Abstract:

In order to protect the copyrights of digital products, a color watermarking algorithm based on lifting wavelet transform (LWT) and singular value decomposition(SVD) is proposed. The LWT is quick and it is suitable for any size of image. The SVD has geometrical invariances and it shows the intrinsic characteristics of the image. This algorithm makes use of the characteristics of the LWT and the SVD, and chooses the blue channel of the color image to embed watermarking. The algorithm firstly uses multilevels LWT on the original image, secondly applies the SVD on low frequency subband and middle frequency subbands, thirdly uses Arnold to scramble the grayscale watermarking, and finally divides it into four parts that are embedded into the singular values matrices .It does not need the original image when the watermarking is extracted, so it can be better applied into the practice. The experiment shows that the algorithm has good transparency and robustness to common attacks and geometric attacks.

Key words: digital watermarking;singular value decomposition;lifting wavelet transform(LWT);transparency;robustness