The residual of prediction-error deconvolution tends to have a white spectrum in time. This aspect of deconvolution is somewhat irritating and in practice it requires us to postfilter for display to regain continuity of signals. As is well known (PVI, for example), an alternative to postfiltering is to put a gap in the filter. This should work with 2-D filters too, but it is too early to describe how experimenters will ultimately choose to arrange gaps, if any, in 2-D filters. There are some interesting possibilities. (Inserting a gap also reduces the required number of CG iterations.)

11/18/1997