Image watermarking via sequencing wavelet filters

We propose to watermark images based on wavelet filter banks by encoding the watermark bits into the choice of the filters, in contrast to the conventional watermarking schemes. Such filters are selected from different classes in such a way that they lead to sufficiently distinguishing subbands upon different sequence of filters. A partial sorting on a chosen subband to mark the watermark existence is developed to better camouflage the watermark and to fend off certain noise injection attacks. The selection strategy of the subband coefficients for the partial sorting can be user defined and aims to achieve better imperception in the selected band. The watermark detection thus hinges on measuring the deviation of sorted coefficients specifically scattered in a targeted subband. Experiments conducted on still images and video frames show that the proposed scheme is robust to both noises and illumination changes.