面向地质应用的天宫一号成像光谱数据评价

天宫一号高光谱数据是继美国Hyperion之后,另一种可应用于地质领域的成像光谱数据.面向地质应用特点与需求,针对反射率产品开展全面、定量的数据质量评价对于深化应用研究具有重要意义.但是,由于航天成像光谱数据与地面实测波谱空间尺度差异甚大,在荒漠戈壁区选取自然地物进行波谱测试,并对其开展评价,特别是定量评价,非常困难.本文以航空HyMap数据为传递,完成了天宫一号成像光谱数据质量的定量评价.结果表明,在矿物识别采用的主要短波红外谱段,天宫一号高光谱数据的信噪比明显优于Hyperion数据.采用2190—2230 nm、2310—2355 nm两个谱段的吸收深度初步对天宫一号高光谱短波红外数据真实性进行了评价,经过校正后,天宫一号数据Al-OH、Mg-OH/CO₃^2-矿物大类或组合的漏提率从71%、67%减小至29%、28%,可有效提高弱信息的检出率.     

Improving radiometry of imaging spectrometers by using programmable spectral regions of interest

Programmable imaging spectrometers can be adjusted to fit specific application requirements that differ from the instrument initial spectral design goals. Sensor spectral characteristics and its signal-to-noise ratio (SNR) can be changed by applying customized online binning patterns.We present a software utility that generates application driven spectral binning patterns by using an SNR dependent sensor model. The utility, named BinGO (BInning patterN Generator and Optimiser), is used to produce predefined binning patterns that either (a) allow an existing imaging spectrometer to optimize its spectral characteristics for a specific application, (b) allow an existing imaging spectrometer to spectral and/or spatially emulate another instrument, or (c) design new multispectral or imaging spectrometer missions (i.e. spaceborne, airborne, terrestrial). We present a variety of BinGO case studies, including the simulation of airborne (APEX) [Itten, K.I. et al., 2008. APEX — The hyperspectral ESA Airborne Prism Experiment. Sensors 8(1), 1–25], spaceborne (SENTINEL III) [Nieke, J., Frerick, J., Stroede, J., Mavrocordatos, C., Berruti, B., 2008. Status of the optical payload and processor development of ESA’s Sentinel 3 mission. In: Proceedings of the Geoscience and Remote Sensing Symposium IGARSS 2008, pp. 427–430], as well as scientific and performance optimized approaches. We conclude that the presented approach can successfully be used to increase the efficiency of spectral information retrieval by using imaging spectroscopy data and to simulate various missions and requirements, finally supporting proper trade-off decisions to be made between performance optimization and scientific requirements. In addition, if specific sensor parameters are known, BinGO can also model other imaging spectrometers.     

成像光谱遥感技术及其图像光谱信息提取的分析研究

成像光谱技术是80年代发展起来的最新遥感方法。本文对其原理、理论基础及图像光谱信息提取的方法进行了探讨,并在红外细分光谱(FIMS)金矿蚀变带信息提取分析研究的基础上,通过对可见光细分19波段AMSS、澳大利亚的24波段GEOSCAN、MKII AMSS及美国GER64通道成像光谱数据的初步处理,发展和形成了一些针对超多波段成像光谱数据的图像处理和分析及光谱信息提取的方法。 成像光谱信息提取的方法,主要包括图像光谱反射率转换技术、图像光谱曲线显示、光谱特征参数测度(光谱吸收特征的波长位置、宽度、深度)、图像地物光谱曲线与地物光谱数据库的信息匹配以及地物光谱识别专家系统。本文以红外细分光谱图像在金矿蚀变带信息提取分析中的应用为例,讨论了成像光谱图像的一种处理分析技术及其发展前景。     

绢云母的光谱特征变异分析及成像光谱地质成因信息提取

鉴于绢云母(和白云母)类粘土矿物对于研究与矿化紧密相关的中低温热液蚀变机制、与温压有关的地质成因过程等的重要意义,开展了绢云母的岩矿光谱特征变异分析和成像光谱矿物识别,并对岩石、矿物的试验室光谱和影像光谱所反映的地质成因信息的提取进行探讨。     

基于谱学的成像光谱遥感技术发展与应用

成像光谱遥感技术是80年代初发展起来的新型遥感技术。近20年来,该技术发展很快,已成为遥感技术发展的3大趋势之一(成像光谱遥感,微波遥感及3S技术系统)。由于成像光谱具有高光谱分辨率的图像与光谱合二为一的特点,它的发展不仅使遥感技术能有效地直接识别地表物质,而且还能更深入地研究地表物质的成分及结构。本文综述成像光谱遥感技术的发展,理论基础,方法技术及其应用。     

