Let Z be the set of real integers and R the set of real numbers. The sampling process may be viewed as partitioning the x-y plane into a grid, with the central coordinates of each grid being from the Cartesian product Z2, that is a set of all ordered pairs (zi, zj), with zi and zj being integers from Z. Then, f(x, y) is a digital image if (x, y) are integers from Z2 and f is a function that assigns a gray-level value (that is, a real number from the set R) to each distinct coordinate pair (x, y). What happens to the digital image if the gray levels also are integers?

• A. The Digital image then becomes a 2-D function whose coordinates and amplitude values are integers
• B. The Digital image then becomes a 1-D function whose coordinates and amplitude values are integers
• C. The gray level can never be integer
• D. None of the mentioned