Improving the performance of wavelet domain spread spectrum watermarking systems using space-time block codes

In this paper, we propose to use Alamouti´s orthogonal space-time block code to improve the performance and the robustness of the spread spectrum watermarking systems. After employing a space-time block code, we embed the coded watermark sequence into the host image in discrete wavelet transform domain. Simulation results show that the use of the space-time block codes considerably increases the robustness of the spead spectrum watermarking system under various attacks.