块状岩石矿物组分热红外光谱反演实验研究

针对地面研究用岩石的热红外光谱反演其矿物组分过程中,由于自然岩石内矿物组分分布不均匀,给确定观测区域内矿物组分的精确值造成困难的问题,该文采用块状矿物拼接的方法模拟自然岩石,使模拟岩石的矿物组分可以精确获取。进一步,针对模拟岩石制订旋转试样法观测方案,从理论上研究该方案存在的观测误差,并通过光谱解混验证其观测精度。     

Using spectral information from the NIR water absorption features for the retrieval of canopy water content

Canopy water content (CWC) is important for mapping and monitoring the condition of the terrestrial ecosystem. Spectral information related to the water absorption features at 970 nm and 1200 nm offers possibilities for deriving information on CWC. In this study, we compare the use of derivative spectra, spectral indices and continuum removal techniques for these regions. Hyperspectral reflectance data representing a range of canopies were simulated using the combined PROSPECT + SAILH model. Best results in estimating CWC were obtained by using spectral derivatives at the slopes of the 970 nm and 1200 nm water absorption features. Real data from two different test sites were analysed. Spectral information at both test sites was obtained with an ASD FieldSpec spectrometer, whereas at the second site HyMap airborne imaging spectrometer data were also acquired. Best results were obtained for the derivative spectra. In order to avoid the potential influence of atmospheric water vapour absorption bands the derivative of the reflectance on the right slope of the canopy water absorption feature at 970 nm can best be used for estimating CWC.     

逐步回归分析在岩石波谱及化学成分分析中的应用

该文主要介绍应用回归分析方法探讨岩石波谱与岩石化学成分之间的相关性, 据其进一步查明控制沉积岩、岩浆岩、喷出岩和变质岩岩石波谱特征的主要化学成分的研究成果。研究发现H₂0⁺和H₂O^-的波谱特性是不同的。该研究成果对评价和应用岩石波谱特征提供了一种有前景的新方法。     

Lithological mapping from hyperspectral data by improved use of spectral angle mapper

The spectral angle mapper (SAM), as a spectral matching method, has been widely used in lithological type identification and mapping using hyperspectral data. The SAM quantifies the spectral similarity between an image pixel spectrum and a reference spectrum with known components. In most existing studies a mean reflectance spectrum has been used as the reference spectrum for a specific lithological class. However, this conventional use of SAM does not take into account the spectral variability, which is an inherent property of many rocks and is further magnified in remote sensing data acquisition process. In this study, two methods of determining reference spectra used in SAM are proposed for the improved lithological mapping. In first method the mean of spectral derivatives was combined with the mean of original spectra, i.e., the mean spectrum and the mean spectral derivative were jointly used in SAM classification, to improve the class separability. The second method is the use of multiple reference spectra in SAM to accommodate the spectral variability. The proposed methods were evaluated in lithological mapping using EO-1 Hyperion hyperspectral data of two arid areas. The spectral variability and separability of the rock types under investigation were also examined and compared using spectral data alone and using both spectral data and first derivatives. The experimental results indicated that spectral variability significantly affected the identification of lithological classes with the conventional SAM method using a mean reference spectrum. The proposed methods achieved significant improvement in the accuracy of lithological mapping, outperforming the conventional use of SAM with a mean spectrum as the reference spectrum, and the matching filtering, a widely used spectral mapping method.     

岩矿光谱特性在资源卫星传感器波段选择中的应用分析

根据矿物、岩石和不同矿床岩矿光谱特征,从遥感地质矿产的研究需求出发,进行多光谱波段模拟选择。将试验区机载成像光谱HyMap数据经大气传输模型模拟到中巴地球资源卫星1号(CBERS-1)的轨道高度,对所选的波段进行综合模拟、应用对比分析,提出我国后续资源卫星多光谱传感器在地质矿产应用上遥感波段的位置、波段的带宽和波段数目。     

