三维地震数据离散光滑插值的共轭梯度法   总被引：5，自引：3，他引：5       下载免费PDF全文

李冰  刘洪  李幼铭 《地球物理学报》2002,45(5):691-699

针对三维地震数据插值,提出采用Laplacian算子进行光滑约束的插值方法,并借鉴Mallet研究的离散光滑插值思路,采用预条件共轭梯度法,直接生成网格节点上的值,从而回避寻求满足插值方程的函数. 为了实现其中Laplacian算子的快速求逆,文中引入Claerbout螺旋坐标系谱因式分解理论. 在螺旋坐标系下,Laplacian算子的表示矩阵具有Toeplitz结构,其快速求逆可由谱法LU分解实现. 基于二维离散光滑插值,文中还给出共轭梯度法与NMO相结合的沿时间切片逐层处理的离散光滑插值流程. 最后,应用该方法对模型数据和实际三维地震数据进行了处理.  相似文献   

基于RDBMS的海量数字高程模型系统     

王永君  龚健雅 《测绘信息与工程》2003,28(6):14-15

介绍了用于海量数字高程模型数据的管理、应用分析以及可视化的系统GeoDEMDB，采用部件对象模型技术，实现了数据管理、空间分析和大范围三维场景漫游的集成，并提供了灵活的选择性。  相似文献   

Three-dimensional imaging of shear wave velocity in the uppermost 30 m of the soil column in Anchorage, Alaska   总被引：1，自引：0，他引：1  

José Badal  Utpal Dutta  Francisco Serón  Niren Biswas 《Geophysical Journal International》2004,158(3):983-997

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The dynamic characteristics and migration of a pyramid dune   总被引：6，自引：0，他引：6  

TAO WANG  WEIMIN ZHANG  ZHIBAO DONG  JIANJUN QU  ZHEFAN JING  WANFU WANG  JIANMIN FENG 《Sedimentology》2005,52(3):429-440

The results of wind tunnel experiments and field observations show that when the intersection angle between airflow direction and dune crest (ridge) line is > 30°, a reverse vortex is formed. Because of the convergence of sand streams from the windward and lee slopes at the crest, sand accumulates in the crestal region, causing vertical growth. Nevertheless, studies also show that the common asymmetry of the two slopes of a dune may significantly influence the evolution of arms of a pyramid dune. The migration rates of pyramid dunes are mediated by the interplay of their arms moving transversely and the vertical growth in response to the variations in wind regimes. Comparing the effects of airflow transverse to a given arm with longitudinal airflow, it is indicated that the transverse airflow is more significant in controlling the arms of pyramid dunes. The whole body of the studied pyramid dune, particularly the upper quarter section, migrated SE direction during the monitoring period. The patterns of wind erosion and deposition change alternately with seasonal variations in wind directions. The W, NE and SE sides undergo constant erosion, deposition and both erosion and deposition, respectively. The results of long-term monitoring of a pyramid dune show that southerly winds, resulting from a local circulation, markedly affect the transverse migration of the whole pyramid dune.  相似文献   

Semantic segmentation of high spatial resolution images with deep neural networks     

Haiping Yang  Jiancheng Luo  Fang Chen 《地理信息系统科学与遥感》2019,56(5):749-768

Availability of reliable delineation of urban lands is fundamental to applications such as infrastructure management and urban planning. An accurate semantic segmentation approach can assign each pixel of remotely sensed imagery a reliable ground object class. In this paper, we propose an end-to-end deep learning architecture to perform the pixel-level understanding of high spatial resolution remote sensing images. Both local and global contextual information are considered. The local contexts are learned by the deep residual net, and the multi-scale global contexts are extracted by a pyramid pooling module. These contextual features are concatenated to predict labels for each pixel. In addition, multiple additional losses are proposed to enhance our deep learning network to optimize multi-level features from different resolution images simultaneously. Two public datasets, including Vaihingen and Potsdam datasets, are used to assess the performance of the proposed deep neural network. Comparison with the results from the published state-of-the-art algorithms demonstrates the effectiveness of our approach.  相似文献   

一种基于复合金字塔模型的三维模型数据组织方法     

王金地  霍亮  慕旭  秦高雅  曹存相 《测绘与空间地理信息》2019,42(4):58-61

针对异构三维模型数据的统一组织和集成管理问题,本文以目前主流金字塔模型、三维场景瓦片的数据组织方法和地图服务规范等相关技术为基础,提出了一种基于复合金字塔模型的三维模型数据组织方法。该方法首先构建覆盖测区的地理格网模型,以此作为异构三维模型数据集成的空间框架。其次,建立三维模型数据与地理格网单元的映射关系,从而构建复合金字塔模型,实现异构三维模型数据的统一管理。最后,在数据结构上对现有数据格式进行扩展,设计了一种面向网络传输的数据格式储存三维模型数据,完成异构三维模型数据的一体化存储。试验结果表明,该方法能够实现异构三维模型数据统一组织与集成管理。  相似文献   

