Transform-based medical image compression using a recursive preprocessing approach

A recursive preprocessing approach to transform-based medical image compression is presented. This preprocessing approach, combined with the cas-cas transform, shows good performance when applied to medical magnetic resonance images (MRIs). Overall, recursive preprocessing significantly improved all transform-based compression schemes tested, with more improvement noted in the fast cas-cas transform (FCCT) than in the fast cosine transform (FCT). By performing a recursive preprocessing step in the space domain before transforming, edge discontinuities are reduced so that energy packing efficiency can be higher. By using the FCCT, a speed advantage is obtained as compared to the commonly used FCT. The preliminary results show that the compression algorithm using the cas-cas transform affords both a higher compression ratio and speedier computation than the conventional cosine transform