Biobjective NSGA-II for optimal spread spectrum watermarking of color frames: Evaluation study
We describe a new watermarking scheme based on intelligent shaping of a digital watermark using Genetic Programming (GP). The proposed method, in addition to achieving a superior tradeoff between watermark robustness and imperceptibility, is also able to structure the watermark in accordance with an anticipated attack. This has been achieved by simultaneously hiding the watermark as well as spreading and fusing it in such a way to resist the conceivable attack. Robustness versus imperceptibility tradeoff and increase in bit correct ratio after attack, have been employed as the optimization criteria in the GP search. The concept of bonus fitness has been used to implement multi-objective fitness based GP evolution. Experiments on standard images indicate that such watermark shaping functions could be developed that are cover image independent and enhance imperceptibility. They offer high resistance against removal and interference attacks of Checkmark benchmark. 2005 Elsevier B.V. All rights reserved.