An unexplored alternative to radial smoothing may be to simply lengthen the micropatches in the radial direction, and not bother smoothing at all. I have not tested this direction very thoroughly, though in the tests I have done, it seems that smoothing may have some important effects beyond just statistically compensating for the small size of a micropatch. Even with very elongated patches, my experience has been that smoothing noticeably improves the final result, particularly where the data are noisy. One possible explanation is that where the data are incoherent, the change in a particular filter coefficient at each iteration is just an average of noisy data samples, which is approximately zero. With the addition of the smoother, the change in nearby filter coefficients fills in.