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利用多基线数据融合提高分布式卫星InSAR系统的干涉相位精度 总被引:1,自引:0,他引:1
分布式卫星干涉合成孔径雷达(InSAR)系统可以通过提供长基线来提高测高灵敏度,但长基线会给干涉相位展开带来困难。结合分布式卫星InSAR系统可以同时提供多个稳定基线的特点,该文提出利用多基线数据融合的方法来解决长基线给干涉相位展开带来的困难。文中采用了有效的数据融合方法最大似然估计(ML)法,对多基线分布式卫星InSAR系统的干涉相位进行了估计。模拟结果表明,经过多基线数据融合的干涉相位展开精度要远远大于长基线干涉相位的直接展开精度。 相似文献
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合成孔径雷达干涉测量中的相位展开 总被引:1,自引:0,他引:1
合成孔径雷达干涉测量技术 (InSAR)是以合成孔径雷达复数据提取的相位信息作为信息源来获取地表的三维信息和变化信息的一项技术。相位展开是InSAR数据处理中的关键步骤之一。本文介绍了合成孔径雷达干涉测量的原理 ,重点讨论了InSAR中的相位展开算法 ,特别对与路径有关的算法和与路径无关的算法进行了分析 ,比较了各类方法的优缺点。指出一些在结构照明型计量中有效的相位展开算法也可以用于合成孔径雷达干涉测量之中的相位展开 相似文献
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Phase unwrapping for large SAR interferograms: statistical segmentation and generalized network models 总被引:10,自引:0,他引:10
Two-dimensional (2-D) phase unwrapping is a key step in the analysis of interferometric synthetic aperture radar (InSAR) data. While challenging even in the best of circumstances, this problem poses unique difficulties when the dimensions of the interferometric input data exceed the limits of one's computational capabilities. In order to deal with such cases, we propose a technique for applying the statistical-cost, network-flow phase-unwrapping algorithm (SNAPHU) of Chen and Zebker (2001) to large datasets. Specifically, we introduce a methodology whereby a large interferogram is partitioned into a set of several smaller tiles that are unwrapped individually and then divided further into independent, irregularly shaped reliable regions. These regions are subsequently assembled into a full unwrapped solution, with the phase offsets between regions computed in a secondary optimization problem whose objective is to maximize the a posteriori probability of the final solution. As this secondary problem assumes the same statistical models as employed in the initial tile-unwrapping stage, the technique results in a solution that approximates the solution that would have been obtained had the full-size interferogram been unwrapped as a single piece. The secondary problem is framed in terms of network-flow ideas, allowing the use of an existing nonlinear solver. Applying the algorithm to a large topographic interferogram acquired over central Alaska, we find that the technique is less prone to unwrapping artifacts than more simple tiling approaches. 相似文献
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城市建筑区域叠掩、阴影严重,图像理解困难且干涉相位变化复杂紊乱,一直是InSAR处理的困难区域。SAR图像仿真能为图像理解和处理方法研究提供数据支撑,然而现有建筑区域SAR图像仿真方法大多无法获得具有相干性的干涉SAR图像对。该文提出了一种面向建筑区域的干涉SAR复图像对仿真方法,能够获得建筑的复数图像对、干涉相位图以及叠掩成分数目等信息,为城区干涉SAR处理及信息提取研究提供仿真数据支撑。同时,基于仿真中对相位变化规律的分析,提出叠掩区相位解缠时的基准确定方法,解决传统解缠方法面临的叠掩区域干涉相位不连续问题,进而反演建筑高程信息。最后,通过建模仿真结果与实际SAR图像和干涉相位的对比,验证了仿真方法的正确性,并对仿真及实际干涉相位进行解缠和高程反演处理,验证了该文高程反演方法的有效性。 相似文献
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We present a novel method of interferometric synthetic aperture radar (InSAR) image restoration. An InSAR image is modeled as a complex-valued Markov random field (CMRF). Corrupted parts, which are indicated by residues in phase data, are restored by using the Monte Carlo Metropolis (MM) method based on their uncorrupted neighbor's CMRF parameter values. The system is implemented as a complex-valued neural network. The restoration process reduces the residue number, which is useful in the phase unwrapping process. The advantage of the method is demonstrated in the unwrapping process of an InSAR image that contains highly dense residues 相似文献
