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为了利用遥感影像进行更加精确的找矿预测,本文选择新疆东天山尾亚地区ASTER数据进行矿化蚀变信息提取方法研究。为了提高信息提取精度,本文提出了结合主成分分析(PCA)、多尺度分割和支持向量机(SVM)的遥感矿化蚀变信息提取方法。首先,分析ASTER数据的特征,选取各矿化蚀变信息的特征波段,对组合波段进行主成分分析,获得主分量图像;然后,对各主分量图像进行多尺度分割,并获得分割之后的均值图像;接着,提取训练样本,利用SVM对训练样本进行训练,采用试验方法求得最优核参数和松弛变量,构造最优SVM模型;最后,运用最优SVM模型完成矿化蚀变信息的提取。进行主成分分析时,铁染蚀变信息选择Band1、2、3、4组合,Al-OH基团蚀变信息选择Band 1、4、6、7组合,OH和CO32-基团蚀变信息采用Band 1、2、8、9组合。在运行SVM时采用了序列最小优化算法(SMO)进行求解,速度提高了12%。实验结果表明,与波段比值法、主成分分析法及基于光谱角和SVM的方法等3种方法相比,本文方法提取铁染蚀变信息、Al-OH基团蚀变信息及OH和CO32-基团蚀变信息的总体精度可达到87.98%、 90.01%及88.93%,Kappa系数分别为0.8011、0.8134及0.8023,与成矿区带、已知矿点和已有不同地质背景成矿特征相关性较好。 相似文献
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《国土资源遥感》2017,(3)
从遥感蚀变异常主分量图像中提取异常信息,目前主要基于数据的正态分布特征,并未考虑地质异常的非线性特征。针对此问题,提出了分维变点提取算法(fractal dimension-change point method,FDCPM)。首先利用分形模型计算蚀变异常的自相似性参数值,再采用变点模型计算蚀变异常的突变性参数值,然后确定蚀变异常临界阈值,达到有效区分地质背景和蚀变异常的目的。以甘肃北山方山口地区为研究区,对识别的ASTER蚀变异常进行测试和验证,并对其提取精度进行初步评价和比较。结果表明:对于实验中的褐铁矿、绢云母和绿泥石3种蚀变矿物来说,分维变点法的总体提取精度略高于门限化方法。利用分维变点法提取3种蚀变矿物的正确率均超过83%,且遥感蚀变异常的分布与化探及重砂异常有较高的吻合度,已知金属矿(化)点也几乎都落在遥感蚀变异常区内或其边缘,表明分维变点法行之有效,可作为今后划分地质背景和蚀变异常的方法之一。 相似文献
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为研究如何利用遥感技术进行蛇绿岩岩矿信息识别和提取,以藏东罗布莎蛇绿岩为例,基于ETM和ASTER遥感数据,分别采用比值法和主成分分析法提取羟基类(蛇纹石、绿泥石)和铁染类(磁铁矿、橄榄石)矿物信息;利用纯净像元指数法(pure pixel index,PPI)提取端元波谱,结合地面已知岩性信息,分别采用光谱角分类法(spectral angle mapping,SAM)和波谱特征拟合法(spectral feature fitting,SFF)识别纯橄岩和橄榄岩,研究了罗布莎蛇绿岩及其主要蚀变矿物的空间分布特征.经过对比分析可知,用多种方法、多种数据提取的岩矿信息可以相互验证;提取出的纯橄岩和橄榄岩与所提取的羟基类和铁染类蚀变遥感异常信息有较好的空间重叠,且与地面调查结果基本吻合.研究表明,该方法用于蛇绿岩遥感岩矿信息提取是可行的,并取得较好的地质效果. 相似文献
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选用ETM+和ASTER影像作为数据源,以西藏某矿区为例,在分析影像波谱特征的基础上,运用比值法、主成分分析等方法进行了矿化蚀变信息提取研究;对不同数据源提取的蚀变信息结果进行空间叠加分析,定量化地分析叠加蚀变信息,从而确定基于不同数据源、不同蚀变信息提取方法的综合蚀变异常信息,提高了矿化蚀变信息提取的准确性与可靠性。 相似文献
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Concealed and fossilized geothermal systems are not characterized by obvious surface manifestations like hotsprings and fumaroles, therefore, could not be easily identifiable using conventional techniques. In this investigation, the applicability of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion data-sets were evaluated in discriminating hydrothermal alteration minerals associated with geothermal systems as a proxy in identifying subtle Geothermal systems at Yankari Park, Nigeria. Feature-oriented principal component selection, spectral angle mapper, linear spectral unmixing were applied to ASTER data based on spectral characteristics of hydrothermal alteration key minerals for a systematic selective extraction of the information of interest. Analytical imaging and geophysics-developed processing methods were applied to Hyperion data for mapping iron oxide/hydroxide minerals and clay mineral assemblages in hydrothermal alteration zones. The results indicate that ASTER and Hyperion could be complemented for reconnaissance stage of targeting subtle alteration mineral assemblages associated with geothermal systems. 相似文献
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ASTER short-wave infrared bands were used to investigate the spectral discrimination of hydrothermally altered materials, based on the presence of minerals with diagnostic spectral features in wavelengths around 2200 nm (e.g. kaolinite and K-micas). Due to the presence of widespread albitized-greisenized materials, the Serra do Mendes granitoid, located in area of tropical savannah environment in Central Brazil, was selected for this study. The Spectral Angle Mapper (SAM) technique was used as an attempt to detect the presence of hydroxyl-bearing minerals in the domain of the hydrothermally altered materials. Results indicated that areas of altered materials were discriminated from the surrounding mainly due to the high overall reflectance of the whitish lithosols in these areas. The detection of hydroxyl-bearing minerals was blurred by the presence of a sparse grass cover in the alteration zone, which caused a slight increase in the SAM classification angles. As a consequence, the remote detection of hydroxyl-bearing minerals was restricted to a small number of pixels from barren areas. Results indicate that, for the environmental conditions of the study area, ASTER data are more efficacious for spectral characterization of rock–soil-vegetation associations than for the detection of alteration-derived minerals. 相似文献
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AbstractRemote sensing techniques provide meaningful information to mineral exploration by identifying the hydrothermally altered minerals and the fracture/fault systems. In this article, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were processed to detect the hydrothermal alteration zones in Hamama area in the central part of the Eastern Desert of Egypt. Band ratios and principal component analyses successfully revealed the extent and the geometry of the hydrothermal alteration zones that trend in an NE–SW direction. Matching pixel spectrum derived from Minimum Noise Fraction, Pixel Purity Index, and n-dimensional visualization with reference spectra allowed characterizing key hydrothermal alteration minerals, including chlorite, kaolinite-smectite, muscovite, and haematite, in a successive alteration pattern. Field investigations and X-Ray Diffraction analysis validated the results revealed by ASTER data. In addition, the present prospects of significant gold and massive sulphide mineralizations are consistent with the detected hydrothermal alteration zone. 相似文献
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矿化蚀变信息的提取是遥感找矿中重要的内容,ASTER遥感数据因波段范围宽、波段多,在蚀变异常与矿产勘探中有较好的应用前景。本文在比较了前人的研究方法,如比值法、主成分分析法、光谱角法基础上,通过对西藏朱诺矿区进行试验研究,得出了在该研究区采用主成分分析法最佳的结论。 相似文献
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