A robust audio watermarking scheme

Spread-spectrum watermarking scheme adds random noise w into the host signal x to generate watermarked signal s. Blind detector computes inner product 〈w, s〉 or its variants (i.e., correlation) and decides if the host signal contains embedded bits or not by its sign of the inner product. Such detection method may not be sufficiently robust in some applications due to high false-positive or false-negative rate. This paper introduces a novel method to reduce detection errors considerably by excluding outliers in the signal. First, this paper identifies the usefulness of the outliers. Second, this paper identifies the problem of outliers. Due to the vague definition of outlier, it was impossible to draw unique criterion for outlier. Thus, third, stable and robust definition of outlier is adopted. Informed watermarking scheme for spread-spectrum is exploited to reduce false-positive and false-negative errors. Such detectors can also enhance detection rate in other watermarking schemes. This scheme can enhance robustness of image watermarking and audio watermarking as well.