控制点影像库在遥感影像几何纠正中的应用   总被引：2，自引：0，他引：2  

陈功  舒宁  王欢  胡勇 《地理空间信息》2006,4(1):58-61

影像几何纠正是遥感图像处理的重要技术。为了克服现有方法在实际应用中的不足,提出利用控制点影像库进行影像自动匹配,然后进行几何变化的方式。这种方法简单有效,快速稳定,匹配得到的同名点数量足够且分布均匀,并通过引入最小二乘匹配使配准达到子像素精度,提高几何纠正的速度与可靠性。  相似文献   

矢量图形与影像图像一体化实现   总被引：3，自引：0，他引：3  

倪建华  秦佐 《四川测绘》2009,32(3):103-105

本文在阐述影像金字塔相关理论（构建方法、影像切割等）的基础上,采用VC2005编程实现了在同一GIS系统中进行矢量数据和栅格数据叠加显示的功能模块。该模块可确定是否加载影像,并根据当前矢量图显示范围自动加载不同分辨率的影像图。  相似文献   

A mapping of the electron localization function for the silica polymorphs: evidence for domains of electron pairs and sites of potential electrophilic attack     

G. V. Gibbs  D. F. Cox  T. D. Crawford  M. B. Boisen Jr  M. Lim 《Physics and Chemistry of Minerals》2002,29(5):307-318

The electron localization function, η, evaluated for first-principles geometry optimized model structures generated for quartz and coesite, reveals that the oxide anions are coordinated by two hemispherically shaped η-isosurfaces located along each of the SiO bond vectors comprising the SiOSi angles. With one exception, they are also coordinated by larger banana-shaped isosurfaces oriented perpendicular to the plane centered in the vicinity of the apex of each angle. The hemispherical isosurfaces, ascribed to domains of localized bond-pair electrons, are centered ～0.70 Å along the bond vectors from the oxide anions and the banana-shaped isosurfaces, ascribed to domains of localized nonbonding lone-pair electrons, are centered ～0.60 Å from the apex of the angle. The oxide anion comprising the straight SiOSi angle in coesite is the one exception in that the banana-shaped isosurface is missing; however, it is coordinated by two hemispherically shaped isosurfaces that lie along the bond vectors. In the case of a first-principles model structure generated for stishovite, the oxide anion is coordinated by five hemispherically shaped η-isosurfaces, one located along each of the three SiO bond vectors (ascribed to domains of bonding-electron pairs) that are linked to the anion with the remaining two (ascribed to domains of nonbonding-electron pairs) located on opposite sides of the plane defined by three vectors, each isosurface at a distance of ～0.5 Å from the anion. The distribution of the five isosurfaces is in a one-to-one correspondence with the distribution of the maxima displayed by experimental Δρ and theoretical ??²ρ maps. Isosurface η maps calculated for quartz and the (HO) ₃ SiOSi(OH) ₃ molecule also exhibit maxima that correspond with the (3,?3) maxima displayed by distributions of ??²ρ. Deformation maps observed for the SiOSi bridges for the silica polymorphs and a number of silicates are similar to that calculated for the molecule but, for the majority, the maxima ascribed to lone-pair features are absent. The domains of localized nonbonding-electron pair coordinating the oxide anions of quartz and coesite provide a basis for explaining the flexibility and the wide range of the SiOSi angles exhibited by the silica polymorphs with four-coordinate Si. They also provide a basis for explaining why the SiO bond length in coesite decreases with increasing angle. As found in studies of the interactions of solute molecules with a solvent, a mapping of η-isosurfaces for geometry-optimized silicates is expected to become a powerful tool for deducing potential sites of electrophilic attack and reactivity for Earth materials. The positions of the features ascribed to the lone pairs in coesite correspond with the positions of the H atoms recently reported for an H-doped coesite crystal.  相似文献   

基于à trous小波变换的Landsat 7 ETM＋图像融合研究     

刘佳佳  管磊  李乐乐 《国土资源遥感》2007,18(2):50-52

 以胶州湾及周边海岸带为研究区，采用Landsat 7 ETM+数据，提出一种基于à trous小波变换的全色图像和多光谱图像融合改进算法。对全色图像和多光谱图像进行适当层数的小波分解，多光谱图像的低频部分采用全色图像和其低频分量的比来调制； 最高分解层外的其余分解层采用多光谱图像和全色图像在该层分解系数的加权和，加权系数由局部区域能量比来确定； 最高分解层则采用绝对值最大准则。实验表明，该方法得到的图像可提高空间分辨率，对多光谱图像的光谱信息扭曲也较小，为提高海岸带地物分类和信息提取精度奠定了基础。  相似文献