ECE/OPTI533 Digital Image Processing class notes 44 Dr. Robert A. Schowengerdt 2003 2-D MATH FUNCTIONS CONTINUOUS 2-D FUNCTIONS • The function f describes a surface in space • The height of the surface at (x,y) is f(x,y) • In our case, f(x,y) represents a continuous physical variable, such as image irradiance (watts/m -2 ) • Special cases Separable functions Radial functions fxy , ( ) x y f(x,y)