Digital watermarking: applications, techniques and challenges

The explosive growth in the use of the Internet has made it an attractive medium for the distribution of multimedia material. However, it has become apparent that the digital nature of such material makes enforcement and proof of copyright ownership virtually impossible. Another problem with digital images and video is that undetectable modifications can be made with very simple and widely available equipment. As a result, the use of digital material for evidential purposes has been called into question at a time when the video surveillance industry is moving towards digital rather than analogue systems. Digital watermarking promises to address these issues. Different types of watermarking systems exist for different applications robust watermarks for copyright protection and fragile watermarks for integrity checking applications. The question is just how good are current digital watermark techniques and what are the issues surrounding their use in real-life situations?.