基于图像块均值量化的自适应盲水印算法

提出了一种新的基于图像分块DWT的自适应盲水印算法。算法以一幅有意义的二值水印图像为水印信号。同时,利用了Hilbert扫描能很好地保持图像空间局部连接性的特点。在图像块的Hilbert序列中选取相邻的3个分块分别进行一层小波变换,计算各分块对应子带的均值并比较大小,根据较大和较小的两个均值决定的步长,调整另外一个均值对应子带系数的大小,从而完成自适应的嵌入水印信号。而且,水印的提取无需原始图像参与,达到真正的盲水印。实验结果表明,该算法是有效的,水印具有较好的不可见性,对通常的图像处理操作和裁剪、挤压、像素移位等几何攻击有较强的鲁棒性.

Self-adaptive blind watermarking algorithm based on the quantification of blocks' average value

A new self-adaptive blind watermarking algorithm based on DWT of image blocks is proposed.The watermark signal is a binary watermark image.By taking full advantage of Hilbert scanning,3 neighboring blocks are selected from the Hilbert sequence of the host image blocks in turn,and 1-level DWT is applied to the two chosen blocks.Then the polarity of the average value of the corresponding bands is determined.According to the biggest and the smallest average value,the watermark strength is determined to modify the other average to embed the watermark.At the same time,the watermark can be extracted without original image.It is truly blind watermark algorithm.The experimental results show that the proposed algorithm is effective,invisible and robust to common image processing operations and some geometric distortions such as cropping,pinching,pixel-shift,and so on.