Digital watermarking using complex wavelets

We propose a blind watermarking algorithm in the complex wavelet domain. We discuss why complex wavelets are preferable to real ones in terms of image adaptability and comment on the precautions required in embedding watermarks in an oversampled domain like the complex wavelet transform. A simple but effective human visual model in the complex wavelet domain is described. By modelling watermarking as a communication process, our results also show that this domain has higher capacity than the real wavelet and spatial domains, hence that complex wavelets provide a potentially good domain for watermarking.