Research On Robust Multi-watermarking Algorithm For Medical Images Based On Patchwork-DCT

With the rapid development of digital information technology,medical information systems are also gradually digitized,which provides great convenience for the storage,transmission and exchange of medical data.Due to the rapid development of modern medical high-tech imaging technology,it is very important to further realize the digital informatization of medical imaging technology.Especially in recent years,remote diagnosis and remote consultation of experts have become more and more common.In order to facilitate patients to receive better medical assistance,doctors need to grasp the information related to the patient’s condition as accurately and comprehensively as possible,which makes it necessary to store and transmit a large number of medical images and medical data.However,in the process of transmitting the required medical data,it may be subject to some malicious attacks,or malicious tampering with the data,and the security is relatively low.Many medical image watermarking algorithms that exist today can improve the security of data as much as possible and solve the impact of attacks or malicious tampering of medical images,so they have been widely used in medical image processing and other related fields.The patient’s pathological data is embedded in the carrier medical image in the form of a watermark,and the watermark information can be effectively extracted even after tampering,attacking and other processing in the communication of medical information.This can not only facilitate the exchange of telecommunications,but also improve the security of digital health systems.However,some algorithms have good effects in resisting conventional attacks,but the effect of resisting geometric attacks is still not ideal,and the security of medical data cannot be better guaranteed.Moreover,in actual use,the integrity requirements for medical image information are relatively high,and more data needs to be embedded in medical images,and the commonly used digital watermarking technology is zero watermark technology and multi-watermark embedding technology.Therefore,this paper mainly proposes a robust watermarking algorithm with zero watermark for two-dimensional and three-dimensional medical images,that is,a robust multi-watermarking algorithm for medical images based on Patchwork-DCT,and the basic research content is as follows:(1)A robust multi-watermarking arithmetic for two-dimensional medical pictures based on Patchwork-DCT is proposed.The first is the feature extraction part,and the32-bit low-frequency coefficient matrix is obtained by Patchwork-DCT transformation.Then,according to the positive and negative judgments,the 8-bit feature vector is selected and XOR is performed on the pseudo-random sequence generated by Logistic to obtain the logical key Key,so as to realize the embedding of the watermark.Finally,XOR operations are performed on Key and feature vector to extract the watermark.This better ensures the integrity and security of the watermark content,and also achieves the effective restoration of the watermark information.Experimental results show that the watermark information can be extracted effectively under both conventional and geometric attacks,showing good robustness.(2)A robust multi-watermarking algorithm for three-dimensional volume data based on Patchwork-DCT is proposed.By comparing the chaotic encryption and chaotic scrambling algorithm based on Logistic Map,an effective and highly secure watermark encryption method is found.The algorithm uses the method of zero watermark embedding when embedding the watermark,and there is no need to change the original body data when extracting the watermark,which will protect the original body data well.Combined with the concepts of chaotic messing,cryptography and third-party methods,the proposed algorithm shows good robustness under conventional attacks and geometric attacks,and has great availability in medical digital information protection.