Research On Reversible Digital Watermarking Algorithm

Digital watermarking technology is an important part of the research field of information hiding technology.Its basic principle is to embed the information that needs to be transmitted as a watermark in the multimedia carrier(such as image,video,audio,etc.)used for dissemination.However,in many important fields,there are higher requirements for the quality of the carrier image.It is hoped that after the watermark information is embedded,the original carrier image will not be lost after the watermark is extracted.With the continuous development of watermarking technology,the introduction of reversible digital watermarking technology solves the problem that the original carrier image changes the pixel value of the image when the watermark information is embedded,and the image is distorted,resulting in the inability to recover the original carrier image after the watermark is extracted.Reversible watermarking technology can be used for anti-counterfeiting,copyright protection,informa t io n transmission and other applications without affecting the quality of the carrier image,and has a large application space in various fields.Digital watermarking technology involves many disciplines,such as computer,digital image processing,mathemat ics,communication and other professional disciplines,which brings huge development space to researchers in different fields.In recent years,the research and application of reversible digital watermarking technology has continued to develop.But in general,the reversible digital watermarking technology has not developed to a mature stage,there are still many technical problems to be solved,and its potential application prospects will be further broadened.According to the location and application field of watermarking,three reversible digital watermarking algorithms are proposed,which are mainly developed from three algorithms,namely three innovative points:(1)In some special fields,such as anti-counterfeiting,information transmiss io n,copyright protection,etc.,watermark information contains important information,and the security of watermark information also needs to be protected.Therefore,it is necessary not only to restore the original carrier image without distortion,but also to ensure the security of the watermark information.,Proposed a histogram shift safe reversible image watermarking algorithm.The algorithm uses the national secret algorithm Zu Chongzhi password to encrypt the watermark information to ensure the confidentiality of the watermark information;in the watermark embedding and extraction stage,the prediction difference is used to construct a two-dimensional histogram,and the two-dimensio na l histogram is used to translate into the watermark embedding.And extract,restore the original carrier image after extraction.Experimental results show that the scheme has good encryption and decryption effects and image quality,and the algorithm is reversible,and can restore the original carrier image lossless.(2)Aiming at the problems of image integrity detection and quality improvement,a reversible image watermarking algorithm based on two-dimensional histogra m modification is proposed.The algorithm first uses preprocessing,uses two-dimensio na l histogram to shrink to solve the problem of pixel overflow;uses two-dimensio na l histogram to expand and embed watermark information,while achieving the effect of contrast enhancement;by comparing the watermark information embedded in the subblock with the extracted watermark The information is the same to determine whether the image has been tampered with,so as to accurately locate the tampered area,which further enhances the authentication of the image integrity.The experimental results show that the algorithm is reversible and can restore the original carrier image lossless.The contrast enhancement effect of the image is realized while the watermark is embedded,and a better visual effect is obtained.(3)According to the embedding method of the watermark,the reversible watermarking technology can be divided into the spatial domain-based and the transform domain-based.Reversible watermarking is based on the algorithm of changing domain and has good robustness in anti-attack.The DCT can resist traditional attack methods,but it has poor resistance to common geometric attacks,such as shearing attacks and rotating attacks.The extracted watermark text messages will be severely lost when subjected to geometric attacks such as rotation attacks and shearing attacks.But SVD has good performance against geometric attacks,but it has weak resistance against attacks such as Gaussian,filtering,and salt and pepper.Both DCT and SVD have their own advantages and disadvantages.In order to solve the single attack resistance in the change domain,in order to solve this problem,this section combines the advantages of DCT and SVD to propose a reversible image watermarking algorithm based on the combination of DCTSVD.For traditional image attacks and geometric attacks,the algorithm has strong antiattack ability,strong robustness,and the algorithm can be reversible.