Digital Watermarking Algorithm Based on Discrete Wavelet Transform and Singular Value Decomposition
Qing Qi · China Printing and Packaging Study · 2012
Nowadays,copyright protection of digital works has gained more and more attention.Digital watermarking is an effective way to protect copyright of digital works.In this paper,the problem of embedding the larger capacity watermarking into an image was studied,and a robust algorithm based on Discrete Wavelet Transform(DWT) and Singular Value Decomposition (SVD) for watermarking grayscale images was proposed.Firstly,a host image was decomposed by DWT into four sub -bands,namely,LL,LH,HL and HH.Next,the diagonal matrix S~t of the low -frequency LL image and the diagonal matrix S~w of the watermarking image were gained by SVD respectively.Then,S~l and S~w were superposed together to accomplish watermarking embedding.The outstanding features of the proposed algorithm are that it provides larger watermarking capacity and is more robust than others.Experiments showed that the proposed approach is robust against most of usual attacks, such as Gaussian Noise,Salt Pepper,rotation,etc.