基于地面反射波谱技术的锂含量定量反演研究

锂是重要的新兴战略资源，四川甲基卡矿田是中国乃至于世界上锂矿资源最集中的地区之一。运用美国ASD FieldSpec-4便携式红外波谱仪，通过对甲基卡最大的矿脉X03号脉钻孔ZK1101孔的波谱测量，对比分析了含锂辉石伟晶岩、不含锂辉石伟晶岩及围岩的波谱特征，得出锂辉石具有1 413、1 900、2 207 nm三处吸收特征，区分含锂辉石伟晶岩、不含锂辉石伟晶岩及围岩的波谱吸收特征主要位于1 900 nm处，并通过1 900 nm吸收谷的吸收深度与锂含量的相关分析，建立了锂含量定量反演模型。本研究开启了对锂辉石这一标志性找矿矿物波谱特征的新认识，同时为今后锂含量定量评估奠定了高光谱理论基础。     

基于地面反射波谱技术的锂含量定量反演研究

锂是重要的新兴战略资源,四川甲基卡矿田是中国乃至于世界上锂矿资源最集中的地区之一。运用美国ASD FieldSpec-4便携式红外波谱仪,通过对甲基卡最大的矿脉X03号脉钻孔ZK1101孔的波谱测量,对比分析了含锂辉石伟晶岩、不含锂辉石伟晶岩及围岩的波谱特征,得出锂辉石具有1 413、1 900、2 207 nm三处吸收特征,区分含锂辉石伟晶岩、不含锂辉石伟晶岩及围岩的波谱吸收特征主要位于1 900 nm处,并通过1 900 nm吸收谷的吸收深度与锂含量的相关分析,建立了锂含量定量反演模型。本研究开启了对锂辉石这一标志性找矿矿物波谱特征的新认识,同时为今后锂含量定量评估奠定了高光谱理论基础。     

江苏西溪贝丘遗址的高光谱遥感考古研究

针对江苏西溪贝丘遗址,通过样品采集对干净贝壳、自然状况下贝壳、土壤样品和地表裸地进行了光谱测量和分析。研究发现贝壳具有明显的光谱特征吸收峰,中心波长为2288nm处,吸收峰带宽在2098~2335nm范围内,与背景土壤粘土2180nm处的特征吸收峰和大多数碳酸岩类地表矿物质2350nm附近的吸收峰具有很好的可区分性。结合贝壳2288nm处特征吸收峰,利用该贝丘遗址发掘前的空间分辨率为6.6m的128波段OMIS航空高光谱遥感飞行数据成功地对该贝丘遗址信息进行有效地提取和圈定。本研究为利用高光谱遥感进行贝丘遗址考古提供了理论依据和有效技术途径。     

高光谱遥感蚀变矿物信息提取研究综述北大核心CSCD

蚀变围岩是热液矿床形成的重要标志之一,围岩蚀变会产生蚀变矿物,其与围岩中的矿物在颜色、结构、化学成分等方面具有明显差异,这些差异可导致蚀变矿物在特定波长区间产生诊断性波谱特征。通常高光谱遥感指的是光谱分辨率在5~15 nm的成像遥感,而绝大多数蚀变矿物的诊断性波谱宽度在20~40 nm,因此利用高光谱遥感技术可以快速地提取蚀变矿物信息,依据蚀变矿物组合及分布特征,划分蚀变分带、圈定矿化异常等具有重要的找矿意义。文章基于现有研究成果,系统总结了典型蚀变矿物的波谱特征、高光谱遥感技术的发展历史、蚀变矿物信息提取方法、不同地表覆盖类型对蚀变矿物信息提取的影响以及蚀变矿物信息提取在不同矿床类型下找矿的应用,最后指出了高光谱蚀变矿物信息提取研究中存在的问题以及未来发展方向。     

间歇硫酸盐法蒸煮过程纸浆卡伯值的近红外光谱法在线测量的研究

研究发现，硫酸盐法蒸煮液在800-900nm近红光谱波段间的吸收主要来自其中的碱木素，而其中的D-葡萄糖、D-甘露糖、D-木糖、D-半乳糖和糖醛酸等碳水化合物的降解产物及二氯甲烷和苯醇抽出物在此波段基本上没有吸收。并在这段波段建立起的纸浆卡伯值近红外光谱测量模型。该模型显示蒸煮液的吸光度与纸浆卡伯值具有较好的线性关系（相关系数R^2为0．996），并有较高的预测精度。因此，建议采用近红外光谱法实现硫酸盐法蒸煮过程纸浆卡伯值的在线测量，并有望开发出蒸煮过程纸浆卡伯值近红外光谱法在线测量仪，真正实现蒸煮过程的纸浆卡伯值的闭环反馈控制。     

