A New Robust Color Digital Image Watermarking Algorithm in DCT Domain Using Genetic Algorithm and Coefficients Exchange Approach

The Internet influence is increasing in daily life as a developing technology. On the other hand, as the capacity of images, sounds and digital videos develops, the undesirable destructive and illegal copyright techniques increase. Watermarking embeds copyright information in a given media, so that it is not recognizable for human visual system. In this paper, a digital image watermarking algorithm in YCbCr color space and DCT domain is proposed that uses coefficients exchange for embedding watermark bits and Genetic algorithm to select the target Y component coefficients of the host image. One of the differences between this method and other methods of coefficients exchange is using Arnold transform to scramble the Y component of the host image in order to spread the distortions of watermarking and increase robustness against cutting attacks. Another difference is using Genetic algorithm for selecting two suitable coefficients to embed watermark bits. The third difference is in defining confidence interval variable and increasing the two coefficients distance equal to the size of this variable, hence watermarking transparency and robustness would be balanced. The evaluation results suggest that the coefficients exchange approach is improved.