vii Compression Examples

The image compression was applied to several test images, see table below. The results show an increase in performance over ordinary wavelet packets and the double tree. This results from the increase in the number of potential bases that are accessible from the space and frequency graph compared to the tree methods. As shown in the table, the bases from the space and frequency library that are optimal for image compression cannot be reached using the wavelet packet tree or the double tree.

JPEG wavelet spatial wavelet double adaptive

quad-tree packet tree graph

28.3db 29.5db 19.1db 32.7db 32.7db 33.0db

33.1db 34.6db 26.5db 37.1db 37.1db 37.7db

38.9db 40.7db 34.7db 43.0db 43.0db 43.8db