Comments on "Subband coding of images using asymmetrical filterbanks"

In the above paper,(1) Egger and Li presented a set of two-channel filterba nks, asymmetrical filterbanks (AFB's), for image coding applications. The b asic properties of these filters are Linear-phase, perfect reconstruction, asymmetric lengths for dual filters, and maximum regularity. In this corres pondence, we point out that the proposed AFB's are not new in the sense tha t the proposed construction is equivalent to the factorization of Lagrange halfband filters, which has been reported by other researchers. In addition , we correct an error in the formulation of constructing AFB's in their pap er.