Research And Implementation Of Digital Watermarking Authentication Algorithm For Medical Images

With the advent of digital age and the progress of medical imaging technology,the development of digital medical imaging technology is more and more mature.Digitalization makes the storage and transmission of medical data more convenient,but at the same time,it also increases the security risk of medical data.When medical data such as medical images are stored or transmitted,they may be illegally copied or maliciously attacked.This contains information about the patient’s medical record,which records the patient’s personal privacy and could cause distress to the patient if it is spread.In addition,malicious attacks on medical images and other medical data can damage their availability,and their illegal dissemination can cause legal disputes.In the face of the above problems,the content integrity of medical images,copyright information and corresponding patient information can be verified to solve the problem,and digital watermarking technology is an effective means to realize the above authentication.Based on the above situation,this paper carried out the following work:(1)A block semi-fragile medical image watermarking authentication algorithm based on SVD is proposed.The algorithm divides the medical image into 4×4 blocks,performs singular value decomposition after Arnold scrambling and encryption,and then verifies the embedding position through logistic mapping.The watermark information is divided into block authentication bit information and self-recovery bit information.The block authentication bit information is composed of the singular value decomposition results of image blocks,which is used to detect tampering of different attack types.Self-recovery bit is composed of the average value of the higher five significant bits of the image block,which is used to realize self-recovery after image tampering.The simulation results show that the algorithm can identify and locate common attacks with tamper,and the self-recovery image quality is more than 30 d B.(2)A robust medical image watermarking algorithm based on optimal block DWT-DCT embedding dynamic code is proposed.In this algorithm,the hospital copyright identity and patient information are stored in the lofted code through the background,the lofted image is encrypted by Arnold transformation to ensure the security of the watermark information,and then the carrier image and the encrypted watermark are transformed by DWT and DCT,and finally the lofted watermark is embedded in the form of the optimal block.Simulation experiments show that the algorithm has strong robustness in the face of JPEG compression,Gaussian noise,salt and pepper noise,filtering attacks,and geometric attacks such as cutting,rotation,translation,etc.At the same time,because of the use of the watermark,it also greatly improves the embedding capacity.The watermark extracted after the attack can be identified successfully.