共查询到20条相似文献，搜索用时 31 毫秒
1.
全极化数据的可得,使得利用极化散射矩阵以减少多视全极化SAR图像中的相干斑成为了可能。其中,被称为最优的多视极化白化滤波器（MPWF）就是一个典型例子。然而,为提高滤波器参数估计的精度,同时能够自适应的检测图像中的结构特征,在滤波时采用适当的窗算法是必要的。本文提出了两个有效的窗算法,并用1994年NASA SIR-C/X-SAR,L band,经过四视处理的天山森林的极化数据进行了仿真。实验结果表明,这两种算法不仅很好的达到了降噪效果,而且对图像的纹理信息以及结构特征（即边缘特征、线性特征、强散射体特征）的保持效果是最佳的。 相似文献
2.
2L-IHP目标检测算法及其在AIRSAR数据中的应用 总被引：1，自引：0，他引：1
简要介绍了2L—IHP（Two-Looks Internal Hermitian Product）算法，并针对实际情况对其作了相应的调整和改进。主要是突破算法对数据源的限制，使得它可以应用到幅度图像中。对于极化SAR图像，使用PWF（Polarimetric Whitening Filter）方云将3个通道的图像合成为一幅检测图，再进行目标检测。利用ADTS（Advanced Detection Technology Sensor）数据，对以上各种算法的检测效果进行了分析比较。应用C、L、P波段的AIRSAR极化数据进行试验，发现3个波段中，L和C波段的检测效果最好；4种极化方式中，HH极化取得最佳的检测效果；并且得出全极化数据的检测结果优于单极化数据的结论。但以上结论还有待进一步验证。 相似文献
3.
Classification comparisons between dual-pol, compact polarimetric and quad-pol SAR imagery 总被引：1，自引：0，他引：1
T.L. Ainsworth J.P. Kelly J.-S. Lee 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(5):464-471
We present a study of the polarimetric information content of dual-pol imaging modes and dual-pol imaging extended by polarimetric scattering models. We compare Wishart classifications both among the partial polarimetric datasets and against the full quad-pol dataset. Our emphasis is the inter-comparisons between the classification results based on dual-pol modes, compact polarimetric modes and scattering model extensions of the compact polarimetric modes. We primarily consider novel dual-pol modes, e.g. transmitting a circular polarization and receiving horizontal and vertical polarizations, and the pseudo-quad-pol data derived from polarimetric scattering models based on dual-pol data. We show that the overall classification accuracy of the pseudo-quad-pol data is essential the same as the classification accuracy obtained directly employing the underlying dual-pol imagery. 相似文献
4.
利用TanDEM-X生成DEM的精度评定 总被引：1，自引：0，他引：1
目前,许多学者对TanDEM-X生成DEM开展了一些研究,其研究成果也显示了TanDEM-X生成高精度DEM的可行性。为了验证TanDEM-X/TerraSAR-X干涉生成的DEM能否满足测图要求,需要对其进行精度评价和分析。相对于C波段的ERS、ASAR和L波段的ALOS,X波段的高分辨率TerraSAR影像干涉条纹更密集,解缠更加困难。针对这一问题,本文设计了一种低分辨率SRTM辅助高分辨率的X波段的TerraSAR干涉相位解缠方案,提高了解缠的效率和精度。同时,本文提出了一种基于协方差函数的方法对TDX/TSX DEM进行精度分析和评价。该方法通过对各个距离上的协方差值进行拟合,消除了高程误差异常对InSAR DEM精度评价的影响,可以更加客观真实地反映DEM的精度。实例分析结果表明：采用协方差函数方法来评价DEM的精度是可行的,对于试验研究区域,TDX/TSX干涉生成的DEM总体精度为1.42 m,能够满足1：10 000测图要求,为我国空白地区的测图提供了有利条件。 相似文献
5.
