Step 7 – The resulting triangular mesh is characterized by a large number of spikes
(situated in the regions far from the intersections) and a few approximately equilateral triangles
(situated in the regions where multiple ‘‘wires’’ intersect).
In order to spot the approximate intersections,
triangles’ form factor f (i.e. the ratio between the height relative to maximum length edge and the edge itself) is analyzed and triangles with 0.5 < f < 1 are selected.
The centroids ci of each connected group of such triangles are assumed to be a first guess for the intersection points.
In Fig. 8
the detail of an intersection region is shown; the color map highlights the differences in triangles’ form factor