Research On Wavelet Digital Watermarking Algorithm Based On Chaotic Property

Wavelet digital watermarking algorithm based on chaotic property is researched.Discuss and experimented on the application of chaos in image encryption algorithmand wavelet in digital watermarking. An algorithm of digital watermarking for colorimages based on discrete wavelet transform (DWT) and chaotic encryption ispresented in this paper, which employs a matrix generated by chaotic algorithm as acipher to encrypt the watermark. By considering both robustness and invisibility, thewatermarks with changed extension are embedded into the low and mediumfrequency subands in the initialized range of DWT domain. The extension of thesequence is adapted to the range of the DWT domain. It is changed back anddecrypted when extracting the watermarks. The embedding order of the informationis adjusted by the importance of the DWT coefficient and the extension makes thedifference between the DWT coefficient changed and the preceding small so as toguarantee and split the difference between the robustness and the invisibility of thewatermark when extracting the watermarks.The digital watermark algorithm is discussed and extended from grey images tocolor images. The RGB color model is changed to HSI model. The characteristics ofhuman visual system (HVS) are utilized to embed the watermarks into the intensitydomain which is not so sensitive, and the invisibility of the watermark is ensured.A wavelet digital watermarking system based on chaotic property is designedand realized. The better stability and the robust of the system is proved. Thewatermark can be extracted without original image and original watermark. Theblind watermark system is conformed to the development of the watermark algorithm.It can meet for special application.