ABSTRACT
The most common method of accessing image frequencies is through a Fourier transform. This chapter reviews Fourier theory. The Cooley–Tukey algorithm provides an efficient method of performing the Fourier transforms by eliminating these massive repetitive computations. This fast Fourier transform is the algorithm of choice that is used in computer programs. The scale property relates a change of input space to the change of scale in the output space. There are three issues that need to be addressed before it is possible to create a viewable Fourier transform image. The first is that the Fourier transform contains complex values. The second is that the DC term is generally several orders of magnitude greater than the other values. The third is that the low frequencies are at the corners and the preference is that they be in the middle of the frame.
