python 实现 巴特沃思低通滤波BLPF

import matplotlib.pyplot as plt
import numpy as np
import cv2
from math import sqrt,pow

def blpf(image,d):
    f = np.fft.fft2(image)
    fshift = np.fft.fftshift(f)
    transfor_matrix = np.zeros(image.shape)
    M = transfor_matrix.shape[0]
    N = transfor_matrix.shape[1]
    for u in range(M):
        for v in range(N):

            D = sqrt((u-M/2)**2+(v-N/2)**2)

            transfor_matrix[u,v]=1/(1+pow(D/d,16))
    new_img = np.abs(np.fft.ifft2(np.fft.ifftshift(fshift * transfor_matrix)))
    return new_img

b_image = blpf(img,40)
plt.subplot(133)
plt.axis("off")
plt.title("b")
plt.imshow(b_image,cmap="gray")
plt.show()