Technical Challenges for Digital Watermarking

The field of digital watermarking has recently seen numerous articles covering novel techniques, theoretical studies, attacks and analysis. In this paper, we focus on technical as well as practical challenges for digital watermarking applications. Challenges include design considerations, requirements analysis, and choice of watermarking techniques, speed, robustness and the tradeoffs involved. Data hiding, a form of steganography embeds data into digital media for various purposes. The technical and practical challenges for data hiding are formidable. Any perforations to fill with data in a host signal, either statistical or perpetual, are likely targets for removal for lossy signal compression. The key to successful data hiding is the finding of holes that are not suitable for exploitation by compression algorithms. A further challenge is to fill these holes with a data in a way that remains invariant to a large class of host signal transformations. This paper lays emphasis on some of the technical as well as practical challenges, which a watermarking process encounters. The article throws light on how much to add and where, spread spectrum communication, properties of visual signals, just noticeable difference (JND), properties of human visual system (HVS)