Research And Implementation Of Dual Watermarking Algorithm For Lung CT Image

With the rapid development of medical imaging and processing technology,medical images have become an important basis for doctorsto diagnose patients in modern medicine,and they play an important role in telemedicine.However,medical images may suffer from illegal copying,malicious tampering and leakage of patient private information during network transmission.Digital watermarking technology has the functions of copyright authentication and integrity authentication,and its ability to hide information can be used to protect patient information.Against the background that the current global novel coronavirus pneumonia epidemic situation is still severe,this article focuses on the security problems faced by lung CT images in network transmission,using lung CT images as a research carrier,and combining its characteristic of having regions of interest and non-interest,a set of dual watermarking algorithm model for lung CT images is designed,and based on the research and summary of existing digital watermarking algorithms,two watermarking algorithms for different regions of lung CT images are proposed to achieve image integrity authentication,copyright authentication and the hiding of patient electronic medical records.The main work of this paper is as follows:(1)In order to make the watermarking system multifunctional,combined with the active code technology,which has the characteristics of high capacity and cloud storage,a set of dual watermarking algorithm model is designed.The model divides the lung CT image into ROI and RONI,uses the reversible watermark algorithm to embed the authentication watermark in the ROI to achieve the integrity authentication of the ROI,and generates active code from the hospital’s copyright logo and patient electronic medical records.The active code is embedded in RONI to realize copyright authentication and the hiding of patient’s private information.(2)A reversible watermark authentication algorithm based on ROI of lung CT image is proposed.The algorithm combines the medical characteristics of lung organs,uses OSTU and morphological operators to automatically extract ROI,uses hash function to generate a key-based authentication watermark,and uses the difference image histogram shifting algorithm to embed the authentication watermark in each block of ROI.Experimental results show that the algorithm has good imperceptibility and reversibility,can realize the integrity authentication of the ROI of lung CT images,and can dectect and locate common tampering attacks.(3)A RONI robust watermarking algorithm based on DWT-SVD and active code is proposed.The algorithm generates active code from the hospital’s copyright logo and patient electronic medical records and then scrambles it to encrypt.Combined with the DWT-SVD algorithm and the strategy of taking pixel values to reshape the matrix,the active code is embedded in RONI to ensure that there is no distortion of ROI.Experimental results show that the algorithm has good robustness,can resist JPEG compression,noise,filtering and other attacks,and realizes the copyright protection of lung CT images and the hiding of high-volume patient information.