Multiple watermarking algorithm based on CDMA technique
基于CDMA技术的多水印算法

Code division multiple access(CDMA) technique was conceptually introduced to watermarking system to realize multiple watermark resolution.Before the watermark embedded,each user used his private key as a seed to generate an address code subjected to pseudorandom noise distribution.Each watermark was modulated into a carrier signal with its corresponding address code.And then these carrier signals were added to host media.During watermark detection,using the same address code,each user extracted his watermark from the detected media via calculating the correlation coefficient between address code and watermarked vector of the detected media.The experiment results show that this scheme can embed and extract watermarks independently for each user and is capable of multiple watermarking.