Distortion measure of watermarking 2D vector maps in the mesh-spectral domain

The two main properties of digital watermarking algorithms for 2D vector data are robustness against attacks and minimization of the original data distortion. This paper proposes conformal energy as a measure of original data distortion to quantify the second property. We modify the watermarking algorithm proposed by Ohbuchi et al., which is, to the best of our knowledge, the most robust one against attacks. Experiments show that the modified algorithm is as resistent against random noise as the original one, but has smaller angle distorsion.