Multiple medical image ROI authentication using watermarking

Medical images are now almost all gathered and stored in a digital representation for easy transmission and archiving. High resolution is mandatory for a detailed diagnosis, which requires accurately known location and density information regarding the important features of the image called the regions of interest (ROI). Such features may include non-displaced fractures or small tumors that can often be difficult to identify. A reduction in size by using compression is necessary for efficient transmission over a wireless link where remote diagnosis may be an only option in many cases. Despite rapid advances in lossy compression, most research in the compression of medical imagery specifies that the ROI must be conserved as much as possible or compressed with a lossless or near-lossless algorithm. To ensure diagnostic integrity of these crucial regions after transmission, a multiple watermarking technique has been developed which can be used to verify the integrity of the ROI prior to diagnosis. This has the benefit of assuring that incidental degradation has not affected any of the crucial regions. A strong focus is placed on the robustness of the watermarking technique to JPEG compression as well as the issue image file size and quality tradeoff. The most useful contribution in our work is assurance of ROI image content integrity after image files are subject to incidental degradation in these environments. This is made possible with extraction of DCT signature coefficients from the ROI and embedding multiply in the Region of Backgrounds (ROB).