Optimization of multi-purpose watermarking algorithm

This work presents an image watermarking method for two purposes: one is to notify the copyright owner with a visible watermark, and the other is to protect the copyright with an invisible watermark. These two watermarks are embedded in different domains with different techniques. An innovative watermarking scheme based on tabu search (TS) algorithms in both the spatial domain and the transform domain is proposed. The fidelity performance of an existing image watermarking scheme is enhanced through the TS optimization. The experimental results show that the proposed techniques can improve the degraded image quality greatly. Simulation results show that the proposed method may improve the PSNR for embedding the visible watermark and enhance the robustness of the invisible watermark.