhou K F, Sun L, et al.Feature extraction altered geological remote sensing research: Example for Xinjiang Kangguer area[J]. Xinjiang Geology, 2008,26(1):39-42. ]

[74]
郭娇,朱谷昌,邹林,等.贵州省道真地区遥感蚀变信息提取研究[J].矿床地质,2014,33(增刊):675-676.正遥感找矿是以现代成矿理论为指导,在查明矿化信息形成机理的基础上,通过各类遥感图像的目视解译和处理,提取和矿产相关的信息,经分析与推理圈定成矿远景区、预测区。1研究区概况贵州省务正道地区(务川县、正安县、道真县)位于贵州省北部,属渝南-黔北铝土矿成矿带的组成部分,本文以道真地区铝土矿为研究区,该区北部与重庆市毗邻;南部分别与正安县、务川县接壤。研究区地理坐标为东经107°40′~108°;北

[ Guo J, Zhu G C, Zou L, et al.The study of extracting remote sensing alteration information in Daozhen area, Guizhou Province[J]. Mineral Deposits, 2014,33(Sup.):675-676. ]

[75]
Honarmand M, Ranjbar H, Shahabpour J.Application of principal component analysis and spectral angle mapper in the mapping of hydrothermal alteration in the Jebal-Barez area, southeastern Iran[J]. Resource Geology, 2012,62(2):119-139.The southeastern part of the central Iranian Cenozoic magmatic belt contains many areas with copper mineralization. In an analysis of this region, we used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Enhanced Thematic Mapper plus (ETM+) images to map the distribution of hydrothermally altered rocks, based on their mineral assemblages. The spectral measurements, based on the field samples and satellite-image-derived spectra, show dominantly Al–OH (sericite and clays) and Fe–O absorption features in the visible–near infrared to shortwave infrared regions of the spectrum. Silica–bearing rocks, as well as silicic alteration, show an intense Si–O vibrational feature in the thermal infrared wavelength region. We analyzed ASTER/ETM+ images, performed a directed principal component analysis, and used spectral angle mapper to map areas of hydrothermal alteration and iron oxide/hydroxide minerals. The individual principal component images compiled by directed principal component analysis reveal the distribution of individual alteration minerals such as sericite, kaolinite, chlorite, epidote, and quartz. The best results, in terms of mapping the distribution of alteration, were obtained using the spectral angle mapper method. The altered areas were then sampled and the samples subjected to X–ray diffraction analysis, spectral analysis, and thin sections were observed under a microscope. Field observations reveal that more than 98% of the known copper mineralization occurs within the interpreted alteration areas. The present results indicate the great potential of ASTER and ETM+ data for mapping the distribution of alteration and exploring for copper mineralization in areas with a similar climate and geological setting to those of the present study.

DOI

[76]
Ghosh U K, Naik K K, Kesari M P.Digital image processing of multispectral ASTER imagery for delineation of alteration and related clay minerals in Sakoli Belt: A case study of Maharashtra[J]. Journal Geological Society of India, 2016(88):464-470.The extraction of spectral signature through remote sensing data in geological studies is very limited in Indian terrain. The present research is an attempt to delineate alteration and associated minerals using high resolution multispectral advanced space borne thermal emission and reflection (ASTER) data in Sakoli volcano-sedimentary sequence. The alteration zones are generally associated with certain types of mineral and mineral aggregates and are localized in the ground that can be mapped remotely using spectral mapping techniques. The band ratio and selective PCT were applied on calibrated ASTER image to extract spectral signature of index mineral. The results showed that high abundance of these minerals within pixels is corresponding to the alteration zones. The field observation, petrography and XRD analysis of the alteration zones confirmed the presence of dominant mineral phases that were identified remotely.

DOI

[77]
Chavez P S, Kwarteng A Y.Extracting spectral contrast in Landsat Thematic Mapper image data using selective principal component analysis[J]. Photogrammetric Engineering and Remote Sensing, 1989,55(3):339-348.

[78]
张晋开,崔承禹,支毅乔.基于主成分分析的植被掩模与模式滤波方法在中等植被覆盖区蚀变信息提取中的应用[J].中国图象图形学报,1996,1(2):108-113.植被干扰的消除对于应用TM图象进行蚀变信息提取是非常重要的。本文从矿物，岩石和植被在TM波段内的波谱响应分析入手，选择了TM5和TM1，TM5和TM7，TM4和TM3这三个组合分别来增强含铁矿物（主要是铁氧化物），含羟基矿物和碳酸盐矿物及植被信息。通过对比值，比值合成以及主成分分析等方法的比较，提出了一种适于中等植被覆盖区蚀变信息提取的新方法，即基于主成分分析的植被掩模和模式滤波相结合的方法。此方法在试验区进行蚀变信息提取中取得良好效果，它不仅识别出了与地表金矿化区一致的蚀变矿物富集区，而且对土石矿的一些矿脉也有较好反映。

