"""
=========================
Plot filtering on images
=========================

Demo filtering for denoising of images.
"""

# Load some data
import scipy as sp
face = sp.datasets.face(gray=True)
face = face[:512, -512:]  # crop out square on right

# Apply a variety of filters
import matplotlib.pyplot as plt

import numpy as np
noisy_face = np.copy(face).astype(float)
noisy_face += face.std() * 0.5 * np.random.standard_normal(face.shape)
blurred_face = sp.ndimage.gaussian_filter(noisy_face, sigma=3)
median_face = sp.ndimage.median_filter(noisy_face, size=5)
wiener_face = sp.signal.wiener(noisy_face, (5, 5))

plt.figure(figsize=(12, 3.5))
plt.subplot(141)
plt.imshow(noisy_face, cmap=plt.cm.gray)
plt.axis('off')
plt.title('noisy')

plt.subplot(142)
plt.imshow(blurred_face, cmap=plt.cm.gray)
plt.axis('off')
plt.title('Gaussian filter')

plt.subplot(143)
plt.imshow(median_face, cmap=plt.cm.gray)
plt.axis('off')
plt.title('median filter')

plt.subplot(144)
plt.imshow(wiener_face, cmap=plt.cm.gray)
plt.title('Wiener filter')
plt.axis('off')

plt.subplots_adjust(wspace=.05, left=.01, bottom=.01, right=.99, top=.99)

plt.show()