Improving TanDEM-X DEMs by Non-local InSAR Filtering

The standard TanDEM-X product meets HRTI-3 DEM specification and comes with a sample spacing of 12 m. In this paper we apply non-local means (NL) interferogram filtering to the TanDEM-X data. Our version of the NL filter is a modification of the original formulation and provides better noise reduction. Based on simulations, phase noise reduction, coherence estimation accuracy and spatial resolution of our NL filter are compared to conventional filters. Finally, the first TanDEM-X DEM with 6m resolution and low noise level is presented.