Multi-baseline interferometric synthetic aperture radar (InSAR) techniques are effective approaches for retrieving the 3-D information of urban areas. In order to obtain a plausible reconstruction, it is necessary to use large-stack interferograms. Hence, these methods are commonly not appropriate for large-scale 3-D urban mapping using TanDEM-X data where only a few acquisitions are available in average for each city. This work proposes a new SAR tomographic processing framework to work with those extremely small stacks, which integrates the non-local filtering into SAR tomography inversion. The applicability of the algorithm is demonstrated using a TanDEM-X multi-baseline stack with 5 bistatic interferograms over the whole city of Munich, Germany. Systematic comparison of our result with airborne LiDAR data shows that the relative height accuracy of two third buildings is within two meters, which outperforms the TanDEM-X raw DEM. The promising performance of the proposed algorithm paved the first step towards high quality large-scale 3-D urban mapping.

翻译：多基线干涉合成孔径雷达（InSAR）技术是获取城市区域三维信息的有效方法。为获得可靠的形貌重建，通常需要采用大堆栈干涉图，因此这些方法一般不适合利用TanDEM-X数据开展大规模三维城市制图——该数据在每个城市平均仅提供少数几景影像。本研究提出一种新型SAR层析处理框架，通过将非局部滤波集成到SAR层析反演中，以应对此类极小堆栈数据。利用覆盖德国慕尼黑全城的5幅双基干涉图构成的TanDEM-X多基线堆栈，验证了该算法的适用性。将结果与机载LiDAR数据进行系统性对比表明，三分之二的建筑物相对高度精度优于两米，性能优于TanDEM-X原始数字高程模型。该算法展现的优异性能迈出了实现高质量大规模三维城市制图的第一步。