fftshift: Swap the quadrants or halves of a 2d matrix.

In mrbsizeR: Scale Space Multiresolution Analysis of Random Signals

Swap the quadrants or halves of a 2d matrix.

Description

fftshift is an R equivalent to the Matlab function fftshift applied on matrices. For more information about fftshift see the Matlab documentation.

Usage

fftshift(inputMatrix, dimension = -1)

Arguments

inputMatrix	Matrix to be swapped.
dimension	Which swap should be performed? 1: swap halves along the rows. 2: swap halves along the columns. -1: swap first quadrant with third and second quadrant with fourth.

Details

It is possible to swap the halves or the quadrants of the input matrix. Halves can be swapped along the rows (dimension = 1) or along the columns (dimension = 2). When swapping the quadrants, fftshift swaps the first quadrant with the third and the second quadrant with the fourth (dimension = -1).

Value

Swapped matrix.

Examples

set.seed(987) 
sampleMat <- matrix(sample(1:10, size = 25, replace = TRUE), nrow = 5)

# Swap halves along the rows:
fftshift(sampleMat, dimension = 1)

# Swap halves along the columns:
fftshift(sampleMat, dimension = 2)

# Swap first quadrant with third and second quadrant with fourth:
fftshift(sampleMat, dimension = -1)

mrbsizeR documentation built on May 29, 2024, 5:45 a.m.