Image Watermarking by Wavelet Decomposition

Digital watermarking has been increasingly recognized as a highly effective means of protecting the intellectual property rights associated with multimedia data. Based on the multiresolution structures of wavelet decomposition, both on a real field and binary field, a multiresolution watermarking technique will be proposed. Since the Human Visual System (HVS) inherently performs a multiresolution structure, each decomposed layer of a binary watermark is embedded into the corresponding decomposed layer of a host image. Therefore, in case of attacks or progressive transmission, the coarser approximation of a watermark is preserved in the coarser version of an image. In a progressive transmission, adding higher frequency components, allows us to obtain higher resolution image, and, correspondingly, extract a higher resolution watermark. Experimental results demonstrate the robustness and validity of the watermarking process proposed herein.