Effect of channel coding on the performance of spatial watermarking for copyright protection

We present a spatial-domain-watermarking scheme for data hiding and copyright protection of still images using the attack characterization approach and demonstrate the effect that the application of channel coding has on the watermark detection performance. The scheme uses techniques such as direct sequence spread spectrum modulation, perceptual analysis and diversity to maximize the robustness of the watermark while keeping it imperceptible. Furthermore, Bose-Chaudhuri-Hocquenghem (BCH) block codes and turbo codes are used to provide error protection against attacks in the watermark channel. Simulation results are provided to demonstrate the improved performance when the proposed approach is implemented with and without channel coding. The superiority of turbo codes against BCH block codes is demonstrated and some constraints involving the application of these codes to watermarking are also discussed.