DOI

[ Zhang J K, Cui C Y, Zhi Y Q.A new method for alteration extraction in mid-vegetated areas using TM data—combined technique of vegetation masking and mode filtering based on principal component analysis[J]. Journal of Image and Graphics, 1996,1(2):108-113. ]

[79]
Fraser S J, Green A A.A software defoliant for geological analysis of band ratios[J]. International Jouranal of Remote Sensing, 1987,8(3):525-532.Vegetation impedes the geological analysis of band ratio images, because it is both widely distributed in the surficial environment and can be spectrally similar to ferric oxides and clays when sampled by broad-band imaging devices. We address this problem by a technique we call 090004directed principal component analysis090005 (DPCA) that involves calculating principal components on two input band ratio images. One ratio is a geological discriminant, conTused by the presence of vegetation; the second ratio is chosen for its suitability as a vegetation index. Once computed, the second DPC has the properties of a geological discriminant, but is less influenced by vegetation. The effects of vegetation, which are strongly correlated between the two input ratios, contribute chiefly to DPC#1. This simple method, applied selectively to airborne thematic mapper data, substantially reduces the effects of vegetation.

DOI

[80]
赵元洪,张福祥,陈南峰.波段比值的主成分复合在热液蚀变信息提取中的应用[J].国土资源遥感,1991,3(3):12-17.lt;p>笔者运用不同波段组合的遥感比值图像的主成份复合技术进行热液蚀变信息增强,研制了一 种利用陆地卫星TM数据在有植被覆盖的湿润亚热带火山岩区自动提取矿化蚀变信息的新方法,并 在浙东新昌拔茅金银多金属矿区的试验研究中获得了成功,不仅有效地显示了矿区内已知蚀变岩 的展布,还揭示出了一些前人未知的热液蚀变岩区、硅化石英脉、控矿物造及火山机构等对成矿 预测极有价值的信息。</p>

DOI

[ Zhao Y H, Zhang F X, Chen N F.The application of principal component integration of band ratios to extracting hydrothermal alteration information[J]. Remote Sensing for Land and Resources, 1991,3(3):12-17. ]

[81]
罗一英,高光明,于信芳,等.基于ETM+的几内亚铝土矿蚀变信息提取方法研究[J].遥感技术与应用,2013,28(2):330-337.lt;p>铝土矿上覆厚度为0.5~9 m的铁矾土(铁帽)的特点使得研究区内铝土矿蚀变信息在一定程度上可以由铁帽信息来表示。在分析区内铝土矿的含矿体系、光谱特征和遥感影像特征的基础上,提出充分利用铝土矿与铁帽信息的相关性,通过提取铁帽信息来间接提取铝土矿蚀变信息。介绍了通过&ldquo;多元数据分析+比值分析+主成分分析+分类&rdquo;提取铝土矿蚀变信息的方法,结果表明:利用该方法提取的蚀变信息与已知矿体的吻合率为63%,蚀变信息提取准确度较主成分分析(44.6%)和比值分析(54.7%)有较大幅度提高。该方法能够抑制植被覆盖及第四系等干扰因素的影响,快速有效地提取几内亚金迪亚地区的铝土矿蚀变信息,初步查明区内铝土矿的分布规律,为进一步找矿勘查工作提供了有效的指示信息,这对于找矿勘查成本高的海外勘探区,具有重要的现实意义。</p>

DOI

[ Luo Y Y, Gao G M, Yu X F, et al.A study on extraction of Bauxite alteration information of Guinea based on ETM+ remote sensing data[J]. Remote Sensing Technology and Application, 2013,28(2):330-337. ]

[82]
沈利霞,刘丽萍,苏新旭,等.不同植被覆盖率地区遥感矿化蚀变提取研究[J].现代地质, 2008,22(2):293-298.lt;p>尖山子&mdash;卡伦断层是贯穿长春市区的一条主要断裂。以往对其缺乏系统的研究，只是通过地貌和水文地质的一些资料，判断它的大致展布形态和活动时代。本次调查通过遥感、电法、探地雷达、浅层人工地震以及钻孔联合剖面相结合的方法，比较准确地确定了尖山子&mdash;卡伦断层在长春市范围内的空间位置、产状和活动时代。调查结果显示，尖山子&mdash;卡伦断层错断了白垩系地层，但没有扰动上覆的中更新统地层，以此推断长春市范围内尖山子&mdash;卡伦断层在中更新世以来是不活动的。</p>

DOI

[ Shen L X, Liu L P, Su X X, et al. Study on identification of altered wall-rock in areas of different vegetation coverages based on remote sensing[J]. Geoscience, 2008,22(2):293-298. ]

[83]
吴志春,郭福生,刘林清,等.基于TM/ETM+影像的复合法遥感蚀变异常提取应用研究[J].地质与勘探,2013,49(3):511-522.

