# Name

periodogram - calculate the periodogram (the modulus squared of a Fourier Transform) of an image.

# Usage

output = periodogram(image)

## Input

- image
- input image (can be real or Fourier).

## Output

- output
- periodogram (the modulus squared of a Fourier Transform)

# Description

For real input image, Fourier transformed is first calculated. Next, a modulus square of the FT is calculated and periodogram is placed in the output image such that the term |F(0,0,0)|^2) is located at (int[n/2], int[n/2], int[n/2]) in 3D, (int[n/2], int[n/2]) in 2D, and at int[n/2] in 1D, i.e., at the center of the real image.

# Reference

# Author / Maintainer

Pawel A. Penczek

# Keywords

- category 1
- FUNDAMENTALS
- category 2
- FOURIER

# Files

periodogram.cpp

# See also

# Maturity

- stable
- works for most people, has been tested; test cases/examples available.

# Bugs

None. It is perfect.