Robust Detection for Additive Watermarking in the DCT-Domain Using Approximate Alpha-Stable Model

This paper presents a robust additive watermark detector in the discrete cosine transform (DCT) domain. The proposed approach uses the approximate alpha-stable distributions to model AC DCT coefficients with distinct impulse distributional behavior. More specifically, the scale mixture of Gaussians as an analytical approximation of alpha-stable distribution is employed. Based on the theory of statistical inference and weak signal detection in non-Gaussian noise, a robust blind detection algorithm is derived. And the validity of the detector is also tested.