A wavelet-based watermarking for still images [articol]

Abstract

We present a robust watermarking method for still images, which uses the similarity of the discrete wavelet transform (DWT) and the human visual system (HVS). In order to make the mark imperceptible, the lowest frequencies are left unmodified, and the rest of the coefficients from the other sub-bands are spatially selected using an adaptive threshold. We test the robustness of the mark against different types of attacks, thus evaluating the robustness of the method proposed herein. We compare our performances with another frequency-based watermarking method.