Description Usage Arguments Value Author(s) Examples

This function is equivalent to R's builtin fft, up to normalisation (R's version is unnormalised, this one is). It calls CImg's implementation. Important note: FFT will compute a multidimensional Fast Fourier Transform, using as many dimensions as you have in the image, meaning that if you have a colour video, it will perform a 4D FFT. If you want to compute separate FFTs across channels, use imsplit.

1 |

`im.real` |
The real part of the input (an image) |

`im.imag` |
The imaginary part (also an image. If missing, assume the signal is real). |

`inverse` |
If true compute the inverse FFT (default: FALSE) |

a list with components "real" (an image) and "imag" (an image), corresponding to the real and imaginary parts of the transform

Simon Barthelme

1 2 3 4 5 6 7 8 | ```
im <- as.cimg(function(x,y) sin(x/5)+cos(x/4)*sin(y/2),128,128)
ff <- FFT(im)
plot(ff$real,main="Real part of the transform")
plot(ff$imag,main="Imaginary part of the transform")
sqrt(ff$real^2+ff$imag^2) %>% plot(main="Power spectrum")
#Check that we do get our image back
check <- FFT(ff$real,ff$imag,inverse=TRUE)$real #Should be the same as original
mean((check-im)^2)
``` |

imager documentation built on May 30, 2018, 9:04 a.m.

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