An Adaptive, Robust and Multiresolution Image Watermarking for Progressive Wavelet Image Coding

An adaptive, multiresolution watermarking approach in DWT domain is introduced. A multiresolution representation of a binary watermark is inserted into the selected coefficients of the wavelet decomposed image that represent the high activity regions of the image. In the lowest frequency subband, coefficients with maximum local variance and in the higher frequency subbands,coefficients with maximum magnitude are selected. The watermarked image is transparent according to the human vision system characteristics and robust against progressive wavelet image coding even at very low bit rates. The watermark extraction process is completely blind and multiple spatial resolution levels of the watermark are detectable from the lossy decoded watermarked image progressively. The proposed approach is a good candidate for secure progressive image transmission especially over heterogeneous networks where different end users with different capabilities (e.g. network access bandwidth) require different levels of security.