Genetic swarm based robust image watermarking

Abstract

This paper presents a new method for adaptive watermark strength optimization in Discrete Cosine Transform (DCT) domain. Watermarking is a method to embed secret information in the host medium. Optimal sub-band and strength selection for watermark is the most critical aspect in the whole process and it had attracted many researchers in the recent past. In the proposed method, DCT sub-band is selected using Genetic Algorithm (GA) and watermark strength is intelligently selected through Particle Swarm Optimization (PSO). GA performs well at exploring a vast search space and it selects the suitable sub-band for watermark embedding. Perceptual shaping of the watermark is done in such a way that watermark embedding is imperceptible to the human visual system. The proposed method shows promising results against different attacks, such as low-pass filter, high-pass filter, median filters, shifting and cropping the marked image. Further, experimental results have shown better performance of the proposed method as compared with the current approaches in practice.