Digital Watermarking Algorithm Based on DWT-SVD

Because of the stability of singular value decomposition (SVD), many digital watermarking algorithms based on SVD are proposed[1]. This paper demonstrates that the watermarking algorithm in paper [2] have some uncertainties in the process of extracting watermark, and a new digital watermarking algorithm is proposed. After the DWT transform of the carrier image, the watermark image is decomposed by SVD, and the S matrix of the watermark is embedded into the LL of the vector image, and the U is embedded into the LH and HH sub bands. Both theoretical analysis and experimental results are indicate that improved algorithm not only has the robustness of the original algorithm, but also can eliminate the above uncertainties.