M. Dabboor V. Karathanassi A. Braun 《International Journal of Applied Earth Observation and Geoinformation》2011
An innovative methodology for dual-polarized Synthetic Aperture Radar (SAR) data segmentation is proposed. The methodology is based on the thresholding of the 1D-histograms of the two images produced by the dual polarimetric bands. Thresholding of the histograms is performed using a nonparametric algorithm. Histograms after thresholding are combined together in a two dimensional histogram-based space in order to define sub-spaces, which are used for image segmentation. Sub-spaces are further divided based on two criteria which lead to a multi-level segmentation approach. Dual-polarized TerraSAR-X data, both HH and VV, are used in a study area located in the southwestern United Kingdom. 相似文献
6.
利用SVM的全极化、双极化与单极化SAR图像分类性能的比较 总被引：1，自引：0，他引：1
支持向量机(SVM)以其在小训练样本时良好的分类性能,目前已广泛应用于多个领域.本文在极化SAR图像特征提取基础上,将SVM应用于极化SAR图像分类,定性和定量地比较了全极化、双极化和单极化SAR图像的分类性能,分析了不同的极化组合对分类结果的影响,并根据地物极化散射特性分析了分类精度差异的成因.实测极化SAR数据的实验结果表明,全极化数据能获得最好的分类性能,双极化次之,单极化最低,且在某些情况下,双极化与全极化分类性能接近. 相似文献
7.
针对经典极化分类算法在处理机载X波段SAR数据时将过多地物分为体散射类型,并且容易受噪声影响,分类结果存在大量误分现象的问题,通过对机载X波段SAR数据非监督分类方法的研究,提出将极化干涉信息用于机载X波段极化干涉SAR数据的分类。通过运用极化干涉数据进行目标分解得到参数A1和A2对数据进行初始分类,然后结合改进的Wishart最大似然分类算法来进行地物的自适应分类。实验结果表明,该方法能有效避免平地效应的影响,抗噪性好,能正确区分三种典型散射类型,分类效果明显优于极化分类效果。 相似文献
8.
目标分解技术在植被覆盖条件下土壤水分计算中的应用 总被引：6，自引：0，他引：6
目标分解技术利用协方差距阵的特征值和特征矢量，将极化雷达后向散射测量值分解为单向散射，双向散射和交叉极化散射三个分量，并建立了植被覆盖地表的一阶物理离散散射模型。通过分解的各分量与该模型的比较，建立重轨极化雷达测量数据估算土壤水分的方法，采用Washita‘92实验区多时相全极化L波段JPL/AIRSAR图像雷达测量数据，利用分解的散射测量值，我们评估了在同一入射角，单频（L波段），多路条件下，分解理论在进行土壤水分估计时减少植被影响的能力。结果表明利用目标分解理论和重轨极化雷达数据可以估算植被覆盖区域土壤水分的变化情况。 相似文献
9.
针对极化SAR定标算法中一些分布式目标并不满足互易性的问题,提出一种对分布式目标互易性进行判断的方法。通过计算选取分布式目标的极化散射矩阵与互易子空间的夹角,来进行互易目标的初步选择,并利用相干性来实现最终分布式目标定标样本的选择。实现了对中电38所海南X波段全极化SAR数据的极化定标,实验证明了该方法的优越性。 相似文献
10.
基于Freeman散射熵和各向异性度的极化SAR影像分类算法研究 总被引：1，自引：0，他引：1
极化SAR影像中阴影、水体和裸露的耕地3种地物类型有非常相似的极化散射特性,常规基于非相干分解的分类方法难以将其有效地区分。对此,本文引入基于Freeman分解的散射熵Hf和各向异性度Af两个特征参数,并将其用于极化SAR影像分类。首先利用Hf和Af参数将阴影和水体提取出来,然后将其他地物按散射机制分为3大类,并对每一类再次利用Hf和Af参数进行细分,最后通过基于Wishart分布的聚类和迭代分类,得到最终的分类结果。通过利用Radarsat-2在河南登封获取的全极化SAR数据进行试验,表明该算法执行效率高,能够有效地区分阴影、水体和裸露的耕地,并且对其他地物类型也有很好的分类效果。 相似文献
11.
