Many multi-dimensional signal processing problems require the computation of signal gradients or directional derivatives. Traditional derivative estimates based on adjacent or central differences are often inappropriate for multi-dimensional problems. As replacements for these traditional operators, we design a set of matched pairs of derivative filters and lowpass prefilters. We demonstrate the superiority of these filters over simple difference operators. Warning: Undefined array key 2 in /System/Volumes/Data/e/1.3/p1/lcv/html_public/pubs/makeAbs.php on line 304