Digital watermarking systems are required to embed as much information as possible in a digital media without the perceptual distortion as well as to extract it correctly with high probabilities even though the media is subjected to many kinds of operations. To this end, guided scrambling (GS) techniques, usually used for a recording channel, are applied to digital watermarking systems. A simple GS scheme can make the power of a watermark signal larger against the power of media noise under the condition of preserving the perceptual fidelity, resulting in smaller error probabilities of the retrieved watermark bits. In addition, watermarking systems based on the GS can have more robustness to some specified operations if the prior information on the operations is given to the embedder. JPEG compression is a good example of such an operation when still images are transmitted over the Internet. In order for watermark signals to be more tolerable to the known JPEG attack, the GS-based watermark embedder having advance knowledge of the JPEG compression is realized. Further, the GS concatenated with turbo coding is introduced to lower the bit error rate more.
Akiomi Kunisa, Akiomi Kunisa,
"Informed digital watermark embedding based on guided scrambling", Proc. SPIE 5020, Security and Watermarking of Multimedia Contents V, (20 June 2003); doi: 10.1117/12.473121; https://doi.org/10.1117/12.473121