Preprocessing for discrete multiwavelet transform of two-dimensional signals

Multiwavelet transform can be implemented by a tree-structured matrix filter bank, which operates on vector sequence input instead of scalar ones. Therefore, unlike in a scalar wavelet system, preprocessing is usually required to extract vector sequence input from the input signal for better performance. A 2-D approximation-based preprocessing scheme for GHM (Geronimo, Hardin and Massopust) discrete multiwavelet transform of 2-D signals is proposed. Compared with the recent 1-D approximation-based method, the proposed scheme reduces the preprocessing computational complexity by 65% while maintaining similar energy compression ability