Robust Watermarking Algorithms For Medical Images Based On DFRFT

With the rapid development of computer network,more and more fields have been affected by digitalization,and the medical field that has attracted much attention has also entered the process of digitalization.Today,with the rapid development of technology,medical information is used for learning,remoting communication and treatment.While people enjoy this convenience,a serious problem is affecting us,and that is the problem of safety.While patients are being treated remotely,they are also concerned that their personal information will be exposed.Therefore,the problem of security is a very urgent problem in this information age.To prevent information leakage,many scholars have proposed digital watermarking and other solutions.Digital watermarking is to store the patient's personal information(name,gender,etc.)in the carrier image as a watermark.Based on this method,we propose a watermarking algorithm based on DFRFT.DFRFT is used to improve the robustness of geometric attack.At the same time,the medical image itself also contains the patient's disease information,which also needs to be kept secret.Therefore,we encrypt the host image to obtain double protection.In view of these problems,we propose the following research:(1)We study the DCT-DFRFT based medical image watermarking algorithm.First,DCT(discrete cosine transform)and Tent Map are used to encrypt the digital watermark which is embedded in medical image.Then the medical image is transformed by DCT,and the low frequency coefficient of the carrier image is extracted,and the extracted low-frequency coefficient is transformed by DFRFT(discrete fractional fourier transform)to extract the feature vector of the medical image.Because medical image is a special image,the original information cannot be changed,so we use zero watermark technology to embed and extract the watermark.After embedding the watermark into the medical image,we need to verify its robust performance.Therefore,we use different attack methods to attack the carrier image.Finally,the results are as follows: the proposed algorithm can restore the watermark well after different attacks and has strong robustness.(2)We study DWT-DFRFT based digital watermarking algorithm for medical images.First,DCT(discrete cosine transform)and Tent Map are used to encrypt the digital watermark which is embedded in medical image.Then,DWT(discrete wavelet transform)and DFRFT(discrete fractional Fourier transform)are applied to medical images to extract the feature vectors of medical images.The embedding and extraction of watermarks are realized by zero watermarking technique.Finally,the results are as follows: the proposed algorithm can restore the watermark well after different attacks and has strong robustness.(3)We study the digital watermarking algorithm of medical image based on DWT-DCT and Tent Map.DWT-DCT and Tent Map were used to encrypt the original medical image and digital watermark.Then we used DWT(discrete wavelet transform)and DCT(discrete cosine transform)to process the encrypted medical image and extract thefeature vector.The embedding and extraction of watermarks are realized by zero watermarking technique.Finally,the results are as follows: the proposed algorithm can restore the watermark well after different attacks and has strong robustness.The algorithm also ensures the security of medical images.