滨海盐渍土可见近红外高光谱特征

土壤光谱是遥感监测的物理基础，盐渍化土壤光谱特征研究对于盐渍化土地的监测有着重要的意义。以黄河三角洲地区的滨海盐渍土为研究对象，通过野外土壤样品采集和高光谱测量，研究在去除水分以及剔除土壤质地影响后，不同盐渍化程度的滨海盐渍土在350~1 100 nm区间的高光谱反射和吸收特征，并且试图构建光谱预测模型。结果表明: 平滑后的光谱曲线能更准确有效地描述光谱的反射特征及吸收峰。不同盐化程度的土壤光谱曲线形态一致，但反射率大小差异较大。连续统去除后，490 nm处轻度盐化土吸收最小,在760~920 nm区间重度盐化土的吸收更强烈。原始光谱不能预测土壤盐渍化信息，但是二阶微分变换能够提高波段敏感性，建立的光谱预测模型能够基本满足预测要求。     

典型煤系岩石的可见-近红外光谱特征研究

为研究基于可见-近红外光谱技术的煤岩识别方法,从山西、山东4个煤矿收集了页岩、砂岩、灰岩三大类11种典型煤系岩石,测定了其可见-近红外波段(400～2 450nm)的反射光谱,分析了其矿物、元素组成对反射光谱特征的影响,获得了碳质物质含量对煤系页岩反射光谱曲线特征参数的影响规律。研究结果表明:①绝大多数煤系岩石的反射光谱曲线在可见光波段(400～780nm)和短波近红外波段(780～1 100nm)呈现出随波长增加的多重吸收谷。在长波近红外波段(1 100～2 450nm),明显的吸收谷主要集中在1 400,1 900,2 200,2 350nm波长,页岩、灰岩吸收谷的波长相对固定,而不同砂岩吸收谷的波长呈现出多种变化。②除碳质物质含量较高的碳质页岩外,同一煤矿各类煤系岩石与煤的可见-近红外波段反射光谱吸收特征差异明显。③当煤系页岩中碳质物质含量增大时,可见-近红外波段反射光谱曲线的光谱斜率和各明显吸收谷深度均呈先快速减小后趋于平缓的特点。     

基于Hyperion影像的辽东湾水体信息自动分类

通过对辽东湾地区(局部)的水体、土壤及植被等主要地物波谱特征的对比分析及海水与淡水的波谱特征的对比分析,确定了高光谱遥感数据中的水体敏感波谱区间及区别海水与淡水的特征波谱区间,提出了基于连续波谱的水体信息提取与分类的利率法及双吸收深度模型,该方法在提取水体信息时不受山地阴影的影响,提高了水体信息的提取准确度。基于此方法和模型对研究区进行了海水与淡水信息的提取与分类,结果与实际情况吻合良好,为利用高光谱遥感数据进行水体信息提取分类,实现更好的水资源管理、洪水监测、海水入侵监测以及内河水入海口对海水的影响监测提供了有效的理论方法和技术手段。     

STM32的瘦肉精含量快速检测系统

为了快速、定量检测肉类食品中瘦肉精含量,采用了一种先进的激光诱导荧光技术进行检测。首先将稀释好的样品滴加在用免疫层析技术制作的试纸卡上,然后使用638nm波长的半导体激光器照射试纸卡,激发出的荧光通过光敏二极管接收,通过采集荧光强度来实现瘦肉精含量的检测。通过实验验证,该检测系统能够快速、定量、精确的检测瘦肉精的含量,检测时间为6s,测量量程为0.0~0.3ppb,检测灵敏度为0.01ppb。     

