  An approach for effective implementation of greedy selection methodologies,
to approximate an image partitioned into blocks, is proposed. The method is
specially designed for approximating partitions on a transformed image. It
evolves by selecting, at each iteration step, i) the elements for approximating
each of the blocks partitioning the image and ii) the hierarchized sequence in
which the blocks are approximated to reach the required global condition on
sparsity.
