Watermarking technology: principles and techniques for copyright protection

WATERMARKING has become a widely used technology in the emerging field of copyright protection (Kalker, 562). According to Bloom (et al.), watermarking can be thought of as a technique for hiding information within a video that is difficult to see, and even more difficult to remove (1269). Further, Evgueni and Mendoza point out that watermarking can be applied to any media, including still images, audio clips, video clips, or any other media (2).

Miller states that watermarking is a way for the copyright owner to "mark" media, which allows identification by that owner. This identification is embedded within the media, and thus, will be transferred along with the media if it is transformed (1496).

Watermarking technology is based on three main principles. First, the watermark must be invisible to the user of the media (Hartung, 81). This generally means the watermarking scheme should be random and noise like. Since most media contains noise, this method allows the watermark to go unnoticed (Hartung, 81). Additionally, the watermark should be secure, in that only those parties authorized should be able to access the watermark (Hartung, 81). According to Mendoza, this security is best achieved by placing the watermarks using informed embedding, a process which allows the embedder to examine the original content of the media prior to placing the watermarks (2). This allows for the most secure placement of the mark (Mendoza, 2).