新疆博州典型荒漠植被光谱反射特征分析

针对博州光谱研究尚少和对光谱一阶导数缺乏定量描述的问题,补充分析了博州光谱,提出了对光谱一阶导数定量描述的方法。以博州为研究区,在2014年7月下旬对锦鸡儿、梭梭、红柳、白刺、萱麻、沙拐枣等地物进行野外光谱数据采集,并对光谱数据进行平均、平滑和一阶微分等处理;分析了不同植被之间、同种植被之间的光谱特征,并对光谱进行对比分析、红边参数特征分析等研究。研究表明:这6种荒漠植被在可见光波段的380~700nm之间的反射率均较低,没有超过15%;除了在480nm和680nm附近有吸收谷外,在970nm附近也有一个吸收谷,并且"蓝谷红移"现象比较明显;红边特征比较明显,其中萱麻的红边特征最明显;在近红外波段1 100nm附近反射率很高,平均峰值达到70%以上。所得结论对于博州荒漠地区光谱特征基础研究、荒漠植被生长情况,以及荒漠化程度的监测具有重要意义。     

Study on the Inversion of Chlorophyll Content of Spartina Alterniflora Leaf in the Yangtze River Estuary Wetland based on Spectral Analysis#br#

Spartina alterniflora is one of the most important invasive species in the coastal wetlands in China,which have a profound impact on the local ecological system.The information of chlorophyll content is an important basic data for quantitative research on key ecological function of wetland ecosystem.The Yangtze River in Chongming Dongtan wetland is the study area.Based on the measured leaf spectral reflectance and total chlorophyll content of Spartina alterniflora,in the range of 400~1 000 nm,the ratio of the original form of the spectral reflectance and first derivative spectral reflectance(RVI)and normalized difference vegetation index(NDVI)in the form of combination are established for the correlation with the content of chlorophyll and the construction of the estimation model.The results show that RVI and NDVI vegetation index form model based on the original spectra have the highest accuracy,whose root mean square error(RMSE)are up to respectively 0.24 and 0.25;Because of the nosie in the first derivative spectral reflectance,the estimation model of chlorophyll has poor results;Based on the band selected from the model,the red edge band is particularly important in the estimation of chlorophyll content of Spartina alterniflora.     

Mapping of jasperoid in the Cedar Mountains,Utah, U.S.A., using imaging spectrometer data

Jasperoid, an important indicator of disseminated gold deposits, is mapped in the Cedar Mountains, Utah U.S.A. using data gathered by the Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS). Ratio analysis is employed to detect the sharp rise in reflectance between 1000 nm and 1700 nm in the jasperoid spectrum due to iron absorption at about 900 nm in association with quartz and bound water. A pre-requisite is to remove the effects of dead and senescent vegetation from the ratio image. This is achieved using a mask of dead vegetation created by absorption band-depth analysis of ligno-cellulose absorptions in the Short-Wave Infra-red (SWIR). The absorption feature at about 2080 nm was used, but this choice is partly dictated by the limestone host rocks which exhibit a strong absorption feature which overlaps with the longer wavelength lingo-cellulose absorptions. Validation of the ratio map is accomplished by overlaying a geologic boundary which defined an area of jasperoid in the field.     

Relationships of leaf nitrogen concentration and canopy nitrogen density with spectral features parameters and narrow-band spectral indices calculated from field winter wheat (Triticum aestivum L.) spectra

Remote sensing is a promising tool that provides quantitative and timely information for crop stress detection over large areas. Nitrogen (N) is one of the important nutrient elements influencing grain yield and quality of winter wheat (Triticum aestivum L.). In this study, canopy spectral parameters were evaluated for N status assessment in winter wheat. A winter wheat field experiment with 25 different cultivars was conducted at the China National Experimental Station for Precision Agriculture, Beijing, China. Wheat canopy spectral reflectance over 350–2500 nm at different stages was measured with an ASD FieldSpec Pro 2500 spectrometer (Analytical Spectral Devices, Boulder, CO, USA) fitted with a 25° field of view (FOV) fibre optic adaptor. Thirteen narrow-band spectral indices, three spectral features parameters associated with the absorption bands centred at 670 and 980 nm and another three related to reflectance maximum values located at 560, 920, 1690 and 2230 nm were calculated and correlated with leaf N concentration (LNC) and canopy N density (CND). The results showed that CND was a more sensitive parameter than LNC in response to the variation of canopy-level spectral parameters. The correlation coefficient values between LNC and CND, on the one hand, and narrow-band spectral indices and spectral features parameters, on the other hand, varied with the growth stages of winter wheat, with no predominance of a single spectral parameter as the best variable. The differences in correlation results for the relationships of CND and LNC with narrow-band spectral indices and spectral features parameters decreased with wheat plant developing from Feekes 4.0 to Feekes 11.1. The red edge position (REP) was demonstrated to be a good indicator for winter wheat LNC estimation. The absorption band depth (ABD) normalized to the area of absorption feature (NBD) at 670 nm (NBD670) was the most reliable indicator for winter wheat canopy N status assessment.     

