共查询到20条相似文献，搜索用时 31 毫秒
1.
针对传统二次滤波算法在空间碎片激光测距微弱信号实时识别中表现出误检率高的问题,基于空间碎片激光测距回波信号时间相关性的特点,本文提出采用一次滤波和线性拟合相结合的方法,顾及微弱信号实时识别的搜索代价与识别精度,实现了空间碎片激光测距微弱信号的实时识别。利用空间碎片激光测距实测数据进行了算法验证,结果表明：本文提出的激光测距微弱信号实时识别算法能够快速准确提取空间碎片的微弱信号,误检率由原来的5.72%降低到0.12%,漏检率由原来的0.77%降低到0.34%,对提高空间碎片的探测成功率具有重要意义。 相似文献
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Eigensubspace-Based Filtering With Application in Narrow-Band Interference Suppression for SAR 总被引：2，自引：0，他引：2
Synthetic aperture radar (SAR) has found wide applications in many areas, e.g., battlefield awareness. However, SAR is vulnerable to various kinds of interference, among which narrow-band interference (NBI) is commonly used. In this letter, an eigensubspace-based filtering approach is proposed for NBI suppression in SAR without using passive-sniff data as the reference signal. Moreover, the proposed method can deal with smart or interrupted NBI. Both simulation and experimental results are provided to illustrate the performance of the proposed approach 相似文献
3.
《Geoscience and Remote Sensing Letters, IEEE》2008,5(4):573-577
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Luc K. Jansen R. W. Kersten P. R. Fiedler R. L. 《Geoscience and Remote Sensing Letters, IEEE》2007,4(2):265-268
Traditionally, interfering emitter signatures have been removed through notched filtering in the range (fast-time) dimension. This works well when a narrowband emitter interferes with a wideband radar pulse; however, when the emitter and radar signal bandwidths are comparable, then this approach fails since the noise is distributed throughout the pulse and the image as well. In cases where the interfering signal is localized in the cross range, joint time-frequency methods can often focus this interference signal, thereby transforming the image. In this transformed image, the interferer is the foreground, and the desired synthetic aperture radar image is blurred and now the background. The focused compressed interferer can be analyzed and censored from the transformed image. Back transformation restores the image with the interference removed. This technique has been fully automated and applied to an Electromagnetics Institute Synthetic Aperture Radar (EMISAR) image contaminated by a nonstationary emitter. The cleansed image is virtually free of the emitter interference 相似文献
5.
针对雷达探测范围会受到复杂地形因素影响,单一地依靠电磁传播模型可视化雷达探测区域很难真实有效地展现电磁覆盖情况的问题,该文提出一种基于GeoSOT-3D空间剖分的雷达探测范围的计算与表达一体化的真三维模型。GeoSOT-3D剖分框架将上至地球50 000km,下至地心的全部地球空间划分成多层次、多尺度空间体元,体元可承载多源异构空间数据。依据GeoSOT-3D的剖分流程,将地形数据、雷达探测空间数据离散化。最后,开发了雷达探测范围可视化验证平台。实验结果表明,该建模方法对复杂的地形适应性强,可视化表现效果真实直观。 相似文献
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基于多尺度空间分析的图像阈值分割方法 总被引：6，自引：0，他引：6
在通过一阶差分确定阈值的基础上，依据多尺度滤波思想，提出一种基于多尺度空间分析的阈值分割方法对图像进行分割，将该方法与其他分割方法进行了比较，证明了本文算法的有效性。 相似文献
8.
Huifu Zhuang Kazhong Deng Hongdong Fan 《Journal of the Indian Society of Remote Sensing》2017,45(5):733-741
If a binary change map (BCM) is generated without considering spatial-contextual information, it can produce a number of false and missed alarms because of the significant speckle noise in synthetic aperture radar (SAR) images. Therefore, this paper first proposes the local continuity assumption of the changed and unchanged areas. Then, a new filtering approach to BCM of SAR images is proposed based on the voter model and spatial-contextual information. Experimental results indicate that the proposed approach can effectively decrease the detection noise, improve the detection accuracy of BCM and perform better than a median filter, mathematical morphological filters and a filter based on a Markov random field. 相似文献
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在讨论整数可逆模糊度变换对模糊度搜索空间影响及直接取整法成功概率的基础上，结合Kalman滤波技术，提出一种新的GPS动态数据处理快速算法－－基于概率计算的模糊度快速分解技术（Probability Based Fast Ambiguity-resolution Technique,简称PBFAT法）。该算法在取整成功概率大于给定限值时，直接对浮点模糊度取整；若取整概率小于给定的值则进行一定范围的模糊度搜索。试验表明该方法的计算速度高于传统方法，所求的模糊度有一个明确的置信水平。 相似文献
10.