成像光谱仪分光技术概览

论文介绍了多种成像光谱仪的分光技术。棱镜或光栅色散型成像光谱仪技术成熟，应用广泛；在发散光束中使用光栅的方法，克服了准直光束用法中的一些缺陷；傅里叶变换光谱仪是遥感探测可见和红外弱辐射的有力工具；光楔成橡光谱仪结构简单，随着渐变滤光片工艺技术的成熟，已走向实用化；采用可调谐滤光片的成像光谱仪由于滤光片水平的限制，投入应用还有待时日；采用二元光学元件的成像光谱仪结构紧凑，体积小，扫描速度快，已研制出地面实用型产品；层析成像光谱仪原理新，目前还处在实验阶段；三维成像光谱仪可以同时获取二维影像和一维光谱信息，可实现对迅变目标的观测。     

An operational method for fast detecting abnormal channels in imaging spectrometers

Data from abnormal channels in an imaging spectrometer almost always exerts an undesired impact on spectrum matching, classification, pattern recognition and other applications in hyperspectral remote sensing. To solve this problem, researchers should get rid of the data acquired by these channels. Selecting abnormal channels just in the way of visually examining each band image in a imaging data set is a conceivably hard and boring job. To relieve the burden, this paper proposes a method which exploits the spatial and spectral autocorrelations inherent in imaging spectrometer data, and can be used to speed up and, to a great degree, automate the detection of abnormal channels in an imaging spectrometer. This method is applied easily and successfully to one PHI data set and one Hymap data set, and can be applied to remotely sensed data from other hyperspectral sensors.     

An Operational Method for Fast Detecting Abnormal Channels in Imaging Spectrometers

Data from abnormal Channels in an imaging spectrometer almost always exerts an undesired impact on spectrum matching,chassification,pattern recognition and other applications in hyperspectral remote sensing.To solve this problem.researchers should get rid of the data acquired by these channels.Selecting abnormal channels just in the way of visually examining each band image in a imaging data set is a conceivably hard and boring job.To relieve the burden,this paper proposes a method which exploits the spatial and spectral autocorrelations inherent in imaging spectrometer data,and can be used to speed up and ,to a great degree,automate the detection of abnormal channels in an imaging spectrometer.This method is applied easily and successfully to one PHI data set and one Hymap data set ,and can be applied to remotely sensed data from other hyperspectral sensors.     

Estimation of chlorophyll fluorescence under natural illumination from hyperspectral data

This paper reports a series of laboratory and field measurements of spectral reflectance under artificial and natural light conditions which demonstrate that effects of natural chlorophyll fluorescence are observable in the reflectance red edge spectral region. These are results from the progress made to link physiologically-based indicators to optical indices from hyperspectral remote sensing in the Bioindicators of Forest Sustainability Project. This study is carried out on twelve sites of Acer saccharum M. in the Algoma Region, Ontario (Canada), where field measurements, laboratory-simulation experiments, and hyperspectral CASI imagery have been carried out in 1997, 1998, 1999 and 2000 campaigns. Leaf samples from the study sites have been used for reflectance and transmittance measurements with the Li-Cor Model 1800 integrating sphere apparatus coupled to an Ocean Optics Model ST1000 fibre spectrometer in which the same leaves are illuminated alternatively with and without fluorescence-exciting radiation. A study of the diurnal change in leaf reflectance spectra, combined with fluorescence measurements with the PAM-2000 Fluorometer show that the difference spectra are consistent with observed diurnal changes in steady-state fluorescence. Small canopies of Acer saccharum M. have been used for laboratory measurements with the CASI hyperspectral sensor, and under natural light conditions with a fibre spectrometer in diurnal trials, in which the variation of measured reflectance is shown experimentally to be consistent with a fluorescence signature imposed on the inherent leaf reflectance signature. Such reflectance changes due to CF are measurable under natural illumination conditions, although airborne experiments with the CASI hyperspectral sensor produced promising but less convincing results in two diurnal experiments carried out in 1999 and 2000, where small variations of reflectance due to the effect of CF were observed.     

Integration of VNIR and SWIR spectral reflectance for mapping mineral resources; A case study,north east of Hajjah,Yemen

Laboratory reflectance spectra of 18 rock samples from the Precambrian basement of north east of Hajjah were measured and analyzed using the instrument of FieldSpec3 with spectral range 0.250–2.500 μm. The aim of this study is to use the spectral reflectance of rocks for mapping the mineral resources in the north east of Hajjah. The altered system in the study area comprises of silicification, sericitification, oxidation, clay minerals and carbonatization. Silicified alteration is not distinguishable in the regions of Visible-Near Infrared (VNIR) and Short wave Infrared (SWIR) of the electromagnetic spectrum, because of lack of diagnostic spectral absorption features in silica in this wavelength. Although the arsenopyrite and pyrite are wide spread in the whole study area their features do not appear in any range of spectra because they exhibit trans-opaque behavior and often lack distinction in VNIR and SWIR. The entire spectral reflectance curves of samples show alteration. Based on the examination of laboratory spectra all samples in the study area show promise in the field of mineral resources.     

