On computing the 2-D extended lapped transforms

A new implementation of the two-dimensional extended lapped transform (2-D ELT) is proposed. Compared to the separable solution, proposed by Malvar (1992), the new realization of the 2-D ELT has a reduced arithmetic complexity. Computational savings are achieved because scaling and inverse scaling of the butterfly matrices, suggested by Malvar for the 1-D case, are, after some modifications of the basic separable algorithm, extended to 2-D case. The new implementation has the same frequency response as Malvar´s. The structures for the ELT analysis filter bank and the ELT synthesis filter bank are shown.