33. The method of claim 32, wherein the step of determining a threshold separation distance comprises the steps of: (a) locating two local maxima separated by a minima in the separation distance histogram; and (b) selecting a threshold separation distance lying between the two local maxima.
33. The method of claim 32, wherein the step of determining a threshold separation distance comprises the steps of: (a) locating two local maxima separated by a minima in the separation distance histogram; and (b) selecting a threshold separation distance lying between the two local maxima. 34. The method of claim 33, wherein the step of selecting a threshold separation distance comprises the step of setting the threshold separation distance to the average of the two maxima.