A multicast "fingerprinting" solution based on image adaptive wavelet watermarking could prevent authorized recipients from releasing images to unauthorized parties.
Current digital image security and privacy protection schemes necessitated by the Health Insurance Portability and Accountability Act provide no mechanism for sending images to unauthorized parties. Researchers at the University of Washington address the issue (Comput Med Imaging Graph 2005;29(5):367-383).
A broadcast image would need to be decoded by watermark keyholders before the image could be used for diagnostic purposes. Assuming a unique watermark per user, watermarking can be used as fingerprinting.
During the process of decoding, two fingerprints that correspond to the original sender and the recipient who performs the decoding are imprinted onto the image.
Researchers considered system implementation issues and completed an analytical performance evaluation. Simulation results conducted on 31 images from five modalities confirmed that the fingerprinted images were of higher quality when compared with 10:1 JPEG compressed images. They withstood various image processing steps, including low-pass filter, high-pass filter, JPEG compression, cropping, and averaging attack, according to the researchers.
