Redundant-wavelet watermarking with pixel-wise masking

An algorithm is presented which implements image watermarking in the domain of an overcomplete, or redundant, wavelet transform. This algorithm expands on a previous method which employs a traditional, critically sampled wavelet transform coupled with perceptually-based watermark casting and optimal Neyman-Pearson detection. Specifically, in the proposed method, the redundancy inherent in the transform facilitates detection of perceptually salient texture local to a given spatial location and guides the placement of watermarking energy so as to minimize the impact on perceptual image quality. Additionally, the optimal detection strategy is adjusted to account for the overcomplete ness of the transform. The performance of the proposed technique is compared to that of its critically sampled counterpart and greater robustness under attack by compression is observed.