Image Watermarking Algorithm Based on Quantization and Integer Wavelet Transform

Geometric attacks are difficult to resist for watermarking algorithms. Although most existing geometric-resisted algorithms can resist some kinds of geometric attacks, however, their robustness to common image processing is weak. A watermarking algorithm which is both strongly robust to geometric attacks and common image processing was proposed in this paper. Watermarking messages combined a Gaussian-noise template were embedded to vertical high frequency coefficients which were produced by one-level integer wavelet transform of the host image. Then the same messages were embedded to each sub-image by quantization repeatedly. Two watermarking images were extracted by correlation calculation and majority rule. Finally, the ultimate watermarking was decided by a judge rule. Experiment results show the algorithm is both robust to geometric attacks and common image processing, meanwhile, the imperceptibility of the algorithm can meet the request.