In Section 8.2 we computed the magnitude and phase spectra of 1D and 2D sequences. The power spectrum is a measure of the distribution of signal energy as a function of energy and graphs of the spectrum are commonly used to visually analyze the frequency content of a signal or the frequency response of a system. The power spectrum is defined as the squared magnitude of the discrete Fourier transform of a signal. Therefore, for the case of 2D signals, we get

Function PowerSpectrum, in addition to the direct realization of Equations (8.2.1) and (8.2.4) , implements three more methods for calculating the power spectrum of a signal or image. These are known as the Bartlett, Welch, and Blackman and Tukey methods [

Opp89,

Pro96,

Lim90].