利用SIFT和静态小波变换的遥感影像配准方法   总被引：1，自引：0，他引：1  

韩舸  牛瑞卿 《测绘科学》2012,37(5):61-64

本文首先利用静态小波变换对影像进行多层分解,在其低频子影像上利用SIFT提取特征点集;之后,通过统计不同阀值下的匹配点集精度和数量信息,利用多项式拟合的方法自动建立约束条件,并以此约束条件自动校正控制点集以得到数量可观且高精度的控制点集。试验结果表明,该方法是一种有效的遥感影像配准控制点自动提取方法。  相似文献   

大地电磁测深数据的时频分析   总被引：1，自引：0，他引：1  

蔡剑华 《地质与勘探》2009,45(4):462-467

大地电磁测深(MT)数据表现出非线性、非平稳、非最小相位特征,不符合以Fourier变化为基础的传统谱分析的基本要求.为寻求更好的谱分析方法,把最新发展的Hilbert-Huang变换(HHT)引入到大地电磁测深数据的时频分析当中来,针对湖北宜万线实测的MT信号,与短时Fourier变换(STFT)、Winger-Ville分布(WVD)和小波变换(WT)进行了时频分析比较.比较分析表明:HHT方法克服了其它一些方法的缺陷,完全取消了窗函数的作用,其结果不受核函数影响与时频测不准原理限制,具有完全的局部时频特性和更好的时频聚集性.分析认为HHT是一种全新而更优越的分析与处理大地电磁测深信号的时频方法,能更好地提取信号的时频本质特征,用于指导生产勘测实践.  相似文献   

基于特征的遥感图像信息融合模式研究   总被引：5，自引：4，他引：1  

付炜  邢广忠  侯蓝田  王文君 《测绘科学》2004,29(6):62-64

基于图像特征的遥感图像信息融合是在突出目标地物的空间结构和纹理特征情况下的信息融合。本文在数字图像小波多分辨率分析理论基础上,采用小波变换方法对高分辨率遥感图像的目标地物边缘进行信息增强,然后与多光谱遥感图像进行特征信息融合。在融合过程中,首先对多光谱图像中的R、G、B三个波段的图像进行小波分解,得到相应的低频图像,并对特征增强后的高分辨率图像进行小波分解,再将分解后的高频图像分别与低频图像进行融合,最后经RGB合成为彩色图像。该方法既改善了图像的清晰度和分辨率,同时也保留了原图像的光谱信息。本文最后通过融合实验验证了上述结论。  相似文献   

分区连续函数的Radon变换的高精度反演法   总被引：4，自引：0，他引：4       下载免费PDF全文

李世雄  林其彭 《地球物理学报》1996,39(2):251-264

Ｒａｄｏｎ变换及其反演是ＣＴ技术的数学基础，常用的反演算法虽然在函数比较光滑的情况下都能获得较满意的结果，但当函数有较强的奇性时精度就比较差．对函数在每一子区域中是光滑，但在不同于区域交界处有间断的情况，本文给出了有高精度的反演算法．  相似文献   

谱分析在GPS自动化监测系统中的应用研究   总被引：1，自引：1，他引：1  

李英冰  徐绍铨  张永军  张小红 《武汉大学学报(信息科学版)》2001,26(4):343-348

利用快速Fourier变换，将形变监测资料和库水位、温度等数据从时域转到频域内进行分析，研究库水位、温度变化速度与大坝变形速度的关系。及时反映大坝变形规律和变形原因，并研制了相应的软件。  相似文献   

基于快速傅立叶变换的干涉SAR基线估计   总被引：5，自引：0，他引：5  

李新武  郭华东  廖静娟  王长林  范典 《测绘学报》2003,32(1):70-72

首先论述干涉SAR初始基线估计的基本原理；接着对用2维快速傅立叶变换（FFT）功率谱进行干涉SAR初始基线估计的具体算法进行了详细阐述；最后，基于1994年10月9日和10日的SIR－C L波段单视复雷达数据，用该算法进行了干涉SAR初始基线的垂直分量估计，并结合用航天飞机轨道数据得到的初始基线平行分量估计值进行去平地相位的试验。将结果与只用航天飞机轨道数据得到的初始基线进行去平地相位的结果及本区域的地形图进行比较分析。  相似文献   

