ABSTRACT
In digital image processing systems, one usually deals with arrays of numbers obtained by spatially sampling points of a physical image. After processing, another array of numbers is produced, and these numbers are then used to reconstruct a continuous image for viewing. Image samples nominally represent some physical measurements of a continuous image field, for example, measurements of the image intensity or photographic density. Measurement uncertainties exist in any physical measurement apparatus. It is important to be able to model these measurement errors in order to specify the validity of the measurements and to design processes for compensation of the measurement errors. Also, it is often not possible to measure an image field directly. Instead, measurements are made of some function related to the desired image field, and this function is then inverted to obtain the desired image field. Inversion operations of this nature are discussed in the chapter on image restoration. In this chapter, the image sampling and reconstruction process is considered for both theoretically exact and practical systems.
