Figure 10

A 4-clique. Here we know the (x,y) coordinates of points A,B,C,D in the image plane, so we can find the equation of straight lines $\overline{\mathit{\text{AC}}},\overline{\mathit{\text{BD}}},\overline{\mathit{\text{AB}}},\overline{\mathit{\text{BC}}},\overline{\mathit{\text{CD}}},\overline{\mathit{\text{AD}}}$. We take the pair of straight line equations $(\overline{\mathit{\text{AC}}},\overline{\mathit{\text{BD}}}),(\overline{\mathit{\text{AB}}},\overline{\mathit{\text{CD}}})$ and $(\overline{\mathit{\text{AD}}},\overline{\mathit{\text{BC}}})$ and find the intersecting points between the pairs. Only one pair $(\overline{\mathit{\text{AC}}},\overline{\mathit{\text{BD}}})$ intersect within the convex hull of points (A,B,C,D) while others pairs are either parallel or will intersect outside the convex hull. By using this we understand that A pairs with C and B pairs with D. Accordingly we assign (X,Z) (The segments containing points A and C) and (W,Y) (The segments containing points B and D) pair with weight from Equation 7 (Blue curve in Figure 8-D) and for other pairs we assign from Equation 8 (Red curve in Figure 8-D).