"""
Segmentation contours
=====================

Visualize segmentation contours on original grayscale image.
"""

from skimage import data, segmentation
# scikit-image has changed its API
try:
    from skimage import filters
except ImportError:
    from skimage import filter as filters
import matplotlib.pyplot as plt
import numpy as np

coins = data.coins()
mask = coins > filters.threshold_otsu(coins)
clean_border = segmentation.clear_border(mask).astype(np.int)

coins_edges = segmentation.mark_boundaries(coins, clean_border)

plt.figure(figsize=(8, 3.5))
plt.subplot(121)
plt.imshow(clean_border, cmap='gray')
plt.axis('off')
plt.subplot(122)
plt.imshow(coins_edges)
plt.axis('off')

plt.tight_layout()
plt.show()