中文摘要：

利用CDMA系统多址复用的特点，提出了一种基于CDMA的多重水印算法，在小波变换域中同时嵌入多个水印。对多个原始水印进行卷积编码和交织编码后，采用Gold码组进行正交扩频，经CDMA编码的水印信息被叠加嵌入在除HH1以外的其他小波子带中。水印嵌入的幅值根据Watson小波域视觉感知模型确定。嵌入位置取决于一个PN序列随机发生器，检测时不需要原始图像。在此基础上对多重水印容量进行了分析，结果表明当嵌入两个水印时，其容量大于任何一个单一水印的容量，但小于两个单一水印容量之和。

英文摘要：

According to the multiple accessing technique of Code Division Multiple Access （CDMA） system, multiple watermarks are encoded with convolution and interleaved in block. Orthogonal Gold sequences are used to spread spectrum of the copyright messages. CDMA encoded copyright messages are embedded into the wavelet sub-bands except HH1 sub-band. The embedded amplitude is decided by Watson＇s perceptual model of wavelet transform domain, and the embedded position in the selected wavelet sub-bands is decided randomly by a Pseudorandom Noise （PN） sequence. Watermarks are extracted without the need of original image. The capacity of proposed algorithm is also discussed. Experimental results show that proposed algorithm improves the detection Bits Error Rate （BER） and that multiple watermarks have preferable robustness and invisibility.