Wavelet Analysis Based Blind Watermarking for 3-D Surface Meshes

As most previous

wavelet analysis

based

3-D mesh watermarking

methods embed the watermark information into wavelet coefficients arranged in a certain order, they have not been used as

blind schemes

since the connectivity information must be exactly known in the watermark extraction process. In this paper, we propose a blind watermarking method based on wavelet analysis for 3-D mesh model. Two new techniques are introduced. One is to exploit the

statistical features

of

scale coefficients

on an approximation (low resolution) level for watermark embedding. Another is to extract the hidden watermark, not from the same resolution level as used in embedding process, but directly from the spatial domain. As the proposed watermark detection does not require the wavelet analysis, any pre-processing such as registration and re-sampling, is not needed. These techniques allow to detect the watermark without referring to the original meshes. In addition, the proposed are applicable directly to

irregular meshes

by using irregular wavelet analysis. Through simulations, we prove that our method is fairly robust against various attacks including topological ones.