基于偏最小二乘的土壤重金属铜含量高光谱估算

为探究高光谱数据估算土壤重金属铜含量的可行性,以石家庄市水源保护区褐土为研究对象,对不同光谱变换数据与重金属铜含量做了相关分析,建立了土壤重金属铜的单光谱变换指标偏最小二乘模型和多光谱变换指标偏最小二乘模型。结果表明：光谱反射率（R）经倒数一阶微分（RTFD）变换后与铜含量的相关性有所提高;光谱敏感波段为418、427、435、446、490、673、1 909、1 920和2 221 nm,基本位于土壤氧化铁、粘土矿物的特征吸收区域;对土壤重金属铜含量估算效果最好的单光谱变换指标偏最小二乘模型为RTFD模型,其模型决定系数（R²）为0.649,均方根误差（RMSE）为1.477;多光谱变换指标偏最小二乘模型R²和RMSE分别为0.751和1.162,建模效果优于单光谱变换指标模型。研究结果可为北方地区褐土类型土壤重金属铜的高光谱估算提供借鉴。     

基于偏最小二乘的土壤重金属铜含量高光谱估算

为探究高光谱数据估算土壤重金属铜含量的可行性，以石家庄市水源保护区褐土为研究对象，对不同光谱变换数据与重金属铜含量做了相关分析，建立了土壤重金属铜的单光谱变换指标偏最小二乘模型和多光谱变换指标偏最小二乘模型。结果表明：光谱反射率（R）经倒数一阶微分（RTFD）变换后与铜含量的相关性有所提高；光谱敏感波段为418、427、435、446、490、673、1 909、1 920和2 221 nm，基本位于土壤氧化铁、粘土矿物的特征吸收区域；对土壤重金属铜含量估算效果最好的单光谱变换指标偏最小二乘模型为RTFD模型，其模型决定系数（R²）为0.649，均方根误差（RMSE）为1.477；多光谱变换指标偏最小二乘模型R²和RMSE分别为0.751和1.162，建模效果优于单光谱变换指标模型。研究结果可为北方地区褐土类型土壤重金属铜的高光谱估算提供借鉴。     

Band depth analysis of CHRIS/PROBA data for the study of a Mediterranean natural ecosystem. Correlations with leaf optical properties and ecophysiological parameters

The absorption feature approach was used in CHRIS multiangular hyperspectral data in order to investigate its potential for ecosystem remote sensing. For that purpose, CHRIS images in mode 1 were acquired throughout a two-year period for a Mediterranean ecosystem dominated by the semi-deciduous shrub Phlomis fruticosa. During each acquisition, coincident in situ Leaf spectra and ecophysiological measurements (Leaf Area Index, leaf pigment content and leaf water potential) were conducted. After data preprocessing, absorption feature information was calculated for both CHRIS and Leaf spectra for the whole spectrum. Three common characteristic absorption features within the spectral areas 450-550 nm, 550-750 nm and 900-1000 nm were detected. Each spectral area was then examined separately and four characteristic parameters were calculated that described the pattern, magnitude and position of the maximum absorption. Correlations between CHRIS and Leaf spectra for each date and viewing angle (VA) were then conducted. All correlations, either on full continuum removed spectra or on spectral areas, showed high coefficients of determination, especially (i) in higher observation angles (VA + 55), (ii) during the wet season and (iii) in strong absorptions such as the “red absorption”. Subsequently, correlations between CHRIS and Leaf absorption parameters of selected spectral areas with field-measured ecophysiological parameters were examined. Ecophysiological parameters proved to be highly correlated to CHRIS and Leaf absorption parameters in magnitude and/or pattern of the absorption feature and less in wavelength of the maximum absorption. CHRIS VAs +/− 36 showed the highest correlations although the type of relation, linear or nonlinear, was not conclusive. Finally, a first comparison between narrowband spectral indices and absorption features in correlations with ecophysiological parameters showed that both methods provide significant and comparable results, with oblique angles showing best performance. However, ecophysiological parameters are generally better predicted linearly by narrowband spectral indices issued from CHRIS, with most significant differences appearing on pigments absorbing mainly within 450-550 nm.     

