ROBUST MESH WATERMARKING
Appears in ACM SIGGRAPH 99
Watermarking provides a mechanism for copyright protection of digital media
by embedding information identifying the owner in the data. The bulk
of the research on digital watermarks has focused on media such as images,
video, audio, and text.
Robust watermarks must be able to survive a variety of
"attacks", including resizing, cropping, and filtering. For resilience
to such attacks, recent watermarking schemes employ a "spread-spectrum"
approach - they transform the document to the frequency domain (e.g. using
DCT) and perturb the coefficients of the perceptually most significant
basis functions. In this paper we extend this spread-spectrum approach
for the robust watermarking of arbitrary triangle meshes.
Generalization of the spread spectrum techniques to surfaces
presents two major challenges. First, arbitrary surfaces lack a natural
parametrization for frequency-based decomposition. Our solution is
to construct a set of scalar basis function over the mesh vertices using
a multiresolution analysis of the mesh. The watermark is embedded
in the mesh by perturbing vertices along the direction of the surface normal,
weighted by the basis functions. The second challenge is that attacks
such as simplification may modify the connectivity of the mesh. We
use an optimization technique to resample an attacked mesh using the original
mesh connectivity. Results demonstrate that our watermarks are resistant
to common mesh processing operations such as translation, rotation, scaling,
cropping, smoothing, simplification, and resampling, as well as malicious
attacks such as the insertion of noise, modification of low-order bits,
or even insertion of other watermarks.
Download the paper.
[ACM SIGGRAPH 99 Proceedings. (PDF)]
[PDF 264KB] [PDF 2.1MB - 300dpi images] )
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