4. Show that subtracting the Laplacian from an image gives a result that is proportional to the unsharp mask in equation 0mask (x, y)-f(x.y) -folurred(x, y) Use the definition of Laplacian given below V(x,y) f(x + 1,y) + f(x - 1,y) +f(x,y 1) + f(x,y - 1) - 4f(x, y)