Global Processing via Graph Theoretic Technique represents edge in the form of graph and search for lowest cost path.

This path correspond to most significant edge. If p and q are 4 neighbors then each element defined has an associated cost.

C (p, q) = max (I) - |f (p) – f (q)|

Where max (I) $\rightarrow$ maximum gray level in image

f (p) and f(q) $\rightarrow$ are corresponding gray level of p and q

(Explain an example, refer Q.9 or Q.10)