Digital Watermarking Algorithm Research And Implement

Digital watermarking is a new hot research field in the international academia. It has a close relation to information safety, information hide , data encrypt and so forth. The developing digital watermarking offered a potential solution for the thing that implement effective copyright protection and problems such as information safety and so forth in recent years. It has paid attention to that by international academia , business and government. Digital watermarking adds some digital information to the multimedia data instead of the seeing and hearing result of influencing the original data, and digital information these all right for some to resume of mixing datum all, in order to reach the function , such as copyright protection and so forth. Digital Watermarking should is security, robust and can't aware characteristic. Watermarking algorithm discerns the relevant information of the owner imbedded in the protection target, and can draw out it while needing . Watermarking can be used for differentiating the target and whether protected, watch protected data to spread around, true and false distinguish , secret communication , sign hide and illegal copy controlling important application of and so forth, this is basic motive force of developing the digital watermarking in fact. The basic principle of image watermarking is to imbed some identification data to reach as the watermarking in the host data, making the watermarking not intangible and safe enough in the host data . The host data caused in order to guarantee the embedding of the watermarking is too distorted to aware of , it must apply to a certain esthesia criterion , and regarded as the request that can't be aware, each the host data change degree of value of sampled point it should stand opposite each other relatively little to compare by oneself. Digital watermarking algorithm in common use includes the embedding , abstraction of the watermarking or measuring of the watermarking two basic respects. Video and image watermarking are very close on base principle, because it is from a series and a space-time in array of video from static picture form. Applying image watermarking base principle in video watermarking array , it is image watermarking algorithm naturally popularize, but the two still have important differences. First , it reflect on the size of space of the signal. To the picture, the space of the signal is very limited. This drives a lot of researchers to use the human vision model of the recessiveness or the dominance, in order to confirm the observability yardstick of the watermarking, the ones that and made the watermarking imbedded possible robust, and to the video array, the signal space is very enormous. Second, video watermarking has real-time or approximate real-time requests. Using the human vision model of the dominancing is not very important , the complexity and validity that calculated have been increased to the comparatively important position. Audio signal compared with image and video data, its data amount is very small . It will be much smaller than media's watermarking algorithm of the vision that this watermarking amount of imbedding information and robust. Another question is that the person's system of sense of hearing is much more sensitive than its vision system, therefore should make the watermarking imbedded unable to hear that is comparatively difficult correspondingly . Boney has been proposed on the basis of spread spectrum audio frequency watermarking method frequently , it mainly utilizes with shelter the characteristic temporarily when different stages strain waves and get the human system of sense of hearing long to PN array. The experiment indicates that this algorithm compresses certain resistance to MP3. Text watermarking is studied less, but text watermarking has very important value too. Brassil and so forth have done extensive research to text watermarking . They imbedded the watermarking to the code after putting forward three kinds of different methods , line shift code,word line shift code and characteristic code. In these three kinds of methods, line shift code is best robust, but even most easy to destroy. The author emphasizes that the method above is only the theory, because it still too tedious in practical application. But the method to put forward is to typing, all certain one is robust to print, take pictures and scan. Digital watermarking should have pictures that can resist the high compression ratio to compress , the ones that have low open characteristics , can resist the picture and quantize the routine picture of strengthening with the picture and so forth operated and can resist geometry lose robust. Generally method of attacks to digital watermarking have briefly attacks, confuse attacks and delete attacks and so forth. In the article, it proposes the copyright protection application technology scheme based on digital watermarking. Because such difficult problems as the digital cheap of duplicating the cost , judicial examine difficult , distorting easy and web page of works is difficult to protect, causing the existing copyright system to be very difficult will offer enough protection to the digital works. This text has address distorted prompt and integrality protection , makes the right to manage information and " administration information " on the basis three kinds of method. The discussion should solve twice watermarking attack, piece together attack and multi-images average attack three problems base on attacking. Proposition that should accelerate making the watermarking technical standard of copyright protection, make the copyright protection watermarking standard of our country as soon as possible , make us obtain the initiative in the possible international intellectual property right dispute in the future. In the text, it analyses to be can fast to realize digital watermarking effective tool Matlab application reason and relevant description of function, and utilize Matlab tool to realize the following three watermarking algorithms fast: 1. LSB(Last ) algorithm on the basis of the airspace. Because the location level of LSB is carrying the watermarking, so in a situation that imbedding the watermarking picture has not produced distortedly, the recovery of the watermarking is very simple, only need to draw the moisture LSB location level which prints the picture , and this kind of watermarking method is to measure algorithms blindly. But the one that deals with the signal and attacks maliciously in greatest defect of LSB algorithm is very bad sane. After carry on simple waves filter , adding noise and so forth,it can't carry on the drawing correctly of thewatermarking . 2. DCT(Discrete Cosine Transform)land picture watermarking algorithm . In DCT watermarking algorithm regards a random array as the watermarking signal and imbeds the range composition of the important weight in picture DCT. Cosine transform and Fourier transform have a clear physics meaning, it is the best that what DCT often considereds to be the thing to the audio and image signal is accurate. This algorithm has very good watermarking no observability and robust to common pattern process, such as shear, scale, mide-value wave filter, compress and noise and so forth and especially geometry rotate. But it need to use the picture of art of work while measuring . 3. Wavelet transform image watermarking algorithm. W-SVD (Wavelet Singular Value Decomposition) digital watermarking algorithm is base on wavelet land. This algorithm imbeds the watermarking in the singular value matrix of the picture , mathematics means simple and distinct , introduce watermarking primitive picture that bring and include error of video watermarking can be quantized and expressed. Such characteristics as this algorithm has good watermarking no observability and robust, but need to use the picture of art of work while measuring . This text studies and realizes the digital watermarking algorithm systematically, have discussed basic theories , method and technology of four kinds of digital watermarking technology ,such as image watermarking, video watermarking , audio watermarking and text watermarking. On this basis, it has proposed the application technology scheme of copyright protection based on digital watermarking. That used Matlab tool to realize three kinds of image watermarking algorithms fast , LSB image watermarking algorithm, DCT image watermarking algorithm and W_SVD image watermarking algorithm varied because of. This text make some helpful tries in digital copyright protection scheme research and digital algorithm of watermarking realize, and it has made certain practical experience. The scheme proposes realizing with the algorithm that though still just explores nature , still a lot of questions need further research and perfection. however, it lay a certain foundation in order to structure the more effective copyright protection system.