Research And Application Of The Image Watermarking Algorithm Based On Transform Domain

As a branch of the hiding information technology, digital watermarking has become aneffective way to protect copyright of digital products and data security. The certain secretinformation using corresponding watermarking algorithm embedded into the carrier such asimages, documents and video, to prove the creator of an important basis for the identification oftort. Due to the urgent needs of the Internet market, digital watermarking technology has becomeone of the most active areas of current research. Compared with the covert communication,digital watermarking algorithm is more robust to prevent the wanton destruction of piracy.Digital watermark is the information hiding technique based on image processing, and usedmore often in real life. The file system processing must be invisible, and the watermarkinformation can not easily be damaged .Because once destroyed it means the loss of copyrightinformation. Digital watermarking system must be designed to have the transparency androbustness. In this paper, we main research the transform domain digital watermarking algorithm,with various geometric attacks on the watermarked image to test the system, to test whether thealgorithm is in line with the practical application. The main contents include the followingaspects:1.Introduces the basic concepts of information hiding and its characteristics, we use specificmodel to demonstrate the working principle of information hiding technology, to lead thesignificance of studying digital watermarking. Combination the inadequacies of existingexamples of traditional security solutions and watermarking technology, it reflects the broadprospects for development of the watermark.2.Through the introduction of the concept, basic features, classification and workingprinciple of digital watermarking ,we proposes a part of existing digital watermarking algorithm.It mainly includes two parts of time-space domain and transform domain, which thewatermarking algorithm based on Discrete Cosine Transform is the focus of this study. Thispaper describes the basic principles of discrete cosine transform and human visual system in thisregard. Proposed a JPEG image compression algorithm based on DCT image compressionprocess is through the coefficients transformation, quantization, and coding to achieve. The simulation results shows the algorithm’s performance.3.Analysis coefficient distribution model of digital images after discrete cosine transform,and compare the four distribution models such as Laplace distribution, Gaussian distribution, theGeneralized Gaussian distribution andα-stable distribution. We use K-S test method to provewhich kind of distribution is more in line with the characteristics of the coefficient. Then Iintroduce a stochastic resonance system, with the method of Runge- Kutta to simulation computethe function of the SR system. Comparison amplitude change of the system in the noise-free andnoise, and the amplitude change of same frequency coefficient when through the SR systembefore and after. We compare K-S values of the four kinds distribution to determine thecoefficient distribution model.4.In this paper, with gray-scale image as a carrier, binary image as watermark, I propose adigital watermarking algorithm based on the SR system, then introduce how to scramble, embedand extract the watermark. Through Arnold scrambling and chaotic encryption watermark imagehas completed the second encryption, it improves the visibility of the watermark. The algorithmmakes the watermark embedded in the exchange coefficient of images ,we use spread spectrumtechnology to make watermark sequence length the same as vector images, the process ofwatermark embedding and extraction is achieved. In the simulation experiment, we attackswatermarked image such as rotation, distortion, clipping, compression, filtering and other waysto verify the stability of the system’s performance. Finally with the help of software we design adigital watermarking system, complete encryption, embedding and extraction process of thewatermark .The most important thing is that the algorithm is a specific application.