Digital image warping

Every branch of science establishes a set of definitions and notation in which to for-

malize concepts and convey ideas. Digital image warping borrows its terminology from

its parent field, digital image processing. In this section, we review some basic

definitions that are fundamental to image processing. They are intended to bridge the

gap between an informal dialogue and a technical treatment of digital image warping.

We begin with a discussion of signals and images.

2.1.1. Signals and Images

A signal is a function that conveys information. In standard signal pmeessing texts,

signals are usually taken to be one-dimensional functions of time, e.g., f (t). In general,

though, signals can be defined in terms of any number of variables. Image processing,

for instance, deals with two-dimensional functions of space, e.g., f (x,y). These signals

are mathematical representations of images, where f (x,y) is the brightness value at spa-

tial coordinate (x,y).

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