Let be an image that has a black background (gray-level = 0) and two objects. The image is square and has the height and the width of 300 pixels. The first object in the image is a square of 60 pixels width with a grey-level of 150. The second object in the image is a rectangle of 50 pixels width and 20 pixels height and has a gray level of 200. Considering that the colormap of the image has 256 gray levels (from 0 to 255), compute and draw the histogram of the image.