1. A machine-implemented pattern testing method comparing a first digital representation of a first pattern against a second digital representation of a second pattern to establish a measure of correspondence between the first pattern and the second pattern, comprising: mapping a first set of characteristic parameters derived from the first digital representation, said first set of characteristic parameters including a first plurality of discrete pattern elements and a first set of relative orientations between combinations of neighboring pattern elements of said first plurality of discrete pattern elements; mapping a second set of characteristic parameters derived from the second digital representation, said second set of characteristic parameters including a second plurality of discrete pattern elements and a first set of relative orientations between combinations of neighboring pattern elements of said second plurality of discrete pattern elements; defining, for each particular discrete pattern element of said first plurality of discrete pattern elements, a set of candidate discrete pattern elements from said second plurality of discrete pattern elements corresponding to said particular discrete pattern element; establishing a degree of correspondence for each said candidate discrete pattern element; and determining a figure of merit between said sets of characteristic parameters responsive to an analysis of said degrees of correspondence for said sets of candidate discrete patterns.