Reversible Medical Image Watermark Based On Interpolation Error Expansion

The development of computer technology and the extensive use of digital media have promoted the process of universal management of electronic medical data,freeing digital medical data from distance limitations and being shared throughout the world.It provides facilities for medical services that require remote connections.However,these conveniences also bring about copyright infringement and malicious falsification of works.Nowadays,there are a large number of pirated works on the Internet.In order to solve these problems,digital watermarks are born,and these problems are solved to a great extent.Watermarks are used in many countries to protect the copyright of digital media.Nowadays,the development of science and technology has also benefited the digitalization of the medical industry.The number of medical digital images has continued to increase and its status has become increasingly important.While sharing these images between experts and hospitals to obtain better and more accurate diagnosis,it should also protect the privacy of patients,and the information contained in medical images is very crucial.When embedding watermarks,they should not affect the quality of images as much as possible.This makes the reversible watermark attracts attention in the field of medical image research.The reversible watermarking is a kind of watermark embedding in the carrier image.At the receiving end,the original carrier image of the watermarking sequence can be restored,and the original image will not be lost.This feature is suitable for images with high precision like medical images..In addition to the accuracy requirements,there are other differences between medical images and natural images,such as large areas of smooth areas(black areas without information),but areas with large changes in the images contain important information.This article focuses on the reversible watermarking of these features of medical images.The main tasks are:(1)This paper presents a reversible watermark embedding algorithm using additive interpolation error expansion technology,which can embed watermark information in medical images by changing the interpolation error.In this method,we embed the watermark bit "1" or "0" in the interpolation error(difference between the interpolation and the corresponding pixel)by adding or expanding the specific pixel.Due to the slight modification of the pixels,the image quality is hardly affected.Experimental results also show that the high value of PSNR ensures perceived integrity compared to prior art methods.(2)Secondly,this paper also uses another method of interpolation error expansion to embed large-capacity watermarks into the performance of carrier medical images.The original medical image is divided into non-overlapping blocks,and the image is interpolated using the same method as in the previous method to obtain a high-resolution image,and the pixels satisfying the threshold range are embedded invariably using the interpolation error expansion technique.At the extractor,the data can be recovered using the same interpolation image without any additional information.Experimental results show that compared with other embedding methods,this method can indeed greatly increase the embedding capacity.