Tampering Resistant Dual Watermarking Method for Copyright Protection of Still Images

摘要

Rapid growth in the number and types of devices accessing the Internet from anywhere, anytime has greatly enhanced the accessibility and distribution of digital media content. Digital media has several inherent advantages such as ease of use, easy reproduction and distribution, etc. However, digital media is still not secure enough for an explosive growth in making it available online. It is not easy to prove the ownership of digital media and some of the existing security controls can easily be defeated. Digital watermarking has emerged as a preferred solution to tackle some of these security challenges. In this paper, a dual watermarking method, resistant to tampering attacks, is proposed which embeds copyright information (watermark) in metadata as well as pixel data. Metadata is non-pixel data and offers more robustness to attacks such as cropping, noising, etc. However, metadata can be dropped automatically by image editing softwares. In such cases, watermark is recovered from pixel data. Experiments have been carried out by tampering the watermarked image to check the robustness of proposed method. Simulation results show the efficiency of the proposed method.