Optimal transform domain watermark embedding via genetic algorithms

The requirements that are needed for an effective watermarking system are application dependent. However, some of these requirements are common to most practical applications; namely, robustness and image quality. Unfortunately, these requirements compete with each other. In the transform-domain watermarking techniques, embedding the watermark into the higher frequency coefficients is not robust, although the watermarked image quality is assured. In contrast, embedding the watermark into the lower frequency coefficients is more robust against common attacks such as low pass filtering and lossy compression but it would cause the resulting watermarked image quality greatly degrades to compare with the original image. In this paper we make use of genetic algorithms (GA) to find the optimal frequency bands for watermark embedding into a DWT-based watermarking system, which can simultaneously improve security, robustness, and image quality of the watermarked image.