#! /usr/bin/env python
# -*- coding: utf-8 -*-
"""
Digital Image processing with PIL

"""
# sources & refs : http://stackoverflow.com/questions/2652415/fft-and-array-to-image-image-to-array-conversion
# http://stackoverflow.com/questions/14577007/grayscale-image-to-numpy-array-for-fourier-transform
# http://optipng.sourceforge.net/pngtech/img/lena.png
# http://stackoverflow.com/questions/14452824/saving-image-in-python-pil/14472089#14472089

import PIL
import Image
import numpy as np
import matplotlib.pyplot as plt

dirfile=""
#filename="x10001-512.tif"
filename="ech14x50001-512.jpg"
im = Image.open(str(dirfile+filename))
im = im.convert('L')    #convert to grayscale
im.show()
data = np.asarray(im) # a is readonly
print type(data), data.ndim, data.shape, data.dtype
datafft = abs(np.fft.rfft2(data))
datafft[0, 0] = 0 # remove DC component for visualization
print type(datafft), datafft.ndim, datafft.shape, datafft.dtype
plt.imshow(np.abs(np.fft.fftshift(datafft)), interpolation='nearest')
plt.show()
plt.imshow(np.abs(np.fft.fftshift(datafft))[192:320, 192:320], interpolation='nearest')
plt.show()
im2 = Image.fromarray(datafft)
im2.show()
im2.save('img2.gif')