CDMA watermarking algorithm based on wavelet basis

A new digital CDMA watermarking algorithm based on orthogonal wavelet basis is proposed in this paper. Harr wavelet basis is changed into a multilevel orthogonal sequence by scaling and translation, which is used to encode the binary image. Then the CDMA encoded watermark is adaptively embedded into the third level detail sub-images of DWT domain. On the extraction of embedding and detecting algorithm for theoretical analysis and discussion, in MATLAB simulation environment where experiments, theoretical analysis and experimental results show that the capacity of the hidden information is raised and the security is enhanced. Compared with Hadamard sequence and improved gold sequence in the simulation, the multilevel sequence performs better than binary sequence in attack-resistance. It shows that the robustness of watermarking algorithm with strong, with large watermarking capacity and performance is better.