抗数字图像区域攻击的自适应盲水印算法

为在保证含水印图像质量的同时有效提升算法抵抗数字图像区域攻击的能力,提出了一种安全、自适应的鲁棒性数字盲水印算法. 引入随机四元组的概念,从宿主图像每个随机四元组中选取3个8×8大小像素块隐藏原始冗余水印,并使用剩余小块隐藏认证水印. 根据块亮度-纹理值自适应地确定冗余水印嵌入量化步长及认证水印的隐藏位置. 为改善提取水印图像的视觉质量,对提取水印进行去噪处理. 实验表明,算法实现了水印信息盲提取,具有安全性高、水印透明性好的特点,在抵抗图像常规区域攻击及联合攻击方面显示了较高的鲁棒性. 

Adaptive Blind Watermarking Algorithm Against Regional Attacks of Digital Images

To enhance the algorithm's ability on resisting against regional attacks of digital images while ensuring the quality of the watermarked images, a secure, self-adaptive and robust digital blind watermarking algorithm was presented in this paper. A conception of random quaternary group was introduced, that was to select three 8×8 size blocks from each random quaternary group of the host image for hiding the redundant watermark bits and to hide the authentication watermark bits with the remaining blocks. According to the blocks' brightness-texture values, the embedding quantization steps of the redundant watermark bits and the embedding positions of the authentication watermark bits was selected adaptively. A denoising process was adopted for the extracted watermarks to improve the visual quality of the extracted watermark images. Experiments results show that, the proposed algorithm can realize the watermark blind extraction with high security and good watermark transparency, and show a high robustness on resisting conventional regional attacks and joint attacks of digital images.