Apply the contrast change formula g(x,y)=af(x,y) to a medical image you like. Adjust the b with (1) a=1, (2) a=1.5, (c) a=2, (d) a=0.5, (e) a=0.2. Illustrate how the change of a will influence the contrast of the image. Show your original image and brightness changed images. You should show similar results as the following but with your own images