Sampling theory, developed for communications, is now applied to a variety of imaging systems. It requires a bandlimited signal, an appropriate sampling rate, and a reconstruction filter. This study covers both temporal and spatial filtering, and seeks to bridge the gap between sampling theory, signal appearance, and system performance. Aliasing and reconstruction - important but often overlooked topics in image processing texts - are also examined. This book should be useful to anyone involved in digital processing. The maths is straightforward and the text is aimed at practising engineers. It describes how to represent digital signals on back-of-the-envelope drawings and should help the system analyst to understand the implications of sampling theory. For the software specialist, it seeks to provide the link between digital and analogue data.