Research On Digital Image Watermarking Algorithm And Its Realization Based On Frequency Domain

In the dissertation, we study two kinds of digital image watermarking algorithms based on frequency domain. The one is based on discrete cosine transform (DCT); the other is based on discrete wavelet transform (DWT).The digital media has become a main way for information communication along with the wide use of network and has played an important role in people's life. As side effects of the popularity of digital representation and distribution over network, some individuals or groups copied, transfered, amended and even sold the digital media without the permission of copyright owners, which greatly damaged the copyrights and commercial benefits of owners. Therefor, the problem how protect the copyright has become a hot one in research work. In the dissertation, we mainly study the technologies of digital watermarking.In the technology of digital watermarking, two new methods on digital watermarking are finished: the first is based on discrete cosine transform and the second is based on discrete wavelet transform. In the first one, after the two values image watermarking is preprocessed by image scrambling, it is directly embedded into the carrier gradation picture DCT transformation territory according to the two different values of watermark picture. In the seconde one, the watermarking is embedded into middle domain of DWT coefficients. The primitive image isn't needed when the watermarking is extracted, named as blind extracting.This paper's watermarking arithmetics are all run in Matlab environment. All the experimentation results show that this paper's static image watermark based on frequency domain application promises well.