ABSTRACT

The medical images of different modalities like CT Scan MR I, XRAY, Ultrasound Etc, are produced on daily basis in the different hospitals around the globe. These medical images are exchanged among the doctors and researchers for their guidance or discussions for solving some research problem. Numbers of issues are concerned with this exchange of medical information, for example (i) Content Authentication and (i i) Copyright protect ion. To address these issues, we propose a medical image watermarking system for the authentication and copyright protection of medical images which embeds two different types of watermarks in the CT scan image medical images. The first watermark is binary pattern, which has been inserted in region of interest (ROI) area of medical image for content authentication the other is robust watermark which is the composite watermark and is inserted in the region of non-interest (RONI) area of medica image for copyright protection. Initially CT Scan image is segmented in ROI.
and RON I parts by segmentation process. For embedding the fragile le watermark, spatial domain has been used. Before embedding the binary pattern in ROI for data authentication the LSB in formation of ROI is extracted first and is saved in separate store. For inserting the robust watermark, the frequency domain is used after applying the Integer Wavelet Transform (IWT). The 4th bit plane of wavelet frequency coefficients is used for embedding the watermark. In order to make room for h id in g the watermark, the bit plane is first compressed using some lossless encoding technique. The payload in both ROI and RON I is embedded with simple LSB substitution technique. The extraction procedure is the reverse of embedding process. However, some steps of extraction procedure are same as in embedding procedure. We have used CT scan image database obtained from Radiology department, Akron University Ohio USA and AGA Khan medical university, Karachi for experimental results. The results show that proposed algorithm provides better security of medica information by addressing both issues of data authentication and copyright protection.