CDMA based blind and reversible watermarking scheme for images in Wavelet domain

Digital watermarking is a well known technique used for copy rights protection of multimedia data. The biggest disadvantage of general watermarking schemes is that they permanently distort original data. Reversible watermarking techniques allow the restoration of original data, after watermark detection. A blind robust and reversible watermarking algorithm based on CDMA is proposed in this paper. Watermark is arithmetically added in the proposed CDMA based watermarking scheme. Therefore, it is not difficult to remove it after detection. In proposed algorithm, spreaded watermark is added to frequency coefficients in Discrete Wavelet domain. Watermark is extracted by using spreading codes only. After extraction, the watermark can be removed from watermarked data only by using same spreading codes. Furthermore, the original watermark is not required during watermark removal process.