| Abstract | Digital elevation maps (DEMs) provide a digital representation of 3-D terrain information. In civilian appli-cations, high-precision DEMs carry a high commercial value owing to the large amount of effort in acquiring
them; and in military applications, DEMs are often used to represent critical geospatial information in sensitive
operations. These call for new technologies to prevent unauthorized distribution and to trace traitors in the event
of information leak related to DEMs. In this paper, we propose a new digital fingerprinting technique to protect
DEM data from illegal re-distribution. The proposed method enables reliable detection of fingerprints from both
3-D DEM data set and its 2-D rendering, whichever format that is available to a detector. Our method starts
with extracting from a DEM a set of critical contours either corresponding to important topographic features
of the terrain or having application-dependent importance. Fingerprints are then embedded into these critical
contours by employing parametric curve modeling and spread spectrum embedding. Finally, a fingerprinted
DEM is constructed to incorporate the marked 2-D contours. Through experimental results, we demonstrate
the robustness of the proposed method against a number of challenging attacks applied to either DEMs or their
contour representations.
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