A method of watermarking with multiresolution analysis and pseudo noise sequences
Junji Onishi, Kineo Matsui · Systems and Computers in Japan · 1998
Various watermarking techniques are under development for copyright protection of image data. However, most of them cannot retain copyright data in a low bit data compression process. Our scheme offers an easy watermarking method taking advantage of multi-resolution analysis and the spread spectrum technique. Each layer of the multi-resolution approximation is spread by a PN-sequence, and a signature is embedded into the spread data. After reversing the layers, the signature is hidden in all of image data without producing visible noise in it. Therefore, the signed image is almost the same as the original image. The hidden signature remains unaffected in the image even if it is subjected to manipulations, such as filtering, re-sampling, or data compression. The pseudo noise sequence is also useful for providing random secret keys. Thus, our method provides high security copyright protection for multimedia applications. © 1998 Scripta Technica, Syst Comp Jpn, 29(5): 11–19, 1998