import numpy as np 
import cv2 
from matplotlib import pyplot as plt
plt.rcParams[‘font.sans-serif']=[‘SimHei'] 
plt.rcParams[‘axes.unicode_minus'] = False 
I = cv2.imread(‘capture3.png') 
cv2.imshow(‘original',I) 
(r,g,b) = cv2.split(I) 
I = cv2.merge([b,g,r]) 
J = np.double(cv2.cvtColor(I,cv2.COLOR_RGB2GRAY)) 
D1 = 30 
D2 = 60 
D3 = 160 
Fuv = np.fft.fftshift(np.fft.fft2(J)) 
print(‘Fuv',Fuv) 
print(I.shape) 
m,n = I.shape[0],I.shape[1] 
xo = np.floor(m/2) 
yo = np.floor(n/2) 
h1 = np.zeros((m,n)) 
h2 = np.zeros((m,n)) 
h3 = np.zeros((m,n)) 
for i in range(m): 
for j in range(n): 
D = np.sqrt((i-xo)**2+(j-yo)**2) 
if D>=D1: 
h1[i,j]=1 
else: 
h1[i,j]=0 
if D>=D2: 
h2[i,j]=1 
else: 
h2[i,j]=0 
if D>=D3: 
h3[i,j]=1 
else: 
h3[i,j]=0 
Guv1 = h1*Fuv 
Guv2 = h2*Fuv 
Guv3 = h3*Fuv 
g1 = np.fft.ifftshift(Guv1) 
g1 = np.uint8(np.real(np.fft.ifft2(g1))) 
print(‘g1',g1) 
g2 = np.fft.ifftshift(Guv2) 
g2 = np.uint8(np.real(np.fft.ifft2(g2))) 
print(‘g2',g2) 
g3 = np.fft.ifftshift(Guv3) 
g3 = np.uint8(np.real(np.fft.ifft2(g3))) 
print(‘g3',g3) 
plt.subplot(2,2,1),plt.imshow(I),plt.title(‘原圖像') 
plt.subplot(2,2,2),plt.imshow(g1),plt.title(‘D0=30') 
plt.subplot(2,2,3),plt.imshow(g2),plt.title(‘D0=60') 
plt.subplot(2,2,4),plt.imshow(g3),plt.title(‘D0=160') 
plt.show()