结合分形编码的小波域水印方法

提出了一种结合分形编码的小波域水印方法。首先，将宿主图像分成互不重叠的子块，利用分形编码的拼贴误差对子块进行降序排列,并根据水印大小依次选取两个等长子块序列；其次，利用Arnold迭代变换置乱水印，按照新的嵌入公式，将置乱水印重复嵌入到所选两子块序列小波变换后的低频子图中；最后，对提取的两个水印进行融合得到最终的水印。实验结果表明，该方法隐蔽性强，安全性高，对剪切、加噪、涂抹、滤波、旋转以及JPEG压缩等具有较强的鲁棒性。

Wavelet Watermarking Technique Combined with Fractal Coding

A wavelet watermarking technique combined with fractal coding is proposed. First, a host image is partitioned into a set of non-overlapping square blocks. These blocks are sorted to become a descending sequence according to their collage errors which are obtained by performing baseline fractal coding, and two equal-length subsequences are chosen respectively according to the watermark size. Second, the watermark, which is first scrambled using arnold transform, is embedded into low-frequency bands in wavelet domains of distinct blocks in the two selected subsequences by a new embedding formula. Last, the watermark is the fusion of the extracted watermarks from the two selected subsequences. The experimental results show that this technique achieves good perceptual invisibility and security, and is also very robust against some image processing such as cropping, adding noise, scribbling, filtering, rotation and JPEG compression.