利用双极化Sentinel-1数据有望得到较单极化数据更好的城市地表形变监测结果。以典型受地表沉降灾害影响的两座超大城市（墨西哥的墨西哥城和中国北京市）为研究区,分别基于长时序单、双极化Sentinel-1数据,利用时序合成孔径雷达干涉测量（interferometric synthetic aperture radar, InSAR）技术和极化时序InSAR技术对两城市近年地表形变进行监测研究。结果表明,利用双极化Sentinel-1数据对干涉图进行极化优化后,干涉图相位质量得到提升,高质量像元比例明显增加。使用双极化数据后,形变监测点密度有显著提升,相比于单极化数据结果,墨西哥城和北京市监测点密度分别提升88%和50%;更高的监测点密度使部分区域双极化数据反演地表形变的准确性更高。与单极化Sentinel-1数据相比,利用双极化Sentinel-1数据进行城市地表形变监测可得到监测点密度更高、可靠性更好的结果。 相似文献
12.
本文在改进的永久散射体(PS)探测方法基础上,应用高分辨率永久散射体雷达干涉(PSI)探测上海市地表沉降,并对沉降原因进行了详细分析。实验选取2008年4月至2010年1月间,由德国卫星TerraSAR-X(TSX)所获取的18幅X波段(波长为3.1 cm)高分辨率SAR影像为数据源,进行PS探测、PSI建模、形变提取和分析。实验结果表明,改进的PS探测方法探测出的PS点是合理和可靠的,且高分辨率SAR影像对地面硬目标识别能力较强,显著提高了PS点的密度和覆盖范围。沉降探测结果显示,最大相对沉降速率达30 mm/yr,平均沉降速率为11.5 mm/yr。 相似文献
13.
From repeat pass SIR-C L band polarimetric SAR interferometric data and fully maximum likelihood inversion decomposition model of PolInSAR, a method for sub-canopy soil moisture estimation using repeat pass SIR-C PolInSAR data is proposed. At the same time, the potential and validity of fully maximum likelihood inversion decomposition model of PolInSAR for sub-canopy soil moisture inversion is investigated. Firstly, from the random oriented volume over ground two layer coherent scattering model and the statistical characteristics of Pol-InSAR coherency matrix, the fully maximum likelihood inversion decomposition model is used to reconstruct or recover the surface polarimetric coherency matrix with volume scattering components significantly removed; then, from recovered surface polarimetric coherency matrix, co-HH, VV and cross-HV polarization backscattering coefficient are obtained, and the sub-canopy soil moisture are inverted from Oh and Dihedral scattering model. At last, Compared the inversion result with the field measurement and the climate data of hetan region from 1951 to 2006, the preliminary result indicates that the proposed method based on fully maximum likelihood inversion decomposition model has enough high inversion accuracy, if the new spaceborne or airborne polarimetric SAR interferometric data with synchronously spaceborne or airborne-ground measurement will be acquired, the validity and accuracy of proposed inversion method will be further investigated and validated. 相似文献
14.
基于MODIS影像的森林火灾火线检测方法 总被引：1，自引：0，他引：1
结合归一化火灾差异指数NDBR(normalized difference burn ratio)和MODIS多波段影像梯度边缘分析手段检测火线, 应用B样条函数拟合火线并确定火势蔓延方向。为对比验证, 基于火线的Kriging插值实现火灾外推预测, 与30min后的火灾参考数据目视对比与统计：火线的预测变化与参考影像基本保持一致, 火灾外推影像的均值和熵约为参考影像的86%和81%, 火迹地检测的Kappa系数达80.2%。试验表明, 提出的森林火线特征自动检测方法在动态火灾监测中是可行、有效的。 相似文献
15.