《Geoscience and Remote Sensing Letters, IEEE》2009,6(3):383-387
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将卫星雷达遥感应用于滑坡灾害的探测与监测，不仅可以从空间尺度上大范围捕捉到滑坡信号，而且可以从时间尺度上以较长周期追踪滑坡的运动状态。但是，卫星雷达遥感本身的局限性和滑坡所处的复杂地形环境使这一应用面临一些挑战。对卫星雷达遥感技术的4个主要挑战进行了总结与分析，同时给出了相应的解决方案:①通过提高卫星雷达影像的空间、时间分辨率，使用较长波段雷达信号或采用增强型时间序列分析技术，可降低密集植被覆盖对相干性的影响。另外，采用像素点偏移量追踪或距离向分频干涉测量方法，可克服传统干涉测量中大梯度形变引起的相位失相干。②大气延迟对卫星遥感的影响较大，尤其是地处山区的滑坡探测和监测，利用通用型卫星雷达大气改正系统可显著减弱干涉影像的大气信号并进一步简化时间序列分析，提高缓慢运动滑坡的探测和监测质量。③对于中等分辨率的雷达影像而言，利用数字高程模型可提前量化分析雷达几何畸变（如叠掩、阴影等）引发的滑坡探测监测的适用性；而对于高分辨率的雷达影像而言，利用机器学习方法无需外部高分辨率数字高程模型即可精确识别雷达影像的阴影和叠掩区并进行掩膜，从而大幅度提高数据处理效率。④针对高坡度地区残余的地形相位引起的解缠误差，可通过基线线性组合的方法予以减弱。此外，提出了一个基于多源对地观测的滑坡探测/监测系统框架，综合卫星雷达遥感与其他对地观测数据（如地基雷达、激光雷达、全球导航定位系统），搭建了一个自动化滑坡探测与监测系统。该研究旨在阐明卫星雷达遥感的优缺点，进一步深化其在滑坡灾害监测方面的应用和推广，引出未来侧重发展方向的思考与探讨。 相似文献
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合成孔径雷达(SAR)稀疏成像模型中的参数选择对于SAR稀疏成像的性能有重要影响,也是当前SAR稀疏成像研究中的难点问题。已有参数选择方法普遍存在适用于个别模型或者运算量大的缺点。基于最大后验概率估计和贝叶斯推理,提出了一种无需额外先验信息的自适应参数选择方法,所有需要的参数都可从已知的数据中获取。通过推导得到模型参数与信号、噪声方差的关系,避免了对数据进行一系列的训练处理,因此极大地减小了计算量。仿真数据和实测数据处理表明,本文方法在实现了较为精确的参数优化选择的前提下,其计算量远低于贝叶斯信息论准则、L-曲线等已有参数选择方法。 相似文献
13.
《ISPRS Journal of Photogrammetry and Remote Sensing》2007,61(5):281-297
Fusion of optical and synthetic aperture radar data has been attempted in the present study for mapping of various lithologic units over a part of the Singhbhum Shear Zone (SSZ) and its surroundings. ERS-2 SAR data over the study area has been enhanced using Fast Fourier Transformation (FFT) based filtering approach, and also using Frost filtering technique. Both the enhanced SAR imagery have been then separately fused with histogram equalized IRS-1C LISS III image using Principal Component Analysis (PCA) technique. Later, Feature-oriented Principal Components Selection (FPCS) technique has been applied to generate False Color Composite (FCC) images, from which corresponding geological maps have been prepared. Finally, GIS techniques have been successfully used for change detection analysis in the lithological interpretation between the published geological map and the fusion based geological maps. In general, there is good agreement between these maps over a large portion of the study area. Based on the change detection studies, few areas could be identified which need attention for further detailed ground-based geological studies. 相似文献
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15.