Hiibert-Huang transform and wavelet analysis of time history signal   总被引：5，自引：0，他引：5  

石春香  罗奇峰 《地震学报(英文版)》2003,16(4):422-429

The brief theories of wavelet analysis and Hilbert-Huang transform (HHT) are introduced firstly in the present paper. Then several signal data were analyzed by using wavelet and HHT methods, respectively. The comparison shows that HHT is not only an effective method for analyzing non-stationary data, but also is a useful tool for examining detailed characters of time history signal.  相似文献   

Quench rates in air, water, and liquid nitrogen, and inference of temperature in volcanic eruption columns     

Zhengjiu Xu  Youxue Zhang   《Earth and Planetary Science Letters》2002,200(3-4):315-330

We apply a geospeedometer previously developed in this lab to investigate cooling rate profiles of rhyolitic samples initially held at 720–750°C and quenched in water, liquid nitrogen, and air. For quench of mm-size samples in liquid nitrogen and in air, the cooling rate is uniform and is controlled by heat transfer in the quench medium instead of heat conduction in the sample. The heat transfer coefficient in ‘static’ air decreases with increasing sample size. For quench of mm-size samples in water, heat transfer in water is rapid and the cooling rate is largely controlled by heat conduction in the sample. Our experimental results are roughly consistent with previous calculations for cooling in air and in water (although constant heat transfer coefficients were used in these calculations), but cooling rate in liquid nitrogen is only 1.8–2.3 times that in ‘static’ air, and slower by a factor of 2 than calculated by previous authors. Cooling rate in compressed airflow is about the same as that in liquid nitrogen. The experimental results are applied to interpret cooling rates of pyroclasts in ash beds of the most recent eruptions of the Mono Craters. Cooling rates of pyroclasts are inversely correlated with sample size and slower than those in air. The results indicate that the hydrous species concentrations of the pyroclasts were frozen in the eruption column, rather than inside ash beds or in flight in ambient air. From the cooling rates, we infer eruption column temperature in a region where and at a time when hydrous species concentrations in a pyroclast were locked in. The temperature ranges from 260 to 570°C for the most recent eruptions of Mono Craters. These are the first estimates of temperatures in volcanic eruption columns. The ability to estimate cooling rates and eruption column temperatures from eruptive products will provide constraints to dynamic models for the eruption columns.  相似文献   

成像光谱仪分光技术概览   总被引：28，自引：0，他引：28  

郑玉权  禹秉熙 《遥感学报》2002,6(1):75-80

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。  相似文献   

Late Quaternary climatic control on erosion and weathering in the eastern Tibetan Plateau and the Mekong Basin     

Zhifei Liu  Christophe Colin  Alain Trentesaux  Giuseppe Siani  Norbert Frank  Dominique Blamart  Segueni Farid 《Quaternary Research》2005,63(3):769-328

High-resolution siliciclastic grain size and bulk mineralogy combined with clay mineralogy, rubidium, strontium, and neodymium isotopes of Core MD01-2393 collected off the Mekong River estuary in the southwestern South China Sea reveals a monsoon-controlled chemical weathering and physical erosion history during the last 190,000 yr in the eastern Tibetan Plateau and the Mekong Basin. The ranges of isotopic composition are limited throughout sedimentary records: ⁸⁷Sr/⁸⁶Sr = 0.7206–0.7240 and ε_Nd(0) = −11.1 to −12.1. These values match well to those of Mekong River sediments and they are considered to reflect this source region. Smectites/(illite + chlorite) and smectites/kaolinite ratios are used as indices of chemical weathering rates, whereas the bulk kaolinite/quartz ratio is used as an index of physical erosion rates in the eastern Tibetan Plateau and the Mekong Basin. Furthermore, the 2.5–6.5 μm/15–55 μm siliciclastic grain size population ratio represents the intensity of sediment discharge of the Mekong River and, in turn, the East Asian summer monsoon intensity. Strengthened chemical weathering corresponds to increased sediment discharge and weakened physical erosion during interglacial periods. In contrast, weakened chemical weathering associated with reduced sediment discharge and intensified physical erosion during glacial periods. Such strong glacial–interglacial correlations between chemical weathering/erosion and sediment discharge imply the monsoon-controlled weathering and erosion.  相似文献