moire no more image fft demo

moire_no_more_image_fft_demo.py

# image fft demo in the following article:
# moire no more: https://www.getrevue.co/profile/shift-happens/issues/moire-no-more-688319
# image fft: https://towardsdatascience.com/image-processing-with-python-application-of-fourier-transformation-5a8584dc175b
# image fft demo in the following article:
# moire no more: https://www.getrevue.co/profile/shift-happens/issues/moire-no-more-688319
# image fft: https://towardsdatascience.com/image-processing-with-python-application-of-fourier-transformation-5a8584dc175b
# also, notch filter for images: https://github.com/imdeep2905/Notch-Filter-for-Image-Processing
# (this repo's readme is basically removing moire dots.)

import os
import numpy as np
import matplotlib.pyplot as plt
from skimage.io import imread, imshow
from skimage.color import rgb2hsv, rgb2gray, rgb2yuv
from skimage import color, exposure, transform
from skimage.exposure import equalize_hist
import requests

#path=os.path.join(r'C:\Users\21745\Pictures','QQ截图20211001063119.png')
#dark_image = imread(path)
response=requests.get('https://i.ibb.co/yRCQBF8/QQ-20211001063119.png')
if response.status_code == 200:
    with open("img.jpg", 'wb') as f:
        f.write(response.content)

dark_image=imread('img.jpg')

dark_image_grey = rgb2gray(dark_image)
plt.figure(num=None, figsize=(8, 6), dpi=80)
plt.imshow(dark_image_grey, cmap='gray');

dark_image_grey_fourier = np.fft.fftshift(np.fft.fft2(dark_image_grey))
plt.figure(num=None, figsize=(8, 6), dpi=80)
plt.imshow(np.log(abs(dark_image_grey_fourier)), cmap='gray');

def fourier_masker_ver(image, i):
    f_size = 15
    dark_image_grey_fourier = np.fft.fftshift(np.fft.fft2(rgb2gray(image)))
    dark_image_grey_fourier[:225, 235:240] = i
    dark_image_grey_fourier[-225:,235:240] = i
    fig, ax = plt.subplots(1,3,figsize=(15,15))
    ax[0].imshow(np.log(abs(dark_image_grey_fourier)), cmap='gray')
    ax[0].set_title('Masked Fourier', fontsize = f_size)
    ax[1].imshow(rgb2gray(image), cmap = 'gray')
    ax[1].set_title('Greyscale Image', fontsize = f_size);
    ax[2].imshow(abs(np.fft.ifft2(dark_image_grey_fourier)), 
                     cmap='gray')
    ax[2].set_title('Transformed Greyscale Image', 
                     fontsize = f_size);
    
fourier_masker_ver(dark_image, 1)

def fourier_masker_hor(image, i):
    f_size = 15
    dark_image_grey_fourier = np.fft.fftshift(np.fft.fft2(rgb2gray(image)))
    dark_image_grey_fourier[235:240, :230] = i
    dark_image_grey_fourier[235:240,-230:] = i
    fig, ax = plt.subplots(1,3,figsize=(15,15))
    ax[0].imshow(np.log(abs(dark_image_grey_fourier)), cmap='gray')
    ax[0].set_title('Masked Fourier', fontsize = f_size)
    ax[1].imshow(rgb2gray(image), cmap = 'gray')
    ax[1].set_title('Greyscale Image', fontsize = f_size);
    ax[2].imshow(abs(np.fft.ifft2(dark_image_grey_fourier)), 
                     cmap='gray')
    ax[2].set_title('Transformed Greyscale Image', 
                     fontsize = f_size);
fourier_masker_hor(dark_image, 1)
plt.show()