Multiwavelet prefilters -: I:: Orthogonal prefilters preserving approximation order p≤2

In applications using multiwavelets, there is a necessary step of associating a given discrete signal with a function in the scaling function space V-0. This association is equivalent to including a prefilter and a post-filter for the filter bank determined by the underlying multiwavelets. We give a construction for orthogonal (paraunitary) finite-impulse esponse (FIR) prefilters that preserve the approximation order of a given arbitrary scaling vector Phi with approximation order p less than or equal to 2, We give several such prefilters for the DGHM multiwavelet.