光谱重建与光谱真实性检验中地物光谱的作用

 将地物光谱与高光谱重建、影像光谱真实性检验相结合,重点阐述地物光谱在高光谱数据预处理中的主要作用。以新疆东天 山航空HyMap数据为例,在光谱重建过程中导入数据区特征地物（白云母和高岭石）光谱,以对利用大气模型校正的视反射率影像光 谱进行平滑、去“伪”或增强处理。进一步利用2种矿物的特征光谱评价重建光谱的真实性,从数据源头确保高光谱遥感数据光谱特 性的准确与可靠。     

Spectral studies of lunar equivalent rocks — A prelude to lunar mineral mapping

Hyperspectral remote sensing technique is widely applied for geological studies including the study of extra-terrestrial rocks. Since it has many spectral bands, discrimination between rocks and minerals can be done more precisely. To perform chemical and mineralogical mapping and to study the rocks on the lunar surface, India has proposed to launch its first lunar remote sensing satellite Chandrayaan-1 in the year 2008. For mineralogical mapping, the mission will carry a Hyperspectral Imager (HySI) instrument, which operates in the VNIR region. This paper presents-an attempt to study the spectral response of lunar-akin terrestrial rocks, in the VNIR region (as in the case of the proposed HySI on-board Chandrayaan-1). For this purpose, rocks similar to those present on the lunar surface were collected and their spectral response in the 64 simulated bands of HySI sensor were studied using a spectro-radiometer. Petrographic studies and modal analysis were carried out using thin sections of the rock samples. On studying the spectral response of the lunar-like rock samples in the 64 HySI bands, it is seen that there are distinct absorption features in bands 58 (923.75nm-927.5nm) and 63 (942.5nm-946.25nm) of the NIR wavelength ranges, for basalt rocks; distinct reflectance features in band 20 (590nm to 600nm) for ganmbbro: distinct reflectance features in band 19 (580nm to 590nm) and absorption in band 18 (570-580nm) for gabbroic anorthosite and distinct reflection features in band 63 (942.5nm to 946.25nm) for anorthosite. Thus, this study demonstrates the possibility of identifying the minerals and rocks on lunar surface using the hyperspectral approach and the spectral signatures of lunar-like rocks present on Earth.     

岩石的热模型分析

在几种岩石热辐射理论模型分析的基础上,考虑到岩石的红外光谱辐射特性和岩石的热性质──热惯量,建立岩石的热传输模型,并将实测数据代人,对岩石表面的一个日照周期内的变化做出计算,绘制出不同热惯量的几种岩石在日周期内表面温度变化曲线。由曲线看出,岩石热惯量大,其昼夜辐射温度变化小;热惯量小的岩石其昼夜辐射温差大。改变岩石的反照率、辐射系数和地面径向热流而得到岩石表面温度日变化曲线,可看出这３个因素只是改变了温度的量值,不像热惯量那样改变曲线的形状。     

川北地区岩石反射谱波特征

四川北部地区既有岩浆岩、变质岩构成的前震旦系结晶变质基底,又有震旦纪以后的沉积盖层,岩石类型十分齐全。本文根据该区的120件岩(矿)石样品反射波谱测试结果,绘制了区内主要岩石类型典型波谱曲线,并对这些波谱曲线进行了初步分析,总结了主要岩石类型的波谱特征,这些岩石波谱特征在西南地区有一定的代表性。     

基于ASTER的蛇绿混杂岩带岩性识别

本文运用ASTER遥感数据识别与提取新疆南天山铜花山地区蛇绿混杂岩带岩性信息。首先,利用比值法快速区别岩性,并比较了识别同一种岩性的不同指数的性能;然后,将对数残差算法应用在ASTER数据的短波红外波段上,在区域尺度上把蛇绿岩杂岩体同围岩区分开来;最后,运用标准光谱数据和光谱角填图法识别出多种蛇绿岩成分及其空间分布。现有地质图和野外验证反映出该方法有一定效果。利用混淆矩阵对光谱角填图法分类结果定量评价,结果表明,把ASTER的可见光-近红外、短波红外波段数据结合在一起进行岩性分类,可以达到比单独用短波红外数据分类更高的分类精度。