Landsat7 ETM＋影像的融合和自动分类研究   总被引：25，自引：0，他引：25  

徐涵秋 《遥感学报》2005,9(2):186-194

利用SFIM、MLT、HPF和修改的Brovey(MB)等遥感影像融合算法对Landsat 7 ETM 影像进行融合和自动分类研究，并就融合影像的光谱保真度、高频空间信息融人度和分类精度对这些方法进行评价。结果表明SFIM变换几乎完全保持了原始影像的光谱特点，并具有最高的平均分类精度；MB变换具有最高的高频空间信息融人度；MLT变换也具有较高的分类精度；只有HPF变换的各项指标都不突出。所有4种融合影像的分类精度都较原始影像的分类精度有明显的提高。这表明，源于同一传感器系统的不同分辨率影像的融合可以避免异源传感器融合影像所常见的各种参数、时相和配准误差，所以能够明显地提高影像的自动分类精度。  相似文献   

基于小波统计特性的遥感图像像素与特征联合最优融合方法   总被引：8，自引：0，他引：8  

肖刚  敬忠良  HenryLeung  王淑 《遥感学报》2005,9(4):381-386

遥感影像的IHS融合方法由于匹配误差导致光谱畸变和退化,而小波变换在变换域具有良好的分频特性,小波系数的统计特性反映了遥感影像的边缘、线和区域等显著特征。提出了基于小波统计特性的遥感影像的像素和特征联合最优融合方法,在IHS空间,对强度分量I的高频部分利用多分辨率小波融合方法进行影像的高频细节特征融合,低频部分选取光谱信息和空间分辨率评价指标作为融合权系数求优指标,进行像素级最优融合,实验结果证明了该方法的有效性。  相似文献   

降水预报的初始场最优化方法     

周成钧耿良国  李军伟 《沙漠与绿洲气象(新疆气象)》2005,28(3):9-11

利用一简单的湿度发展方程，尝试用非线性最优化方法讨论降水预报中的最优初值场的获得。试验结果表明，通过非线性最优化分析方法，可以找到一最优初始场，使得模式预报结果与实际观测场一致，这为将来在实际应用中如何改善更复杂模式的初始场，提高预报准确率提供了一个很有意义的思路。  相似文献   

Optimal design of passive energy dissipation systems based on H∞ and H2 performances     

J. N. Yang  S. Lin  J‐H. Kim  A. K. Agrawal 《地震工程与结构动力学》2002,31(4):921-936

Passive energy dissipation devices (EDDs), such as viscous dampers, viscoelastic dampers, etc., have been used to effectively reduce the dynamic response of civil infrastructures, such as buildings and bridges, subject to earthquakes and strong winds. The design of these passive energy dissipation devices (EDDs) involves the determination of the optimal locations and the corresponding capacities. In this paper, we present two optimal design methodologies for passive EDDs based on active control theories, including H_∞ and H₂ performances, respectively. The optimal design methodologies presented are capable of determining the optimal locations and the corresponding capacities of EDDs. Emphasis is placed on the application of linear matrix inequality (LMI) for the effective design of passive EDDs using the popular MATLAB toolboxes. One important advantage of the proposed approaches is that the computation of the structural response is not needed in the design process. The proposed optimal design methodologies have been applied to: (i) a 10‐storey building and a 24‐storey building both subject to earthquake excitations, and (ii) a 76‐storey wind‐excited benchmark building, to demonstrate the advantages of the proposed design methodologies over the conventional equal capacity design. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Multi‐objective optimal design of FLC driven hybrid mass damper for seismically excited structures     

