单天线SAR动目标的检测和聚焦

单天线SAR运动目标检测系统具有结构简单、算法容易实现等特点,它的运动目标检测性能的完善很有应用意义.首先建立了运动目标SAR回波模型,结合单天线SAR运动目标检测系统,提出了一种基于频域对称扰动的能够对具有方位向速度的运动目标检测的新方法,在详细分析运动目标散焦程度和方位向速度关系的基础上,给出了检测原理以及实现检测的方法.对检测到运动目标的距离门单元,提出了用基于图像域的偏移自聚焦算法估计动目标的调频率,进而完成运动目标在SAR图像上的聚焦成像.并用计算机仿真结果和实测数据验证了算法的有效性.     

Azimuth resolution improvement for spaceborne SAR images with quasi-non-overlapped Doppler bandwidth

The azimuth resolution improvement problem is solved via a coherent combination of synthetic aperture radar （SAR） ima-ges with the quasi-non-overlapped Doppler bandwidth. Prior to the spectra combination, SAR images should be coregistered, while phase biases induced by topography, atmospheric propagation delays and baseline measurement errors should be calibrated. However, the coregistration accuracy suffers from large Doppler decorrelation caused by the quasi-non-overlapped Doppler band-width. Furthermore, the method used to estimate phase biases from interferogram of azimuth prefiltered SAR image pairs wil fail when there is no overlapped spectrum. The fringe simulation and maximum sharpness optimization are adopted to deal with the problems. Accordingly, a novel algorithm to coherently synthesize SAR images is presented. The experiment with the Terra SAR X-band （TerraSAR-X） satel ite data validates the performance of the presented method.     

极化SAR图像相干斑滤波性能评估

针对相干斑抑制能力强弱,对极化白化滤波(PWF)和功率图(Span)两种极化合成孔径雷达(SAR)图像相干斑滤波器进行了性能评估,应用等效视数指标,提出分别在高、中、低灰度均匀区域进行测试的方法,并在ESAR与PiSAR图像上进行了检验。结果表明,在占图像比例较大的中等灰度区域内,使用全局参数时,PWF滤波输出的结果优于Span图像的输出结果,但在占图像比例较小的低灰度区域,由于参数估计不够准确,PWF的滤波结果并不优于Span图像。     

基于直方图形态的SAR图像灰度变换性能评估

以合成孔径雷达(syntheticapertureradar,SAR)图像灰度变换前后直方图形态一致性为依据,对现有的7种变换算法性能进行了评价。首先对原始图像进行灰度线性变换,以线性变换图像作为参考图像,对7种变换算法的结果图像进行评估。提出3个检测直方图形态差异的统计参数:相对均值偏量、相对方差偏量和相对偏态差。经真实SAR图像检验,表明基于辐射度统计多分辨率分析(RMA)的灰度变换方法性能最优。     

SAR image target segmentation based on entropy maximization and morphology

Entropy maximization thresholding is a simple, effective image segmentation method. The relation between the histogram entropy and the gray level of an image is analyzed. An approach, which speeds the computation of optimal threshold based on entropy maximization, is proposed. The suggested method has been applied to the synthetic aperture radar (SAR) image targets segmentation. Mathematical morphology works well in reducing the residual noise.     

皖南民居和人居环境的承继和发展——SAP理论在未来村落建设中的应用

文章以皖南民居为例分析其居住环境,将其聚居空间提炼为主体空间和情趣空间,此两种空间的组合创造了皖南古民居丰富多彩居住环境。文章还讨论主体空间和情趣空间与SAR理论中支撑体与可分体的对应关系,为使未来的村落建设成更适宜人居住的环境提供有益的启示。     

The Study of a New Method for Forecasting Non—stationary Series

A new method for forecasting non-stationary series is developed.Its steps are as follows.Step 1.Data delaminating.Non-stationary series is delaminated into several multi-scale steady data layers and one trend layer.Step 2.Modeling and forecasting each stationary data layer.Step 2.Imitating trend layer using polynomial.Step4.Combining the forecasting layers and imitating layer into one series,The EMD(Empirical Mode Decomposition) method suitable to preocess non-stationary series is selected to delaminate data,while ARMA(Auto Regressive Moving Aver age)model is employed to model and forecast stationary data layer and least square error method for trend layer regression.Aiming at forecasting length,forecasting orientation and selective method,experiments are performed for SAR(Synthetic Aperture Radar) images.Finally,an example is provided,in which the whole SAR image is restored via the method proposed by this paper.     

Stormwater Management in Hong Kong

IntroductionStormwater management(SWM) in Hong Kong isthe responsibility of the drainage servicesdepartment (DSD) of the Governmentof the HongKong Special Administrative Region.Thedepartment is charged with the formulation ofpolicy and the design,construction,operation andmaintenance of all public stormwater drainagesystems,as well as approving private drainsthrough an administrative framework.　 The principal concern of SWM is the reductionof the risk and extent of flooding.Thus,thesuc…     

生产系统柔性的边界分析

生产系统是一个感知系统，在进行系统分析时可以以边界分析为中心。柔性生产系统的边界具有丰富的构成，生产系统的要素可以区分快变量和慢变量，生产系统的柔性大小与这些变量的反应速度、与感知反应临界带的宽度、与感知反应流的构成都有密切的关系。本文利用边界分析法对生产系统的柔性进行研究，试图找到增加生产系统柔性的方法和途径。     

Long term monitoring of urban subsidence by Permanent Scatterer DInSAR

When using differential SAR interferometry (DInSAR) to monitor the surface deformation over a long time scale, it is often strongly affected by the spatial and temporal decorrelations and atmospheric dishomogeneities. The recently developed Permanent Scatterers (PS) technique proposed by Fertti et al. can overcome these difficulties by interpreting time-series of interferometric phase only at coherent point scatterers. In this study, we apply this PS technique using 25 ERS-1/2 scenes from 1992 to 2000 to monitor the subsidence in Suzhou. By using the linear deformation model, the deformation map in Suzhou urban area over the eight years is obtained. And the calculated results are in good agreement with the measurements of leveling.