In [1]:
import numpy as np
import matplotlib.pyplot as plt
In [2]:
A = plt.imread("../weerstanden/4k7_P9080318.jpg")
In [3]:
plt.figure(figsize=(15, 15))
plt.imshow(A)
plt.axis("off")
plt.tight_layout()
plt.show()
In [4]:
def powspec(img):
    F = np.fft.fft2(img)
    Fsym = np.fft.fftshift(F)
    AS = np.abs(Fsym)
    PS = AS**2
    dB = 10 * np.log(PS + 1)
    return dB
In [5]:
plt.figure(figsize=(16, 12))

# grayscale
plt.subplot(221)
plt.imshow(powspec(np.mean(A, axis=2)))

# red
plt.subplot(222)
plt.imshow(powspec(A[:,:,0]))

# green
plt.subplot(223)
plt.imshow(powspec(A[:,:,1]))

# blue
plt.subplot(224)
plt.imshow(powspec(A[:,:,2]))

plt.tight_layout()
plt.show()