Hybrid Watermark System for Color Images based on DCT, DWT and Kohonen Network

Abstract

Digital watermarking is the process of embedding data into multimedia such as image, audio, and video to protect the digital content from counterfeiting and stealing. In this paper, the hybrid algorithm is proposed by using discrete wavelet transform (DWT) and discrete cosine transform (DCT) with generation a secret key to determine locations of the cover which used in embedding and extracting the watermark depended on Kohonen network. The aim of the study is to achieve higher robustness and imperceptibility by applying more than one transform domain operation on the host image. The proposed method attempts to choose the best from discrete wavelet transform and discrete cosine transform techniques based on their individual suitability to distinct regions in the image. Results have shown that the proposed method provides images with good quality after embedding the watermark. The efficiency is measured using PSNR and NC.