Block-based digital image watermarking using Genetic Algorithm

This paper introduces a new method of adaptive blind digital image watermarking in spatial domain. Watermarking is a way to hide secret information in a cover image or host medium. Amount of information to hide in the cover image is limited because there is a trade-off between imperceptibility and payload of the data to hide. So increasing the payload in the cover image while watermark remain imperceptible is a critical aspect in watermarking process and has attracted many researchers in the recent past. In the proposed method both cover and secret images are partitioned into equal size blocks. Then host for each secret image block is intelligently selected through Genetic Algorithm (GA). GA helps in identifying the target blocks of the cover image such that with the LSB embedding, visual quality of the cover image and imperceptibility of secret image remains least affected. At the watermark extraction phase only watermarked image is required from which using Jigsaw Puzzle Solver (JPS) the secret image is reconstructed. In spite of increasing the payload 2 times experimental results have shown better imperceptibility i.e. PSNR results of the proposed method as compared to the current approaches in this domain.