Adaptive watermark strength selection using Particle Swarm Optimization

Abstract

This study investigates 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 strength selection for watermark is the most critical aspect in the whole process and it had attracted many researchers, recently. In the proposed method watermark strength is intelligently selected through Particle Swarm Optimization (PSO). PSO helps in perceptual shaping of the watermark such that it is less perceivable to the human visual system. Proposed method shows promising results against different attacks, such as low-pass filter, high-pass filter, median filters, shifting and cropping the marked image. Experimental results for quantitative measures of imperceptibility, i.e. Peak Signal to Noise Ratio (PSNR) and Structure Similarity Index Measure (SSIM) are presented. Robustness and imperceptibility tests reveal better performance of the proposed method than the current approaches in practice. ICIC International © 2010 ISSN 1881-803X.