Yes yes fourier transforms is what make mathematicians go mad and or religious.
Re:3D scatterplot of an image
by seanlinehan on Friday December 15, 2017 @11:59AM
(#15933152)
Do you have any examples of this? Sounds cool
I did a Jupyter notebook http://nbviewer.jupyter.org/github/Yorwba/image_frequency_sc...
I should have probably written more comments, but I really need to go sleep now.
Re:3D scatterplot of an image
by crispyambulance on Friday December 15, 2017 @03:55PM
(#15935014)
Yep, that's it! Here's the same thing in R...
library(imager)
download.file("https://upload.wikimedia.org/wikipedia/en/2/24/Lenna.png",'lena.png', mode = 'wb')
lena <- load.image("./lena.png")
plot(lena)
lena_fft <- FFT(lena)
lena_pwr <- sqrt( lena_fft$real^2 + lena_fft$imag^2)
lena_ph <- atan2(lena_fft$imag, lena_fft$real)
lena_ph[1:512,1:512,1,] <- matrix(runif(512*512,-pi,pi),ncol=512)
lena_mess <- FFT(lena_pwr*cos(lena_ph),lena_pwr*sin(lena_ph),inverse = TRUE)
plot(sqrt(lena_mess$real^2 + lena_mess$imag^2))
* Take fourier transform of the image for each color R, G, B
* Randomly scramble the phase of the transformed image.
* Perform the fourier inverse of that scrambled phase image.
The result is another 2D image with the same colors AND spatial frequencies as the original image. It looks like you took the original photo and vaporized it into gas. Interesting.