Watermarking approach of embedding patient facial information into RONI of Brain CT scan image

This paper presents a watermarking approach which has been proposed for embedding patient facial information into region of non-information (RONI) part of Brain CT (computed tomography) scan image for image authentication and integrity verification. As the doctors diagnose from region of information (ROI), modification of even one bit is not tolerated in ROI. Therefore, the integrity of ROI must be strictly controlled. In the proposed approach, the information of ROI has been embedded into patient face image, which has been embedded into RONI of Brain CT scan image for authentication. The proposed method is based on two level discrete wavelet transform (DWT). Two dimensional Arnold´s cat map and encoding technique have been used in proposed scheme to scramble and encode the patient face image before embedding. The scrambled and encoded patient face image with information of ROI has been embedded into the coefficients of RONI of Brain CT scan image by technically using additive algorithm. As the facial information has been technically embedded using additive algorithm, no original document is required in extraction stage except secret key, which means the proposed approach focused on blind watermarking. Experimental results obtained from proposed method have been compared with other existing methods by using several performance parameters including mean square error, peak signal to noise ratio and structural similarity index. From experimental results, it can be seen that the proposed method outperforms the other methods by confirming good quality of watermarked image.