A novel method for embedding gray image watermarking into orthogonal fractal compression image

Traditional watermarking techniques based on fractal coding are generally using 0, 1 sequence as watermark, thus impossible for gray image embedding. A novel fast watermarking technique is proposed in this paper to overcome the above mentioned shortage by employing the orthogonal fractal coding technique. With the proof that fractal decoding parameters during iterations is mean-invariant, watermarks are embedded into decoding parameters directly. Theoretical analyses and experiments indicate that gray image embedding process has little effect on the fractal compression image and this scheme gets better performance than conventional methods on robustness against many attacks like cutting, low-passing filtering, and JPEG compression.