Wavelet Watermarking Technique Combined with Fractal Coding
结合分形编码的小波域水印方法

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.