'''
Učitati sliku peppers.png i filtrirati je u frekvencijskom domenu sa 
idealnim VF filtrom nastalim pomoću idealnog NF filtra sa parametrom D0=50. 
Prikazati usputne slike.
'''

import plotly.express as px
from skimage import io
import numpy as np

def ideal_nf(H_size,D0):
    u = np.arange(H_size[0]).reshape(-1,1) - np.floor(H_size[0]/2)
    v = np.arange(H_size[1]) - np.floor(H_size[1]/2)

    D = np.sqrt(u**2 + v**2)
    H = D <= D0
    return H

img = io.imread('peppers.png')
fig = px.imshow(img, color_continuous_scale='gray')
fig.show()

IMG = np.fft.fftshift(np.fft.fft2(img, s=(2*img.shape[0],2*img.shape[0])))
fig = px.imshow(np.log(np.abs(IMG)+1), color_continuous_scale='gray')
fig.show()

#VF Filtriranje
H1 = 1 - ideal_nf(IMG.shape, 50)
fig = px.imshow(np.abs(H1), color_continuous_scale='gray')
fig.show()

#filtriranje
IMG1 = IMG * H1

fig = px.imshow(np.log(np.abs(IMG1)+1), color_continuous_scale='gray')
fig.show()

img1 = np.real(np.fft.ifft2(np.fft.ifftshift(IMG1)))
img1 = img1[0:img.shape[0],0:img.shape[1]]

fig = px.imshow(img1, color_continuous_scale='gray')
fig.show()