A novel method for suitable selection of watermark strength in digital image watermarking based on imperialist competitive algorithm

Watermarking systems have specific feathers in accordance with their applications. In many applications transparency and robustness are needed which are the most important features. These two features are in contrast to each other and are controlled by a parameter named watermark strength. With decreasing the watermark strength, transparency of the watermarking system increases while the robustness of the watermarking system decreases and vice versa. Having these two features is not possible at the same time in a watermarking system and there should be tradeoff between transparency and robustness choosing correct watermark strength. In this paper, the imperialist competitive algorithm is used for determining the watermark strength for having transparency and robustness at the same time. The simulation results show that the imperialist competitive algorithm can propose proper watermark strength for a watermarking system with less computational complexity.