A novel method for building height estmation using TanDEM-X data

The main goal of the German TanDEM-X mission (TDM) is the provision of a global digital elevation model (DEM) at the unique spatial resolution of ~12m, which, compared to other freely available DEMs [e.g., STRM-DEM (90m), ASTER-GDEM (30m)], holds the potential to discriminate objects above the ground as, e.g., buildings. Accordingly, in this paper we present a novel unsupervised method for automatically estimating local height variations in built-up areas by means of the TanDEM-X DEM. In the first step, we identify points lying on the ground surface by means of a dedicated algorithm. In particular, the basic idea is that pixels associated with potential infrastructural elements can be identified and then excluded by analyzing the relative change in elevation with respect to their neighbors (indeed they locally exhibit greater height values with respect to ground pixels). Next, the remaining samples are used to generate a digital terrain model (DTM) of the investigated region by employing the Natural Neighbors (NN) interpolation algorithm. The local building height is finally estimated by subtracting the DTM from the original DEM. Preliminary experimental results obtained for the area of Dongying (China) which includes the Yellow River Delta (YRD) assess the effectiveness of the proposed approach and its potential to provide a reliable indication of the overall distribution of building height at large scale.