Research Of Image Digital Watermarking Based On Fractional Fourier Transform

With the rapid development of Information technology and Internet technology,people can easily make the exchange and transmission of digital information. Althoughthis allows people to live and work more convenient, work efficiency, but it also bringsdigital media piracy. Some ones, for reaping huge illegal profits, in the absence of theauthor’s permission access to digital media, on free to copy and disseminatecopyright-protected digital works. The digital watermarking technology is an importantissue for the digital media copyright protection and authentication methods, so more andmore researchers get on researching it. Based on researching and analysis of digitalwatermarking technology and fractional Fourier transform, we propose a binarywatermarking algorithm based on fractional Fourier transform and a fragilewatermarking algorithm based on fractional Fourier transform. The main contents ofthis article are as follows:1. Besides of analysis definitions, classifications, basic principles of digitalwatermarking technology, we study on the robustness of the watermark and fragilewatermark and describe several typical watermark attack methods and evaluationmethods.2. Study of the definition and basic nature of fractional Fourier transform, get thefurther discussion of the discrete fractional Fourier transform with the numericalcalculation, and numerical simulation. Study the use of fractional Fourier transform indigital watermarking.3. Through a typical sequence of fractional Fourier watermarking algorithmresearch and analysis, simulation modeling, and analysis of advantages anddisadvantages of the algorithm, and then proposed the binary image watermarkingalgorithm based on fractional Fourier transform. We introduce the smart gray relationalanalysis method in Extracted watermark. Its biggest feature is the sample size and notstrict requirements, does not require the subject to any distribution to calculate theamount of small, very suitable algorithm for the frequent computing requirement. Andthen through simulation experiments and robustness tests, the results are verysatisfactory.4. Discussion fractional Fourier transform spectrum, based on image blockprinciple and sensitivity of the chaos mapping initial value, we propose a fragilewatermarking algorithm based on fractional Fourier transform. We get a good resultthrough several simulation experiment.