Medical image compression by cosine and wavelet transforms.

The investigation results for improving lossy compression techniques for ultrasound and angiographic images are presented. The goal was to clear out where the compression process could be improved for the medical application, and to make efforts to improve it. It is proved that wavelet transform outperforms discrete cosine transform applied for ultrasound and angiographic images. A lot of wavelet classes were tried for choosing the best one suited for corresponding image classes, which were characterized by content complexity criterion. The analysis of international image compression standards was carried out. Special attention was paid to algorithmical and high level service structure of a new still image compression standard JPEG2000. Its open architecture enables including some wavelet classes which we would like to suggest for medical images.