| With the rapid development of network and multimedia technology, we haveentered the digital age today. Digital products almost affect everyone’s daily life.Copyright protection, information security and digital security etc., closely rela tedto the digital products, received widespread attention. Digital watermarkingtechnology is an effective method of copyright protection. The focus of the currentdigital watermarking research is to embed digital watermarking in the transformdomain, such as DCT domain, DFT domain and DWT domain. Fractional Fouriertransform domain is a brand-new time-frequency analysis tool. It has good ability tocommunicate information in airspace and frequency domains.In this paper, the algorithm of double random phase digital watermarking isproposed based on the fractional Fourier transform that has many excellentproperties in the signal processing. First, the watermarking is encrypted with doublerandom phase encoding on the domain of fractional Fourier transform. Then it isdivided into amplitude part and phase part. The two parts are both composed ofdecimals, which are converted into integers. The integers are transformed intobinary data. The amplitude and phase watermark images are converted into multiplebinary watermarks. Secondly, the original image is divided into amplitude part andphase part by using the fractional Fourier transform. Using binary watermarkembedding methods，the binary images of amplitude and phase are embedded intothe amplitude and the phase of original image respectively. The new amplitude andphase parts are obtained and merged into images with imbedded watermark. At last,the processes of embedding and extracting are simulated. The robustness analysisvalidates that the proposed method has good resistance for white noise, shearing,and rotation attack. The robustness of the method is excellent and the security,reliability and confidentiality of watermarking are increased, in premise ofinvisibility and robustness. |
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