New subband decompositions and coders for image and video compression

A review of the spectral partitioning commonly used in subband image coders and new directional subband decompositions is presented. The theoretical coding gain (TCG) is then estimated for a broad class of images, and it is revealed that for natural images, the increase in performance of the directional subband decompositions relative to the more traditional rectangularly separable decompositions is only marginal. However, if a two-band subband decomposition is performed (in the temporal dimension) of a progressively scanned video sequence, then notable gains can be achieved by encoding the high-temporal-frequency band using the directional subband decompositions