Optimal Detector for Multiplicative Watermarks Embedded in the DFT Domain of Non-White Signals

This paper deals with the statistical analysis of the behavior of a blind robust watermarking system based on pseudorandom signals embedded in the magnitude of the Fourier transform of the host data. The host data that the watermark is embedded into is one-dimensional and non-white, following a specific probability model. The analysis performed involves theoretical evaluation of the statistics of the Fourier coefficients and the design of an optimal detector for multiplicative watermark embedding. Finally, experimental results are presented in order to show the performance of the proposed detector versus that of the correlator detector.