[ Wu Z C, Guo F S, Liu L Q, et al.Application of remote sensing alteration anomaly extraction with the method of composite algorithm based on TM/ETM images[J]. Geology and Exploration, 2013,49(3):511-522. ]

[84]
吴志春,胡荣泉,郭福生,等.江西省相山铀矿田植被覆盖区遥感蚀变异常提取[J].铀矿地质,2013,29(2):112-118.

[ Wu Z C, Hu R Q, Guo F S, et al.The extraction of alteration anomaly with remote sensing image of vegetation covered area in Xiangshan uranium field, Jiangxi Province[J]. Uranium Geology, 2013,29(2):112-118. ]

[85]
韩先菊,葛良胜,张惠玉,等.新疆托里金矿带矿化蚀变体系及遥感混合蚀变信息分解-复合提取研究[J].地质找矿论丛,2006,21(增刊):99-106.文章以新疆西准噶尔托里金矿带为例,基于ETM数据源,在矿区矿化蚀变体系系统研究基础上,以典型岩、矿石地物波谱的差异性为依据,设计出适合本区的混合矿化蚀变信息分解-复合提取方法,通过混合蚀变信息分解、多变量蚀变信息增强、对增强图像(复合)合成3个工作环节,形成最终的蚀变信息提取图像.经对比后,有18处遥感异常为已知金矿的反映,有3处遥感异常已提供国土资源大调查使用.

DOI

[ Han X J, Ge L S, Zhang H Y, et al.Study on the mineralization alteration systems and decomposing and compounding extraction of the mixed remote sensing alteration information in Tuoli gold ore belt, Xinjiang, China[J]. Contributions to Geology and Mineral Resources Research, 2006,21(Sup.):99-106. ]

[86]
陈勇敢,刘桂阁,路彦明,等.甘肃陇南阳山金矿区金矿遥感蚀变信息提取探讨[J].矿床地质,2008,27(增刊):85-90.根据研究区的景观特征及金矿化蚀变组合类型,在应用掩膜技术剔除非致矿地质信息干扰因素的前提下,应用波段比值、K-L变换、密度分割等方法组合对研究区金矿化蚀变信息进行提取,获得了能较客观反映研究区实际蚀变信息的羟基蚀变与铁染蚀变图像,取得了较好的效果,所提取的蚀变信息能为本区金矿成矿预测提供一定的依据,以期对本区的下一步金矿找矿工作有所帮助。

[ Chen Y G, Liu G G, Lu Y M, et al.The extraction of remote sensing alteration information from the Yangshan gold deposit in Longnan county, Gansu Province[J]. Mineral Deposits, 2008,27(Sup.):85-90. ]

[87]
杨波,吴德文,陈云浩,等.矿化信息提取的混合蚀变遥感模型——以鹰嘴山金矿区为例[J]. 国土资源遥感, 2005(1):20-25.complicated mineralizations. According to the difference in spectral characteristics between mineralized alterationrocks and wall rocks, the authors made correlation analysis and factor analysis between the in-situ measuredspectral data and multivariate data of rocks and minerals, set up remote sensing models for mixed alteration, andselected the best variable or variable unit. The abnormal information of mixed alteration was also extracted.Practice has proved that such a method is effective in extracting mineralization information.

DOI

[ Yang B, Wu D W, Chen Y H, et al.A mixed alteration remote sensing model for extracting mineralization information: A case study of the Yingzuishan gold deposit[J]. Remote Sensing for Land and Resources, 2005(1):20-25. ]

[88]
余凤鸣,王磊.武当地区矿化蚀变的遥感信息提取与应用[J].矿床地质,2010,29(增刊):699-700.武当地区夹持于华北板块与扬子板块之间，为南秦岭造山带的重要组成部份。矿产资源十分丰富，矿化蚀变信息较强，很适合利用遥感技术方法来探测未知区的矿化信息。本文采用特征主成分分析技术对武当地区进行了几类蚀变矿物的遥感蚀变信息的提取，并进一步对各个因子进行二次主成分分析，得出混合蚀变异常信息，对区域找矿具有一定的指导意义。

[ Yu F M, Wang L.Remote sensing alteration information extraction and application in Wudan area[J]. Mineral Deposits, 2010,29(Sup.):699-700. ]

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