PIL Cannot Handle This Data Type

Question

I\'m attempting to use the fft module in numpy:

import Image, numpy

i = Image.open(\'img.png\')
a = numpy.asarray(i, numpy.uint8)

b = abs(numpy.fft.rfft2(a         


        

Answer 1

I think perhaps the rfft2 is being performed over the wrong axes. By default, it uses the last two axes: axes=(-2,-1). The third axis represents the RGB channels. Instead, it seems more plausible that one would want to perform an FFT over the spatial axes, axes=(0,1):

import Image
import numpy as np

i = Image.open('image.png').convert('RGB')
a = np.asarray(i, np.uint8)
print(a.shape)

b = abs(np.fft.rfft2(a,axes=(0,1)))
b = np.uint8(b)
j = Image.fromarray(b)
j.save('/tmp/img2.png')