A performance analysis of spread-spectrum watermarking based on redundant transforms

Spread-spectrum watermarking, in which random noise is added to transform coefficients and detected with a correlation operator, has become a preferred paradigm for many watermarking applications. This paper analyzes the performance of such a watermarking system when the underlying transform is a tight frame rather than a traditional orthonormal expansion. The analysis indicates that a tight frame offers no inherent performance advantage over an orthonormal transform in the watermark-detection process despite the well known ability of redundant transforms to accommodate greater amounts of added noise for a given distortion.