% edginess, expression

function e = edginess(A,i,j)
e = sqrt(((A(i,j)-A(i+1,j+1))^(2))*(A(i+1,j)-A(i,j+1))^(2)+(A(i,j)*A(i+1,j+1)-A(i+1,j)*A(i,j+1))^(2));