exp3.py

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

plt.rcParams['font.sans-serif'] = ['SimHei']
plt.rcParams['axes.unicode_minus'] = False
img = cv2.imread('1.jpg', 0)
dft = np.fft.fft2(img)
dft_fftshift = np.fft.fftshift(dft)
magnitude00 = 20 * np.log(1 + np.abs(dft))
magnitude01 = 20 * np.log(1 + np.abs(dft_fftshift))
row, col = img.shape[:2]
img1 = np.zeros((row, col), dtype=np.float64)
for i in range(row):
    for j in range(col):
        img1[i, j] = img[i, j] * ((-1) ** (i + j))
dft1 = np.fft.fft2(img1)
magnitude1 = 20 * np.log(1 + np.abs(dft1))
plt.figure(figsize=(10, 6))
plt.subplot(141), plt.imshow(img, cmap='gray')
plt.title('原图像'), plt.axis('off')
plt.subplot(142), plt.imshow(magnitude00, cmap='gray')
plt.title('幅值谱'), plt.axis('off')
plt.subplot(143), plt.imshow(magnitude01, cmap='gray')
plt.title(' fftshift低频移中'), plt.axis('off')
plt.subplot(144), plt.imshow(magnitude1, cmap='gray')
plt.title('空域乘以复指数的幅值谱'), plt.axis('off')
# plt.savefig("ch4-11.jpg")
plt.show()