航天INSAR复影像对的自动快速匹配   总被引：3，自引：0，他引：3  

靳国旺 徐青朱彩英  杨培章张燕 《测绘学院学报》2005,22(2):128-130,133

针对航天INSAR主、辅影像数据的特点，提出了加大匹配窗口、加大锚点间隔的匹配策略，以提高匹配的可靠性和速度。在匹配过程中，综合利用轨道参数和强度影像金字塔进行粗匹配，并对强度影像采用相关系数与最小二乘相结合的双向匹配方案，实现了自动、快速、高可靠性和高精度的航天INSAR复影像匹配。最后总结了航天INSAR复影像匹配的特点。  相似文献   

水气两相流系统K-S-P模型参数反演的最优估计   总被引：1，自引：0，他引：1       下载免费PDF全文

薛强  冯夏庭  梁冰  刘建军 《水科学进展》2005,16(4):488-493

应用渗流力学和参数反演辨识最优化理论,建立了水气两相流控制方程,给出了控制两相流系统K-S-P模型参数之间的本构关系,并对其中的相关参数进行数值反演辨识,得出待求参数的最优估计值。对不同质地土壤的实验测试值进行对比分析,其结果吻合较好,验证了模型的适定性和可靠性,解决了实验数据处理以及结果对初值的敏感性问题,并且该数值方法可通过多组初值参数进行数值实验,结合实验结果来满足实际工程的需求。这不仅对非饱和带内污染物传输、气藏工程试井计算、填埋气体的释放以及挥发性有机污染物的去污分析中两相流数值计算提供基础,而且对K-S-P本构关系之间参数的确定提供了可靠的理论依据。  相似文献   

航空影像分割的最小二乘支持向量机方法   总被引：5，自引：0，他引：5  

徐芳  梅文胜  张志华 《武汉大学学报(信息科学版)》2005,30(8):694-698

将最小支持向量机LS-SVM用于航空影像的分割,讨论了不同核函数对分割结果的影响和稀疏化处理对决策函数的影响。试验表明了LS-SVM方法用于航空影像分割的可行性。  相似文献   

GIS叠置图层方差分量的极大似然估计   总被引：1，自引：0，他引：1  

王新洲  游扬声  刘星  史文中 《武汉大学学报(信息科学版)》2005,30(10):892-896

针对GIS叠置中的同名点,以维希特分布密度为似然函数,提出了各图层方差分量的极大似然估计方法。该方法不依赖残差,不需要迭代就能估计未知参数和方差分量。  相似文献   

平差系统的模型误差及其识别方法研究   总被引：2，自引：0，他引：2  

张朝玉  陶本藻 《武汉大学学报(信息科学版)》2005,30(10):897-899,904

论述了模型误差影响参数估值的一些理论问题,指出了随机模型误差和函数模型误差之间的相互作用和转化。为讨论平差系统最优模型的选取,给出了与现有文献将模型误差纳入平差系统的思路不同的一个估计和识别模型误差的理论基础公式,由此导出了相应的实用公式,给出了平差系统模型的优选方法。  相似文献   

基于立体补偿的遥感立体像对压缩方法     

李飞鹏  马国锐  秦前清  李德仁 《遥感学报》2005,9(2):195-203

提出研究遥感立体像对的压缩问题。主要讨论了左右影像的视差补偿和辐射补偿。针对遥感立体像对视差分布不均以及左右影像存在辐射差的特点,提出了一种基于立体补偿的遥感立体像对压缩算法。该算法以左片为基准图像,采用自适应视差估计计算出右片的视差矢量,结合辐射校正和重叠块视差补偿技术得到平滑的右片的预测图像,以右片减去预测图像得到残差图像,然后采用小波压缩算法对残差图像进行压缩。实验结果表明,该算法能显著提高遥感立体像对的压缩性能。  相似文献   

Integer aperture bootstrapping: a new GNSS ambiguity estimator with controllable fail-rate   总被引：1，自引：0，他引：1  

