Digital elevation models of underwater structures from UAV imagery

The paper presents a workflow for the generation of digital elevation models (DEMs) of underwater areas from aerial images. Standard software products do not provide the possibility to triangulate correctly through refractive interfaces, such as water. Known procedures are based on oriented images and known water levels with DEM determination via forward intersection based on reconstructed image ray paths (ray tracing). In this article an integrated procedure for image orientation as well as DEM extraction from aerial imagery containing both land and underwater areas is presented. The proof of concept was done by capturing UAV imagery of shallow water areas of a high-alpine lake in the Swiss Alps. The processed data set will be presented and the extraction and matching of image points observed through water are discussed. The accuracy potential as well as practical limitations of processing multimedia data are analysed.

UAV | DEM | underwater | multimedia | bundle adjustment