The Research On Digital Watermarking Algorithm Of Medical CT Image

With the development of computer technology, transmission and application of a large numberof digital products become more and more convenient. So, copyright protection and informationhiding has attracted more and more attention. Thus digital watermarking technology is producedand rapidly developed. However, CT medical images during network transmission may be tamperedand copied illegally. Digital watermarking technology can resolve that problem. Some digital logoinformation or some secret information can be embedded into the digital medical image. Thewatermarking technology realize the function of informational hidding or copyright authentication.In this thesis, we design three watermarking algorithms based on region of interest (ROI) of medicalimage. The main research contents are as follows:(1) Describing background and significance of the research and introducing the the related theoryand basic frame of digital watermark in the image. It shows that the digital watermarking in medicalimage is necessary.(2) Designing a watermarking algorithm based on region of interest of medical image. Threewatermarks are embedded into the medical lung CT image of no region of interest. In this algorithm,the region of interest of CT image is not distortion. At the same time, it achieves the authenticationof patient information and medical images and confirms whether the medical image has beentampered.(3) In this thesis, we design a blind watermarking algorithm based on ROI of medical image. It usesBCH code to encode three different watermarks, then they are embedded into CT image of noregion of interest. Region of interest of the medical image is not distortion. This algorithm realizescertification of CT image, and confirms the image whether or not has been tampered.(4) we design a lossless watermarking algorithm of region of interest of medical image which basedon DWT. The two different original watermarks information are encryptied by logistic ChaoticSequence. Then they are embedded into the discrete wavelet low frequency coefficient of nointeresting region of image. We get a robust watermarking algorithm which realizes the certificationof patient information and medical images. Throughing the message of abstract code confirms thatthe region of interest of the medical image whether or not has been tampered.