Watermarking via zero assigned filter banks

Cataloged from PDF version of article.In order to identify the owner and distributor of digital data, a watermarking scheme in frequency domain for multimedia files is proposed. The scheme satisfies the imperceptibility and persistence requirements and it is robust against additive noise. It consists of a few stages of wavelet decomposition of several subblocks of the original signal using special zero assigned filter banks. By assigning zeros to filters on the high frequency portion of the spectrum, filter banks with frequency selective response are obtained. The information is then inserted in the wavelet-decomposed and compressed signal. Several robustness tests are performed on male voice, female voice, and music files, color and gray level images. The algorithm is tested under white Gaussian noise and against JPEG compression and it is observed to be robust even when exposed to high levels of corruption. & 2009 Elsevier B.V. All rights reserve

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

An image watermarking algorithm via Zero Assigned Filter Banks

In this paper a new method for digital image watermarking based on Zero Assigned Filter Banks and Embedded Zero Tree Wavelet (EZW) algorithm is presented. An image is partitioned into 128 × 128 subblocks and each block is processed in a three stage decomposition structure by a filter bank which is assigned a zero around the stop band. The coefficients to be marked are chosen according to the EZW algorithm. This method not only provides a robust watermarking scheme but may also be used as an effective compression strategy. The algorithm is tested under white Gaussian noise and against JPEG compression and it is observed to be robust even when exposed to high levels of corruption. © 2005 IEEE