Two methods for medical image compression.
Depending on the purpose for which a medical image is taken, some areas of it contain more clinical information than others. These areas are usually considered as regions of interest (ROI). The area outside the ROI is either the background or contains some clinical information with relative importance. In this paper we introduce two preprocessing and error-free compression routines. The first preprocessing routine, if applied to X-ray images, could result in a reconstructed image with a controllable amount of deterioration in its various areas. The second preprocessing routine is applied to X-ray CT, MR and radionuclide images prior to the compression. Its aim is to automatically detect the ROI and neglect the background. The background is replaced by an optional gray level when these images are being reconstructed. These routines were applied to a variety of medical images and relatively good compression ratios were obtained.