Research, Image Watermarking Algorithm Based On Dct Domain

In the 21st century, with the rapid development of Internet technology, digital multimedia works were randomly unauthorized tampering copy and distribute multi- media information. These problems make digital copyright issue more and more seriously. Digital watermarking as traditional cryptography effectively complement to solve the problems of the protection of copyright, provides a novel ideas. The image as a digital media part in research works copyright has an important role.This article focuses on the digital image watermarking technology. The main works of this paper are listed as follows:1.Firstly, introduce the development of information, the states about home and aboard, the basic knowledge, and given the basic model about information hiding. introduces the research background and significance, digital watermarking research status. Analyzed and integrated digital watermarking, digital watermarking was given the basic model.2.A new algorithm of public image transformation for Information Hiding based on DCT and Texture complexity. First, preprocess the Watermarking, a Carrier image is divided to some 8×8 blocks,Calculate each image block's variance and sort the value, and transferred by DCT. The watermarking image is also divided to some 8×8 blocks,Calculate each image block's variance and sort the value and is hidden into coefficient of middle frequency. So the time of calculating is reduced, what's more, the security is enhanced greatly. it is tested the robustness with many attack experiments such as cutting, bigsmall,plus denoising, JPEG compression and median filtering attack, The experimental results show that the improved algorithm than primitive dct-based transform watermark algorithm is more available and efficiency.3.According to the characteristics of singular value decomposition, a combination of DCT and SVD watermarking algorithm has been proposed. Using the improved Anorld transform to pretreat watermark image and block the carrier image.Then a Carrier image is divided to some 8×8 blocks and transferred by DCT. For the new image matrix by singular value decomposition. Pretreatment watermark is embedded into diagonal matrix S, decomposite the singular value again, and then carrying out inverse DCT to achieve the embedding. the improved algorithm combines the DCT and SVD advantages and uses the improved Anorld transformation and DCT transform to ensure watermark invisible characteristics, Combined with singular values of stability, it can improve the confidentiality and image watermarking robustness, and also can achieve the purpose of copyright protection. The algorithm based on pure singular value decomposition algorithm were compared. Through the experiment, it is concluded that the proposed algorithm has feasibility, make the watermark invisible and robust has greatly improved.