基于高容量强鲁棒的图像水印算法

High-capacity and robust image watermarking algorithm

提出一种可靠的数字水印技术,首次对水印图像采用半色调和四叉树技术进行预处理,将内容的位置信息提取出来作为实际的嵌入值;载体图像进行离散小波变换(DWT),对高频子图进行8×8分割和最佳离散余弦变换(DCT)操作;信息嵌入到DCT变换矩阵失真最小的位置。在提取水印时,通过系数矩阵最佳位置数据对的比较规则,准确提取出水印内容的位置信息,进而恢复水印图片。仿真实验分析表明,本文算法不仅能够提高水印的有效嵌入量和鲁棒性,而且在剪切、噪声、JPEG压缩和过滤等常规攻击中具备较强的抗攻击能力。

This paper presents a reliable digital watermarking technique.For the first time,the watermark image is preprocessed by halftone and quad tree techniques,and the position information of the content is extracted as the actual embedded value.The cover image is processed by Discrete Wavelet Transform(DWT),and then the high frequency sub-band is divided into blocks,sized by.The blocks were processed by an optimal Discrete Cosine Transform(DCT)psychovisual threshold.Embedding process in this paper utilizes certain frequency regions of DCT such that insertion of watermark bits causes the least image distortion.The information was extracted by comparing certain coefficients based on some rules.According to the information,the watermark image can be reconstructed.The experimental results show that our algorithm achieves higher capacity and robustness than the existing schemes.The watermark extraction produces high image quality after cutting,noise,filter and JPEG compression attacks.