摘要
数字水印问题研究中,DCT块效应是困扰版权保护的一大难点.结合小波特性,提出一种改进的层式DCT算法,并应用于数字水印.将DCT变换后所得子块的低中频系数分别抽样,然后将水印信息的变换域量值分别叠加到原始载体经改进的层式DCT变换后的低中频系数中,同时对改进的层式DCT变换的分层层数进行了研究.实验结果表明,水印方案具有很好的整体去方块效应,提高了水印的不可见性,对抗压缩、剪切等常规几何攻击具有较强的鲁棒性,并且两者之间达到了一个较好的平衡.进一步扩大了层式DCT的实际应用.
In the research of digital watermark,blocking-artifact problem is a very big difficulty of copyright protection.An improved layer DCT algorithm is proposed based on wavelet features,and it is applied to the digital watermark.The low-frequency and middle-frequency coefficients were extracted after DCT transform and reconstructed by the spatial position.The digital watermark was embedded in low-frequency and middle-frequency domain,and the number of layers which should be chosen was researched.The result shows that the improved layer DCT algorithm does well in removing the blocking artifact,and satisfies the request of invisibility.The improved layer DCT algorithm has better robustness with the attacking experiments,and the practical application of layer DCT is enlarged.
出处
《微电子学与计算机》
CSCD
北大核心
2012年第2期103-106,共4页
Microelectronics & Computer
基金
甘肃省自然科学基金(0803RJZA109)
甘肃省自然科学研究基金计划(1010RJZA019)
甘肃省科技攻关项目(2GS052-A052-011)
关键词
数字水印
抽样
子带
鲁棒性
不可见性
digital watermarking
sampling
sub-bands
robustness
invisibility