Two-Stage Change Detection for Synthetic Aperture Radar
Two-Stage Change Detection for Synthetic Aperture Radar
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DOI：
10.1109/tgrs.2015.2444092
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发表时间：
2015-07
影响因子：
8.2
通讯作者：
Miriam Cha;R. D. Phillips;P. Wolfe;C. Richmond
中科院分区：
文献类型：
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作者：
Miriam Cha;R. D. Phillips;P. Wolfe;C. Richmond
使用成对的合成孔径雷达（SAR）图像的相干变化检测通常是使用一个经典的相干估计，这是不变的人口的真实方差下每个成对的样本。虽然有吸引力，但这种估计是有偏差的，需要大量的样本才能产生良好的性能。增加样本大小通常会导致图像分辨率降低。因此，我们建议使用伯杰的相干估计，因为，与相同数量的像素，估计有效地增加了一倍的样本支持，而不牺牲分辨率时，基本的人口方差相等或接近相等。这种方法的一个潜在缺点是它不是不变的，因为它的分布取决于像素对人口方差。虽然伯杰的估计是固有的人口方差的不平等敏感，我们提出了一种方法，绝缘检测器从这个敏锐度。两阶段的变化统计量被引入到联合收割机组合的样本方差比，其次是替代的Berger估计，它假设人口方差相等的非相干强度变化统计。第一阶段检测器识别具有不相等方差的像素对作为由相当大的对象的位移引起的变化。在第一级中被识别为具有相等或接近相等方差的像素对被用作第二级的输入。第二阶段测试使用替代的Berger相干估计器来检测轮胎痕迹和脚印等细微变化。我们的实验表明，所提出的方法产生更高的对比度SAR变化检测图像比经典的相干变化检测器（最先进的），替代相干变化检测器，和强度变化检测器。实验结果表明了该算法在SAR变化检测中的有效性和鲁棒性。
Coherent change detection using paired synthetic aperture radar (SAR) images is often performed using a classical coherence estimator that is invariant to the true variances of the populations underlying each paired sample. While attractive, this estimator is biased and requires a significant number of samples to yield good performance. Increasing sample size often results in decreased image resolution. Thus, we propose the use of Berger's coherence estimate because, with the same number of pixels, the estimator effectively doubles the sample support without sacrificing resolution when the underlying population variances are equal or near equal. A potential drawback of this approach is that it is not invariant since its distribution depends on the pixel pair population variances. While Berger's estimator is inherently sensitive to the inequality of population variances, we propose a method of insulating the detector from this acuity. A two-stage change statistic is introduced to combine a noncoherent intensity change statistic given by the sample variance ratio, followed by the alternative Berger estimator, which assumes equal population variances. The first-stage detector identifies pixel pairs that have nonequal variances as changes caused by the displacement of sizeable object. The pixel pairs that are identified to have equal or near-equal variances in the first stage are used as an input to the second stage. The second-stage test uses the alternative Berger coherence estimator to detect subtle changes such as tire tracks and footprints. We show experimentally that the proposed method yields higher contrast SAR change detection images than the classical coherent change detector (state of the art), the alternative coherent change detector, and the intensity change detector. Experimental results are presented to show the effectiveness and robustness of the proposed algorithm for SAR change detection.