Python - Filtro de paso bajo

import cv2

import numpy as np

from matplotlib import pyplot as plt

import skimage.transform as tf

import math

lena = cv2.imread('Lena.png',0)

f= np.fft.fft2(lena)

fshift = np.fft.fftshift (f)

print (fshift.shape, fshift.dtype)

Espectro = np. log (np.abs(fshift))

plt.title('Espectro')

plt.imshow(Espectro,cmap ='gray')

rows,cols =lena.shape

crow,ccol = rows//2, cols//2

mask = np.zeros((rows,cols),np.uint8)

mask[crow-30:crow+30, ccol-30:ccol+30]=1

print (fshift.shape)

fshift =fshift*mask

f_ishift = np.fft.ifftshift(fshift)

lena_filtro = np.fft.ifft2(f_ishift)

lena_filtro = np.abs(lena_filtro)

plt.title('Lena LPF')

plt.imshow(lena_filtro,cmap='gray'