Automatic alignment of 3D reconstructions using a Digital Surface Model

We present a novel technique for the automatic alignment of Structure from Motion (SfM) models, acquired at ground level or by micro aerial vehicles, to an overhead Digital Surface Model (DSM) using GPS information. An additional refinement step based on the correlation of the DSM height map with the model height map corrects for the GPS localization uncertainties and results in precisely aligned models. Our approach successfully handles cases where previous methods had problems, including objects on the ground, unoccupied space, and models covering a small area. We conclude our work by presenting several applications of our approach, namely the fusion of detailed SfM model information into the original DSM, season-invariant matching using aligned models, and alignment for providing context in visualization.