A. S. Ahlawat  A. Ramaswamy 《地震工程与结构动力学》2002,31(7):1459-1479

Structural vibration control using active or passive control strategy is a viable technology for enhancing structural functionality and safety against natural hazards such as strong earthquakes and high wind gusts. Both the active and passive control systems have their limitations. The passive control system has limited capability to control the structural response whereas the active control system depends on external power. The power requirement for active control of civil engineering structures is usually quite high. Thus, a hybrid control system is a viable solution to alleviate some of the limitations. In this paper a multi‐objective optimal design of a hybrid control system for seismically excited building structures has been proposed. A tuned mass damper (TMD) and an active mass driver (AMD) have been used as the passive and active control components of the hybrid control system, respectively. A fuzzy logic controller (FLC) has been used to drive the AMD as the FLC has inherent robustness and ability to handle the non‐linearities and uncertainties. The genetic algorithm has been used for the optimization of the control system. Peak acceleration and displacement responses non‐dimensionalized with respect to the uncontrolled peak acceleration and displacement responses, respectively, have been used as the two objectives of the multi‐objective optimization problem. The proposed design approach for an optimum hybrid mass damper (HMD) system, driven by FLC has been demonstrated with the help of a numerical example. It is shown that the optimum values of the design parameters of the hybrid control system can be determined without specifying the modes to be controlled. The proposed FLC driven HMD has been found to be very effective for vibration control of seismically excited buildings in comparison with the available results for the same example structure but with a different optimal absorber. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

利用卫星影像和航空影像更新基础地理信息方法研究     

狄沙力 《安徽地质》2002,12(3):204-207

基础地理信息的更新,是保证地理信息系统现势性的充要条件.卫星遥感影像数据具有周期短、信息丰富、现势性强等特征.利用卫星影像数据来更新基础地理信息数据是一种行之有效的方法.如何利用遥感数据融合技术,将多传感器获取的各种影像数据中所含的信息优势有机地结合起来,更是成为目前研究的热点.利用航空影像和Landsat多光谱波段影像进行数据融合,能够有效地提高影像空间分辨率,以获取更高质量的信息.  相似文献   

洛带气田蓬莱镇气藏开发部署优化研究     

张箭 《矿物岩石》2002,22(4):83-86

气藏评价尚未结束之前，开发的早期部署工作非常困难。针对洛带气田蓬莱镇组气藏的开发部署工作，利用目前许多新方法对开发层系划分、采气规模、开发规划、合理配产和井网部署等进行了优化研究，对气藏开发提出了指导性意见，且对类似气藏也具有参考意义。  相似文献   

Optimal placement of dampers and actuators based on stochastic approach     

Franklin Y. Cheng  Hongping Jiang  Xiaozhe Zhang Ph.D. Candidate 《地震工程与工程振动(英文版)》2002,1(2):237-249

A general method is developed for optimal application of dampers and actuators by installing them at optimal location on seismic-resistant structures. The study includes development of a statistical criterion, formulation of a general optimization problem and establishment of a solution procedure. Numerical analysis of the seismic response in time-history of controlled structures is used to verify the proposed method for optimal device application and to demonstrate the effectiveness of seismic response control with optimal device location. This study shows that the proposed method for the optimal device application is simple and general, and that the optimally applied dampers and actuators are very efficient for seismic response reduction.  相似文献   

Nonlinear earthquake response analysis and energy calculation for seismic slit shear wall structures     

蒋欢军  吕西林 《地震工程与工程振动(英文版)》2002,1(2):227-237

Based on the concept of structural passive control, a new type of slit shear wall, with improved seismic performance when compared to an ordinary solid shear wall, was proposed by the authors in 1996. The idea has been verified by a series of pseudo-static and dynamic tests. In this paper a macro numerical model is developed for the wall element and the energy dissipation device. Then, nonlinear time history analysis is carried out for a 10-story slit shear wall model tested on a shaking table. Furthermore, the seismic input energy and the individual energy dissipated by the components are calculated by a method based on Newmark-β assumptions for this shear wall model, and the advantages of this shear wall are further demonstrated by the calculation results from the viewpoint of energy. Finally, according to the seismic damage criterion on the basis of plastic accumulative energy and maximum response, the optimal analysis is carried out to select design parameters for the energy dissipation device.  相似文献   

A Bayes filter in Friedland form for INS/GPS vector gravimetry     

B. Schaffrin  J. H. Kwon 《Geophysical Journal International》2002,149(1):64-75

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