Ownership Protection on Digital Elevation Model (DEM) Using Transform-Based Watermarking

This research aims to protect Digital Elevation Model (DEM) data from piracy or counterfeiting. An invisible watermark inserted into the data, which will not considerably change value, is necessary. The proposed method involves use of two-dimensional discrete cosine transform (2D DCT), a combination 2D DCT and wavelet (DWT), Fourier DFT) in frequency domain. used include National DEM file downloaded geoportal Geospatial Information Agency (Badan Informasi Geospasial—BIG). Three files represent mountainous, lowland/urban, coastal areas. “attack” also conducted on watermarked by cropping. results indicate that well recognized. can be read 100% for DCT, while DFT 90.50%. distortion value elevation under technique demonstrates smallest maximum 0.1 m compared with 4.5 1.1 DCT–DWT. Meanwhile, height difference (Max Delta), peak signal-to-noise ratio, root mean squared error (RMSE) are highest lowland, areas, respectively. Overall, superior the2D Although only one recognize nine watermarks each sheet, DEMs attacked cropping process still identified. However, this finding sufficiently confirm belong BIG.