Optimizing predictive models for leaf chlorophyll concentration based on continuous wavelet analysis of hyperspectral data

Recent studies have demonstrated that the decomposition of hyperspectral data using wavelet analysis is able to generate wavelet coefficients that can be used for estimating leaf chlorophyll (chl) concentrations. However, there is considerable scope for refining such techniques and this study addresses this issue by identifying the optimal spectral domain for use in constructing predictive models. Leaf reflectance spectra were simulated with the PROSPECT model (a model of leaf optical properties spectra) using randomly selected values for the input parameters. From reflectance and first derivative spectra different spectral wavelength domains were extracted, ranging from 400–450 to 400–2500 nm, using increments of 50 nm for the upper wavelength limit. Using the data for each wavelength domain, continuous wavelet decomposition was applied using 53 different wavelets, in turn. The resulting wavelet coefficients, from scales 1 to 128, were used as independent factors to construct predictive models for leaf chl concentration. Wavelet coefficients (at a specific scale generated by a given wavelet) in the chl absorption region remain constant when using spectral wavelength domains of 400–900 nm and broader, but narrower domains cause variability in the coefficients. Lower scale wavelet coefficients (scales 1–32) contain little information on chl concentration and their predictive performance does not vary with the spectral wavelength domain used. The higher scale wavelet coefficients (scales 64 and 128) can capture information on chl concentration, and predictive capability increases rapidly when the spectral wavelength domains vary from 400–700 to 400–900 nm but it can decrease or fluctuate for broader domains. In terms of accuracy and computational efficiency, models derived from the spectral wavelength domain 400–900 nm which use wavelet coefficients from scale 64 are optimal and a range of wavelet functions are suitable for performing the decomposition. The importance of optimizing the spectral wavelength domain highlighted by these findings has broader significance for the use of wavelet decomposition of hyperspectral data in quantifying other vegetation biochemicals and in other remote sensing applications.     

基于Hyperion影像的高光谱水汽含量反演的算法比较研究

基于高光谱遥感图像数据的大气参数反演和一体化辐射校正具有重要研究意义和应用价值。首先,通过6S模型辐射传输计算分析了EO-1/Hyperion遥感影像在940和1 130nm附近水汽吸收区域的光谱吸收特点。其次,采用两通道比值法和三通道比值法,比较了不同波段组合的大气含水量高光谱遥感反演精度并进行了敏感性分析,模拟实验结果表明采用三波段比值算法的相关系数和均方根误差均优于对应的两波段算法。最后,利用张掖地区2008年3景EO-1Hyperion高光谱遥感影像,反演了大气含水量,并与地基CE-318太阳分光光度计测量数据进行对比验证,结果表明:1 124nm水汽吸收通道反演精度优于940nm,两通道和三通道比值法的均方根误差分别为0.369和0.128g/cm2,三通道比值方法优于两通道比值方法,与地面观测结果一致。     

高光谱技术提取不同作物叶片类胡萝卜素信息

以棉花、玉米、大豆、甘薯四种作物为材料，各采集叶片30张(处于不同部位、不同功能期)，分别测定其反射光谱和叶绿素、类胡萝卜素含量。目的在于探讨利用高光谱技术提取类胡萝卜素信息的可行性方法。结果表明，由于叶绿素与类胡萝卜素间存在显的相关性，在叶片水平，利用高光谱反射率估测叶片类胡萝卜素绝对量是可行的。与类胡萝卜素／叶绿素比值或类胡萝卜素含量相比，类胡萝卜素密度(单位叶片面积类胡萝卜素总量，Cardens)与光谱反射率间的相关性更为稳定。类胡萝卜素光谱吸收峰(470nm)附近的反射光谱与Cardens间的相关性较差，基于类胡萝卜素吸收峰附近反射光谱的光谱指数(如PSSRc、PSNDc)与Cardens间也表现出较弱的相关性。叶绿素光谱指数(如SR705、ND705)与Cardens间存在良好的相关性，红边光谱区的微分光谱、包络线归一化吸收深度等高光谱指数与Cardens间也表现出了良好的相关性。