基于构造约束的波阻抗边界刻画          下载免费PDF全文

张宏兵  杨长春  尚作萍 《地球物理学进展》2007,22(3):817-825

通过边界保护正则化和约束反演，在反演的目标函数中引入各种先验信息约束，以解决波阻抗反演的病态问题和带限问题.为了克服波阻抗模型边界过于平滑，在反演中引入地层和断层等构造信息约束，并且通过调整地层分界面和断层处的正则参数值来实现构造约束.此外，采用各向异性扩散法进行平滑处理，改善反演结果.通过合成数据测试和实际资料反演，证明了本文提出的方法对刻画模型边界是有效的.  相似文献   

An Aggregate Constraint Method for Inequality-constrained Least Squares Problems   总被引：3，自引：0，他引：3  

Junhuan Peng  Hongping Zhang  Suli Shong  Chunxi Guo 《Journal of Geodesy》2006,79(12):705-713

The inequality-constrained least squares (ICLS) problem can be solved by the simplex algorithm of quadratic programming. The ICLS problem may also be reformulated as a Bayesian problem and solved by using the Bayesian principle. This paper proposes using the aggregate constraint method of non-linear programming to solve the ICLS problem by converting many inequality constraints into one equality constraint, which is a basic augmented Lagrangean algorithm for deriving the solution to equality-constrained non-linear programming problems. Since the new approach finds the active constraints, we can derive the approximate algorithm-dependent statistical properties of the solution. As a result, some conclusions about the superiority of the estimator can be approximately made. Two simulated examples are given to show how to compute the approximate statistical properties and to show that the reasonable inequality constraints can improve the results of geodetic network with an ill-conditioned normal matrix.  相似文献   

GIS线目标间拓扑关系描述的4交差模型   总被引：3，自引：0，他引：3  

邓敏  李志林  李永礼  张雪松 《武汉大学学报(信息科学版)》2006,31(11):945-949

提出了利用连通度不变量来区分单个线目标上具有不同拓扑特性的点，进一步定义了线目标的端点集和内点集。在此基础上，建立了IR^1和IR^2中线目标间拓扑关系的基本模型。该模型能有效地表达线目标间拓扑关系的变化特性。  相似文献   

基于图模犁和拓扑约束的管网数据一致性检测     

韦人玮吴小芳  杜清运 《地理空间信息》2006,4(1):52-54

正确可靠的数据是GIS系统的核心。针对管网数据的复杂性，提出利用圈数据模型描述管网拓扑关系．并使用拓扑约束方法对管网数据一致性进行检测，以确保数据的正确性。该方法吸收了基于连接规则以及基于拓扑关系约束的方法的优点，能够更好的描述管网系统的整体结构并对其进行拓扑约束，使得一致性检测更加全面。  相似文献   

基于标点随机过程的遥感影像道路提取   总被引：1，自引：1，他引：1  

余长慧  孟令奎  秦昆 《武汉大学学报(信息科学版)》2006,31(1):59-62

在分析贝叶斯方法用于遥感影像目标提取技术的基础上．基于标点随机过程方法，利用线状地物的整体几何约束和地物之间的空间结构及相关关系对目标构建数学模型．提取线状地物．并以道路网的自动提取为例，详细阐述了此算法。  相似文献   

Testing the correctness of the sequential algorithm for simulating Gaussian random fields   总被引：2，自引：2，他引：0  

X.?EmeryEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2004,18(6):401-413

The sequential algorithm is widely used to simulate Gaussian random fields. However, a rigorous application of this algorithm is impractical and some simplifications are required, in particular a moving neighborhood has to be defined. To examine the effect of such restriction on the quality of the realizations, a reference case is presented and several parameters are reviewed, mainly the histogram, variogram, indicator variograms, as well as the ergodic fluctuations in the first and second-order statistics. The study concludes that, even in a favorable case where the simulated domain is large with respect to the range of the model, the realizations may poorly reproduce the second-order statistics and be inconsistent with the stationarity and ergodicity assumptions. Practical tips such as the multiple-grid strategy do not overcome these impediments. Finally, extending the original algorithm by using an ordinary kriging should be avoided, unless an intrinsic random function model is sought after.  相似文献   

A linear tessellation model to identify spatial pattern in urban street networks     

Yakun He  Wenhao Yu  Xiang Zhang 《International journal of geographical information science》2017,31(8):1541-1561

Street patterns reflect the distribution characteristics of a street network and affect the urban structure and human behavior. The recognition of street patterns has been a topic of interest for decades. In this study, a linear tessellation model is proposed to identify the spatial patterns in street networks. The street segments are broken into consecutive linear units with equal length. We define five focal operations using neighborhood analysis to extract the geometric and topological characteristics of each linear unit for the purpose of grid-pattern recognition. These are then classified by Support Vector Machine, and the result is optimized based on Gestalt principles. The experimental results demonstrate that our method is effective for mining grid patterns in a street network.  相似文献   

基于结构导向的梯度属性边缘检测技术   总被引：1，自引：1，他引：0       下载免费PDF全文

宋建国  孙永壮  任登振 《地球物理学报》2013,56(10):3561-3571

地震数据中的不连续性检测对于识别和刻画地下地质体边界具有重要意义.随着勘探目标向岩性油藏和复杂断块油藏的转变,解释人员需要对小断裂、微裂缝等微幅地质体边界信息进行精细刻画.常规边缘检测算子由于算法的局限性不能满足上述需求.本文通过引入能量归一化和沿层检测思想对常规检测算子进行改进,提出一种基于结构导向的梯度属性边缘检测技术.该技术通过结构张量估计得到局部地层区域的倾角和方位角,利用得到的倾角和方位角信息作为约束,使用二维边缘检测算子实现三维数据中的沿层不连续性检测.经过实际资料处理,并与结构导向方差属性对比分析,证实该方法在地层不连续性检测方面具有很好效果,检测得到的不连续性信息在细节上表现更丰富,可以作为地层横向差异和地质体边界识别的有力工具.  相似文献   

基于SuperMap GIS的道路网络特征分析     

王少华  卢浩  黄骞  梁启君 《测绘与空间地理信息》2013,(Z1):109-112

道路网络特征分析是进行交通网络分析的基础,本文基于SuperMap GIS分析了道路网络特征,其中包括网络统计特征、网络中心性等网络特征,并以北京市道路网络数据为例进行了实验分析,实验结果表明SuperMapGIS是研究道路网络特征分析的重要计算平台。  相似文献   

GPS姿态测量中模糊度搜索方法的确定与比较     

罗京辉  张文  姜德才  高峰  陈继伟  段彩梅 《测绘与空间地理信息》2013,(10):64-65,69

GPS载波相位观测值作为高精度观测量在姿态测量中得到广泛应用。姿态测量系统中,基线长度可以通过提前量测精确求得。作为约束条件,可以用于模糊度搜索,提高模糊度搜索效率和准确度。本文介绍了传统的LAMBDA方法,且在此基础上提出了附有基线长度约束的LAMBDA搜索方法,并比较了两者的搜索效率。  相似文献