共查询到18条相似文献,搜索用时 62 毫秒
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几何校正是SAR图像应用的基础,而影响校正效果的要素有多种。论文首先从SAR图像成像机理出发,阐述了几何校正中定位模型的建立和解算过程,主要分析了两类影响要素:高程和卫星轨道插值方法。然后以一幅高分辨率TerraSAR-X图像的几何校正为基础,对比分析了三种高程和两种轨道插值算法对定位精度的影响。实验结果表明,只有距离向定位受这些因素的影响,高程的分辨率和垂直精度对定位精度都有很大影响、四次多项式直接插值方法只能满足一般的几何校正需要,更高精度的校正还需要其他辅助手段。 相似文献
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基于SAR影像模拟几何校正算法参数误差影响分析 总被引:1,自引:0,他引:1
基于SAR影像模拟的几何校正算法以其不需要提供地面控制点、精确的成像参数以及所有操作可自动完成等优点,在SAR图像几何校正中受到了广泛的关注和应用。然而测量设备误差的存在,使得算法输入参数(航向角、飞行高度、近端斜距、DEM高程)存在误差,这会引起SAR模拟图像特征发生变化,严重时还会引起图像匹配参数(控制点)误差,降低几何校正精度。论文分析了算法输入参数和控制点对SAR影像模拟和图像匹配的影响,在此基础上完成了关于参数误差影响的较完整的分析,导出了一套相应的计算公式,弥补了现有文献中的一些空缺。 相似文献
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一种星载SAR图像的系统级几何校正技术 总被引:3,自引:0,他引:3
在星历参数和星载SAR空间几何模型的基础上,本文实现了星载SAR图像的系统级几何校正,给出了一种基于空间几何模型的星载SAR图像像素定位技术,说明了经纬网中任意点所在距离线被雷达波束中心照射的时刻的估算方法。最后利用仿真数据验证了这种几何校正方法的有效性。 相似文献
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一种校正畸变图像边缘的改进算法 总被引:1,自引:0,他引:1
在已知畸变参数的条件下,针对轮廓简单的畸变图像,提出了综合校正法.该方法通过先直接后间接的空间变换方式来建立理想图像与畸变图像的坐标映射关系.根据图像边缘直线的属性即斜率及截距,来验证综合校正与直接校正的校正精度;同时对综合校正和间接校正的计算量及实时性进行比较.实验结果表明:综合法的校正精度在边缘直线的斜率方面比直接校正提高了的8倍,在边缘直线的截距上提高了的100倍;与间接校正相比,综合校正的实时性好,计算量小. 相似文献
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Processing of multiple-receiver spaceborne arrays for wide-area SAR 总被引:16,自引:0,他引:16
Goodman N.A. Sih Chung Lin Rajakrishna D. Stiles J.M. 《Geoscience and Remote Sensing, IEEE Transactions on》2002,40(4):841-852
The instantaneous area illuminated by a single-aperture synthetic aperture radar (SAR) is fundamentally limited by the minimum SAR antenna area constraint. This limitation is due to the fact that the number of illuminated resolution cells cannot exceed the number of collected data samples. However, if spatial sampling is added through the use of multiple-receiver arrays, then the maximum unambiguous illumination area is increased because multiple beams can be formed to reject range-Doppler ambiguities. Furthermore, the maximum unambiguous illumination area increases with the number of receivers in the array. One spaceborne implementation of multiple-aperture SAR that has been proposed is a constellation of formation-flying satellites. In this implementation, several satellites fly in a cluster and work together as a single coherent system. There are many advantages to the constellation implementation including cost benefits, graceful performance degradation, and the possibility of performing in multiple modes. The disadvantage is that the spatial samples provided by such a constellation will be sparse and irregularly spaced; consequently, traditional matched filtering produces unsatisfactory results. We investigate SAR performance and processing of sparse, multiple-aperture arrays. Three filters are evaluated: the matched filter, maximum-likelihood filter, and minimum mean-square error filter 相似文献
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Four-component scattering model for polarimetric SAR image decomposition 总被引:16,自引:0,他引:16
Yamaguchi Y. Moriyama T. Ishido M. Yamada H. 《Geoscience and Remote Sensing, IEEE Transactions on》2005,43(8):1699-1706
A four-component scattering model is proposed to decompose polarimetric synthetic aperture radar (SAR) images. The covariance matrix approach is used to deal with the nonreflection symmetric scattering case. This scheme includes and extends the three-component decomposition method introduced by Freeman and Durden dealing with the reflection symmetry condition that the co-pol and the cross-pol correlations are close to zero. Helix scattering power is added as the fourth component to the three-component scattering model which describes surface, double bounce, and volume scattering. This helix scattering term is added to take account of the co-pol and the cross-pol correlations which generally appear in complex urban area scattering and disappear for a natural distributed scatterer. This term is relevant for describing man-made targets in urban area scattering. In addition, asymmetric volume scattering covariance matrices are introduced in dependence of the relative backscattering magnitude between HH and VV. A modification of probability density function for a cloud of dipole scatterers yields asymmetric covariance matrices. An appropriate choice among the symmetric or asymmetric volume scattering covariance matrices allows us to make a best fit to the measured data. A four-component decomposition algorithm is developed to deal with a general scattering case. The result of this decomposition is demonstrated with L-band Pi-SAR images taken over the city of Niigata, Japan. 相似文献
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Signal properties of spaceborne squint-mode SAR 总被引:7,自引:0,他引:7
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提出了一种无监督SAR图像变化检测算法,利用数据聚类思想,通过进化算法寻找最小均方误差,得到变化检测结果.在原有Memetic算法基础上,针对图像自身特点,提出全新的搜索策略并根据当前检测结果动态调整局部搜索算法,实现了粗细结合的搜索过程.算法不受分布模型限制,不需要先验知识,适用性较强.将改进的算法与GA、ICSA及原MA进行比较,实验证明,该算法可以快速收敛.对真实SAR图像进行检测,可以得到较好的检测结果. 相似文献
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红外焦平面阵列(IRFPA)像元响应存在不一致性,会严重影响红外成像系统成像的质量,实际应用中需要采用响应的非均匀性校正(NUC)技术。传统的神经网络校正算法在校正结果中存在图像模糊和伪像的问题,影响人们对于目标的观察。在分析了传统的神经网络性校正算法所出现问题原因的基础上,提出了有效的改进算法:用非线性滤波器代替传统算法中使用的均值滤波器。算法改进之后所得到的校正图像,不仅在清晰度方面有明显的改善,而且有效的消除了传统算法中存在伪像的问题。 相似文献