Novel Invisible Watermarking for Various Images using HWT- GA-PSO based Hybrid Optimization

In this paper a novel invisible robust watermarking scheme for embedding and extracting a digital watermark in an image is presented. The novelty lies in determining perceptually important coefficients of transform in the host image using simple Haar Wavelet Transform (HWT) and Genetic Algorithm(GA)-Particle Swarm Optimization(PSO) based hybrid optimization. Invisible watermark is embedded such that it does not destroy or degrade the esthetic quality and value of the image. The proposed method is found more suitable for copyright protection as it is more imperceptible and robust than purely wavelet transform based or DCT-PSO based or only DWT-GA or DWT-PSO based watermarking techniques. The horizontal and vertical sub bands are selected for embedding watermark. In order to have a watermarked image with the best possible quality, GA-PSO is used to find the best DWT coefficients for embedding the watermark sequence. The method exhibits impressively high PSNR values as compared with previous techniques. It has been found that the method works well with the standard image processing database images as well as standard medical images the method shows high performance for black and white as well as colour images. HWT-GA-PSO based hybrid optimization method is shown to be robust against many signal processing operations. Keywords— HWT-Haar Wavelet Transform, HPSO-Hybrid PSO, HWT-GA-PSO : Haar Wavelet TransformGenetic Algorithm-Particle Swarm Optimization, GPSO-Gentic Algorithm and PSO,DCT-PSO: Descrete Cosine Transform and Paricle Swarm Optimization, DWT-PSO: Discrete Wavelet transform and Particle Swarm Optimization