Research On Digital Image Watermarking Algorithm Based On Error Correcting Codes

With the rapid development of network and multimedia technology, digital image, digital video and digital audio digital multimedia works has been widely used.Facilitate the storage, reproduction and transmission of digital multimedia works, the resulting illegal copying and tamper with the copyright information security problems, such as increasing, bring serious social problems.Digital watermark technology is a good way to solve these problems, is the effective means to realize copyright protection, has become a hot research topic in the field of multimedia information security.This paper is to ensure that digital watermarking algorithm under the premise of not perceptual, enhance the robustness of digital watermarking algorithm.Based on digital watermarking algorithm based on communication model is analyzed, by using error correction code error detection and error correction ability, improved digital watermarking algorithm in a variety of complex environments the ability to resist various attacks.Therefore, this article mainly the following several aspects.⑴ Aiming at inefficient problem of long encoding in traditional BCH, this article proposed a long BCH encoding fast algorithm. In order to avoid repeated calculating all roots, the algorithm made use of cyclotomic cosets and Chinese remainder theorem to construct cyclotomic cosets of minimal polynomial roots when it was determining the generator polynomial. It used the equivalent polynomial substituting for the division polynomial, and joined the minimal polynomial and ideal generating element to cyclotomic cosets. The subsequent encoding could obtain equivalent remainder polynomial by looking for cyclotomic cosets, which reduced division operation time. The experimental results show that compared with traditional BCH algorithm and relevant algorithm, the algorithm has higher encoding efficiency for long BCH code, especially for very long BCH code, the effect is more obvious.⑵ According to the improved BCH coding algorithm based on the theory of Chinese remainder theorem, improves the efficiency of BCH coding algorithm, and then the improved BCH coding algorithm and transform domain DCT technology integration, can not be achieved in the balance between the perception and robustness, embedding the choice of middle frequency coefficients in DCT transform domain digital image watermarking algorithm, to solve the robustness the problem, simulation results show that, this algorithm has better anti attack ability, also has good imperceptibility.⑶ To improve the robustness of digital watermarking algorithm against the attacks with high intensity and combination attacks, a novel digital image watermarking scheme for against various combination attacks is proposed. Integrating the two of error correction code and discrete cosine transform, the scheme use of QC-LDPC error correction technology to digital watermarking system, improve the robustness of the algorithm; Using discrete cosine transform to embed the watermark in the intermediate frequency coefficient, in order to solve the imperceptibility and robustness of digital watermarking balance problem; adaptive computing embedding strength factor based on texture and brightness characteristics of the image; improve noise immunity through adaptive filtering algorithm, makes the algorithm more robust comprehensive ability. Experimental results show that the scheme proposed in this paper can effectively resist the combination attacks, as well as common attacks including noise, cropping, compression, filtering.