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排序方式: 共有764条查询结果,搜索用时 550 毫秒
741.
742.
J.C. Crelling I.J. Glasspool J.R. Gibbins M. Seitz 《International Journal of Coal Geology》2005,64(3-4):204-216
Although bireflectance measurements are routine, to date they have been limited to selected single point measurements. This study uses a 360° rotating polarizer in the incident light path combined with digital imaging to map the optical bireflectance of a polished specimen over the complete field of view, a system herein referred to as ‘Bireflectance Imaging of Coal and Carbon Specimens’ (BRICCS). True maximum reflectance maps and maps of polarizer angle for maximum reflectance (to identify co-ordered regions) are obtainable from the same data. A variety of coal, coke, char, graphite, and carbon/carbon specimens have been examined with the BRICCS system and the results demonstrate that the system can produce accurate maximum and apparent minimum reflectance, bireflectance, and extinction angle images. For example, flakes of natural graphite show no bireflectance along their long axis except in areas that have been strained. The images are maps showing the value of every pixel that has been calibrated by mineral reflectance standards. The maps are unique in that they show fields of view that cannot be seen by normal viewing through the microscope. For example, the bireflectance maps show the maximum difference between the maximum and apparent minimum reflectances for each of the million pixels at twenty orientations of the polarizer. 相似文献
743.
应用多种遥感影像处理方法提取玛尼7.5级地震中的热红外异常信息 总被引:2,自引:0,他引:2
以1997年11月8日发生在西藏玛尼的Ms7.5地震为例,应用多种红外遥感影像处理方法,提取地震发生前后的红外辐射的时空演变信息。结果发现,在震前4天震中所在的玛尔盖茶卡断层以及东昆仑断裂带,出现3—5℃的增温现象,该异常在地震后逐渐消失。 相似文献
744.
本文以1995年甘肃省境内5.8级地震引起的黄土地区震陷灾害实例,对黄土微结构孔隙性进行了定量研究。通过电镜扫描手段和SEM图像处理技术,对极震区震陷性黄土微观结构的各项指标进行了比较分析,得出不同地点的黄土孔隙分布曲线;对极震区受地震破坏和未受破坏典型架空孔隙结构的黄土进行了定量处理,较好地解释了土体的工程性质,结合激光粒度分析仪对极震区黄土进行了测量和统计分析。同时对无震区与强震区黄土孔隙分布曲线进行了对比研究。结果表明:不同极震区的孔隙分布特征不同,同一深度不同区域孔隙分布曲线亦有明显的差异。 相似文献
745.
Yangrong Ling Manfred Ehlers E. Lynn Usery Marguerite Madden 《ISPRS Journal of Photogrammetry and Remote Sensing》2007,61(6):381-392
Existing image fusion techniques such as the intensity–hue–saturation (IHS) transform and principal components analysis (PCA) methods may not be optimal for fusing the new generation commercial high-resolution satellite images such as Ikonos and QuickBird. One problem is color distortion in the fused image, which causes visual changes as well as spectral differences between the original and fused images. In this paper, a fast Fourier transform (FFT)-enhanced IHS method is developed for fusing new generation high-resolution satellite images. This method combines a standard IHS transform with FFT filtering of both the panchromatic image and the intensity component of the original multispectral image. Ikonos and QuickBird data are used to assess the FFT-enhanced IHS transform method. Experimental results indicate that the FFT-enhanced IHS transform method may improve upon the standard IHS transform and the PCA methods in preserving spectral and spatial information. 相似文献
746.
747.
748.
Laboratory validation of lattice Boltzmann method for modeling pore-scale flow in granular materials
Characteristics of fluid flow through various engineering structures, such as granular filters and asphalt pavements, influence their design life. Numerical simulation of fluid flow is useful for evaluating the hydraulic characteristics of these materials. Among various techniques, the lattice Boltzmann (LB) method is widely accepted due to the ease of implementing boundary conditions and the numerical stability in a wide variety of flow conditions. It has proven to be extremely efficient in the simulation of fluid flow through the complex geometries of granular materials. In this study, two-dimensional and three-dimensional LB models were developed to represent pore-scale monophasic Newtonian incompressible fluid flow in granular materials. Three-dimensional geometries of compacted aggregates and asphalt specimens were generated from X-ray Computed Tomography technique and used as input for the LB model. The accuracy of the models was verified by comparing the results with analytical solutions of simple geometries and hydraulic conductivity measurements on the compacted aggregates and hot mix asphalt specimens. The results of LB simulations were in excellent agreement with those obtained from analytical calculations and laboratory measurements. 相似文献
749.
遥感技术是研究土地利用/覆被变化状况的重要手段之一,目前该技术已有一套较成熟的研究方法,本文从遥感数据选择、图像预处理方法、土地利用/覆被变化遥感分类、土地利用/覆被变化动态信息提取等方面对土地利用/覆被变化遥感动态监测技术进行了系统的论述,最后指出多信息源、综合的信息处理机制将是土地利用/覆被变化遥感动态监测技术发展的必然方向。 相似文献
750.
为了满足不会或者不能熟练使用地图的用户需求,本文提出用道路实景来增强地理信息的可视性。设计并实现了道路实景获取系统,用于道路实景数据的自动采集。通过建立道路实景数据的索引和道路实景数据与地理信息的级联查询方法,解决了道路实景数据发布的两项关键技术。最后本文对用道路实景在门户网站中增强地理信息的可视性应用前景进行了展望。 相似文献