US Patent 7277489 Two dimensional discrete wavelet transforms

The method performs a two-dimensional discrete wavelet transform on an image. The image comprises a plurality of blocks of pixels. The method generates (340) a current output block of subband data corresponding to a current block. The current output block is generated before either a one-dimensional discrete wavelet row or column transformation of a next block of pixels is completed, using intermediate lifting values stored (310, 350) during the generation of a plurality of previous blocks of subband data.