Research On Reversible Data Hiding Schemes Based On Medical Images

With the establishment and perfection of medical information management system,medical information is gradually developping towards digitalization,which is convenient for the storage,transmission and sharing of medical information.The rapid development of network technology and multimedia technology provides a new technical method for remote medical treatment,remote diagnosis and remote operation.However,while the new techniques have brought a lot of convenience to people,they are a series of information security,such as illegal copy and malicious tampering.Therefore,how to protect the security of medical information has become one of the problems to be solved in the development process of medical information management system.Encryption,as a traditional information security protection method,can protect the information content security.However,the encrypted information is easy to cause the attention of the attackers.What is more,there is no longer any protective effect once the encrypted information has been decrypted.Reversible data hiding technique is an important branch of data hiding technique.Since reversible data hiding technique can sure that the carrier image can be recovered losslesssly,it is widely used in medical,military and other areas which has a higher requirement for image quality and becomes a research hotspot in recent years.This paper studies reversible data hiding schemes for medical images systematically and analyzes the advantages and disadvantages of the existing schemes,then proposes two ROI-based reversible data hiding schemes for medical images.These two schemes are based on the characteristic of medical image partition,that the region of interest(ROI)and the region of non-interest(RONI).The main works are as follows:(1)This paper proposes a ROI-based reversible data hiding scheme for medical images with tamper detection,which is not only able to hide electronic patient record(EPR)but also can protect the ROI region with tamper localization and recovery.The proposed scheme adopts two different embedding atrategy based on different texture features of the ROI region and the RONI region.In the ROI region,prediction error expansion and sorting technique are combined for embedding EPR;in the RONI region,histogram shifting(HS)method,which hardly leads to the overflow and underflow problems,is used for embedding the integrity authentication and recoverey information.The receiver realizes the integrity authentication by comparing the hash value of the ROI region.If the hash values are different,the recoverey information will be extracted from the RONI region and used to localise and recover the tampered area inside the ROI region.The method can improve the embedding capacity while maintaining the image quality.(2)This paper proposes a ROI-based reversible data hiding scheme in encrypted medical images.Firstly,the content owner partitions the original medical image into the ROI region and the RONI region,then rearranges it and encrypts it using an encryption key.The data-hider compresses the least significant bits(LSB)of the encrypted ROI and the additional data and then embeds the compressed data into the encrypted image by LSB substitution algorithm.With the encrypted medical image containing additional data,the receiver can extract the embedded data and recover the ROI region losslessly after extracting the embedded data.Both encryption technique and reversible data hiding technique are different methods of protecting the information security,the combination of them can bulid a more secure system.At last,this paper summarizes all the works and discusses the shortages and main issues of the reversible data hiding schemes for medical images,and then the future research is prospected.