Research On Digital Watermarking Technique Of Static Image In Wavelet Domain

People are enjoying unprecedented convenience and happiness brought by explosive increase of digital media. At the same time they are also confronted with some new challenges. Especially, Digital media product copyright protection is an impending problem needed to be solved, but it cannot be solved effectively by using Cryptology, Digital Signature and other traditional techniques, a new technique — Digital Watermarking emerged as the times required. The wavelet technology has been improved rapidly since 1980s, and now it has been used widely in image processing. Wavelet transform is the key technologies in the new image compressed standard—JPEG2000, now more and more people focus on the watermarking based on the DWT.In this thesis the techniques of digital watermarking in discrete wavelet transform domain is studied. The contribution of this thesis is following:An image watermarking algorithm based on significant wavelet tree was proposed. The binary watermark images with copyright information were embedded into significant wavelet tree with different chaotic sequences. The extraction of.watermark used the method of cascade extraction and Variance control, improved the accuracy and rate of extraction. Experiments show that the watermarked image is invisible and robust to common image manipulations.The second algorithm used a gray image as the watermark, dealt with it by Arnold confusion and wavelet compression. Based on the human visibility model, watermark was added in sub band images with different directions and levels, improved the robust of watermark. The advantage of the algorithm was it utilized HVS to embedded huge data into original image and experimental results show that our scheme has very excellent effect.