P.J.G. Teunissen 《Journal of Geodesy》2005,79(6-7):389-397

In this contribution, we introduce a new bootstrap-based method for Global Navigation Satellite System (GNSS) carrier-phase ambiguity resolution. Integer bootstrapping is known to be one of the simplest methods for integer ambiguity estimation with close-to-optimal performance. Its outcome is easy to compute due to the absence of an integer search, and its performance is close to optimal if the decorrelating Z-transformation of the LAMBDA method is used. Moreover, the bootstrapped estimator is presently the only integer estimator for which an exact and easy-to-compute expression of its fail-rate can be given. A possible disadvantage is, however, that the user has only a limited control over the fail-rate. Once the underlying mathematical model is given, the user has no freedom left in changing the value of the fail-rate. Here, we present an ambiguity estimator for which the user is given additional freedom. For this purpose, use is made of the class of integer aperture estimators as introduced in Teunissen (2003). This class is larger than the class of integer estimators. Integer aperture estimators are of a hybrid nature and can have integer outcomes as well as non-integer outcomes. The new estimator is referred to as integer aperture bootstrapping. This new estimator has all the advantages known from integer bootstrapping with the additional advantage that its fail-rate can be controlled by the user. This is made possible by giving the user the freedom over the aperture of the pull-in region. We also give an exact and easy-to-compute expression for its controllable fail-rate.  相似文献   

A new method for indentifying the model error of adjustment system     

Tao Benzao  Zhang Chaoyu 《地球空间信息科学学报》2005,8(3):189-192

Some theory problems affecting parameter estimation are discussed in this paper. Influence and transformation between errors of stochastic and functional models is pointed out as well. For choosing the best adjustment model, a formula, which is different from the literatures existing methods, for estimating and identifying the model error, is proposed. On the basis of the proposed formula, an effective approach of selecting the best model of adjustment system is given. Project supported by the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University (No. 905276031-04-10).  相似文献   

Investigating the propagation mechanism of unmodelled systematic errors on coordinate time series estimated using least squares   总被引：6，自引：8，他引：6  

M. P. Stewart  N. T. Penna  D. D. Lichti 《Journal of Geodesy》2005,79(8):479-489

The propagation of unmodelled systematic errors into coordinate time series computed using least squares is investigated, to improve the understanding of unexplained signals and apparent noise in geodetic (especially GPS) coordinate time series. Such coordinate time series are invariably based on a functional model linearised using only zero and first-order terms of a (Taylor) series expansion about the approximate coordinates of the unknown point. The effect of such truncation errors is investigated through the derivation of a generalised systematic error model for the simple case of range observations from a single known reference point to a point which is assumed to be at rest by the least squares model but is in fact in motion. The systematic error function for a one pseudo-satellite two-dimensional case, designed to be as simple but as analogous to GPS positioning as possible, is quantified. It is shown that the combination of a moving reference point and unmodelled periodic displacement at the unknown point of interest, due to ocean tide loading, for example, results in an output coordinate time series containing many periodic terms when only zero and first-order expansion terms are used in the linearisation of the functional model. The amplitude, phase and period of these terms is dependent on the input amplitude, the locations of the unknown point and reference point, and the period of the reference point's motion. The dominant output signals that arise due to truncation errors match those found in coordinate time series obtained from both simulated data and real three-dimensional GPS data.  相似文献   

K 近邻非参数回归概率预报技术及其应用   总被引：7，自引：1，他引：7       下载免费PDF全文

翟宇梅赵瑞星  肖仁春王力维 《应用气象学报》2005,16(4):453-460

针对参数回归技术制作概率预报存在拟合好、但预报结果不稳定的现象, 提出了用K近邻非参数回归技术制作概率预报的新途径。K 近邻非参数回归技术包括历史样本数据库、近邻子集生成和优化以及预报量估计4 个主要部分。利用该技术进行了单要素概率预报(主要包括云量和降水)和多维联合概率预报(降水、总云量、风速和气温)试验, 并对试验结果进行了检验。实例研究结果表明:该文所给出的计算方案预报稳定性好, 准确率较高,具有良好的业务应用价值。  相似文献