Robust digital image watermarking using singular value decomposition

This paper presents a blind robust digital image watermarking scheme based on singular value decomposition in wavelet domain for copyright protection. The proposed algorithm inserts bits of singular values of the watermark image in the wavelet coefficients of the host image. In the first step, the wavelet coefficients of each sub-band of the transformed image are grouped into 2×2 blocks. These blocks are sorted according to the defined sequence of singular values of watermark image embedding. To access to bits, we define an algorithm which converts the entries of each wavelet block and the singular values of grey-scale watermark image to new defined semi-binary arrays. Then, the bits of singular values of the watermark are inserted into the arrays of the blocks entries. Finally, the new entries of each block are constructed to make the watermarked image. The experimental results show that the proposed method is more robust against different attacks and the watermarked image has good transparency.