A Robust Watermarking Method for Copyright Protection of Digital Images using Wavelet Transformation

Abstract

A multiresolution wavelet transformation based robust watermarking method is introduced. The coefficients of watermark are embedded into those of host image at different transformation level using a secret key. Watermark is extracted using the same key and by inverse transformation at each level. Finally, the watermark is estimated by taking mean value of the obtained watermarks. The introduced method is tested on gray and color images with added Gaussian, salt and pepper, Speckle, and JPEG noises. Correlation coefficients are used to compare the embedded and extracted watermarks. Comparison result with an earlier work is presented.