Table 1.

Pseudo‐code for the global threshold algorithm using the gradient of region boundaries.

Find minimum L Min and maximum L Max grey levels of image I

Compute image gradient (Sobel filter or Beucher gradient G = (I ⊕ A) – (I ⊖ A))

For all values L from L Min to L Max {

Set a test threshold at L

Create a thresholded phase B(L) by labelling pixels valued 0 to L as foreground

Compute the phase boundary E(L) = B(L) – (B(L) ⊖ A)

Store the total G Total(L) (or average G Average(L)) gradient (in G) of pixels in E(L)

}

Set T Optimal to the L with maximum G Total (L) (or average G Average (L))