Intelligent Perceptual Shaping in Digital Watermarking

With the rapid technological advancement in the development, storage and transmission of digital content, watermarking applications are both growing in number and becoming complex. This has prompted the use of computational intelligence in watermarking, especially for thwarting attacks. In this context, we describe the development of a new watermarking system based on intelligent perceptual shaping of a digital watermark using Genetic Programming (GP). The proposed approach utilizes optimum embedding strength together with appropriate DCT position selection and information pertaining to conceivable attack in order to achieve superior tradeoff in terms of the two conflicting properties in digital watermarking, namely, robustness and imperceptibility. This tradeoff is achieved by developing superior perceptual shaping functions using GP, which learn the content of a cover image by exploiting the sensitivities/insensitivities of Human Visual System (HVS) as well as attack information. The improvement in imperceptibility and bit correct ratio after attack are employed as the multi-objective fitness criteria in the GP search.