【摘要】 在小波包变换(WPT)和离散余弦变换(DCT)分析的基础上,结合码分多址(CDMA)技术,提出了一种基于小波包变换和离散余弦变换的CDMA数字水印算法.该算法首先对二值图像水印作预处理置乱,再用Gold序列对其进行扩频,形成互相叠加的CDMA编码水印,然后对原始宿主图像进行小波包分解,将编码水印嵌入到图像各个分解层分量的DCT域中.试验结果表明,所提出的算法在保证图像具有良好的可视化的同时,还具有较强的鲁棒性和较大的水印嵌入容量.更多还原

【Abstract】 Wavelet packet transforms(WPT) and discrete cosine transform(DCT) were analyzed.Combined with code division multiple access(CDMA) watermarking algorithm was proposed with the help of WPT and DCT.The binary image watermarking was re-processed and turned the confusion.Then the orthogonal Gold sequences were used to spread spectrum of the watermark.After the host image was decomposed by wavelet package transform,the CDMA encoded watermark was embedded into the DCT domain of corresponding decomposed layer of the host image.The experiment results demonstrate that the proposed algorithm ensures the good visualization on the image,and provides the higher embedding capacity as well as the more robust against attack.更多还原