Adaptive Watermarking Based on Fractal Image Coding in Wavelet Domain
Lei Shi · Mini-micro Systems · 2004
An adaptive watermarking based on fractal image coding in wavelet domain is described.The optimum fractally-matched domain block is searched in the subimage of the same orientation but lower resolution than that of the range block.According to tree structure relation of the wavelet coefficients,the domain blocks can extend through different resolutions along the same orientation to form a set of domain trees.Each watermark bit is embedded by modifying code of a certain range block from range tree,i.e.substituting the corresponding domain block of the first-matched domain tree for that of the second-matched dormain tree.The embedded sequence can be extracted without restoring to the original unmarked image.The experimental results show that the watermark is invisible and robust and extraction keeps the false positive rate significant small.