在分析合成孔径雷达（ＳＡＲ）成象机理及雪盖参数散射特性的基础上，利用航天飞机承载的成象雷达（ＳＩＲ—Ｃ）获取的多波段、多极化ＳＡＲ数据，进行提取雪盖信息的实验。结果表明Ｃ波段ＨＨ、ＶＶ影象能很好地区别湿雪与非雪盖区，而区分干雪与岩石较困难；Ｌ波段ＨＨ、ＶＶ影象较容易将雪盖同其它物体区分开；Ｃ、Ｌ波段的交叉极化ＨＶ、ＶＨ区分干雪与岩石效果很好。故利用多波段、多极化ＳＡＲ进行雪盖制图是可行的。 相似文献
16.
This study assesses the use of TerraSAR-X data for monitoring rice cultivation in the Sanjiang Plain in Heilongjiang Province, Northeast China. The main objective is the understanding of the coherent co-polarized X-band backscattering signature of rice at different phenological stages in order to retrieve growth status.For this, multi-temporal dual polarimetric TerraSAR-X High Resolution SpotLight data (HH/VV) as well as single polarized StripMap (VV) data were acquired over the test site. In conjunction with the satellite data acquisition, a ground truth field campaign was carried out.The backscattering coefficients at HH and VV of the observed fields were extracted on the different dates and analysed as a function of rice phenology to provide a physical interpretation for the co-polarized backscatter response in a temporal and spatial manner. Then, a correlation analysis was carried out between TerraSAR-X backscattering signal and rice biomass of stem, leaf and head to evaluate the relationship with different vertical layers within the rice vegetation.HH and VV signatures show two phases of backscatter increase, one at the beginning up to 46 days after transplanting and a second one from 80 days after transplanting onwards. The first increase is related to increasing double bounce reflection from the surface–stem interaction. Then, a decreasing trend of both polarizations can be observed due to signal attenuation by increasing leaf density. A second slight increase is observed during senescence. Correlation analysis showed a significant relationship with different vertical layers at different phenological stages which prove the physical interpretation of X-band backscatter of rice. The seasonal backscatter coefficient showed that X-band is highly sensitive to changes in size, orientation and density of the dominant elements in the upper canopy. 相似文献
17.
18.
多频率InSAR提取沼泽湿地DEM精度对比分析 总被引：1，自引：1，他引：0
选取3种波长的干涉SAR数据对提取沼泽湿地区域的DEM,并随机从1：10 000地形图中选取111个点数据进行精度验证,最后对比分析了沼泽湿地植被对于不同SAR波长的干涉相干性差异。结果表明：L-band ALOS-1 PALSAR精细模式的HH单视复数数据与1：10 000地形图数据吻合度较好,76.58%的高程值差异在3 m以内,其相干系数比C-band Sentinel-1A IW模式的VV单视复数数据和X-band TerraSAR HH单视复数数据要高;更适合利用雷达干涉测量技术提取沼泽湿地的DEM;不同湿地植被类型的相干系数有较大差异,岛状林和灌草结合的湿地植被分布区相干系数值较大,而浅水沼泽植被区和深水沼泽植被区相对较低。 相似文献
19.
TerraSAR-X (TSX) can acquire high-resolution SAR images and due to its high orbit precision as well as its ability to acquire data from different off-nadir viewing angles, the high-precision stereo geolocation can be obtained. In this study, we investigate the absolute geolocation accuracy of TSX high-resolution images in Wuhan, China. We present a direct stereo SAR geolocation method and analyze the 2D and 3D geoposition accuracy of two corner reflectors. The sub-meter localization accuracy was achieved using only atmospheric correction information available in the TSX metadata. 相似文献
20.
This letter proposes a generalized-likelihood ratio test-based edge detector to be fed by possibly polarimetric synthetic aperture radar (SAR) data. It can be used to detect dark spots on the sea surface and, hence, as the first stage of a system for identification and monitoring of oil spills. The proposed constant false alarm rate (CFAR) detector does not require secondary data (namely pixels from a slick-free area); remarkably, a preliminary performance assessment, carried out by resorting to real SAR recordings, shows that it guarantees detection capabilities comparable to those of previously proposed polarimetric CFAR detectors (which though make use of secondary data). The preliminary performance assessment also seems to indicate that processing polarimetric data does not ensure improved detection capabilities. 相似文献