# Fundamentals of Image Processing-free book-2

Sampling: Continuous to Discrete (and back) It is often more convenient to process a continuous-time signal with a discrete-time system. Such a system may consist of three distinct stages: (1) the conversion of a continuous-time signal to a discrete-time signal (C/D converter); (2) the processing through a discrete-time system; and (3) the conversion of the output discretetime signal back to a continuous-time signal (D/C converter). Earlier we focused on the discrete-time processing, and now we will concentrate on the conversions between discrete- and continuoustime signals. Of particular interest is the somewhat remarkable fact that under certain conditions, a continuous-time signal can be fully represented by a discrete-time signal!