DFT1

# -*- coding: utf-8 -*-
"""
Created on Tue Nov 29 12:02:11 2021

@author: Sajid
"""



import cv2
import numpy as np
from matplotlib import pyplot as plt

def gauss_low_pass_filter(row,col,sigma):

    row = int(row) // 2
    col = int(col) // 2

    x, y = np.mgrid[-row:row, -col:col]
    normal = 1 / (2.0 * np.pi * sigma**2)
    g =  np.exp(-((x**2 + y**2) / (2.0*sigma**2))) * normal
    factor = 255/ g.max()
    gaussian_image = g*factor
    print(gaussian_image)
    cv2.imshow('Gaussian Smoothed Image',gaussian_image)
    plt.plot(gaussian_image)
    return g

img = cv2.imread('download.jpg',0)


f = np.fft.fft2(img)
fshift = np.fft.fftshift(f)
magnitude_spectrum = 20*np.log(np.abs(fshift))


mag = np.abs(fshift)

print(mag)
ang = np.angle(fshift)

sigma = float(input('Enter Cut Off: '))
mask = gauss_low_pass_filter(img.shape[0],img.shape[1],sigma)

combined = np.multiply(mag*mask, np.exp(1j*ang))

imgCombined = np.real(np.fft.ifft2(np.fft.ifftshift(combined)))


plt.subplot(121),plt.imshow(img, cmap = 'gray')
plt.title('Input Image'), plt.xticks([]), plt.yticks([])

plt.subplot(122),plt.imshow(imgCombined, cmap = 'gray')
plt.title('Output image'), plt.xticks([]), plt.yticks([])

#plt.imshow(imgCombined, cmap='gray')


plt.show()
cv2.waitKey(0)
cv2.destroyAllWindows()