Watermarking for Copyright Protection

In recent years digital representations of images, audio and video have become increasingly popular and offer a number of advantages. The major disadvantage of digital media is that an unlimited number of perfect copies can be made and freely distributed. This poses a threat to content owners' rights and introduces the problem of copyright protection for such media. Digital watermarking has been proposed as a solution to the problem of copyright protection. The idea is that the copyright information is embedded into the media by means of a hidden watermark that is impossible to remove. This thesis proposes a blind spatial domain digital image watermarking scheme for copyright protection. The scheme is loosely based on the paradigm of spread spectrum communications whereby the narrowband watermark is spread to a wideband signal using an m-sequence and the spread spectrum watermark is directly embedded into the image data. The retriever uses cross correlation techniques to retrieve the embedded watermark. Although the proposed scheme is functional, producing an imperceptible watermark, it is not robust to common image processing techniques without embedding a watermark with such high amplitude that the image quality is degradedSchool of Computing, Communications and Electronic