A multiple copyright identification watermarking algorithm based on code division multiple access  

作　　者：张帆 li Jie Su Yuting Zhang Chuntian 

机构地区：[1]College of-Computer ＆ Information Engineering, Henan University, Kaifeng 475001 P. R. China [2]College of Electronic ＆ Information Engineering, Tianjin University, Tianjin 300072, P.R. China

出　　处：《High Technology Letters》2008年第4期377-383,共7页高技术通讯（英文版）

基　　金：the National High Technology Research and Development Programme of China(No 2006AA01Z407,No.2007AA01Z478);the Postdoctoral Science Foundation of China(No.20070420707)

摘　　要：A multiple watermarking algorithm is presented according to the multiple accessing technique of the code division multiple access （CDMA） system. Multiple watermarks are embedded into digital images in the wavelet transform domain. Each of the watermarks is embedded and extracted independently without impacts to each other. Multiple watermarks are convolution encoded and block interleaved, and the orthogonal Gold sequences are used to spread spectrum of the copyright messages. CDMA encoded water-mark messages are embedded into the wavelet sub-bands excluding the wavelet HH1 sub-bands. The embedment amplitude is decided by Watson＇ s perceptual model of wavelet transform domain, and the embedmeut position in the selected wavelet sub-bands is decided randomly by a pseudo-random noise （PN） sequence. As a blind watermm＇king algorithm, watermarks are extracted without original image. The watermarking capacity of proposed algorithm is also discussed. When two watermarks are embedded in an image at the same time, the capacity is larger than the capacity when a single watermark is embedded, and is smaller than the sum of the capacity of two separately embedded watermarks. Experimental results show that the proposed algorithm improves the detection bits error rate （BER） observably, and the multiple watermarks have a preferable robustness and invisibility.A multiple watermarking algorithm is presented according to the multiple accessing technique of thecode division multiple access (CDMA) system.Multiple watermarks are embedded into digital images inthe wavelet transform domain.Each of the watermarks is embedded and extracted independently withoutimpacts to each other.Multiple watermarks are convolution encoded and block interleaved,and the or-thogonal Gold sequences are used to spread spectrum of the copyright messages.CDMA encoded water-mark messages are embedded into the wavelet sub-bands excluding the wavelet HH1 sub-bands.The em-bedment amplitude is decided by Watson's perceptual model of wavelet transform domain,and the em-bedment position in the selected wavelet sub-bands is decided randomly by a pseudo-random noise (PN)sequence.As a blind watermarking algorithm,watermarks are extracted without original image.The wa-termarking capacity of proposed algorithm is also discussed.When two watermarks are embedded in animage at the same time,the capacity is larger than the capacity when a single watermark is embedded,and is smaller than the sum of the capacity of two separately embedded watermarks.Experimental resultsshow that the proposed algorithm improves the detection bits error rate (BER) observably,and the multi-pie watermarks have a preferable robustness and invisibility.

关 键 词：code division multiple access （CDMA） WATERMARKING convolutional coding 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]