Luo Xingjun, Wang Changcheng, Shen Peng
School of Geosciences and Info-Physics, Central South University, Changsha 410083, China.
Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of Education, Changsha 410083, China.
Sensors (Basel). 2020 Mar 11;20(6):1555. doi: 10.3390/s20061555.
In the traditional single polarimetric persistent scatterers interferometric (PSI) technology, the amplitude dispersion index (ADI) is usually used to select persistent scatterer candidates (PSC). Obviously, based on single polarimetric information, it is difficult to use the statistical characteristics for comprehensively describing the temporal stability of scatterers, which leads to a decrease in persistent scatterer (PS) density. Considering that the temporal polarimetric stationarity of PS, the paper is based on complex Wishart distribution and proposes the polarimetric stationarity omnibus test (PSOT) for identifying PSC. The nonstationary pixels can be removed by the preset significance threshold, which reduces the subsequent processing error and the calculation cost. Then, the exhaustive search polarimetric optimization (ESPO) method is selected for improving the phase quality of PSCs while suppressing the sidelobe of the strong scatterer effectively. For validating the effectiveness of the proposed method, we select a time-series quad-polarimetric ALOS PALSAR-1 images in an urban area as experimental data and mainly perform five group experiments for detailed analysis, including the PSOT+ESPO, ADI+ESPO, ADI+HH, ADI+HV, and ADI+VV. The results show that the proposed PSOT+ESPO method has a better performance on both PSC selection and interferometric phase optimization aspects than that of other methods. Specifically, compared to the last four methods, both the PSCs and PSs identified by the proposed PSOT+ESPO are more concentrated in the high-coherence region. The PSs with the standard deviation (STD) less than 5mm in the PSOT+ESPO method account for 94% of all PSs, which is greater than that of the ADI+ESPO, ADI+HH, ADI+HV, and ADI+VV methods, respectively.
在传统的单极化永久散射体干涉测量（PSI）技术中，通常使用幅度色散指数（ADI）来选择永久散射体候选点（PSC）。显然，基于单极化信息，很难利用统计特征全面描述散射体的时间稳定性，这导致永久散射体（PS）密度降低。考虑到PS的时间极化平稳性，本文基于复Wishart分布，提出了用于识别PSC的极化平稳综合检验（PSOT）。可以通过预设的显著性阈值去除非平稳像素，这减少了后续处理误差和计算成本。然后，选择穷举搜索极化优化（ESPO）方法来提高PSC的相位质量，同时有效抑制强散射体的旁瓣。为了验证所提方法的有效性，我们选择某城市区域的一组时间序列四极化ALOS PALSAR-1图像作为实验数据，并主要进行了五组实验进行详细分析，包括PSOT+ESPO、ADI+ESPO、ADI+HH、ADI+HV和ADI+VV。结果表明，所提的PSOT+ESPO方法在PSC选择和干涉相位优化方面均比其他方法具有更好的性能。具体而言，与后四种方法相比，所提PSOT+ESPO识别出的PSC和PS更集中在高相干区域。PSOT+ESPO方法中标准差（STD）小于5mm的PS占所有PS的94%，分别大于ADI+ESPO、ADI+HH、ADI+HV和ADI+VV方法。
