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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
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Histogram and variogram inference in the multigaussian model 总被引：1，自引：4，他引：1
Xavier Emery Julián M. Ortiz 《Stochastic Environmental Research and Risk Assessment (SERRA)》2005,19(1):48-58
Several iterative algorithms are proposed to improve the histogram and variogram inference in the framework of the multigaussian model. The starting point is the variogram obtained after a traditional normal score transform. The subsequent step consists in simulating many sets of gaussian values with this variogram at the data locations, so that the ranking of the original values is honored. The expected gaussian transformation and the expected variogram are computed by an averaging operation over the simulated datasets. The variogram model is then updated and the procedure is repeated until convergence. Such an iterative algorithm can adapt to the case of tied data and despike the histogram. Two additional issues are also examined, referred to the modeling of the empirical transformation function and to the optimal pair weighting when computing the sample variogram. 相似文献
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该文利用GMS 5原始数据、GMS 5展宽数据、FY-2A展宽数据和FY-2B展宽数据, 采用伪彩色增强和灰度直方图分析方法, 分别对这4种数据的红外、水汽、可见光通道图像进行了针对杂散光的对比分析以及对杂散信号来源分析。分析表明这三颗静止气象卫星的图像中都存在一定的杂散信号。该文提出了解决杂散光问题主要依靠优化辐射计光路设计; 地面系统在实时处理、展宽图像时采取简单剔除处理, 可以减小或消除图像冷空间区域的杂散信号, 但是去掉地球圆盘图像内部的杂散信号将非常困难。 相似文献
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Declustering of Clustered Preferential Sampling for?Histogram and Semivariogram Inference 总被引：1，自引：0，他引：1
Ricardo A. Olea 《Mathematical Geology》2007,39(5):453-467
Measurements of attributes obtained more as a consequence of business ventures than sampling design frequently result in samplings
that are preferential both in location and value, typically in the form of clusters along the pay. Preferential sampling requires
preprocessing for the purpose of properly inferring characteristics of the parent population, such as the cumulative distribution
and the semivariogram. Consideration of the distance to the nearest neighbor allows preparation of resampled sets that produce
comparable results to those from previously proposed methods. A clustered sampling of size 140, taken from an exhaustive sampling,
is employed to illustrate this approach. 相似文献
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基于灰度直方图和几何特征的声纳图像目标识别 总被引：2，自引：0，他引：2
目标形状因子和长、宽、高等几何特征,与目标类别具有很大的关系,而灰度直方图也是目标物理特性的直接表现。根据采用马尔可夫随机场理论分割后的声纳目标和阴影图像,利用其灰度直方图曲线进行目标的聚类分析,再利用几何特征进行类别识别,经实测的数据验证,取得了较好的效果。证明该方法可有效表征不同目标的物理特性,从而区分不同类别的目标,避免了目标绝对反向散射强度的复杂计算,增强了抗噪性。以搜寻目标的几何特征为输入参数,可迅速锁定要搜寻的目标,借助其它探测手段,实现目标的自动识别。 相似文献
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从低层视觉特征与地物空间关系特征对影像内容进行描述,建立检索模板与目标影像间的相似性直方图表达,提出一种适用于高分辨率遥感影像检索的新方法。首先,利用Quin+树将大幅面原始遥感影像分解为一系列同尺寸的序列子块;然后,分别提取各子块的低层视觉特征与地物关系特征,并以子块为基元构建候选子块的特征直方图;最后,对比检索模板与候选子块间的特征直方图相似性,实现高分辨率遥感影像的检索。使用多幅多源高分辨率遥感影像进行实验,结果表明本文方法对耕地、水系、建筑物等地类的检索精度大都维持在0.8以上,且各项检索性能指标均优于已有的两种遥感图像检索算法。 相似文献
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消除CCD图像中宇宙射线的算法的比较 总被引：1，自引：0，他引：1
CCD天文图像在采集过程中会受到各种噪声的影响,其中宇宙射线噪声有时会严重影响到图像中的有用信息。研究如何有效识别和剔除宇宙射线噪声对于天文图像的信息提取是非常重要的。针对目前国际上较新的三种消除宇宙射线的算法:Laplacian边缘检测算法(A Laplacian Edge Detection Algorithm),基于直方图的快速算法(A Fast Algorithm BasedOn Histogram)以及万能噪声消除算法(A Universal Noise Removal Algorithm),采用由云南天文台1m望远镜拍摄的CCD图像进行了模拟实验和实际宇宙射线的处理。实验表明Laplacian边缘检测算法能相对准确地探测到恒星和星系图像上的宇宙射线。并对算法的效果和复杂度进行比较和分析。最后探讨了如何准确替代宇宙射线像素点的灰度值。 相似文献