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A Joint Image Coregistration, Phase Noise Suppression, and Phase Unwrapping Method Based on Subspace Projection for Multibaseline InSAR Systems 总被引:6,自引:0,他引:6
Zhenfang Li Zheng Bao Zhiyong Suo 《Geoscience and Remote Sensing, IEEE Transactions on》2007,45(3):584-591
As is well known, image coregistration, interferometric phase noise suppression, and phase unwrapping are three key processing procedures of synthetic aperture radar interferometry (InSAR). The three procedures are cascaded in the conventional processing flow of InSAR. Unlike the conventional processing flow, in this paper we propose a joint processing idea to carry out image coregistration, interferometric phase noise filtering, and phase unwrapping simultaneously based on subspace projection for multibaseline InSAR systems. The joint processing method can perform the fine coregistration of all SAR images implicitly by extracting the correlation information in the neighboring pixel sets, suppress the phase noise by utilizing the orthogonality of the signal subspace and the corresponding noise subspace, and optimally estimate the unwrapped interferometric phases (or the terrain heights) by combining the pixel coherence and the baseline diversity of a multibaseline InSAR system. Simulated results are presented to verify the effectiveness of the joint processing method 相似文献
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提出一种利用图像翻转和复域编码消除离轴干涉载频影响,进而实现相位恢复的方法。方法通过旋转样品干涉图180,得到翻转干涉图。样品干涉图与翻转干涉图首先被复数域编码为一幅合成的干涉图。继而进行傅里叶变换,可通过带通滤波器提取频谱中相互分离的共轭项用于相位恢复。通过逆傅里叶变换,可以获得含有样品干涉图和翻转干涉图的相位分布、载频信息的结果。通过除法运算,载频得以在无需复杂运算、解包裹、系统先验信息的情况下被消除。通过仿真和实验验证了算法的可行性。实验结果表明该方法可获得精确的相位恢复结果。在恢复薄相位样品时,该方法的恢复时间仅为原图像翻转方法的23.32%。 相似文献
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本文分析了二维相位展开算法的特点,探讨了基于干涉图质量参数的相位展开方法。按干涉图质量优劣排序,对InSAR干涉图进行相位展开,可以有效减小截断相位中无效点对相位展开结果的影响。文中给出了算法的详细描述,以及按干涉图质量参数排序进行相位展开的实验结果。 相似文献
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与其它波段相比,毫米波系统具有体积小、重量轻、分辨率高等优点,成为近几年InSAR技术的研究热点。但因其波长短,毫米波InSAR对平台运动轨迹测量精度要求更高,非理想运动情况下传统成像方法数据处理及干涉相位提取困难,另外传统方法基于平面投影成像,在地形陡变时干涉相位缠绕和目标几何畸变较严重。为了解决传统方法在毫米波InSAR成像的以上不足,该文提出了一种基于曲面投影的毫米波InSAR成像方法,将不同通道回波数据投影到相同地形高程曲面上进行成像及干涉相位提取,并推导了曲面下地形高程与干涉相位的关系。仿真和实测数据结果验证了该文方法的有效性,结果显示该方法在平台非理想运动下较传统算法获得更好的InSAR成像和干涉相位质量,且减小了地形高程起伏引起的几何畸变及干涉相位缠绕,更有利于毫米波InSAR图像地形特征描述及高程提取。 相似文献
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对流层水汽引起的大气相位延迟是制约重复轨道InSAR 高精度测量的重要因素之一。为有效解决InSAR 中大气相位延迟的问题,对InSAR 中大气延迟误差进行了分析,研究了利用MODIS 水汽数据对ASAR 干涉图大气改正的方法及其关键技术,并以太原地区的ASAR 干涉图为例,对其进行大气改正。实验结果表明,MODIS/ASAR 大气改正方法可以显著地提高干涉图的质量,同时形变反演的精度也得到了明显的改善,验证了MODIS 与ASAR 数据融合获取地表形变信息的必要性和可靠性。 相似文献
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对基于图像分割与合并的相位展开算法的改进 总被引:2,自引:1,他引:1
为了提高基于图像分割与合并的相位展开算法的精度,对已有的一种算法进行多方面改进,采取区域不等分措施,使得区域信息完整、准确再现;针对不同区域的噪声及欠采样情况,分别采取不同的相位展开算法;对分块合并时重叠区域进行加权叠加处理。利用仿真和实测数据对算法进行了验证,结果表明,改进算法能更准确、快速地恢复出被测物体的相位信息。改进后的算法不但适合于超大规模图像的相位展开,也适合于部分区域条纹过密的包裹相位图的展开。 相似文献
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