A New Correlation-Based Watermarking Method Using Wavelet Tree andMathematical Morphology

摘要

This paper proposes a new correlation-based watermarking method using the wavelet tree and the mathematical morphology. In this method a watermark is a two-dimensional pseudorandom array of {-1, 1} with the same size as a host image to be watermarked. The watermark is embedded into a Resilient Tree Structure (RTS) which is created by applying the mathematical morphology, the dilation operation, to the wavelet tree. The dilation operation improves the reliability of the proposed method by increasing the number of coefficients involved in watermarking. Furthermore an improved perceptual weighting function of the Human Visual System is used for preserving the image quality. In a watermark detection process the linear correlation between the watermark and the coefficients of the RTS of a tested image is computed to judge the presence of the watermark. The experimental results show that the proposed method outperforms current correlation-based watermarking methods.