Martinez-Espla J.J. Martinez-Marin T. Lopez-Sanchez J.M. 《Geoscience and Remote Sensing Letters, IEEE》2008,5(2):147-151
This letter presents a phase-unwrapping (PU) algorithm for synthetic aperture radar interferometry based on a grid-based filter. The proposed PU algorithm, which is based on state-space techniques, simultaneously performs noise filtering and PU. The formulation of this technique provides independence from noise statistics and is not constrained by the nonlinearity of the problem. Results obtained with synthetic data show a significant improvement with respect to other conventional PU algorithms in some situations. 相似文献
16.
利用卡方分布改进N-FINDR端元提取算法 总被引：3，自引：0，他引：3
针对N-FINDR算法计算速度慢、搜索范围较大的特点,提出改进的快速N-FINDR算法,通过提供一个像元个数较少的候选端元集合,为N-FINDR算法提供一个较小的搜索范围。在N-FINDR算法中,所有的端元被认为是处于所有像元构成的单形体的顶点位置,表示这些像元远离像元聚类中心。因此,利用卡方分布的分位点可以分离出这些像元,形成数量较少的候选端元集合。利用合成的和真实的高光谱数据对该算法的性能进行了验证。实验表明,在与N-FINDR算法有相同的端元提取精度的前提下,该算法计算速度更快。 相似文献
17.
TRMM PR雷达与阜阳雷达降水资料的对比研究 总被引：8，自引：0，他引：8
选取了1998年与1999年HUBEX观测资料，将TRMM卫星上的星载降雨雷达PR与阜阳的713数字化天气雷达资料在以下3个方面做了比较：(1)强度场的分布；(2)平均反射率廓线；(3)灵敏度。分析、比较结果可知阜阳雷达在探测灵敏度和水平方向的分辨率要高于PR，但由于波束宽度、衰减和资料转化过程计算误差的原因，其远距离处的观测值与真实值有一定偏差。PR波长短，对衰减敏感，尤其是在垂直方向上经过强衰减后，订正值仍偏小。但由于探测方式的不同PR在水平方向上不存在衰减的问题，且其资料分布均匀，因此提出一种用PR资料来订正地基雷达资料的方法用以提高地基雷达探测的精确度。 相似文献
18.
Phase unwrapping is a key problem not only in all quantitative applications of synthetic aperture radar (SAR) interferometry but also in other fields. In this letter, a new phase unwrapping approach is investigated. Our study is based on the model of the optimum data vector. In order to autocoregister the SAR images, the proposed method takes advantage of the multibaseline optimal weighted joint data vector by extracting all the coherence information available in the neighboring pixels. Moreover, the method employs the projection of the joint signal subspace onto the corresponding noise subspace to estimate the unwrapped interferometric phases (or the terrain heights). The proposed method can accurately determine the dimensions of the noise subspace and provide the robust unwrapped interferometric phases even in the presence of the large image coregistration errors. Moreover, the multibaseline processing idea is a combination of data optimization, image coregistration, interferogram filtering, and phase unwrapping. 相似文献
19.
合成孔径雷达（ＳＡＲ）是一种重要的微波遥感工具。其关键技术是成像处理,即把接收到的雷达信号转换成雷达图像。事实上,合成孔径就是通过成像处理来实现的。该文在总结目前星载ＳＡＲ各种成像处理算法的基础上,提出一种匹配滤波与ＣｈｉｒｐＳｃａｌｉｎｇ相结合的处理方法。处理过程无需插值便可进行距离迁移校正,还可获得好的聚焦与相位保持性能。所得图像质量超过现有的其它ＳＡＲ成像处理方法所得图像质量。 相似文献
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在分析干涉条纹图噪声特征的基础上, 提出了一种能有效保持干涉图条纹的边缘和细节信息的InSAR干涉图滤波算法——基于最优化融合的自适应方向平滑算法。该算法首先对8个线性方向窗口进行统计分析, 然后根据干涉图的相干性选择合适的线性方向窗口, 按照最优化融合的方法, 以方差倒数为权重对各个方向窗口的均值进行加权平均。模拟和真实干涉图数据的实验结果表明新方法不仅能有效的抑制干涉图噪声, 而且能较好的保持干涉图的细节和边缘信息, 具有很好的信息保持能力。 相似文献