3 research outputs found
Wavelet packet based digital watermarking
International audienceWe present a method for digital image watermarking based on the modification of certain subsets of the wavelet packet decomposition. These subsets are determined both from a secret key and an image dependent procedure that chooses a best basis from an energy criterion. The mark is set by imposing a parity constraint at each level of the decomposition. We elaborate on the choice of some of the parameters of the model, showing how they can be tuned so as to obtain good resistance to attacks. Examples are displayed to assess the validity of our approach
Watermarking via zero assigned filter banks
Cataloged from PDF version of article.A watermarking scheme for audio and image files is proposed based on wavelet
decomposition via zero assigned filter banks. Zero assigned filter banks are perfect
reconstruction, conjugate quadrature mirror filter banks with assigned zeros
in low pass and high pass filters. They correspond to a generalization of filter
banks that yield Daubechies wavelets.
The watermarking method consists of partitioning a given time or space signal
into frames of fixed size, wavelet decomposing each frame via one of two filter
banks with different assigned zeros, compressing a suitable set of coefficients in
the wavelet decomposition, and reconstructing the signal from the compressed
coefficients of frames. In effect, this method encodes the bit ‘0’ or ‘1’ in each
frame depending on the filter bank that is used in the wavelet decomposition of
that frame.
The method is shown to be perceptually transparent and robust against channel
noise as well as against various attacks to remove the watermark such as denoising,
estimation, and compression. Moreover, the original signal is not needed
for detection and the bandwidth requirement of the multiple authentication keys
that are used in this method is very modest.Yücel, ZeynepM.S