Robust watermarking and compression for medical images based on genetic algorithms

A ROI (region of interest) of a medical image is an area including important information and must be stored without any distortion. In order to achieve optimal compression as well as satisfactory visualization of medical images, we compress the ROI by lossless compression, and the rest by lossy compression. Furthermore, security is an important issue in web-based medical information system. Watermarking skill is often used for protecting medical images. In this paper, we present a robust technique embedding the watermark of signature information or textual data around the ROI of a medical image based on genetic algorithms. A fragile watermark is adopted to detect any unauthorized modification. The embedding of watermark in the frequency domain is more difficult to be pirated than in spatial domain.