A Maximum Likelihood Watermark Decoding Scheme
This conference paper was originally published as Lu, W, Li, W, Safavi-Naini, R, Ogunbona, P, A Maximum Likelihood Watermark Decoding Scheme, 2007 IEEE International Conference on Multimedia and Expo ICME 2007, Beijing, 2-5 July 2007, 1247-1250. The original paper is available here.
Based on the observation that an attack applied on a watermarked image, from a decoding point of view, modifies the distribution of the detection values away from the ideal distribution (without attack) for corresponding watermarking scheme, we propose a generic maximum likelihood decoding scheme by approximating the distribution with a finite Gaussian mixture model. The parameters of the model are estimated using expectation-maximization algorithm. The scheme allows the decoding to be automatically adapted to attacks that the watermarked images have undergone and, in consequence, to improve the decoding accuracy. Experiments on a QIM based watermarking system have clearly verified the significant improvement of the decoding accuracy achieved by the proposed maximum likelihood decoding in comparison to conventional threshold decoding
W. Lu, W. Li, R. Safavi-Naini, and P. Ogunbona. "A Maximum Likelihood Watermark Decoding Scheme" Faculty of Informatics - Papers (2007).
Available at: http://works.bepress.com/rsafavinaini/27